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EASL New HCV Drugs
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By Jules Levin
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PRECLINICAL CHARACTERIZATION OF SCH 900518, A NOVEL MECHANISM-BASED INHIBITOR OF HCV NS3 PROTEASE
X. Tong1, A. Arasappan2, F. Bennett2, R. Chase1, B. Feld1, Z. Guo3, A. Hart1, V. Madison3, B. Malcolm1, J. Pichardo1, A. Prongay3, R. Ralston1, A. Skelton1, E. Xia1, F..G. Njoroge2 1Virology, 2Medicinal Chemistry, 3Structural Chemistry, Schering-Plough Research Institute, Kenilworth, NJ, USA
Background and aims: Small molecule HCV NS3 protease inhibitors have shown antiviral activity as monotherapy and in combination with pegylated interferon-alpha and ribavirin in clinical trials; however, clinical efficacy can be limited by inadequate drug exposure and development of viral resistance. Improvement in inhibitor potency and pharmacokinetic properties offers opportunities to overcome such limitations and to further increase SVR.
Methods: Inhibition of HCV NS3 protease was measured using a single-chain NS3 (3-181)/4A protease. The antiviral effect and resistance study of protease inhibitors were evaluated using genotype 1b HCV replicon cells.
Results: Combination of medicinal chemistry and structure-based design has led to the discovery of SCH 900518, a novel ketoamide protease inhibitor which forms a reversible covalent bond with the active site serine with an inhibition constant (Ki*) of 7 nM. SCH 900518 showed a 10-fold improvement in replicon potency (EC90 = 40 nM) compared to boceprevir and telaprevir. In biochemical assays, SCH 900518 was active against proteases of genotypes 1a, 1b, 2 and 3. A 2-week treatment with 5xEC90 of the inhibitor reduced replicon RNA by 3-log. High exposures of SCH 900518 had minimal effects on a variety of human normal and tumor cell lines. Selection of replicon cells with SCH 900518 resulted in outgrowth of several major resistant mutants (T54A/S, A156S/T/V). Preclinical cross-resistance studies demonstrated that the majority of mutations against boceprevir and telaprevir showed similar fold loss of activity against all three inhibitors; however, SCH 900518 retained more activity against these mutants due to its higher intrinsic potency. Combination treatment with interferon-alpha enhanced inhibition of replicon RNA and suppressed emergence of resistant replicon colonies, supporting the use of SCH 900518/peginterferon combination therapy in the clinic.
Conclusions: The preclinical characterization of SCH 900518 supports its progression towards clinical evaluation of safety, pharmacokinetic and pharmacodynamic parameters.
SAFETY AND ANTIVIRAL ACTIVITY OF SCH 900518 (Schering-Plough protease) ADMINISTERED AS MONOTHERAPY AND IN COMBINATION WITH PEGINTERFERON ALFA-2B TO naive AND TREATMENT-EXPERIENCED HCV-1 INFECTED PATIENTS
H. Reesink1, J. Bergmann2, J. de Bruijne1, C. Weegink1, J. van Lier3, A.. van Vliet3, A.. Keung4, J. Li4, E. O'Mara4, M. Treitel4, E. Hughes4, H. Janssen2, R.. de Knegt2
1Hepatology, Academic Medical Center, Amsterdam, 2Hepatology, Erasmus MC University Hospital, Rotterdam,3PRA, PRA International, Zuidlaren, The Netherlands, 4SPRI, Schering-Plough, Kenilworth, USA
Background SCH 900518, a novel HCV NS3 protease inhibitor, demonstrates potent antiviral activity (EC90 of 40 nM).. This study explored the safety and antiviral activity of SCH 900518, administered as monotherapy and combination therapy with PegIntron (± ritonavir) to HCV genotype 1 infected patients.
Methods: This was a two period study in HCV genotype 1 infected subjects (naive and treatment-experienced). SCH 900518 was administered as an suspension for 7 days (800 mg TID or 400 mg BID with ritonavir). After a 4 week washout, SCH 900518 was administered at the same dose in combination with PegIntron for 14 days. Safety, PK, and antiviral activity were assessed. After the study, all patients initiated SOC treatment..
Results: Forty subjects completed the study. SCH 900518 (± ritonavir) alone or in combination with PegIntron was found to be well tolerated. Both dose regimens resulted in trough plasma concentrations of SCH 900518 above the EC90 as determined by the HCV replicon assay. There were no clinically significant changes from baseline in vital signs, laboratory values, or ECGs. The majority of AEs were mild or moderate.. An SAE of fever occurred during follow-up (treatment with PegIntron and ribavirin only) and was unlikely related to SCH 900518. A rapid and continuous decline in plasma HCV RNA was observed in both treatment-experienced and naive subjects during 7 days of SCH 900518 monotherapy (± ritonavir). A high percentage of both treatment-experienced and naive patients had plasma HCV RNA below the LLQ (< 25 IU/mL) during combination therapy with PegIntron (± ritonavir) on Day 15 (see table).
Conclusions: SCH 900518 administered alone or in combination with PegIntron was safe and well tolerated. Robust reductions in plasma HCV RNA levels were achieved in both treatment-experienced and naive HCV genotype 1-infected patients..
A REGIONAL GASTROINTESTINAL ABSORPTION STUDY OF THE HCV NS3 PROTEASE INHIBITOR SCH 900518 IN HEALTHY VOLUNTEERS
E. Hughes1, Y. Wan1, M. Treitel1, S. Gupta1, C. Hu1, B. Yue1, A. Sheth1, M. Corpus1, D. Marchisin1, P. Prasad1, E. O'Mara1, J. de Bres2, A. Connor2, K. Palaniappan2 1SPRI, Schering-Plough, Kenilworth, NJ, USA, 2PPL, Pharmaceitical Profiles Limited, Nottingham, UK
Background SCH 900518, a novel HCV NS3 protease inhibitor, demonstrates potent antiviral activity with an EC90 of 40 nM in the replicon assay. This study investigated the relative bioavailability of SCH 900518, when delivered to the small bowel and ascending colon (AC), in comparison to an immediate release (IR) formulation, in order to help guide the development of an extended release formulation.
Methods: This was a randomized, crossover, open-label study of SCH 900518 conducted in healthy volunteers.. This study employed the Enterion™ capsule system, a unique remote-controlled drug delivery device that delivers any form of drug to key regions of the human GI tract. During each of the five periods, 10 subjects received one of five 100 mg single-dose treatments; IR reference formulation of SCH 900518 (microemulsion), Enterion™ delivery of SCH 900518 (microemulsion) to the proximal small bowel (PSB), Enterion™ delivery of SCH 900518 (microemulsion) to the distal small bowel (DSB), Enterion™ delivery of SCH 900518 (microemulsion) to the AC, and Enterion™ delivery of SCH 900518 (micronized) to the AC.
Results: Ten subjects enrolled in the study and two subjects discontinued for non-AE related reasons. Plasma concentrations of SCH 900518 (microemulsion) were similar following administration of an IR formulation and delivery to the PSB, while exposure of SCH 900518 (microemulsion) was slightly lower following administration to the DSB. The rate/extent of absorption of SCH 900518 (microemulsion) was significantly reduced following delivery to the colon. Delivery of the micronized formulation of SCH 900518 to the colon resulted in very little absorption (< LLQ). The relative bioavailability of the SCH 900518 (microemulsion) was highest when delivered in the PSB (99.18%), followed by in the DSB 66.00%, and lowest (20.21%) in the AC.
Conclusions: SCH 900518 was safe and well-tolerated as single doses in healthy adult subjects. The rate and extent of absorption of SCH 900518 is decreased as the formulation is delivered more distally in the GI tract.
A SINGLE- AND MULTIPLE-DOSE ASSESSMENT OF THE SAFETY AND PHARMACOKINETICS OF SCH 900518 AND ITS EFFECT ON THE PHARMACOKINETICS OF MIDAZOLAM IN HEALTHY SUBJECTS
E. Hughes1, M. Treitel1, S. Gupta1, C. Xu1, C. Hu1, B. Yue1, A. Sheth1, M. Corpus1, D.. Marchisin1, P. Prasad1, E. O'Mara1, A.. van Vliet2, J. van Lier2 1SPRI, Schering-Plough, Kenilworth, NJ, USA, 2PRA, PRA International, Zuidlaren, The Netherlands
Background SCH 900518, a novel HCV NS3 protease inhibitor, demonstrates potent antiviral activity with an EC90 of 40 nM in the replicon assay. This study explored single and multiple doses of SCH 900518 and its effect on midazolam (MDZ) in healthy subjects.
Methods: This was a randomized, placebo-controlled study composed of 8 cohorts of healthy subjects. Cohorts 1 to 6 received single doses of SCH 900518 as an oral suspension in the fasted state (50, 150, 400, 800, 1500, or 2000 mg). Subjects who received 800 mg also received a single 800 mg dose after a high-fat meal. Cohorts 7 and 8 received multiple doses of SCH 900518 in the fasted state (oral suspension, API two different particle sizes), as well as a single 4 mg dose of midazolam before and after SCH 900518. Safety, tolerability, and PK were assessed.
Results: 63 subjects completed the study. Single and multiple doses of SCH 900518 were well-tolerated. There were no SAEs, or clinically significant changes in vital signs, clinical laboratories, or ECG recordings. The majority of AEs were mild or moderate. SCH 900518 was rapidly absorbed following a single oral dose. There was a dose-related increase in Cmax and AUC of SCH 900518. The bioavailability of SCH 900518 increased when given with a high-fat meal. Following multiple doses, there was a minor accumulation of SCH 900518 and no clinically significant change in the MDZ:1-OH-MDZ ratios. Exposures of SCH 900518 were greater using a smaller particle size of API in the oral suspension. Trough concentrations during multiple doses were above the EC90 of the compound as determined by the HCV replicon assay (See table).
Conclusions: SCH 900518 was safe and well tolerated as single and multiple doses in healthy subjects. Multiple doses of SCH 900518 (400 mg TID) achieved potentially therapeutic exposures as predicted by the in vitro HCV replicon assay.
TELAPREVIR IN HEPATITIS C GENOTYPE-1-INFECTED PATIENTS WITH PRIOR NON-RESPONSE, VIRAL BREAKTHROUGH OR RELAPSE TO PEGINTERFERON-ALFA-2A/B AND RIBAVIRIN THERAPY: SVR RESULTS OF THE PROVE3 STUDY
M. Manns1, A. Muir2, N. Adda3, I. Jacobson4, N. Afdhal5, J. Heathcote6, S. Zeuzem7, H. Reesink8, N. Terrault9, M. Bsharat3, S. George3, J. McHutchison2, A. Di Bisceglie101Medical School Hannover, Hannover, Germany, 2Duke University Medical Center, Durham, 3Vertex Pharmaceuticals, Cambridge, 4Weill Cornell Medical College, New York, 5Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, USA, 6University of Toronto, Toronto, Canada, 7Johann Wolfgang Goethe University Hospital, Frankfurt/Main, Germany, 8Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands, 9University of California San Francisco, San Francisco, 10Saint Louis University School of Medicine, Saint Louis, USA
Background PROVE3 is a randomized, placebo-controlled Phase 2 study assessing safety and efficacy of telaprevir (T) plus Peginterferon-alfa-2a (P) ± Ribavirin (R) in HCV genotype 1 patients who previously failed PR treatment.
Methods: Randomization was 1:1:1:1 to: T/PR for 12-wks, then PR for 12-wks (T12/PR24); T/PR for 24-wks, then PR for 24-wks (T24/PR48); T/P for 24-wks (T24/P24); or placebo/PR (P 180µg/wk, R 1000-1200mg/day) for 24-wks, then PR for 24-wks (PR48).
Results: Of 453 patients included in ITT analysis, 418 (92%) had baseline HCV RNA ≥800,000 IU/mL, 196 (43%) had cirrhosis or bridging fibrosis and 40 (9%) were black; 235 (52%) patients completed assigned treatment.
The most frequent adverse events that occurred with a greater incidence in T12/PR24 or T24/PR48 than PR48 were fatigue, nausea, headache, rash, pruritus, diarrhea, anemia, insomnia, pyrexia, alopecia, and chills. Grade 3 rash was observed in 7 (6%), 5 (4%), 6 (5%) and 1 (1%) patients in T12/PR24, T24/PR48, T24/P24, and PR48, respectively. Grade 3 anemia was observed in 0 (0%), 7 (6%), 1 (1%) and 1 (1%) patients in T12/PR24, T24/PR48, T24/P24 and PR48, respectively. Eleven (10%), 29 (25%), 10 (9%), and 5 (4%) patients discontinued due to AEs in T12/PR24, T24/PR48, T24/P24, and PR48, respectively.
Conclusions: SVR rates in all treatment groups receiving T/PR regimens were significantly higher than with PR48. The general safety profile of T12/PR24 was similar to that observed in treatment-naive patients. The higher relapse rate in T12/PR24 compared with T24/PR48 may warrant a total of 48-wks of PR in treatment-experienced patients. A Phase 3 study evaluating two T12/PR48 regimens is underway.
HCV SPRINT-1 FINAL RESULTS : SVR 24 FROM A PHASE 2 STUDY OF BOCEPREVIR PLUS PEGINTRONTM(PEGINTERFERON ALFA-2B)/RIBAVIRIN IN TREATMENT-naive SUBJECTS WITH GENOTYPE-1 CHRONIC HEPATITIS C
P. Kwo1, E. Lawitz2, J. McCone3, E. Schiff4, J. Vierling5, D. Pound6, M.. Davis7, J. Galati8, S. Gordon9, N. Ravendhran10, L. Rossaro11, F. Anderson12, I. Jacobson13, R. Rubin14, K. Koury15, C. Brass15, E. Chaudhri15, J. Albrecht15
1Department of Medicine, Indiana University School of Medicine, Indianapolis, 2Alamo Medical Research, San Antonio, 3Mount Vernon Endoscopy Center, Alexandria, 4Center for Liver Diseases, University of Miami Miller School of Medicine, Miami, 5Professor of Medicine and Surgery, Baylor College of Medicine, Houston,6Indianapolis Gastroenterology Research Foundation, Indianapolis, 7Digestive Care/South Florida Center of Gastroenterology, Wellington, 8Liver Specialists of Texas, Houston, 9Department of Hepatology, Henry Ford Health Systems, Detroit, 10Digestive Disease Associates, Baltimore, 11Internal Medicine, University of California-Davis Medical Center, Sacramento, USA, 12The Liver & Intestinal Research Center, Vancouver, Canada, 13Weill Cornell Medical College, New York, 14Digestive Healthcare of Georgia, Atlanta, 15Schering-Plough Research Institute, Kenilworth, USA
Background HCV SPRINT-1 assessed the safety and efficacy of boceprevir, an oral inhibitor of HCV-NS3 protease, plus PegIntron (P) (1.5 µg/kg/QW) and ribavirin (R) (400-1400 mg/day).
Methods: P/R(800-1400 mg/day) for 48 weeks compared to five boceprevir(800 mg TID) regimens: 4 weeks of P/R lead-in followed by P/R(800-1400 mg/day)/boceprevir for 24 or 44 weeks; P/R(800-1400 mg/day)/boceprevir for 28 or 48 weeks; and P/low-dose R(400-1000 mg/day)/boceprevir for 48 weeks. The primary endpoint was sustained virologic response (SVR) at 24 weeks post-treatment (Roche TaqMan LLD=15 IU/mL).
Results: Of 595 patients treated in US (77%), Canada and Europe, 60% were male, 16% Black, 7% cirrhotic, 56% genotype 1a and 89% had high viral load (>600,000 IU/mL). SVR was significantly increased in the 28 and 48 week boceprevir arms compared to P/R Control. RVR and EVR were highly predictive of SVR with boceprevir combinations. Rash-related AEs were similar for boceprevir regimens and P/R Control....
Conclusions: Both 28 and 48 week boceprevir regimens significantly increased SVR with very low relapse rates in 48 week regimens. However, low dose ribavirin with PegIntron and boceprevir was associated with increased viral breakthrough, relapse and lower efficacy. In contrast, P/R lead-in prior to boceprevir substantially increased SVR and reduced viral breakthrough.
ANTIVIRAL ACTIVITY AND SAFETY OF ITMN-191 (Roche protease) IN COMBINATION WITH PEGINTERFERON ALFA-2A AND RIBAVIRIN IN PATIENTS WITH CHRONIC HEPATITIS C VIRUS (HCV)
N. Forestier1, D. Larrey2, P. Marcellin3, Y. Benhamou4, D. Guyader5, W. Bradford6, S. Porter6, A. Patat7, R. Rouzier8, S. Zeuzem1
1J.W. Goethe Universitat, Frankfurt, Germany, 2CHU Montpellier, Montpellier, 3Hopital Beaujon, Clichy,4Assistance Publique Hopitaux de Paris, Paris, 5CHU Hopital Ponchaillou, Rennes, France, 6Intermune, Inc., Brisbane, USA, 7Biotrial, Rennes, 8Centre CAP, Montpellier, France
Background ITMN-191 is a potent HCV NS3/4A protease inhibitor that achieves high liver concentrations following oral administration. In a phase 1 multiple ascending dose study, ITMN-191 was safe and demonstrated substantial antiviral activity when administered for 14 days to treatment-naive HCV genotype-1 patients. The present study was designed to evaluate ITMN-191 in combination with standard of care (SOC) in patients with HCV genotype-1 infection.
Methods: In a double-blind, placebo-controlled, multiple ascending dose study, treatment-naive HCV genotype-1 patients were randomized (8:2) to receive ITMN-191 or placebo in combination with peginterferon alfa-2a (180 mg SC weekly) and ribavirin (1000-1200 mg PO BID) for 14 days. Patients were sequestered in a Phase I research facility for 16 days and completed standard clinical and laboratory evaluations.
Results: Dosing has been completed in five cohorts in this ongoing study. Based on preliminary blinded data, ITMN-191 appears generally safe and well tolerated. Adverse events (AE) were predominantly mild to moderate and consistent with the well described AE profile of SOC. No AE's lead to treatment discontinuation and there were no SAE's during study treatment. A single unrelated SAE of viral gastroenteritis occurred following completion of study treatment. HCV RNA levels declined rapidly and were below the limit of quantitation in the majority of ITMN-191 treated patients in all q12h and q8h dosing cohorts at Day 15 (Table 1). No virologic rebound was observed during study treatment.
Conclusion: ITMN-191 appears generally safe and well tolerated when administered in combination with SOC to HCV genotype-1 patients for 14 days. The addition of ITMN-191 to SOC resulted in substantial and sustained decreases in HCV RNA in each of the first 5 cohorts. Higher q12h doses are currently being studied.
BI 201335, A POTENT HCV NS3 PROTEASE INHIBITOR, IN TREATMENT-naive AND -EXPERIENCED CHRONIC HCV GENOTYPE-1 INFECTION: GENOTYPIC AND PHENOTYPIC ANALYSIS OF THE NS3 PROTEASE DOMAIN
G. Kukolj1, Y. Benhamou2, M.P. Manns3, M. Bourliere4, S. Pol5, M. Schuchmann6, M. Cartier1, D. Huang7, L. Lagace1, G. Steinmann8, J.O. Stern7 1Biological Sciences, Boehringer Ingelheim (Canada) Ltd. R&D, Laval, QC, Canada, 2Service Hepato-Gastroenterologie, Batiment des Cliniques Medicales, Hopital Pitie Salpetriere, Paris, France, 3Zentrum Innere Medizin, Abteilung fur Gastroenterologie, Hepatologie und Endokrinologie, Medizinische Hochschule Hannover, Hannover, Germany, 4Service d'Hepato-Gastro-Enterologie, Hopital Saint Joseph, Marseille, 5Pole Medico Chirurgical d'Hepato-Gastro-Enterologie, Unite d'Hepatologie, Hopital Cochin, Paris, France, 6I. Med. Klinik und Poliklinik, Klinikum der Johannes Gutenberg, Universitat Mainz, Mainz, Germany, 7Virology, Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT, USA, 8Clinical Research, Virology, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
Background BI 201335, a potent and specific HCV NS3/4A protease inhibitor, has been studied with chronic genotype (GT) 1 HCV infection for 14-days monotherapy in treatment-naive patients followed by combination with PegIFN/RBV for an additional 14 days; and in treatment-experienced patients for 28 days as combination therapy with PegIFN/RBV. All dose groups achieved median viral load reductions of ≥ 3 log10. On-treatment viral rebound was observed in most patients receiving monotherapy, but in only 3/19 treatment-experienced patients receiving triple combination therapy with lower dosages of BI 201335. Genotypic and phenotypic characterization of viral isolates from this study has been performed.
Methods: HCV RNA was collected and extracted from 53 patients at baseline, days 14 and 28, and during follow-up. Population sequencing was performed on the complete NS3/4A region. Clonal sequencing permitted the quantification and identification of major and minor variants (LLOQ: 5%) in the NS3 protease domain. Chimeric HCV sub-genomic replicons were constructed to determine BI 201335 EC50 values against patient-derived protease sequences.
Results: Population sequencing of baseline isolates revealed one encoding an NS3 V/I170T substitution that conferred an 8-fold reduction in BI 201335 EC50 relative to the subtype reference. Mean EC50 values for the other GT 1a (10 ± 8 nM) or 1b (9 ± 4 nM) baseline-derived samples were within three-fold of the reference values. The predominant GT 1a resistance mutations in on-treatment viral rebound samples encoded an R155K substitution, whereas GT 1b viruses mainly encoded changes at D168, with valine as a predominant substitution. R155K variants conferred reductions in sensitivity to BI 201335 with EC50 values of 1.8 - 6.5 µM, whereas the EC50s for D168V variants were 3.6 -15 µM. Rapid changes in mutant prevalence at the end of dosing suggest that D168V variants are significantly less fit than R155K variants.
Conclusion: HCV NS3 variants that confer resistance to BI 201335 were selected during treatment; these variants do not alter the sensitivity to PegIFN/RBV as the majority of treatment naive patients with resistant virus subsequently displayed anti-viral responses during combination therapy.
SAFETY, TOLERABILITY AND PHARMACOKINETICS OF THE HCV POLYMERASE INHIBITOR VCH-222 FOLLOWING SINGLE DOSE ADMINISTRATION IN HEALTHY VOLUNTEERS AND ANTIVIRAL ACTIVITY IN HCV-INFECTED INDIVIDUALS
C. Cooper1, R.. Larouche2, B. Bourgault3, N. Chauret3, L. Proulx3 1The Ottawa Hospital, Ottawa, ON, 2Anapharm, A Pharmanet Company, Montreal, 3ViroChem Pharma Inc., Laval, QC, Canada
Background and aims: VHC-222 is a novel non-nucleoside inhibitor of the HCV NS5B polymerase. It has demonstrated potent in-vitro antiviral activity in genotype 1a and 1b replicon systems with IC90 values of 65 and 41 nM (29 and 18 ng/mL), respectively.
Methods: A Phase I, randomized, double-blind, ascending, single dose trial was conducted to evaluate the safety, tolerability, pharmacokinetics and food effect of VCH-222. Healthy subjects were randomized into four treatment cohorts (250, 500, 1000 and 1500 mg). All doses were administered in the fasted state with the exception of the 500 mg-fed group. An open cohort of 6 subjects with HCV genotype-1 infection was dosed with 750 mg bid for 3 days.
Results: VCH-222 was well tolerated at all doses tested. There have been no serious adverse events and all adverse events observed were classified as mild to moderate with no apparent dose relationship. There have been no clinically significant changes in other safety assessments. Under fasted condition, the rate and extent of absorption (Cmax and AUC) appeared relatively proportional between the doses of 250 and 1,500 mg.. The half-life was approximately 4 hours and the plasma levels observed at 24 h (C24h) were above the IC90 replicon values in all cohorts. In the subjects treated for 3 days with 750 mg bid there was a 2-fold increase in Cmax and AUC observed between Day 1 and Day 3. Preliminary efficacy results on the first 4 treatment-naive subjects dosed for 3 days reveal a mean log10 reduction of 3.2 (range 3.0-3.3) within 24 hours of dosing and of 3.7 (range 3.2-4.2) on Day 4.
Conclusions: VCH-222 was safe and well tolerated up to 1,500 mg administered as a single dose or at 750 mg bid for 3 days. In terms of exposure versus in vitro potency, excellent pharmacokinetic properties were exhibited. In vivo, high HCV virological potency was demonstrated.
IDENTIFICATION AND CHARACTERIZATION OF VCH-222, A NOVEL POTENT AND SELECTIVE NON-NUCLEOSIDE HCV POLYMERASE INHIBITOR
J. Bedard1, O. Nicolas1, D. Bilimoria1, L. L'Heureux1, P. Fex1, M. David1, L. Chan2 1Virology, 2Chemistry, ViroChem Pharma Inc., Laval, QC, Canada
Background Infection with HCV has become a major health concern as disease progression and often results in impairment of liver function. The effectiveness of current therapy, pegylated interferon in combination with ribavirin, is strongly genotype selective and side-effects are often severe. This has generated intense research efforts in the discovery and development of novel anti-HCV inhibitors. SAR studies to further optimize the thiophene-2-carboxylic acid series have led to VCH-222 as a development candidate. The aim of the study is to characterize its in vitro anti-HCV properties.
Methods: In vitro inhibition studies of VCH-222 were performed using the MultiScreen™ assay with a Δ21 HCV polymerase.. In vitro selectivity against human DNA polymerases and other RNA viruses were also investigated. The anti-HCV inhibitory effect of VCH-222 in sub-genomic HCV replicons 1a, 1b, and 2a was quantified using a luciferase assay and quantitative real time PCR. The in vitro cytotoxicity profile was determined by measuring the incorporation of 3[H]-thymidine in Huh-7 ET cells.
Results: VCH-222 was found to be a selective inhibitor of NS5B genotype 1a and 1b at low-micromolar IC50. Analysis of the kinetic behavior displayed by VCH-222 using double reciprocal plots was indicative of a non competitive mode of inhibition with respect to UTP. VCH-222 was found to be selective against human DNA polymerases α, ß and γ (IC50 ≥ 56 µM). In the replicon assay, VCH-222 was active against genotype 1a and 1b with EC50 values of 23.3 ± 9.0 and 12.0 ± 4.0 hM respectively, activity against genotype 2a was 4.6 ± 1.4 µM. The compound had an average CC50 value of 45 µM when tested on exponentially growing replicon cells with a TI of ~4000. The lack of antiviral activity against respiratory syncytial virus, Influenza A and B, and West Nile virus supports the view that this compound is selective for Hepatitis C virus.
Conclusions: The results presented demonstrate that VCH-222 is a selective inhibitor of HCV NS5B polymerase with low-nanomolar activity against subgenomic HCV replicons. VCH-222 is presently evaluated in HCV-infected subjects.
PRECLINICAL PHARMACOKINETIC AND ADME CHARACTERIZATION OF VCH-222, A NOVEL NON-NUCLEOSIDE HCV NS5B POLYMERASE INHIBITOR
N. Chauret, C. Chagnon-Labelle, M. Diallo, J. Laquerre, J. Laterreur, S.. May, L. Ste-Marie DMPK, ViroChem Pharma Inc., Laval, QC, Canada
Background and aims: VCH-222 is a novel non-nucleoside HCV RNA polymerase inhibitor. It has demonstrated low nanomolar IC50 activity against the HCV replicons of genotype 1a and 1b and is currently being evaluated for antiviral efficacy in chronically infected HCV patients. The objectives of these studies were to characterize the pharmacokinetic profile in relevant animal models and ADME properties of VCH-222.
Methods: Pharmacokinetic studies were conducted following intravenous and oral administration of VCH-222 in rats and dogs. The routes of excretion of the compound were determined in rats following oral and iv administrations of [14C]-VCH-222. The absorption, metabolic stability, protein binding, human biliary clearance and the potential of VCH-222 to cause P-glycoprotein inhibition, cytochrome 450 inhibition and induction were evaluated in vitro in systems derived from human and/or animal species.
Results: In rats and dogs, VCH-222 displayed low total body clearance with excellent oral bioavailability (greater than 30 %). The exposure of VCH-222 in rat liver was 5-fold higher than in plasma. Excretion studies in bile-duct cannulated rats indicated that, upon oral and iv administration, [14C]-VCH-222 was excreted mainly intact in bile or as glucuronide adducts. VCH-222 was metabolically stable in human microsomes and hepatocytes. Both oxidation and glucuronidation pathways were observed. Phenotyping studies indicated that several enzymes were involved in the biotransformations of VCH-222 (CYP1A1, 2A6, 2B6, 2C8, CYP 3A4, UGT1A3). In in vitro studies, VCH-222 demonstrated limited potential to cause human CYP inhibition or CYP induction. The absorption potential of VCH-222 was shown to be acceptable based on its good permeability in Caco-2 cell monolayer and minimal recognition by intestinal efflux proteins. In addition, VCH-222 had no significant effect of digoxin permeability. Based on sandwich-cultured hepatocyte studies, VCH-222 is predicted to be actively transported in liver and to have a low biliary clearance in humans.
Conclusion: VCH-222 has a good oral bioavailability and ADME properties in terms of permeability, metabolic behaviours and distribution in hepatic tissue/cell. VCH-222 is neither a CYP inhibitor/inducer nor a Pgp inhibitor reducing the likelihood of VCH-222 to be involved in drug interactions. From these data, a favorable pharmacokinetic profile is expected in humans..
SAFETY AND ANTIVIRAL EFFICAY OF 14 DAYS OF THE CYCOPHILIN INHIBITOR NIM811 IN COMBINATION WITH PEGYLATED INTERFERON α2A IN RELAPSED GENOTYPE 1 HCV INFECTED PATIENTS
E. Lawitz1, R. Rouzier2, T. Nguyen3, M. Huang4, J. Ke5, J. Praestgaard5, D. Serra5, M. Koziel4, T. Evans4
1Alamo Medical Research, San Antonio, USA, 2Centre CAP, Montpellier, France, 3Research and Education Inc, San Diego, 4Novartis Institute for Biomedical Research, Cambridge, 5Novartis Institute for Biomedical Research, East Hanover, USA
Background Cyclophilins are thought to be important in the HCV life cycle. NIM811, an oral non-immunosuppressive cyclophilin inhibitor, has in vitro activity against HCV , which is additive in combination with interferon.
Methods: This was a double blind placebo controlled trial of 21 patients with relapse after PEG IFN and ribavirin, of whom 20 received one dose of treatment. Patients were randomized 1:1 to receive oral 600 mg bid of NIM811 or matching placebo for 14 days in combination with 180 µg PEG IFN alfa 2a on study days 0 and 7.
Results: The mean drop in HCV RNA was 2.78 log in patients who received the combination of NIM811 + PEG IFN, compared to a 0.58 log drop in the PEG IFN arm (Figure 1; p< 0.0001). Mean ALT fell from 78.4 U/L at baseline to 26.3 U/L by day 14 in the combination group, but was unchanged at 66.0 U/L in the PEG IFN alone group. The major safety concern was a decrease in platelets. In patients treated with combination therapy, the mean platelets were 209 on day 0 and fell to 104 by day 14, whereas for patients treated with PEG IFN the corresponding values were 176 and 139 (p = .025). There was a statistical but not clinically significant increase in serum bilirubin. There were no serious adverse events.
Conclusions: NIM811, when combined with pegylated interferon alpha, shows marked antiviral activity, and warrants further development as a novel therapeutic host target agent for chronic hepatitis C
PHASE 2 RANDOMIZED, DOUBLE-BLIND, PLACEBO-CONTROLLED STUDY OF NITAZOXANIDE PLUS PEGINTERFERON AND RIBAVIRIN IN HCV GENOTYPE 1 PATIENTS: INTERIM ANALYSIS SHOWS INCREASE IN EVR
B. Bacon1, M. Shiffman2, J. Lim3, A. Berman4, V. Rustgi5, E.... Keeffe6,7
1Medicine / Gastroenterology, St. Louis University, St. Louis, 2Medicine / Hepatology, Virginia Commonwealth University Medical Center, Richmond, 3Medicine / Gastroenterology, Yale University Medical Center, New Haven,4Florida Center for Gastroenterology, Largo, 5Medicine / Hepatology, Georgetown University Medical Center, Fairfax, 6Romark Institute for Medical Research, Romark Laboratories, Sausalito, 7Medicine / Gastroenterology, Stanford University Medical Center, Stanford, USA
Background and aims: Nitazoxanide (NTZ) is undergoing study for treatment of chronic hepatitis C (CHC) and shows complete EVR (cEVR) rates of 68% to 86% and SVR rates of 79% and 80% in naive genotype 4 patients. The antiviral mechanism of action of NTZ appears to be induction of PKR, a mediator of cellular antiviral responses. The aim of this study is to determine the efficacy of NTZ in combination with peginterferon alfa-2a (PegIFN) and ribavirin (RBV) in naive patients with CHC genotype 1; this is the first interim analysis of RVR, cEVR, and EVR rates.
Methods: 112 treatment-naive patients with CHC genotype 1 underwent 2:1 randomization in 13 U.S. centers in this double-blind, placebo-controlled study to receive either NTZ (n=75) or placebo (PBO) (n=37) twice daily over a 4-week lead-in followed by continued NTZ or PBO plus PegINF 180 mcg weekly and weight-based RBV (1000 to 1200 mg/d) for 48 weeks. Serum HCV RNA was measured using the Roche Cobas Taqman assay. Discontinuation criteria include failure to achieve EVR or detectable HCV RNA after 24 weeks of combination therapy.
Results: Mean ages (±SD) in the NTZ and PBO groups were 50 ± 7 and 51 ± 8 years, respectively, and 65% of patients were men in both groups. Median baseline HCV RNA was 6.4 log10 IU/mL in the NTZ group and 6.6 log10IU/mL in the PBO group. Analysis of data was by intention-to-treat.
In patients with HCV RNA levels >600,000 IU/mL, cEVR and EVR rates were higher in the NTZ (n=67) vs. PBO (n=31) groups (57% vs. 39%, and 79% vs. 61%, respectively). There were 21 SAEs and no significant differences in AEs between the two treatment groups....
Conclusions: Interim results of this study in genotype 1 naive patients with CHC shows that the addition of NTZ increases EVR rates. Moreover, these findings are consistent with the previously observed EVR results in naive genotype 4 patients.
ANTIVIRAL ACTIVITY OF FILIBUVIR (Pfizer NNRTI) IN COMBINATION WITH PEGYLATED INTERFERON ALFA-2A AND RIBAVIRIN FOR 28 DAYS IN TREATMENT naive PATIENTS CHRONICALLY INFECTED WITH HCV GENOTYPE 1
I. Jacobson1, P. Pockros2, J. Lalezari3, E. Lawitz4, M. Rodriguez-Torres5, E. DeJesus6, F. Haas7, C. Martorell8, R. Pruitt9, K. Durham10, S.. Srinivasan10, M. Rosario10, S. Jagannatha10, J. Hammond10
1Weill Cornell Medical College, New York, 2The Scripps Clinic, La Jolla, 3Quest Clinical Research, San Francisco,4Alamo Medical Research, San Antonio, 5Fundacion de Investigacion de Diego & Ponce School of Medicine, Santurce, 6Orlando Immunology Center, Orlando, 7University of Oklahoma-Schusterman Clinic, Tulsa, 8The Research Institute, Springfield, 9Nashville Medical Research Institute, Nashville, 10Pfizer Global Research and Development, New London, USA
Background Filibuvir (FBV; formerly PF-00868554) is a non-nucleoside inhibitor of HCV polymerase. As monotherapy (100-450 mg BID or 300 mg TID x 8 days), FBV demonstrated dose-dependent inhibition of viral replication, with mean maximum reductions in HCV RNA ranging from -0.97 to -2.13 (log10 IU/mL). In this study, the safety and efficacy of FBV in combination with pegylated interferon alfa-2a (pegIFN) and ribavirin (RBV) was evaluated.
Methods: Eligible patients (treatment naive, HCV genotype 1) were randomized 1:1:1:1 to receive FBV (200, 300 or 500 mg BID) or placebo in combination with pegIFN (180 ug/wk) and RBV (1000/1200 mg/day) for 4 weeks. Patients are continuing on open label pegIFN/RBV for an additional 44 weeks. Results from the Week 4 analysis are described here. HCV RNA was measured using the Roche COBAS Taqman (LLD = 25 IU/mL).
Results: A total of 35 patients were enrolled and 34 completed Week 4. The majority were Caucasian (69%), genotype 1a (80%) and male (51%). The most frequently reported AEs were headache, fatigue, insomnia and nausea. There were no trends towards increased frequency or severity of AEs with increasing dose of FBV. The incidence and severity of laboratory test abnormalities was similar across treatment groups. There was one treatment-related SAE (elevated creatinine) in the FBV 300 mg group, which resolved following IV hydration. No other renal AEs were reported.. The mean reduction (log10 IU/mL) in HCV RNA at Day 4 for placebo (n=8), 200 (n=10), 300 (n=9) and 500 (n=8) mg BID was -0.58, -2.29, -2.72 and -2.83, respectively, and -2.10, -4.46, -4.67 and -3.62 at Day 28. The percent of patients achieving RVR (undetectable HCV RNA by Week 4) for placebo, 200, 300 and 500 mg BID was 0%, 60%, 75% and 63%, respectively. Of those patients treated with 200, 300 and 500 mg BID who achieved a RVR, 33%, 33% and 80% achieved undetectable HCV RNA within two weeks of treatment, respectively.
Conclusions: The addition of FBV to pegIFN/RBV was well tolerated and markedly increased the percentage of patients achieving RVR. Assessment of response to pegIFN/RBV therapy subsequent to Week 4 is ongoing.
SAFETY, PHARMACOKINETICS AND ANTIVIRAL EFFECT OF BI 207127 (Boehringer Ingelheim NNRTI), A NOVEL HCV RNA POLYMERASE INHIBITOR, AFTER 5 DAYS ORAL TREATMENT IN PATIENTS WITH CHRONIC HEPATITIS C
D. Larrey1, Y. Benhamou2, A.W. Lohse3, C. Trepo4, C. Moelleken5, J.-P... Bronowicki6, K. Arasteh7, M.. Bourliere8, M. Heim9, J. Enrequez10, A. Erhardt11, J.-P. Zarski12, R. Wiest13, T.. Gerlach14, H. Wedemeyer15, T. Berg16, J. Stern17, K. Wu17, N. Abdallah18, G. Nehmiz19, W. Boecher19, J. Steffgen19
1INSERM632-CIC Hopital Saint Eloi Montpellier, Montpellier, 2Hopital La Pitie Salpetriere Paris, Paris, France,3Universitatsklinikum Hamburg-Eppendorf, Hamburg, Germany, 4Hopital Hotel Dieu Lyon, Lyon, France,5Universitatsklinik Bochum, Bochum, Germany, 6Hopital de Brabois Nancy, Nancy, France, 7Epimed GmbH Berlin, Berlin, Germany, 8Hopital Saint Joseph Marseille, Marseille, France, 9Universitatsspital Basel, Basel, Switzerland,10Hospital de la Santa Creu I Sant Pau Barcelona, Barcelona, Spain, 11Universitatsklinikum Dusseldorf, Dusseldorf, Germany, 12Hopital Michalon Grenoble, Grenoble, France, 13Klinikum der Universitat Regensburg, Regensburg, Germany, 14Kantonsspital St. Gallen, St. Gallen, Switzerland, 15Medizinische Hochschule Hannover, Hannover, 16Charite Berlin Campus Virchow-Klinikum, Berlin, Germany, 17Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, USA, 18Boehringer Ingelheim France, Reims, France, 19Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
Background BI 207127 is a potent and specific non-nucleoside inhibitor of the HCV RNA-dependent RNA polymerase in-vitro.
Methods: In a double blinded, sequential group comparison, 48 male and female HCV genotype-1 patients with minimal to mild liver fibrosis were randomized (9 active, 3 placebo per group) and treated with 100, 200, 400 or 800 mg BI 207127 Q8h over 5 days, given p.o. as experimental tablet. A further dose level with 1200 mg is ongoing. All patients were followed 10-14 days. Plasma HCV RNA virus load (VL) was measured by Roche COBAS TaqMan assay.
Results: Mean age was 49.5 +/- 10.2 years, BMI 25.3 +/- 3.0 kg/m2. 13/48 patients were naive for anti-HCV therapy. Mean LOG10 VL (IU/mL) at baseline was 6.40. VL decreased by >1 LOG10 in 2/9, 6/9, 8/9 and 8/9 patients treated with 100, 200, 400 and 800 mg, respectively. No response was seen with placebo. No breakthrough was observed during treatment. In the 800 mg group, 5/9 patients showed a >4 LOG10 drop in virus load, and the effect persisted at least 24 hours after the last drug intake. Mean VL drops on day 5 were 0.6, 1.2, 1.9 and 3.1 LOG10 steps, respectively. One SAE was reported for 800 mg, a moderate generalized erythema with facial involvement, which resolved within 2 days after discontinuation of BI 207127 and after antihistaminic treatment. A further, mild localized rash was also reported on 800 mg.These 2 patients showed by far the highest PK exposures. All other AEs were rated "mild" or "moderate" and were not dose-related. Investigators judged tolerability as "good" in 42/48 patients. Laboratory parameters did not show any relevant changes from baseline. Plasma drug levels exhibited supra-proportional pharmacokinetics from 400 mg on. The 1st phase of VL decline was correlated with the early BI 207127 plasma exposure.
Conclusions: BI 207127, given as monotherapy p.o., demonstrated reliable antiviral activity against HCV genotype 1. Further clinical development of this high-potential direct antiviral in combination therapy is warranted.
BI 201335, A POTENT HCV NS3 PROTEASE INHIBITOR, IN TREATMENT-naive AND -EXPERIENCED CHRONIC HCV GENOTYPE-1 INFECTION: GENOTYPIC AND PHENOTYPIC ANALYSIS OF THE NS3 PROTEASE DOMAIN
G. Kukolj1, Y. Benhamou2, M.P. Manns3, M. Bourliere4, S. Pol5, M. Schuchmann6, M. Cartier1, D. Huang7, L. Lagace1, G.. Steinmann8, J.O. Stern7
1Biological Sciences, Boehringer Ingelheim (Canada) Ltd. R&D, Laval, Canada, 2Service Hepato-Gastroenterologie, Batiment des Cliniques Medicales, Hopital Pitie Salpetriere, Paris, France, 3Zentrum Innere Medizin, Abteilung fur Gastroenterologie, Hepatologie und Endokrinologie, Medizinische Hochschule Hannover, Hannover, Germany, 4Service d'Hepato-Gastro-Enterologie, Hopital Saint Joseph, Marseille, 5Pole Medico Chirurgical d'Hepato-Gastro-Enterologie, Unite d'Hepatologie, Hopital Cochin, Paris, France, 6I. Med. Klinik und Poliklinik, Klinikum der Johannes Gutenberg, Universitat Mainz, Mainz, Germany, 7Virology, Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, USA, 8Clinical Research, Virology, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
Background BI 201335, a potent and specific HCV NS3/4A protease inhibitor, has been studied with chronic genotype (GT) 1 HCV infection for 14-days monotherapy in treatment-naive patients followed by combination with PegIFN/RBV for an additional 14 days; and in treatment-experienced patients for 28 days as combination therapy with PegIFN/RBV. All dose groups achieved median viral load reductions of ≥ 3 log10. On-treatment viral rebound was observed in most patients receiving monotherapy, but in only 3/19 treatment-experienced patients receiving triple combination therapy with lower dosages of BI 201335. Genotypic and phenotypic characterization of viral isolates from this study has been performed.
Methods: HCV RNA was collected and extracted from 53 patients at baseline, days 14 and 28, and during follow-up. Population sequencing was performed on the complete NS3/4A region. Clonal sequencing permitted the quantification and identification of major and minor variants (LLOQ: 5%) in the NS3 protease domain.... Chimeric HCV sub-genomic replicons were constructed to determine BI 201335 EC50 values against patient-derived protease sequences.
Results: Population sequencing of baseline isolates revealed one encoding an NS3 V/I170T substitution that conferred an 8-fold reduction in BI 201335 EC50 relative to the subtype reference. Mean EC50 values for the other GT 1a (10 ± 8 nM) or 1b (9 ± 4 nM) baseline-derived samples were within three-fold of the reference values. The predominant GT 1a resistance mutations in on-treatment viral rebound samples encoded an R155K substitution, whereas GT 1b viruses mainly encoded changes at D168, with valine as a predominant substitution. R155K variants conferred reductions in sensitivity to BI 201335 with EC50 values of 1.8 - 6.5 µM, whereas the EC50s for D168V variants were 3.6 -15 µM. Rapid changes in mutant prevalence at the end of dosing suggest that D168V variants are significantly less fit than R155K variants.
Conclusion: HCV NS3 variants that confer resistance to BI 201335 were selected during treatment; these variants do not alter the sensitivity to PegIFN/RBV as the majority of treatment naive patients with resistant virus subsequently displayed anti-viral responses during combination therapy.
ANTIVIRAL ACTIVITY OF ANA598, A POTENT NON-NUCLEOSIDE POLYMERASE INHIBITOR, IN CHRONIC HEPATITIS C PATIENTS
E. Lawitz1, M. Rodriguez-Torres2, M. DeMicco3, T. Nguyen4, E. Godofsky5, J. Appleman6, M. Rahimy6, C. Crowley6, J. Freddo6
1Alamo Medical Research, San Antonio, 2Fundacion de Investigacion de Diego, Santurce, 3Advanced Clinical Research Institute, Anaheim, 4Research and Education Inc, San Diego, 5University Hepatitis Center at Bach and Godofsky, Sarasota, 6Anadys Pharmaceuticals, Inc, San Diego, USA
Background ANA598 is a non-nucleoside inhibitor of HCV polymerase with potent in-vitro antiviral activity. ANA598 was well tolerated at single doses up to 3000mg in healthy subjects. Plasma exposure generally increased with increasing doses and increased several fold after consumption of food. Plasma t1/2 averaged ~24 hours. Initial results from an ongoing Phase 1b trial in HCV patients are reported here....
Methods: Study ANA598-502 is a randomized, double-blind, placebo-controlled, multiple ascending dose trial designed to evaluate safety, tolerability and antiviral activity of orally administered ANA598 in treatment-naive patients with chronic HCV genotype 1 infection. Patients were treated with ANA598 (or matching placebo) at doses of 200mg, 400mg or 800 mg each given BID for 3 days . Viral load at day 4 (12 hours after the last dose) was compared to baseline HCV RNA levels. Plasma drug levels were measured 12 hours following each dose for assessment of trough concentration. HCV RNA levels were measured using the COBAS AmpliPrep/COBAS TaqMan HCV test.
Results: At the 200 mg bid dose level, 6 genotype 1b and 5 genotype 1a patients received ANA598. The age range for the 13 patients (including placebo) was 21 - 61; there were 8 males and 5 females.. Median viral load at baseline was 2,540,000 IU/ml (range 191,000 to 14,700,000 IU/ml).. The median viral load decline at the end of treatment was 2.4 log 10 (with a range of 0.4 - 3.4 log 10). The 5 1a patients demonstrated a median viral load decline of 1.5 log 10; the 6 1b patients demonstrated a median decline of 2.6 log 10.No patient showed evidence of viral rebound while on ANA598. ANA598 was well tolerated and no serious adverse events were reported.
Conclusions: ANA598 dosed 200 mg BID for 3 days as monotherapy demonstrated potent antiviral activity, with median viral load decline of 2.4 log 10 in treatment naive genotype 1 patients. This abstract will be updated with data from the 400 mg and 800 mg BID cohorts. Further studies are planned with ANA598 in combination with SOC.
MK-7009 (Merck protease) SIGNIFICANTLY IMPROVES RAPID VIRAL RESPONSE (RVR) IN COMBINATION WITH PEGYLATED INTERFERON ALFA-2A AND RIBAVIRIN IN PATIENTS WITH CHRONIC HEPATITIS C (CHC) GENOTYPE 1 INFECTION
M.P. Manns1, E. Gane2, M. Rodriguez-Torres3, A. Stoehr4, C.-T. Yeh5, R. Wiedmann6, P. Hwang7, E. Quirk6, J. Silber6, A. Lee6
1Department of Gastroenterology, Hepatology and Endocrinology, Medical School of Hannover, Hannover, Germany, 2New Zealand Liver Transplant Unit, Auckland City Hospital, Auckland, New Zealand, 3Fundacion de Investigacion de Diego, Ponce School of Medicine, San Juan, USA, 4Institute for Interdisciplinary Medicine, Medical Care Center Hamburg, Hamburg, Germany, 5Chang Gung Memorial Hospital, Taipei, Taiwan R.O.C.,6Clinical Research, Infectious Diseases/Vaccines, Merck, 7Biostatistics, Merck, Inc., North Wales, USA
Background MK-7009 is a noncovalent competitive inhibitor of HCV NS3/4A protease, with demonstrated safety and efficacy when administered as monotherapy for 8 days. We now present the primary analysis from an ongoing Phase IIa study of MK-7009 for 28 days in combination with pegylated-interferon and ribavirin (peg-IFN/RBV).
Methods: This is a randomized, placebo-controlled, double-blind study of MK-7009 in treatment-naive CHC patients. MK-7009 was administered for 28 days with peg-IFN/RBV in 1 of 5 regimens: placebo, 300 mg BID, 600 mg BID, 600 mg QD, or 800 mg QD; all patients continue peg-IFN/RBV for an additional 44 weeks. The primary endpoint was the percent of subjects with undetectable HCV RNA (< 10 IU/mL by Roche Cobas Taqman) at day 28 (RVR).
Results: 94 subjects (mean age 46.1 years, 59% male, mean baseline HCV RNA 6.70log10 IU/mL) were randomized and treated. MK-7009 in combination with peg-IFN/RBV was well tolerated, with no serious adverse events (SAEs) and no discontinuations due to an AE during the first 42 days. The most common AEs reported were nausea, headache, and flu-like symptoms. The incidence of nausea and vomiting appeared to be higher compared to placebo. The proportion of subjects who achieved RVR in the MK-7009-containing arms ranged from 69% to 82% (table), vs. 6% of the control (per-protocol population). Each of the MK-7009 doses tested met superiority criteria over the control regimen (p< 0.0001). Viral suppression continued after MK-7009 was stopped; HCV RNA was undetectable in 77-94% of the MK-7009-treated patients vs. 12% of control on day 42. Resistance mutation data will be presented.
Conclusions: In this first study of MK-7009 in combination with peg-IFN/RBV, MK-7009 is a well-tolerated and potent inhibitor of HCV. The results support further development of MK-7009 for HCV treatment.
SAFETY, TOLERABILITY, AND PHARMACOKINETICS AFTER SINGLE AND MULTIPLE DOSES OF MK-3281 (Merck NNRTI) IN HEALTHY SUBJECTS
D. Brainard1, D.H. Wright1, K. Sneddon2, C. Cummings2, P. Sun1, J. Valentine1, M. Anderson1, S. Warrington3, B. Sanderson4, J. Chodakewitz1, J.. Wagner1 1Merck, Inc.., Whitehouse Station, NJ, USA, 2Merck, Sharp & Dohme, Inc., Hoddesdon, 3Hammersmith Medicines Research, London, 4Chiltern (Early Phase) Limited, Dundee, UK
Introduction: MK-3281 is a novel non-nucleoside hepatitis C virus polymerase inhibitor with potent and selective in vitro activity against genotype 1 hepatitis C viruses (genotype 1b replicon assay, EC90 = 241 nM in 50% human serum). Pharmacokinetic and safety data after single-dose (SD) and multiple-dose (MD) administration in healthy subjects were collected.
Methods: SD: Alternating panel, multiple period, dose escalation study in 16 healthy males who received 25 to 2250 mg single doses of MK-3281 or placebo in the fed or fasted state; MD: Ongoing serial-panel study in 24 healthy males who received 100 to 400 mg MK-3281 or placebo q12 hr for 10 days. Safety evaluations were performed throughout the studies. Plasma samples for MK-3281 concentration determination and pharmacokinetics were collected.
Results: There were no serious adverse experiences reported and no discontinuations due to adverse experiences. SD: Following oral administration, MK-3281 increased in plasma with median Tmax values of 2.5 - 3.5 hours. Thereafter, concentrations declined in a biphasic manner with mean terminal t1/2 ~14.3 - 18.6 hours. Administration of 800 mg with a high-fat meal had no clinically meaningful effect on the pharmacokinetic parameters. Mean AUC0-∞, Cmax and C12hr values appeared to increase in a dose proportional fashion through 200 mg and in a less than dose proportional manner at doses greater than 200 mg. MD: Steady state was achieved after 4-5 days. Accumulation over the 10-day period occurred in all subjects for AUC0-12 hr (geometric mean ratio (GMR) 2.3-2..8), Cmax (GMR 1.7-2.8) and C12hr (GMR 2..5 to 2.7). In general, AUC012 hr, Cmax and C12hr appear to increase less than dose proportionally on Day 1 and on Day 10. The apparent terminal half-life on Day 10 following multiple twice daily doses in the present study (e.g., ~17 hours) was consistent with values from the SD study.
Conclusions: MK-3281 is generally well tolerated and exhibits a pharmacokinetic profile supportive of twice daily dosing.
ANTIVIRAL ACTIVITY AND SAFETY OF TMC435 (Tibotec protease) COMBINED WITH PEGINTERFERON ALPHA-2A AND RIBAVIRIN IN PATIENTS WITH GENOTYPE 1 HEPATITIS C INFECTION WHO FAILED PREVIOUS IFN-BASED THERAPY
P. Marcellin1, H. Reesink2, T. Berg3, M. Cramp4, R. Flisiak5, H. Van Vlierberghe6, R. Verloes7, O.. Lenz7, M. Peeters7, V. Sekar8, G. De Smedt7
1Hopital Beaujon, Clichy, France, 2Amsterdam Medical Center, Amsterdam, The Netherlands, 3Charite Campus Virchow Klinikum, Berlin, Germany, 4Derriford Hospital and Peninsula Medical School, Plymouth, UK, 5Medical University of Bialystok, Bialystok, Poland, 6University Hospital Ghent, Ghent, 7Tibotec BVBA, Mechelen, Belgium,8Tibotec Inc., Yardley, USA
Background TMC435 is an NS3/4A protease inhibitor in development for the treatment of hepatitis C virus (HCV) infection. OPERA-1 is an ongoing double blind, placebo-controlled Phase IIa trial to assess the antiviral activity, safety, and pharmacokinetics of once-daily (QD) regimens of TMC435 in HCV genotype 1 infected patients.. This interim analysis of cohort 4 evaluated the antiviral activity of TMC435 combined with Peg-IFN/RBV for 28 days in non-responders or relapsers to previous IFN-based therapy.
Methods: Patients were randomized to receive 28 days of triple therapy with once daily TMC435 75, 150, 200mg or placebo, in combination with PegIFN-2a/RBV, followed by PegIFN-2a/RBV alone for up to 48 weeks. An intent-to-treat analysis was performed when all subjects had completed week 4 of treatment or discontinued earlier.
Results: 37 patients (25 non-responders and 12 relapsers) were enrolled. Baseline characteristics were balanced across arms. Mean decreases in plasma HCV RNA from baseline in patients receiving 75, 150 and 200mg QD were 4.3, 5.5 and 5.3 log10 IU/mL at Week 4, respectively compared to 1..5 log10 IU/mL in the placebo group. At Week 4, 4/9 (44%), 7/9 (78%) and 7/10 (70%) patients receiving 75, 150 and 200mg QD achieved HCV RNA below the lower limit of quantification (< 25 IU/mL) compared to 0/9 patients in the placebo group. Three viral breakthroughs were observed; 2 in the 75mg QD and 1 in the 150mg QD group.No serious AEs or discontinuations due to AEs were reported. Most common AEs were headache, influenza-like illness, dyspnoea and nausea. ALT/AST levels decreased over time in all TMC435 groups. Mild to moderate increases in bilirubin (direct and indirect) were observed in the 200mg QD group. No dose trends or clinically relevant changes were noted in any of the other laboratory parameters, ECG parameters or vital signs.
Conclusion: In this interim analysis, TMC435 at doses of 75mg, 150mg and 200mg QD administered for 4 weeks in combination with PegIFN-2a/RBV was well tolerated and demonstrated potent antiviral activity in HCV genotype 1 infected treatment-experienced patients. The results support further development of TMC435 for patients who failed previous IFN-based HCV therapies.
OPERA-1 TRIAL: INTERIM ANALYSIS OF SAFETY AND ANTIVIRAL ACTIVITY OF TMC435 IN TREATMENT-naive GENOTYPE 1 HCV PATIENTS
M. Manns1, H. Reesink2, C. Moreno3, T. Berg4, Y. Benhamou5, Y. Horsmans6, G. Dusheiko7, R. Flisiak8, P. Meyvisch9, O. Lenz9, V. Sekar10, G. van't Klooster9, K. Simmen9, R. Verloes9
1Medizinische Hochschule Hannover, Hannover, Germany, 2Amsterdam Medical Center, Amsterdam, The Netherlands, 3Erasme Hospital, Universite Libre de Bruxelles, Brussel, Belgium, 4Charite-Universitatsmedizin Berlin, Campus Virchow-Klinikum, Berlin, Germany, 5Centre Hospitalier Universitaire Pitie-Salpetriere Paris, Paris, France, 6Saint-Luc Universite Catholique de Louvain, Brussel, Belgium, 7Royal Free Hospital, London, UK,8Medical University of Bialystok, Bialystok, Poland, 9Tibotec BVBA, Mechelen, Belgium, 10Tibotec Pharmaceuticals, Yardley, USA
Background TMC435 is an NS3/NS4A protease inhibitor in development for treatment of HCV infection.
Methods: OPERA-1 is an ongoing double blind, placebo-controlled Phase IIa trial to assess the antiviral activity, safety and pharmacokinetics of once-daily (QD) regimens of TMC435 in HCV genotype 1 treatment-naive and treatment-experienced patients. Interim 4-week results of three dose cohorts (25, 75 or 200mg QD) in treatment-naive patients are reported here. Patients were randomized to receive either 7 days of monotherapy of TMC435 or placebo followed by 21 days triple therapy with TMC435 or placebo, PegIFNα-2a and ribavirin (RBV) (Panel A); or 28 days of triple therapy with TMC435 or placebo, and PegIFNα-2a/RBV (Panel B). Thereafter, patients continued on PegIFNα-2a/RBV (Standard Of Care). Stopping rules were included.
Results: There were no TMC435-related treatment discontinuations, Grade 3 or 4 adverse events (AEs) or serious AEs. AEs were generally mild to moderate. Hepatic AST and ALT values improved during therapy. There were no clinically relevant changes in other laboratory parameters, ECGs, QTc, and vital signs. All three TMC435 doses in combination with PegIFN/RBV showed antiviral activity superior to PegIFN/RBV alone. During 7-day monotherapy, an antiviral dose-relationship was observed for TMC435. On triple therapy, a similar antiviral activity was noted between the 75mg and 200mg doses. In the 25, 75, 200mg 4-week triple therapy arms, 6/9, 9/9 and 10/10 patients had HCV RNA concentrations below the lower limit of quantification (< 25 IU/mL) and 3/9, 8/9 and 7/10 had undetectable HCV RNA (< 10 IU/mL) at day 28, respectively. At week 12, 6/9 patients of the 25mg and all patients of the 75mg triple arm had undetectable HCV RNA. Viral breakthroughs during TMC435 treatment were only observed in Panel A and were associated with mutations conferring reduced susceptibility to TMC435 in vitro.
Conclusion: TMC435 at doses of 25, 75 or 200mg QD administered for 4 weeks was well tolerated and demonstrated potent antiviral activity. The trial is ongoing for treatment-experienced patients.
PHASE 2 RANDOMIZED, DOUBLE-BLIND, PLACEBO-CONTROLLED STUDY OF NITAZOXANIDE WITH PEGINTERFERON ALFA-2A AND RIBAVIRIN IN NONRESPONDERS (NR) WITH CHRONIC HCV GENOTYPE 1: WEEK 28 INTERIM ANALYSIS
M. Shiffman1, A. Ahmed2, I. Jacobson3, R. Pruitt4, E. Keeffe2,5
1Medicine / Hepatology, Virginia Commonwealth University Medical Center, Richmond, 2Medicine / Gastroenterology, Stanford University Medical Center, Stanford, 3Medicine / Gastroenterology, Weill Cornell Medical College, New York, 4Nashville GI Specialists, Nashville, 5Romark Institute for Medical Research, Romark Laboratories, Sausalito, USA
Background and aims: Nitazoxanide (NTZ) is undergoing study for treatment of chronic hepatitis C (CHC) and shows promising results in naive genotype 4 patients. The antiviral mechanism of action of NTZ appears to be induction of PKR, a mediator of cellular antiviral responses. The aim of this study is to determine the efficacy of NTZ in combination with peginterferon alfa-2a (PegIFN) and ribavirin (RBV) in patients with CHC genotype 1 who are NR to PegIFN plus RBV.
Methods: Sixty-four patients with CHC genotype 1 and prior NR to PegIFN/RBV underwent 2:1 randomization in 10 U.S. centers in this double-blind, placebo-controlled study to receive either NTZ (n=42) or placebo (PBO) (n=22) twice daily over a 4-week lead-in followed by continued NTZ or PBO plus PegINF 180 mcg weekly and weight-based RBV (1000 to 1200 mg/d) for 48 weeks. Therapy was discontinued if patients failed to achieve an EVR or had detectable HCV RNA after 24 weeks of combination therapy.
Results: Mean ages (±SD) in the NTZ and PBO groups were 54 ± 8 and 53 ± 6; there were 69% and 64% men in the NTZ and PBO groups, respectively. Serum HCV RNA was measured using the Roche Cobas Taqman assay (LOQ = 50 IU/mL). Median baseline serum HCV RNA was 6.8 log10 IU/mL in the NTZ group and 6.5 log10 IU/mL in the PBO group. Analysis of data was by intention-to-treat.
*Week 24 of combination therapy; **two subjects were prior relapsers and excluded from efficacy analysis. There were 3 SAEs; no AEs required discontinuation of treatment; and AEs were not significantly different in the two treatment groups.
Conclusions: Compared with PBO, NTZ showed modest incremental early virologic responses (cEVR and undetectable HCV RNA after 24 weeks of combination therapy). These findings may be explained by the interferon-like mechanism of action of NTZ, which account for only modest interim virologic response rates in patients proven refractory to prior interferon-based therapy.
PRECLINICAL CHARACTERIZATION OF PRO 206, AN ORALLY ACTIVE SMALL-MOLECULE HEPATITIS C (HCV) ENTRY INHIBITOR
D. Qian1, G. Coburn1, A.Q. Han1, J.-M. de Muys1, C. Gauss1, K. Provoncha1, M. Canfield1, D. Paul1, S. Mohamed1, S. Moorji1, D. Fisch1, J. Murga1, Y. Rotshteyn2, P.J. Maddon3, W.C. Olson1
1Research and Development, 2Preclinical Development, 3CEO, Progenics Pharmaceuticals Inc..., Tarrytown, USA
Background Combinations of specific anti-viral drugs, with complementary mechanisms of action and determinants of resistance, offer the potential to improve sustained virologic response rates and to improve tolerability for HCV infected patients. To date, most drug discovery and development efforts have targeted two HCV enzymes: the NS3/4A serine protease and the NS5B RNA-dependent RNA polymerase. Targeting HCV entry represents a novel therapeutic approach that has been validated clinically for other pathogenic viruses. We have discovered a small-molecule inhibitor of HCV entry, PRO 206, and describe herein its preclinical characteristics.
Methods: The activity of PRO 206 was evaluated in an HCV pseudo-particle (HCVpp) assay using fusogenic envelopes isolated from multiple HCV+ patients. Antiviral activity was also measured against authentic HCV in cell culture (HCVcc)... Cytotoxicity was assessed in a standard CellTiter Glo assay. Selectivity was determined against a panel of pseudoviral particles that were typed with the envelope glycoproteins from unrelated viruses. PRO 206 was also profiled against a broad panel of human receptor and enzyme targets of pharmacologic interest. Pharmacokinetic properties were characterized in rats after intravenous or oral administration. ADME (absorption/distribution/ metabolism/excretion) properties were assessed in a panel of in vitro assays including Caco2 permeability, human microsomal stability, and inhibition of cytochrome P450s.
Results: PRO 206 demonstrated potent and selective inhibitory activity against HCVpp and HCVcc at concentrations that had no measurable effect on cell viability, entry of unrelated viruses, or a broad panel of human receptors and enzymes. PRO 206 also demonstrated favorable ADME properties, as well as high oral bioavailability and a prolonged pharmacokinetic half-life in animals.
Conclusions: Preclinical data indicate that PRO 206 was a potent, selective, non-cytotoxic and orally bioavailable inhibitor of HCV entry. The antiviral and pharmacokinetic properties of PRO 206 suggest the potential for once-daily dosing in humans. Based on these data, PRO 206 has been selected for preclinical development and is currently undergoing IND-enabling studies to support the initiation of testing in humans for the treatment of HCV infection.
SAFETY, PLASMA PHARMACOKINETICS, AND ANTI-VIRAL ACTIVITY OF SCY-635 IN ADULT PATIENTS WITH CHRONIC HEPATITIS C VIRUS INFECTION
S. Hopkins1, D. Heuman2, E. Gavis2, J. Lalezari3, E. Glutzer3, B. DiMassimo1, P. Rusnak1, S. Wring1, C. Smitley1, Y. Ribeill1
1Research, Scynexis Inc, Durham, 2Hepatology, McGuire VA Medical Center, Richmond, 3Clinical Development, Quest Clinical Research, San Francisco, USA
Background and aims: SCY-635 is a non-immunosuppressive analog of cyclosporine A that exhibits potent suppression of HCV RNA replication in vitro. SCY-635 binds to human cyclophilin A at nanomolar concentrations. Exposure of replicon cells to SCY-635 upregulates efflux of cyclophilin A. This phase 1b clinical study was conducted to determine if treatment with SCY-635 monotherapy could suppress HCV-associated plasma RNA.
Methods: Enrollment was open to adults with genotype 1 infection and plasma RNA exceeding 100,000 IU/mL.. Subjects with evidence of co-infection with HIV-1, HBV, decompensated liver function, or ALT values 2.5 times above the ULN were excluded. Patients were sequentially enrolled into one of three ascending cohorts. Within cohorts patients were randomized to receive SCY-635 or placebo in a 6:1 ratio. Total daily doses were 300, 600 and 900 milligrams. Study medications were given orally in divided doses three times per day for 15 days. Intensive sampling for pharmacokinetic assessments and viral load monitoring was performed throughout the treatment period.
Results: Cohorts exhibited similar baseline characteristics. All subjects were male (n = 20); 75% were African American. Average age was 53.0 years. Average HCV RNA at baseline was 5.6x106 IU/mL. 55% of patients were treatment naive. There were no deaths, no Serious Adverse Events and no discontinuations. Adverse events were similar across cohorts. There were no trends in Adverse Events indicative of a Dose Limiting Toxicity. Greater than proportional increases in plasma exposure to SCY-635 were observed with dose. Steady state was achieved on Day 3. In the 900 milligram cohort mean trough plasma concentrations remained above the replicon derived EC90 value from Days 3 through 15. Consistent decreases in plasma RNA were observed only in the 900 milligram cohort. Maximum responses were observed on Days 11 and 15. Group mean and median nadir values were 2.20 and 1.82 log10 below baseline. One subject achieved undetectable RNA levels at Day 15.
Conclusions: The demonstration of clinically relevant suppression of plasma RNA in the absence of dose-limiting toxicity establishes Proof of Concept for SCY-635 as a new anti-viral agent for treating individuals with chronic hepatitis C infection.
(2 Abbott proease inhibitors) POTENT HCV PROTEASE INHIBITORS WITH THE POTENTIAL FOR ONCE-DAILY DOSING AND BROAD GENOTYPE COVERAGE
L.J. Jiang1, Y.. Gai1, T. Middleton2, K. Kurtz2, L. Lu2, S. Liu1, T. Phan1, X. Luo1, T. Poon1, B. Brasher1, K. McDaniel2, D. Kempf2, Y.S. Or1
1Enanta Pharmaceuticals, Inc., Watertown, 2Abbott Laboratories, Chicago, USA
Background Chronic hepatitis C (HCV) is becoming a major global health burden; current therapies have sub-optimal response rates and are associated with significant side effects. The design of HCV protease inhibitors (PI) EA-058 and EA-063 was undertaken in response to this unmet medical need.
Methods: IC50 and EC50 values were determined in a biochemical assay using recombinant HCV protease and in a replicon system using a luciferase readout, respectively. Rats were dosed orally at 20 mg/kg of EA-058, and plasma and tissue samples were analyzed by LC/MS/MS. Intrinsic clearance in human liver microsomes was calculated by disappearance of parent compound.
Results: IC50 values for EA-058 against genotype 1a, 1b, 2a, 2b, 3a and 4a protease were 0.04, 0.1, 0.3, 1.0, 16 and 0.1 nM, and for EA-063 were 0.03, 0.1, 0.09, 0.4, 0.4, 0.7 and 0.08 nM, respectively. EC50 values for EA-058 against genotype 1a and 1b replicons were 0..8 and 1.5 nM, and for EA-063 were 0.1 and 0.2 nM, respectively, providing selectivity indices of >280,000. The EC50's of EA-063 against genotype 1a R155K, D168E, D168K resistant mutants were 0.7, 0.5, and 27 nM, and against genotype 1b R155K, A156T and D168V resistant mutants were 1.2, 15.1, and 4.3 nM, respectively. Following a single PO dose of 20 mg/kg EA-058 in rats, the ratio of liver exposure over plasma exposure was 440. In contrast, EA-058 levels in the heart were below detection limit of 10 ng/mL across 48 hours. The intrinsic clearance values for EA-058, EA-063, TMC-435350, MK-7009 and ITMN-191 in human liver microsomes were 6.2, 3.6, 4.0, 45.9 and 144.3 µL/min/kg, respectively.
Conclusions: EA-058 and EA-063 are highly potent PIs with broad genotype coverage and excellent in vitrosafety windows; and their virological profiles are superior to ITMN-191, MK-7009 and TMC-435340 which were tested side by side.. EA-058 and EA-063 have equal metabolic stability to TMC-435350, suggesting the potential for once daily dosing. They concentrate in the liver with minimal plasma and heart exposure in rats, providing the potential to minimize extra-hepatic adverse effects in humans.
CHARACTERIZATION OF RESISTANCE MUTATIONS SELECTED IN VITRO BY THE NON-NUCLEOSIDE HCV POLYMERASE INHIBITORS ABT-333 AND ABT-072
G. Koev, R. Mondal, J. Beyer, T. Reisch, S. Masse, W. Kati, D. Hutchinson, C. Flentge, J. Randolph, P. Donner, A. Krueger, R. Wagner, P. Yan, T. Lin, C. Maring, A. Molla Global Pharmaceutical Research & Development, Abbott, Abbott Park, IL, USA
Background and aims: ABT-333 and ABT-072 are non-nucleoside inhibitors of HCV polymerase that are being evaluated for safety, pharmacokinetics and antiviral activity in chronically HCV-infected patients. Both compounds are highly active against genotype 1a and 1b replicons. In this study, the development of resistance to ABT-333 and ABT-072 was examined in the HCV replicon.
Methods: Selection studies were conducted in stable cell lines harboring subgenomic replicons derived from HCV genotypes 1a-H77 and 1b-Con 1. Replicon cells were maintained in growth medium containing either ABT-333 or ABT-072 at concentrations 10-fold and 100-fold above their respective EC50 values together with G418 (400 µg/ml) to select drug-resistant replicon clones. The NS5B polymerase coding regions of resistant replicons were sequenced, and single-mutant replicons were constructed by site-directed mutagenesis.
Results: The most frequently observed resistance mutations selected by ABT-333 and ABT-072 were C316Y, M414T, Y448H/C, or S556G. Phenotypic characterization of the resistant variants showed a loss susceptibility to either ABT-333 or ABT-072 ranging from less than ten to more than one thousand-fold. Most resistant mutants, however, have significantly lower replication capacity than wild type. Combinations of ABT-333 or ABT-072 with interferon in both short-term and long-term replicon assays exhibit additive to synergistic antiviral interactions.
Conclusions: ABT-333 and ABT-072 are highly potent non-nucleoside inhibitors of HCV polymerase. Replicon resistance selection studies with these compounds have revealed mutant variants with reduced susceptibility. Combination treatments of ABT-333 or ABT-072 with IFN show additive to synergistic interactions in HCV replicon, suggesting therapeutic utility of these combinations in vivo.
PRECLINICAL POTENCY, PHARMACOKINETIC AND ADME CHARACTERIZATION OF ABT-333, A NOVEL NON-NUCLEOSIDE HCV POLYMERASE INHIBITOR
C. Maring, R. Wagner, D. Hutchinson, C. Flentge, W. Kati, G. Koev, Y. Liu, D. Beno, J. Shen, Y.Y. Lau, Y. Gao, J. Fischer, S. Vaidyanathan, B.H.. Lim, J. Beyer, R. Mondal, A. Molla Global Pharmaceutical Research & Development, Abbott, Abbott Park, IL, USA
Background and aims: ABT-333 is a novel non-nucleoside HCV polymerase inhibitor with potent activity against genotype 1a and 1b HCV replicons. This compound is currently being evaluated for safety, pharmacokinetics and antiviral activity in chronically infected HCV patients... The objective of this report will be to disclose the potency, pharmacokinetic and ADME profile of ABT-333 in preclinical model systems.
Methods: The polymerase inhibition profile and selectivity of ABT-333 was determined with a panel of HCV NS5B and human polymerase enzymes. Its HCV replicon potency was assessed with and without 40% human plasma. ADME studies with 3H-ABT-333 were conducted in vitro with human microsomes and hepatocytes and in vivo in rats. ABT-333 plasma pharmacokinetics in multiple species was determined after IV and oral dosing, and its liver levels at 12h after oral dosing.
Results: ABT-333 exhibits highly potent (IC50 < 10 nM) and selective activity for genotype 1a and 1b HCV polymerases. The EC50s for ABT-333 in genotype 1 replicons range from 2 to 7 nM and its potency is attenuated by 10- to 14-fold in 40% human plasma. ABT-333 has high Caco-2 permeability and good in vitro stability in human microsomes. ABT-333 does not inhibit CYP enzymes or induce CYP3A4 expression in hepatocytes. Metabolite profiles in hepatocytes indicate a primary oxidative pathway followed by subsequent conjugation primarily as a glucuronide. Subsequent rat ADME studies with ABT-333 confirmed this in vitro metabolism profile and showed that it is eliminated primarily by biliary excretion. ABT-333 has oral bioavailability in rat and dog and is highly distributed to liver producing 12-hour drug levels at significant multiples over its EC50.
Conclusion: ABT-333 is a potent non-nucleoside inhibitor of genotype 1a and 1b HCV polymerase with oral bioavailability in rat and dog. The compound exhibits a preclinical ADME profile of high permeability, in vitro metabolic stability and low potential for drug interactions that predicts favorable pharmacokinetics in humans.
PHARMACOKINETICS, TOLERABILITY AND EFFECT OF FOOD ON HCV POLYMERASE INHIBITOR ABT-333 FOLLOWING SINGLE ASCENDING DOSES IN HEALTHY ADULT VOLUNTEERS
R. Menon1, D. Cohen2, A. Nada1, E. Olson Dumas1, Y.-L. Chiu1, T. Podsadecki2, W. Awni1, B. Bernstein2, C.. Klein1 1Clinical Pharmacology and Pharmacometrics, 2Global Pharmaceutical Research and Development, Abbott Laboratories Inc, North Chicago, IL, USA
Background and aims: ABT-333 is a novel non-nucleoside NS5B polymerase inhibitor being developed for the treatment of HCV genotype 1 infection. The objectives of this study were to evaluate the safety, tolerability and pharmacokinetics (PK) of escalating, single, oral doses of ABT-333 and to determine the effect of food on the PK of ABT-333 in healthy subjects.
Methods: The double-blind, placebo-controlled, single-ascending dose (10 to 1200 mg) portion of this study was conducted in 9 sequential groups. In each dose group, healthy adult subjects were randomized to receive oral doses of either ABT-333 (8) or Placebo (2) under nonfasting conditions. The single-dose, open-label, food-effect portion of this study dosed 8 healthy adult subjects with 100 mg ABT-333 under fasting and nonfasting conditions in a 2-period crossover design. Plasma samples were collected for up to 72 hours after dosing for pharmacokinetic analyses. Safety and tolerability were monitored throughout the study.
Results: Maximum plasma concentrations (Cmax) of ABT-333 occurred at approximately 3 hours post-dose. The mean half-life (t1/2) was 5 to 8 hours. The Cmax and area under the plasma concentration-time curve (AUC) increased proportionally across all treatment groups and mean values ranged from 31 ng/mL to 3053 ng/mL (Cmax) and 317 to 23939 ng.hr/mL (AUC). Food did not impact the Cmax and AUC of ABT-333. Single doses of ABT-333 up to the maximum dose tested, 1200 mg, were well tolerated with no dose limiting toxicity identified. There were no clinically significant changes from baseline in laboratory values, vital signs, or ECG recordings.
Conclusions: The PK of ABT-333 increased in a dose proportional fashion. Food did not impact the Cmax and AUC of ABT-333. ABT-333 was well tolerated up to the maximum dose tested, 1200 mg.
PHARMACOKINETICS, SAFETY AND TOLERABILITY OF THE HCV POLYMERASE INHIBITOR ABT-333 FOLLOWING MULTIPLE ASCENDING DOSES AND EFFECT OF CO-ADMINISTRATION OF KETOCONAZOLE IN HEALTHY SUBJECTS
R. Menon1, D. Cohen2, A.. Nada1, Y.-L. Chiu1, T. Podsadecki1, W.. Awni1, B. Bernstein2, C.. Klein1 1Clinical Pharmacology and Pharmacometrics, 2Global Pharmaceutical Research and Development, Abbott Laboratories Inc, North Chicago, IL, USA
Background and aims: ABT-333 is a novel non-nucleoside NS5B polymerase inhibitor being developed for the treatment of HCV genotype 1 infection. This study evaluated the safety, tolerability and pharmacokinetics of multiple oral doses of ABT-333 and assessed the effect of a potent CYP3A inhibitor on the pharmacokinetics of ABT-333 in healthy subjects.
Methods: Healthy adult subjects received ABT-333 200 and 400 mg BID for 10 days in a double-blind, placebo-controlled fashion in sequential groups. In each dose group, subjects were randomized to receive oral doses of either ABT-333 (8) or Placebo (4) under nonfasting conditions. Serial plasma samples were collected on Day 1 and Days 10 to 13. Plasma samples were also collected prior to morning dose on days 2, 3, 5, 7, 8 and 9. Safety and tolerability were monitored throughout the study. In the 200 mg dose group, on day 11, an additional morning dose of ABT-333 was co-administered with 400 mg ketoconazole.
Results: The mean maximum plasma concentration (Cmax) and area under the concentration-time curve (AUC12) for the 200 mg dose group on Day 10 were 405 ng/mL and 2807 ng*hr/mL, respectively... The dose-normalized maximum plasma concentration (Cmax) and area under the concentration-time curve AUC were comparable for the 200 and 400 mg BID dose groups. Minimal accumulation between Day 1 and 10 was noted with multiple dose administration. The Cmax and AUC values for evening dose and morning dose on Day 10 were comparable indicating no significant diurnal variation in the pharmacokinetics of ABT-333. Ketoconazole co-dosing resulted in a modest increase in ABT-333 Cmax (53%) and AUC (64%). ABT-333 was well tolerated with few adverse events and no clinically significant dose-related changes from baseline in laboratory values, vital signs, or ECG recordings.
Conclusions: The pharmacokinetics of ABT-333 were dose proportional following 10 days of administration.. ABT-333 showed minimal accumulation with no diurnal variation. As the fold increase in ABT-333 exposure in the presence of ketoconazole was between 1.25 and 2, based on FDA guidance, ABT-333 is not a "sensitive substrate" of CYP3A. ABT-333 was well tolerated following multiple dosing for 10 days.
PRECLINICAL CHARACTERIZATION OF ABT-072: A NOVEL NON-NUCLEOSIDE HCV POLYMERASE INHIBITOR
R. Wagner, C. Maring, P... Donner, J. Randolph, A. Krueger, W. Kati, G. Koev, Y.. Liu, D. Beno, J.. Shen, Y. Gao, Y.Y. Lau, J. Fischer, S. Vaidyanathan, J. Beyer, B.H. Lim, R. Mondal, T. Rockway, J. Pratt, D. Liu, M. Tufano, A. Molla Global Pharmaceutical Research & Development, Abbott, Abbott Park, IL, USA
Background and aims: ABT-072 is a novel non-nucleoside HCV polymerase inhibitor that is currently in clinical development and being evaluated for safety and pharmacokinetics in healthy human volunteers. The objective of this report will be to disclose the potency, pharmacokinetic and ADME profile of ABT-072 in preclinical model systems.
Methods: ABT-072 was evaluated in genotype 1a and 1b NS5B enzyme inhibition, as well as replicon cell based assays in the absence or presence of 40% human plasma. ADME studies with 3H-ABT-072 were conducted in vitro with human microsomes and hepatocytes and in vivo in rats. ABT-072 plasma pharmacokinetics in multiple preclinical species were determined after IV and oral dosing, and its liver drug levels at 12h after oral dosing.
Results: The EC50s of ABT-072 in genotype 1a and 1b replicon assays range from 0.3 to 5.3 nM. In the presence of 40% human plasma, the EC50s increased by 8- to 17-fold. ABT-072 has high Caco-2 permeability and good in vitro stability in human microsomes. Metabolic profiling shows no potent cytochrome P450 inhibition or induction. ABT-072 has also shown good to excellent oral bioavailability in rat and dog, and the compound is highly distributed to liver in all species.
Conclusion: ABT-072 is a highly potent, non-nucleoside polymerase inhibitor. The compound is orally bioavailable, demonstrating plasma and high liver levels in multiple species. ABT-072 exhibits a preclinical metabolism profile consistent with a low potential of encountering drug-drug interactions. The ADME characteristics, combined with the extraordinary potency of the compound are consistent with the goal of achieving antiviral activity with oral dosing in human subjects.
RESULTS OF A PROOF OF CONCEPT STUDY (C210) OF TELAPREVIR MONOTHERAPY AND IN COMBINATION WITH PEGINTERFERON ALFA-2A AND RIBAVIRIN IN TREATMENT-naive GENOTYPE 4 HCV PATIENTS
Y. Benhamou1, J. Moussalli1, V. Ratziu2, P. Lebray1, V. Gysen3, K. de Backer3, A. Ghys3, R.. van Heeswijk3, T. Vangeneugden3, G. Picchio4, M. Beumont-Mauviel3
1Hopital Pitie-Salpetriere, 2Universite Pierre et Marie Curie, Paris VI, Paris, France, 3Tibotec BVBA, Mechelen, Belgium, 4Tibotec Inc., Yardley, USA
Background C210 is an ongoing, partially blinded, randomized, Phase 2a study of telaprevir (TVR), administered as monotherapy and in combination with peginterferon alfa 2a (Peg-IFN) and ribavirin (RBV), investigating early viral kinetics of HCV-RNA decay in treatment-naive subjects with genotype 4 infection. We report results of the primary analysis conducted at day 15 of treatment.
Methods: HCV genotype 4 subjects were randomized to receive TVR 750mg q8h alone (arm A; n=8), TVR with Peg-IFN 180µg/week and RBV 1000-1200mg/day (arm B; n=8), or Peg-IFN and RBV plus placebo (arm C; n=8) for 15 days. Viral load was measured using Taqman assay (limit of detection < 10 IU/mL). Viral breakthrough (vBT) was defined as >1-log increase in HCV-RNA above nadir or >100 IU/mL HCV-RNA after previously undetectable HCV-RNA. An ITT analysis was performed when all treated subjects had completed 15 days of dosing or had discontinued earlier.
Results: 38% of enrolled patients were Egyptian and 25% were Caucasian; none had cirrhosis and 58% had HCV-RNA >800,000 IU/mL. Genotype 4a was the most prevalent subtype (50%). The mean (SE) log10 changes in HCV-RNA at days 3/15 were -1.2(0.28)/-0.9(0.46), -2.1(0.29)/-3.4(0.65), and -1.0(0.26)/-2.0(0.40), while the mean (SE) log10 maximum HCV-RNA change was -1.4(0.30), -3.5(0.48) and -2..0(0.40) for arms A, B and C, respectively. By day 15, 0%, 13%, and 0% of subjects had undetectable (< 10 IU/mL) HCV-RNA in arms A, B and C, respectively; vBT during the dosing period was observed in 5, 1 and 0 patients, respectively. The overall incidence of adverse events (AEs) was similar across arms and in line with previous reports. One patient in arm A had a serious AE that was considered unrelated to TVR but led to treatment discontinuation.
Conclusions: TVR in combination with Peg-IFN and RBV had greater activity against HCV genotype 4 than Peg-IFN and RBV alone or TVR monotherapy. The potential role of TVR in combination with Peg-IFN and RBV in the treatment of HCV genotype 4-infected patients remains under investigation.
DETECTION OF RESISTANT VARIANTS IN THE HEPATITIS C VIRUS NS3 PROTEASE GENE BY CLONAL SEQUENCING AT LONG-TERM FOLLOW-UP IN PATIENTS TREATED WITH BOCEPREVIR
S. Susser, N. Forestier, M..W. Welker, J. Vermehren, U. Karey, S. Zeuzem, C. Sarrazin
Medizinische Klinik 1, Klinikum der Johann Wolfgang Goethe-Universitat, Frankfurt am Main, Germany
Background Boceprevir (SCH503034) is a highly selective inhibitor of the hepatitis C virus (HCV) NS3/4A protease which is currently investigated in phase 3 studies in combination with pegylated interferon alfa 2b and ribavirin. Recently, selection of resistant variants within the HCV quasispecies during treatment with boceprevir has been described. The frequency of resistant isolates declined 2 weeks after treatment with boceprevir was stopped. However, the possibility of long-term persistence of NS3 resistance mutations and their impact on re-treatment with protease inhibitors is unknown.
Methods: Patients with chronic hepatitis C genotype 1 infection investigated in the present long-term follow-up study were initially enrolled in two different phase 1b studies: (1) treatment with boceprevir 100mg BID, 200mg BID, 400mg BID, or 400mg TID alone for 14 days or (2) peginterferon alfa 2b for one week followed by combination therapy of boceprevir 400mg TID/QID with peginterferon alfa 2b for 24 weeks. Samples from long-term follow-up after up to 4 years after the initial therapy with boceprevir are available from a subgroup of patients with persistent chronic hepatitis C (n=14). For resistance analysis a highly sensitive cloning and sequencing method for the entire NS3 protease gene and in addition a phenotypic assay was applied.
Results: Sequencing results are available currently for 6 patients: two patients after monotherapy with boceprevir and 4 patients who received combination therapy with peginterferon. None of the patients received further antiviral therapy. HCV RNA serum concentrations 1 to 4 years after treatment with boceprevir ranged between 74,000 and 3.1 Million IU/ml. Clonal sequence analysis in these patients revealed different resistant variants (V36M/A, T54A/S, R155K) within the NS3 protease at 4% to 80% frequency in 4 of 6 patients. The entire analysis of the 14 patients and phenotypic characterization of resistant variants for different protease inhibitors will be presented.
Conclusions: Follow-up for up to 4 years showed the facility of long-term persistence of resistance mutations within the NS3 protease in patients treated with boceprevir alone or in combination with pegylated interferon. High frequencies of resistant variants were detected in two patients after 1 year follow-up.
A PHASE 2, RANDOMIZED STUDY OF HCV-796 IN COMBINATION WITH PEGYLATED-INTERFERON (PEG) PLUS RIBAVIRIN (RBV) VERSUS PEG PLUS RBV IN HEPATITIS C VIRUS GENOTYPE-1 INFECTION
P. Pockros1, M. Rodriguez-Torres2, S. Villano3, E. Maller4, M. Chojkier5
1Division of Gastroenterology/Hepatology, The Scripps Clinic, La Jolla, 2Fundacion de Investigacion de Diego & Ponce School of Medicine, San Juan, 3ViroPharma Inc., Exton, 4Wyeth Pharmaceuticals, Collegeville, 5University of California, San Diego & VA Medical Center, La Jolla, USA
Background HCV-796 is a non-nucleoside allosteric inhibitor of HCV RNA dependent RNA polymerase (NS5B), which is essential for viral replication. This was a phase 2, randomized, open-label study of the safety, antiviral activity, and pharmacokinetics of HCV-796 administered in combination with pegylated-interferon-alfa-2b (PEG) plus RBV versus PEG plus RBV in HCV genotype-1-infected subjects who were either naive to treatment (TN) or who had failed treatment (< 2 log reduction in HCV RNA at week 12 of prior PEG±RBV; non-responders, NR).
Methods: 244 genotype-1 subjects at 36 US sites were assigned into 3 arms: TN PEG+RBV (n=78), TN HCV-796+PEG+RBV (n=82), and NR HCV-796+PEG+RBV (n=84). Subjects received HCV-796 500 mg BID. At randomization, subjects were prospectively stratified by race (AA or non-AA). Subjects with a Metavir biopsy score =4 were excluded. Primary and secondary pre-specified endpoints were cEVR and RVR, respectively. HCV RNA was analyzed using the Roche Taqman (LLD < 10 IU/ml) assay.
Results: Table 1 shows the summary of results. RVR and cEVR (< 50 IU/mL; missing values excluded) were better in HCV-796 TN arm versus control arm. This benefit was less notable in AA population and in NRs. Grade 3/4 elevations in LFTs occurred in 3 subjects receiving HCV-796 (2 TN, 1 NR). Other adverse events resulting in study discontinuation were infrequent in all 3 arms. There was no increase in anemia or neutropenia in HCV-796 arms. HCV-796 dosing was suspended for all subjects after LFT elevations were recognized
Conclusions: This study demonstrates that a non-nucleoside allosteric polymerase inhibitor of HCV has effective antiviral activity and improves RVR and cEVR in genotype-1 subjects when used in combination with PEG and RBV. Although this compound will not be further developed due to unexpected elevations in liver enzymes, other non-nucleoside polymerase inhibitors are in development and may be effective in genotype-1 HCV.
EFFICACY AND SAFETY OF WEIGHT-BASED REGIMENS OF TARIBAVIRIN OR RIBAVIRIN, GIVEN WITH PEGINTERFERON ALFA-2B, AT 12 WEEKS AFTER TREATMENT (SVR12) IN naive PATIENTS WITH GENOTYPE 1 CHRONIC-HEPATITIS C
F.. Poordad1, E.. Lawitz2, R. Pozza3, M. Shiffman4, B. Bacon5, E. Godofsky6, D. Halliman7, J. Heise7, E. Chun7, J. Hammond7
1Cedars-Sinai Medical Center, Los Angeles, 2Alamo Medical Research, San Antonio, 3SCTI Research Foundation Liver Center, San Clemente, 4Virginia Commonwealth University Medical Center, Richmond, 5Saint Louis University School of Medicine, Saint Louis, 6University Hepatitis Center at Bach and Godofsky, Sarasota, 7Valeant Pharmaceuticals North America, Aliso Viejo, USA
Background and aims: Taribavirin (TBV) is an oral pro-drug of ribavirin (RBV). The current study determines if weight based dosing (WBD) of TBV demonstrates efficacy comparable to that of RBV while maintaining its previously demonstrated anemia advantage when it was administered at a fixed dose.
Methods: A US phase 2b randomized, open-label, active-controlled, parallel-group study is being conducted in treatment-naive, genotype 1 patients stratified by body weight and baseline viral load. Patients were randomized 1:1:1:1 to receive TBV (20, 25, or 30 mg/kg/day) or RBV (800, 1000, 1200, or 1400 mg/day) with PEG alfa-2b for 48 weeks.
Results: 278 patients were randomized: mean age 49 yr; 61% male; 30% African-American or Latino; 81% viral load ≥400,000 IU/mL; and mean body weight 82 kg. Rates of virologic response for treatment weeks (TWs) 4, 12, and 48 and SVR at 12 weeks after treatment (SVR12) are shown here along with anemia rates.
The most common adverse events (AEs) through SVR12 in all groups are fatigue, diarrhea, insomnia, and chills. Diarrhea, reported about twice as frequently in TBV patients, is generally mild and not dose-limiting.
Conclusions: At SVR12, all doses of TBV/PEG demonstrated efficacy and tolerability comparable to that of RBV/PEG. Rates of anemia are statistically significantly lower for TBV 20-25 mg/kg than for RBV. Response rates are similar to those of previous studies with a higher proportion of African-American and Latino patients. These data suggest WBD with TBV provides a safe and effective alternative to RBV for the treatment of chronic hepatitis C.
ACTIVITY OF TELAPREVIR ALONE OR IN COMBINATION WITH PEGINTERFERON ALFA-2A AND RIBAVIRIN IN TREATMENT-naive GENOTYPE 2 AND 3 HEPATITIS-C PATIENTS: INTERIM RESULTS OF STUDY C209
G.R. Foster1, C. Hezode2, J.-P. Bronowicki3, G. Carosi4, O. Weiland5, L. Verlinden6, R. van Heeswijk6, T. Vangeneugden6, G. Picchio7, M. Beumont-Mauviel6
1Barts and The London School of Medicine, Institute of Cellular and Molecular Science, London, UK, 2Hopital Henri-Mondor, AP-HP, Universite Paris XII, Creteil, 3Centre Hospitalier Universitaire de Nancy, Vandoeuvre-les-Nancy, France, 4Clinic of Infectious and Tropical Diseases, University of Brescia, Brescia, Italy, 5Karolinska University Hospital Huddinge, Stockholm, Sweden, 6Tibotec BVBA, Mechelen, Belgium, 7Tibotec Inc., Yardley, USA
Background Telaprevir (TVR) produces rapid and consistent reductions of HCV-RNA plasma levels in G1 patients. Study C209 is an ongoing, partially blinded, randomized, Phase-2a study of TVR, administered alone or with peginterferon-alfa-2a (Peg-IFN) and ribavirin (RBV), investigating early viral kinetics of HCV-RNA decay in treatment-naive subjects with genotype 2/3 (G2/3) infection.. We report the results of the primary analysis conducted after 15 days of treatment.
Methods: 49 subjects were randomized to receive 15 days of either TVR 750mg q8h alone (armA;G2/3;n=10/8), TVR 750mg q8h with Peg-IFN 180µg/week and RBV 800mg/day (armB;G2/3;n=5/9), or Peg-IFN 180µg/week and RBV 800mg/day plus placebo (armC;G2/3;n=8/9) . Viral load was measured using Taqman assay (LOD< 10 IU/mL). Viral breakthrough (vBT) was defined as >1-log increase in HCV-RNA above nadir or >100 IU/mL HCV-RNA after previously undetectable HCV-RNA. An ITT analysis was performed when all treated subjects had completed 15 days of dosing or discontinued earlier.
Results: Mean baseline log10 HCV-RNA was 6.45 and 6.44 IU/mL among G2- and G3-infected subjects, respectively. The mean (SE) log10 changes in HCV-RNA at days 3/15 in G2-infected subjects were -3.0(0.37)/-3.1(0.64), -3.9(0.23)/-5.3(0.27), and -2.2(0.56)/-4...0(0.70) and in G3-infected subjects -0.8(0.33)/-0.5(0.11), -2.9(0.24)/-4.7(0.32), and -2.6(0.40)/-4.5(0..36) for arms A, B, and C, respectively.. The mean (SE) log10 maximum HCV RNA change in G2/G3-infected subjects was -4.0(0.49)/-0.8(0.33), -5.5(0.24)/-4.7(0.32) and -4.0(0.70)/-4.5(0.36) for arms A, B and C, respectively. In G3-infected subjects, responses varied across subtypes. The proportion of G2/G3-infected subjects with undetectable HCV-RNA at day15 was 0%/0%, 40%/22% and 25%/11% for arms A, B and C, respectively. Among G2/G3 subjects receiving TVR monotherapy, 6 and 5 patients, respectively, developed a vBT by day15; no vBTs were observed in arms B or C. Overall incidence of AEs was similar across arms and the most common AEs in TVR arms were rash-related events, nausea, and influenza-like illness, in line with previous reports.. One patient in arm B discontinued therapy due to rash. No SAEs were reported in this trial.
Conclusions: TVR demonstrated substantial antiviral activity against HCV G2, while its activity against G3 was limited. These findings support additional investigation of TVR for the treatment of G2 HCV infection.
PRECLINICAL PHARMACOKINETIC AND SAFETY PROFILE OF IDX375, A NOVEL AND POTENT NON-NUCLEOSIDE HCV POLYMERASE INHIBITORS.
S. Good1, C. Bu1, M. Camire1, B. Hernandez-Santiago1, M. Larsson1, H. Rashidzadeh1, X.-R. Pan-Zhou1, S. Luo1, J. Selden1, C.B. Dousson2, D. Surleraux2
1Idenix Pharmaceuticals, Inc., Cambridge, USA, 2Idenix Pharmaceuticals, Inc., Montpellier, France
Background and aims: IDX375 is a potent and selective non-nucleoside inhibitor of HCV polymerase with an EC50 value of 2..3 nM in the HCV 1b replicon system.. The preclinical pharmacokinetic and in vitro and in vivo safety profiles of IDX375 are presented.
Methods: Single-dose plasma pharmacokinetic parameters were obtained in male CD-1 mice (n=3/timepoint) and Sprague-Dawley rats (n=3/dose) at 15 mg/kg (IV and oral) and at 50 and 250 mg/kg (oral). Pharmacokinetic and toxicologic evaluations were conducted in cynomolgus monkeys (n=2/dose) in a 7-day oral toxicity study at 10 and 100 mg/kg/day. Cytochrome P450 inhibition was evaluated using recombinant human CYP1A2, 2B6, 2C9, 2D6 and 3A4. Freshly isolated hepatocytes were used to determine the extent of IDX375 metabolism (24-h incubations) and cytotoxicity (48-h incubations).
Results: After a 15 mg/kg dose, the mean Cmax and half-life of IDX375 in mice and rats were, respectively, 569 and 2210 ng/mL and 4.4 and 1.9 h. Absolute oral bioavailabilities were 34 and 16% in these rodents.. In orally dosed mice (15 mg/kg) and monkeys (10 mg/kg), mean 24-h plasma levels were, respectively, 6- and 37-fold above the EC50. Additionally, IDX375 was selectively concentrated in the liver of all three species, with liver/plasma ratios ranging from 54-376 between 2 and 24 h post dose. After oral administration, high systemic exposures were observed in rodents dosed up to 250 mg/kg and in monkeys dosed up to 100 mg/kg. Greater than dose-proportional increases in AUC in mice and monkeys and proportional increases in rats were observed. In monkeys given 10 or 100 mg/kg oral doses for 7 days, no adverse effects were observed, including no meaningful changes in clinical chemistries and no histological abnormalities. IDX375 showed no significant inhibition (IC50 >20 µM) of five major human cytochrome P450 isozymes. In mouse, rat, monkey and human hepatocytes, IDX375 showed limited metabolism and no cytotoxicity (CC50 >10 µM).
Conclusion: IDX375 is a promising clinical candidate based on its favorable safety profile and preclinical pharmacokinetics that suggest once- or twice-daily dosing in humans.
PRECLINICAL PROFILES OF IDX136 AND IDX316, TWO NOVEL MACROCYCLIC HCV PROTEASE INHIBITORS
L.B. Lallos1, J.P. Bilello1, M.A. Soubasakos1, J. Gillum1, M. La Colla1, M.. Liuzzi2, J. Mc Carville1, M. Seifer1, S.S. Good1, M. Larsson1, J. Selden1, C.. Parsy3, D.. Surleraux3, D.N.. Standring1
1Idenix Pharmaceuticals, Inc., Cambridge, USA, 2Idenix Pharmaceuticals, Inc.., Cagliari, Italy, 3Idenix Pharmaceuticals, Inc., Montpellier, France
Background and aims: This study profiled the in vitro activity and pharmacological properties of IDX136 and IDX316, two potent and specific macrocyclic HCV protease inhibitor (PI) clinical candidates.
Methods: The antiviral activity and specificity of IDX136 and IDX316 were evaluated in a variety of assays utilizing purified proteases and HCV replicons. Combination treatment of replicon cells with these compounds and standard-of-care agents or other direct antivirals was also evaluated. Pharmacokinetics were conducted in the mouse, rat and monkey following oral and IV administration. Preclinical safety was evaluated in rhesus monkeys.
Results: IDX136 and IDX316 were potent and selective non-covalent inhibitors of HCV protease enzymes of genotypes 1a, 1b and 4 (IC50=1-3 nM) and the 1b replicon (EC50=4 to 10 nM) with no activity against human cellular proteases. Treatment of replicon cells for 14 days with each IDX PI led to ≥ 2.8 log10 reduction in replicon RNA levels. Enhanced antiviral activity of IDX PIs was observed when tested in vitro in combination with standard-of-care agents or other direct antivirals. In mice, rats and monkeys dosed with 10 or 15 mg/kg of IDX316, plasma half-lives ranged from 4..0-5.2 h and oral bioavailability ranged from 9-19%. Parent drug was selectively concentrated in the liver and plasma concentrations at 24h remained well above the EC50 value in rats and monkeys after a single oral dose.. Rhesus monkeys given 10 or 100 mg/kg oral doses of either IDX136 or IDX316 for 7 days showed no adverse effects, including no meaningful changes in clinical chemistries and no histological abnormalities. Neither drug showed significant inhibition of five human cytochrome P450 isozymes nor cytotoxicity to freshly isolated hepatocytes from mouse, rat, cynomologus monkey or human.
Conclusions: IDX136 and IDX316 are potent and selective HCV inhibitors in in vitro biochemical and cell-based assays. Based on the favorable preclinical safety profile and pharmacokinetics that suggest once- or twice-daily dosing, IDX136 and IDX316 are currently undergoing IND-enabling pharmacology and toxicology studies to support initiating studies in man.
BBPS100K01: A PROMISING HCV NS3/4A PROTEASE INHIBITOR ORIGINATED FROM TRADITIONAL CHINESE MEDICINAL ANIMAL
X.J. Wang1, X.H. Wu1, H. Sun1, C.M. Ma2, W.J. Sun1, M. Hatorri2, Y. Kano2
1Pharmacognosy Department, Heilongjiang University of Chinese Medicine, Harbin, China, 2Institute of Natural Medicines, Toyama University, Toyama, Japan
Background and aims: Hepatitis C virus (HCV) infects an estimated 3% of the world's population, of all individuals infected with HCV, 85% develop persistent infections. Anti-HCV Drug is in need urgently worldwide. Fel. Ursi one of traditional Chinese drug originated from animal, has been used for treating Hepatitis C related syndrome for about 3000 years, it is still in work clinically.There is potentiality to create a HCV protease inhibitor based on the proved clinical experiences of Chinese medicine.
Method: The activity of HCV NS3/4A Protease was detected by SensoLyteTM520 HCV Protease Assay Kit. The active constituents were obtained by bioactivity-guided separation with Silica gel, ODS, Sephadex column chromatography and preparative HPLC, coupled with membrane filter and enzymolysis, they were identified by MS and NMR spectrum etc.
Result: The water solution of Fel Ursi inhibited the activity of HCV NS3/4A Protease in a dose-depended manner with an IC50 of 0.3µg/ml; all of the small molecular compounds isolated from Fel Ursi powder, which were identified as bile acids including TUDCA and TCDCA, possessed less than 40% of inhibiting activity at the concentration of 100µg/ml, all individuals, as well as the mixture of them, were not as effective as Fel Ursi powder. However the larger molecule constituents, the rejection of Fel Ursi water solution by 100K membrane filter, had shown higher inhibiting activity than 90% at 100µg/ml, the activity was reduced to less than 10% by enzymolysis only with proteinase, the rejection with more 100000 molecule weight was proposed active proteins. By further separation with Sephadex G100, 4 fraction with different molecule weight were collected, F01 is the largest molecule fraction in the rejection which has been named BBP100K01, it is the most effective protein with more than 95% of inhibiting activity at 100µg/ml which activity is much better than that of Fel Ursi powder.
Conclusion Both Fel Ursi and BBP100K01 is effective HCV NS3/4A protease inhibitor. Fel Ursi may show expected effect for Hepatitis C clinically, BBP100K01 is a promising drug lead of anti-HCV.. Traditional wisdom in clinical practice can be a super modern solution for hepatitis C.
PARTICULAR IN VITRO ANTI-HCV ACTIVITIES AND RESISTANCE PROFILE OF THE CYCLOPHILIN INHIBITOR DEBIO 025
L. Coelmont1, P. Gallay2, M. Bobardt2, S. Kaptein1, J. Paeshuyse1, I. Vliegen1, G.. Vuagniaux3, J. Neyts1
1Rega Institute, Leuven, Belgium, 2The Scripps Research Institute, La Jolla, USA, 3Debiopharm, Lausanne, Switzerland
Background Debio 025 (D25) is a potent inhibitor of HCV replication in vitro and in patients [Hepatology 43:761-70; Hepatology 47:817-26]. This study was aimed at better characterising the in vitro anti-HCV properties and resistance profile of the molecule.
Methods: Combination with interferon-α (IFN-α), ribavirin or specifically targeted antiviral therapy for HCV (STAT-C) inhibitors, clearance and rebound, and resistance selection experiments were performed using Huh7 cells containing subgenomic HCV replicons.
Results: Combinations of D25 with either IFN-α, ribavirin or STAT-C inhibitors resulted in an additive to slightly synergistic antiviral activity. D25 showed the unique ability to rapidly clear hepatoma cells from their HCV replicon when used alone or at low concentration in combination with IFN-α and STAT-C inhibitors. Development of escape variants against STAT-C inhibitors in colony formation assays was delayed by D25 and the drug proved equipotent against wild-type HCV, as against HCV replicons that are resistant to STAT-C inhibitors. Replicons were selected that are resistant to D25 (3 independent selections) with mutations clustered in the nonstructural 5A gene following long term culture. Re-engineering of these mutations in a WT background only partially recovered resistance.. D25 resistant replicons remained fully susceptible to IFN-α and STAT-C inhibitors. Huh Lunet cells were stably transfected with D25res replicon RNA, which resulted in a partial transfer of the resistance indicating that also host cell factors may be involved in the observed resistance in vitro. Such potential candidate host factors were further studied.
Conclusions: The particular in vitro anti-HCV activities and unique resistance profile of D25 indicate that the drug forms an attractive drug candidate for the treatment of HCV infections in combination with standard of care and/or STAT-C.
MOLECULAR CHARACTERIZATION OF HCV RESISTANCE TO TELAPREVIR, A NOVEL, POTENT HCV PROTEASE INHIBITOR
S. Chevaliez1, A. Ahmed-Belkacem1, L. Barbotte1, A. Soulier1, D. Bartels2, Y. Zhou2, A. Ardzinski2, N. Mani2, G. Rao2, C. Hezode1, S. George2, A. Kwong2, J..-M. Pawlotsky1
1French National Reference Center for Viral Hepatitis B, C and Delta, INSERM U841, Hopital Henri Mondor, Universite Paris 12, Creteil, France, 2Vertex Pharmaceuticals, Cambridge, USA
Telaprevir (VX-950, Vertex Pharmaceuticals) is a potent inhibitor of HCV NS3 serine protease. Resistance to telaprevir monotherapy occurs early as a result of the selection of amino acid substitutions at 4 positions (V36, T54, R155 and/or A156).
Objective: To characterize HCV resistance to telaprevir at the molecular level in patients also receiving peginterferon alpha with or without ribavirin.
Results: Among 20 patients with HCV genotype 1 infection included in the Phase II PROVE 2 trial, a breakthrough on therapy or post-treatment relapse occurred in 6 patients receiving telaprevir, 750 mg q8h, and peginterferon alpha-2a, 180 microg qw, without ribavirin, for 12 weeks (3 breakthroughs, all subtype 1a; 3 relapses, 1 subtype 1a) and 2 patients receiving the triple combination of telaprevir, peginterferon alpha-2a and ribavirin for 12 weeks. In all instances, the wild-type virus was replaced by complex mixtures of viral quasispecies variants bearing known telaprevir resistance substitutions at the time of breakthrough/relapse that subsequently deeply fluctuated in their composition. Most of the selected variants bore additional amino acid changes together with the known telaprevir resistance-associated substitutions. 3D-modeling suggested that none of them affected telaprevir binding to NS3 protease, except maybe T42S and A40T. In a replicon-based phenotypic assay, these additional amino acid changes did not confer a significant change in baseline sensitivity to telaprevir, suggesting that their selection was related to an improvement in fitness for telaprevir-resistant variants. A novel resistance mutation at a known resistance position (V36C) was observed in one patient receiving the triple combination who stopped therapy early. This substitution increased the IC50 by 8.6 fold, while the relative in vitro replication capacity and kinetic parameters were not different from the wild-type V36 variant.
Conclusion: Breakthroughs during and relapses after telaprevir administration in combination with peginterferon alpha with or without ribavirin are associated with the selection of complex mixtures of viral variants bearing amino acid substitutions that confer resistance to telaprevir plus additional changes likely conferring improved fitness to the telaprevir-resistant variants.
SAFETY, PLASMA PHARMACOKINETICS, AND ANTI-VIRAL ACTIVITY OF SCY-635 IN ADULT PATIENTS WITH CHRONIC HEPATITIS C VIRUS INFECTION
S... Hopkins1, D. Heuman2, E. Gavis2, J. Lalezari3, E. Glutzer3, B.. DiMassimo1, P. Rusnak1, S. Wring1, C. Smitley1, Y. Ribeill1
1Research, Scynexis Inc, Durham, 2Hepatology, McGuire VA Medical Center, Richmond, 3Clinical Development, Quest Clinical Research, San Francisco, USA
Background and aims: SCY-635 is a non-immunosuppressive analog of cyclosporine A that exhibits potent suppression of HCV RNA replication in vitro. SCY-635 binds to human cyclophilin A at nanomolar concentrations. Exposure of replicon cells to SCY-635 upregulates efflux of cyclophilin A. This phase 1b clinical study was conducted to determine if treatment with SCY-635 monotherapy could suppress HCV-associated plasma RNA.
Methods: Enrollment was open to adults with genotype 1 infection and plasma RNA exceeding 100,000 IU/mL. Subjects with evidence of co-infection with HIV-1, HBV, decompensated liver function, or ALT values 2.5 times above the ULN were excluded... Patients were sequentially enrolled into one of three ascending cohorts. Within cohorts patients were randomized to receive SCY-635 or placebo in a 6:1 ratio. Total daily doses were 300, 600 and 900 milligrams. Study medications were given orally in divided doses three times per day for 15 days.. Intensive sampling for pharmacokinetic assessments and viral load monitoring was performed throughout the treatment period.
Results: Cohorts exhibited similar baseline characteristics.. All subjects were male (n = 20); 75% were African American. Average age was 53..0 years. Average HCV RNA at baseline was 5.6x106 IU/mL. 55% of patients were treatment naive. There were no deaths, no Serious Adverse Events and no discontinuations. Adverse events were similar across cohorts. There were no trends in Adverse Events indicative of a Dose Limiting Toxicity. Greater than proportional increases in plasma exposure to SCY-635 were observed with dose. Steady state was achieved on Day 3. In the 900 milligram cohort mean trough plasma concentrations remained above the replicon derived EC90value from Days 3 through 15. Consistent decreases in plasma RNA were observed only in the 900 milligram cohort. Maximum responses were observed on Days 11 and 15. Group mean and median nadir values were 2.20 and 1.82 log10 below baseline. One subject achieved undetectable RNA levels at Day 15.
Conclusions: The demonstration of clinically relevant suppression of plasma RNA in the absence of dose-limiting toxicity establishes Proof of Concept for SCY-635 as a new anti-viral agent for treating individuals with chronic hepatitis C infection.
SAFETY, TOLERABILITY AND ANTIVIRAL ACTIVITY OF VCH-916, A NOVEL NON-NUCLEOSIDE HCV POLYMERASE INHIBITOR IN PATIENTS WITH CHRONIC HCV GENOTYPE-1 INFECTION
E.. Lawitz1, C. Cooper2, M. Rodriguez-Torres3, R. Ghalib4, R. Lalonde5, A. Sheikh6, B. Bourgault7, N. Chauret7, L. Proulx7, J. McHutchison8
1Alamo Medical Research, San Antonio, USA, 2The Ottawa Hospital, Ottawa, Canada, 3Fundacion de Investigacion de Diego, San Juan, 4The Liver Institute at Methodist Dallas, Dallas, USA, 5Royal Victoria Hospital, Montreal, Canada, 6Gastrointestinal Specialists of Georgia, Marietta, USA, 7ViroChem Pharma Inc., Laval, Canada, 8Duke Clinical Research Institute, Durham, USA
Background and aims: VCH-916 is a novel, non-nucleoside inhibitor of Hepatitis C virus RNA-dependent polymerase. It has demonstrated sub-micromolar IC50 against the HCV replicon of both genotypes 1a and 1b.
Methods: The study assessed the effect on viral kinetics, pharmacokinetics, safety and tolerability of VCH-916 given as monotherapy for 14 days (100 and 200 mg tid doses) and for 3 days (300 and 400 mg bid doses). Four cohorts of treatment-naive (n=38) or experienced (n=2) chronic hepatitis C subjects received either placebo (n=2) or active treatment (n=8) in each cohort. VCH-916 plasma levels were assessed over 6 hours for the tid doses on Day 1 and 14 and over 12 hours for the bid doses on Day 1.
Results: Forty subjects (82% genotype 1a) were enrolled and completed the study. The rate and extent of absorption appeared proportional between the selected doses. There was no plasma accumulation over 14 days of treatment. The maximal decline in log10 HCV RNA values ranged between 0.2-1.8 for the 100 mg tid, 0.4-2.1 for the 200 mg tid, 1.1-2..5 for the 300 mg bid and 0.6-2..3 for the 400 mg bid doses. The mean maximal decrease over 3 days of treatment was 0.6, 1.5, 1.5 and 1.5 log for the 100 and 200 mg tid doses and 300 and 400 mg bid doses respectively..
VCH-916 was well tolerated over 14 days with the most frequently reported adverse events (95% mild, 5% moderate) being gastrointestinal (35%) and CNS symptoms (25%) and throat irritation (20%). In the 300 and 400 mg bid 3-day cohorts, throat irritation and nausea were reported by 50% and 33% of subjects. No abnormal laboratory pattern or ECG abnormalities were observed..
Conclusions: VCH-916 displayed linear pharmacokinetics over the range studied with no accumulation upon repeated administration. The drug was well tolerated with no serious adverse events.. VCH-916 achieved a mean maximal log decline in HCV RNA of 1.5 log at doses of 200 mg tid and 300 and 400 mg bid over 3 days of monotherapy. Further development of this polymerase inhibitor in combination with other anti-HCV agents is being pursued.
EFFICACY AND SAFETY OF THE CYCLOPHILIN INHIBITOR DEBIO 025 IN COMBINATION WITH PEGYLATED INTERFERON ALPHA-2A AND RIBAVIRIN IN PREVIOUSLY NULL-RESPONDER GENOTYPE 1 HCV PATIENTS
D.R. Nelson1, R.H. Ghalib2, M. Sulkowski3, E.. Schiff4, V. Rustgi5, P.J.. Pockros6, C.. Wang7, G. Decosterd Kerhuel8, P. Grosgurin8, H. Porchet8, R. Crabbe8
1University of Florida, Gainesville, 2Methodist Transplant Physicians, Dallas, 3The Johns Hopkins University School of Medicine, Baltimore, 4University of Miami Center for Liver Diseases, Miami, 5Metropolitan Research, Fairfax, 6Scripps Clinic, La Jolla, 7Virginia Mason Medical Center, Seattle, USA, 8Debiopharm SA, Lausanne, Switzerland
Introduction: Debio 025 is a cylophilin inhibitor with potent anti-HCV effect in treatment-naive HCV patients.
Methods: We investigated different dosing regimens of Debio 025 (D25) in combination with pegylated Interferon alpha-2a (P) 180 microg/week and Ribavirin (R) 1000/1200 mg/day in genotype 1 chronic HCV patients that were previously null responders (< 2 log10 HCV-RNA reduction after 12 weeks P+R). Fifty patients were randomised in an open phase IIa study to receive one of five treatment regimens for 29 days.. Afterwards patients continued treatment on P+R.
Results: (ITT population)]
D25+P+R triple therapy demonstrated significant antiviral activity in previous null responders. By day 29, viral load was reduced by -1.96 log in group E (D25 400 mg OD with initial loading dose +P+R) and -2.38 log in group D (D25 800 mg OD +P+R). D25 monotherapy at a dose of 400 mg OD did not show antiviral activity in this population. Incremental antiviral activity was gained by adding P and P+R. The addition of a loading dose (400 bid for 7 days) in group E led to significant antiviral activity by day 29 that was 1.08 log greater than the non loading dose comparator arm A (p=0.033).
Safety: D25 treatment was well tolerated. Three out of 50 patients developed reversible increases of bilirubin resulting in hyperbilirubinaemia (Total bilirubin > 3 mg/dl, range 3.1 - 4.5).
Conclusion: Debio 025 at doses of 400 mg (with initial loading) and 800 mg daily for 29 days shows a significant reduction of HCV RNA when co-administered with Peg-IFN alpha-2a and Ribavirin in previous null responders. A loading dose of Debio 025 at the start of treatment accelerates the onset of action and enhances efficacy in the early stage of treatment.
EFFICACY AND SAFETY OF (Albuferon) ALBINTERFERON ALFA-2B IN COMBINATION WITH RIBAVIRIN IN TREATMENT-naive, CHRONIC HEPATITIS C GENOTYPE 1 (CHC G1) PATIENTS
S. Zeuzem1, M. Sulkowski2, E. Lawitz3, V. Rustgi4, Y. Lurie5, M. Grigorescu6, A. Muir7, P. Cronin8, E. Pulkstenis8, M. Subramanian8, J. McHutchison7
1W. Goethe-University Hospital, Frankfurt, Germany, 2Johns Hopkins University, Baltimore, 3Alamo Medical Research, San Antonio, 4Metropolitan Research, New York, USA, 5Sourasky Medical Centeris, Tel-Aviv, Israel,6Clinica Medicala III, Cluj-Napoca, Romania, 7Duke Clinical Research Institute, Chapel Hill, 8Human Genome Sciences, Rockville, USA
Background A phase 3, randomized, active controlled, multi-center study evaluated the efficacy and safety of albinterferon alfa-2b (albIFN), a genetic fusion polypeptide of albumin and interferon alfa-2b in CHC G1 patients.
Methods: In total, 1331 patients were randomized 1:1:1 to one of the 3 treatment groups: alb-IFN900µg q2weeks; alb-IFN1200 µg q2weeks; PEG-IFNα2a 180 µg q1week for 48 weeks, in combination with weight-based oral ribavirin 1000-1200 mg/day.. Randomization was stratified by baseline HCV RNA levels (≥ or < 800,000 IU/mL), BMI (≥ or < 25 kg/m2) and race (African-American or other). The primary end point was sustained virologic response (SVR), defined as serum HCV RNA < 10 IU/mL at week 72. The sample size provided 90% power to demonstrate non-inferiority with a margin of 12%. According to Data Monitoring Committee recommendation, all patients receiving alb-IFN 1200µg were reduced to 900µg q2weeks, which impacted 51% of this group.
Results: The study achieved the primary objective of demonstrating non-inferiority of albIFN 900µg (p=0.0008) and albIFN 1200µg (p=0.0029) versus PEG-IFNα2a for SVR. In the intention-to-treat population, SVR rates were 51.0% (225/441), 48.2% (213/442), and 47.3% (208/440) in the PEG-IFNα2a, albIFN900 and albIFN1200 groups respectively. Multivariate analysis identified the following predictors of SVR: HCV RNA < 400,000 IU/ml, age < 45, normal GGT, high ALT, F0-2 fibrosis, and race, consistent with previous studies. Safety analyses showed: 1) Rates of serious and/or severe adverse events (AE) were 23.1%, 24.0% and 28.2%; 2) Treatment discontinuations due to AEs were 4.1%, 10.4% and 10.0%; 3) Severe or serious pulmonary events were rare and blinded central review of Chest X-rays (n=753) during treatment showed comparable rates of interstitial lung findings: 4.2%, 2.4% and 4.5%; 4) Mortality rates of 1/441, 0/442 and 2/440 in the PEG-IFNα2a, albIFN900 and albIFN1200 groups, respectively. The rates of hematologic abnormalities were numerically lower in albIFN900 versus PEG-IFNα2a.
Conclusions: Albinterferon alfa-2b 900µg administered q2wk demonstrated comparable efficacy to PEG-IFNα2a in patients with chronic hepatitis C genotype 1. The overall incidence of adverse events, serious or severe adverse events was similar between these two treatments.
EFFICACY AND SAFETY RESULTS OF (Albuferon) ALBINTERFERON ALFA-2B IN COMBINATION WITH RIBAVIRIN IN INTERFERON-ALFA TREATMENT naive PATIENTS WITH GENOTYPE 2 OR 3 CHRONIC HEPATITIS C
D. Nelson1, Y. Benhamou2, W.L. Chuang3, E. Lawitz4, R. Flisiak5, M. Rodriguez-Torres6, V. Bain7, K. Patel8, P.W. Cronin9, E. Pulkstenis9, G.M. Subramanian9, J.G.. McHutchison8
1Hepatology and Liver Transplantation, University of Florida College of Medicine, Gainesville, USA, 2Dept of Hepatology and Gastroenterology, Hopital Pitie-Salpetriere, Paris, France, 3Kaohsiung Medical University Hospital, Kaohsiung, Taiwan R.O..C., 4Alamo Medical Research, San Antonio, USA, 5Wojewodzki Szpital Specjalistyczny, Biaystok, Poland, 6Gastroenterology, Fundacion de Investigacion de Diego, Santurce, USA,7Liver Unit, University of Alberta, Edmonton, Alberta, Canada, 8Duke Clinical Research Institute, Durham, 9Human Genome Sciences, Inc., Rockville, USA
Background and aims: A phase 3, randomized, active-controlled, multicenter study evaluated efficacy/safety of albinterferon alfa-2b (albIFN), a genetic fusion protein of albumin/IFN-α-2b, in treatment-naive patients with genotype 2/3 CHC.
Methods: Randomized 933 patients 1:1:1 to 1 of 3 treatment groups combined with oral ribavirin 800 mg/d: PEG-IFNα-2a 180µg qwk, or albIFN 900 or 1200µg q2wk for 24 weeks. Primary endpoint: sustained virologic response (SVR; HCV RNA < 10 IU/mL at week 48).. Sample size provided 90% power to demonstrate noninferiority (margin: 12%). Randomization stratified by baseline HCV-RNA levels (≥/< 800,000 IU/mL) and genotype 2/3. During the study, independent data monitoring committee (reviewing both ongoing phase 3 studies) recommended dose reduction for all patients receiving albIFN 1200µg to 900µg due to increased pulmonary events with 1200µg. Only 36% of patients in the 1200µg arm were still receiving drug at that time.
Results: Patient and viral characteristics were balanced across groups. Primary endpoint of SVR noninferiority: achieved for albIFN 900µg (P=..009) and 1200µg (P=.006). In the intention-to-treat population, SVR rates were 84.8%, 79.8%, and 80.0% for PEG-IFNα-2a, and albIFN 900 and 1200µg, respectively. SVR predictors: HCV RNA < 400,000 IU/mL, age < 45 years, BMI < 30, genotype 2, normal γ-glutamyl transpeptidase, high ALT, fibrosis score F0-2, and Asian region (latter for PEG-IFNα-2a only). Subgroup analysis showed SVR rates in Asian region (n=271) of 95.5%, 79.8%, and 81.8% for PEG-IFNα-2a, and albIFN 900 and 1200µg, respectively, vs 80.5%, 79.8%, and 79..3% in all other regions (n=662). Overall, safety/tolerability of albIFN was similar to PEG-IFNα-2a. Incidence of serious (7%-8%) or severe (13%-16%) AEs, or death (0.3%-0.6%), was similar across groups. Discontinuation rates due to AEs: 3.6%, 4.8%, and 5.5% for PEG-IFNα-2a, and albIFN 900 and 1200µg, respectively. Severe/serious pulmonary infections and interstitial lung disease were rare; rates were similar across treatment groups.
Conclusions: AlbIFN 900µg q2wk demonstrated comparable efficacy to PEG-IFNα-2a, and comparable rates of serious or severe adverse events and discontinuations due to adverse events in patients with genotype 2/3 CHC.
JTK-652 IS A NOVEL HCV ENTRY INHIBITOR: RESULTS OF A PHASE 1 STUDY EVALUATING SAFETY, TOLERABILITY AND ANTIVIRAL ACTIVITY IN CHRONIC HEPATITIS C PATIENTS
J. de Bruijne1, J.. Bergmann2, C. Weegink1, K. van Nieuwkerk3, R. de Knegt2, J. van de Wetering de Rooij4, A.. van Vliet4, R. Molenkamp5, J. Schinkel5, H. Reesink1, H. Janssen2 1Department of Gastroenterology and Hepatology, Academic Medical Center, University of Amsterdam, Amsterdam,2Department of Gastroenterology and Hepatology, Erasmus MC, University Medical Center, Rotterdam, 3Department of Gastroenterology and Hepatology, VU Medical Center, Amsterdam, 4PRA International, Zuidlaren, 5Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
Background JTK-652, a novel HCV entry inhibitor, showed potent inhibitory activity against HCV genotype 1a and 1b pseudotyped viruses bearing HCV E1E2 envelope proteins in HepG2 cells and human primary hepatocytes.. Treatment with single ascending doses of JTK-652 or placebo (6:3 ratio), ranging from 100 mg to 1200 mg, was safe and well tolerated in 18 healthy male subjects. Treatment with multiple ascending doses of 400 mg (n=9) and 800 mg (n=9) JTK-652 TID or placebo (6:3 ratio) for 14 days was safe and well tolerated in 8/12 healthy male subjects.. Four subjects (400 mg, n=1; 800mg, n=3) developed an almost generalized drug eruption of mild intensity. This study evaluated safety, tolerability, pharmacokinetics and antiviral activity of JTK-652 in HCV genotype 1 infected patients.
Methods: The study was randomized, double blind and placebo controlled. Ten HCV genotype 1 infected patients (naive (n=2) and treatment-experienced (n=8), HCV RNA ≥ 10e5 IU/mL) received an oral dose of 100 mg JTK-652 TID or placebo (8:2 ratio) for 4 weeks.
Results: Eight patients completed the study (7 active, 1 placebo).. Premature discontinuation occurred in 2 patients (1 active, 1 placebo) on day 13 and day 19, respectively, due to an almost generalized drug eruption of mild intensity. This rash disappeared within days after stopping JTK-652 administration and additional treatment was not necessary. No other clinically significant adverse events (AEs) were considered to be related to study drug administration. No significant clinical laboratory, vital signs, ECG or physical examination abnormalities were observed.. JTK-652 was found to be well tolerated, all AEs were mild in severity. At day 29 (end of treatment) no significant changes in HCV RNA compared to baseline were observed in the individual patients; mean HCV RNA change from baseline was + 0.19 IU/mL at end of treatment.
Conclusion: Results from this phase 1 study indicated that, beside a mild drug eruption in 1 patient, JTK-652 was safe and well tolerated at a 100 mg TID dose level. However, plasma HCV RNA levels did not decline during 28 days of dosing. Further development of this compound was stopped.
VIRAL KINETIC MODELING DURING TREATMENT WITH INTERFERON LAMBDA-1A IN GENOTYPE 1 CHRONIC HEPATITIS C PATIENTS
M.G. Dodds1, D.F. Hausman2, D.M. Miller1 1Preclinical Development, 2Clinical Development, ZymoGenetics, Inc, Seattle, WA, USA
Background and aims: Peginterferon lambda-1a (PEG-IFN-λ1a) is a novel Type III interferon that binds to a unique cell surface receptor and induces an intracellular antiviral response similar to that induced by IFN-α. As the expression of the IFN-λ receptor is more limited than the IFN-α receptor, we hypothesize that treatment of chronic hepatitis C (CHC) with PEG-IFN-λ1a will result in fewer toxicities and an improved therapeutic index. As part of ongoing trial in treatment-relapsed chronic hepatitis C patients, changes in viral mRNA were analyzed using a mathematical model to assess the dose-response relationship of PEG-IFN-λ1a.
Methods: Models assuming constant drug effectiveness have been shown to successfully predict plasma HCV mRNA decline in patients after IFN-α therapy. One such model was fit to patient data from the following treatment cohorts: 1.5 mcg/kg PEG-IFN-λ1a QW with and without standard Ribavirin therapy for four weeks. The model describing viral mRNA concentrations over time after an initial rapid decline, V(t), is: V(t)=(1-ε)*V0*exp(-ε*σ*t) where V0 is pre-treatment viral mRNA concentration (copies/mL); ε is the constant drug effectiveness (%); σ is the clearance rate constant of productively infected hepatocytes (1/day); t is time (day).
Results: Patient viral kinetics were compatible with the existing model previously developed for IFN-α's. In the cohort treated with 1..5 mcg/kg PEG-IFN-lλa alone QW for four weeks, constant drug effect estimates ranged from 45.3 to 98.6%, which are comparable to pegylated IFN-α therapy estimates. Data from later cohorts will be presented.
Conclusions: Model estimates after PEG-IFN-λ1a therapy are in agreement with IFN-α therapy estimates, supporting the idea of a common mechanism of action. Model estimates at well-tolerated doses of PEG-IFN-λ1a, as demonstrated in the ongoing clinical trial, are similar to reported pegylated IFN-α therapy estimates. More complex models that link drug serum concentration to effect (PK/PD models) are in development.
NOVEL GLUCOSIDASE INHIBITORS WITH ANTI-HBV AND ANTI-HCV ACTIVITY
C. Chapel1, E. Samuel1, P. Compain2, J. Blu2, C. Alotte1, B. Bartosch3, C. Trepo3, F. Zoulim3, D. Durantel3 1Unit 871, INSERM/Universite de Lyon, Dardilly, 2ICOA, ICOA/UMR6005, Orleans, 3Unit 871, INSERM/Universite de Lyon/HCL, Dardilly, France
Background/ aims: Glucosidase inhibitors (Gluc-I) have antiviral properties against hepatitis B and C viruses. We have previously shown that glucosidase inhibitors derived from glucose (i.e. deoxynojirimycin (DNJ) derivatives) could inhibit HBV and HCV morphogenesis in cellulo via the inhibition of ER-glucosidases resulting in the perturbation of the folding and assembly of viral envelope glycoprotein. A pro-drug of castanospermine, another potent Gluc-I, has proven beneficial activity in a phase-II clinical trial on HCV-infected patients in combination with Peg-IFN/ribavirin. One of the main side effects of Gluc-I results from the inhibition of gastrointestinal (GI) osidases. Therefore the development of Gluc-I with a better selectivity toward ER-glucosidases would be of interest. Here we report the anti-HBV and anti-HCV activity of two alpha-1-C-alkyl-1-deoxynojirimycin derivatives, i.e. butyl and nonyl forms, (CB-DNJ and CN-DNJ), which differ from N-butyl-DNJ (NB-DNJ) and N-nonyl-DNJ (NN-DNJ) by the position of the alkyl chain on the ring. Indeed, the alkyl chain was displaced from the nitrogen atom to the carbon C1 of the sugar ring to decrease the steric obstruction around the positive charge of the nitrogen atom.
Methods: We have used BVDV, HCVpp, and HCVcc models, as well as HepG2.2.15 cells or HBV-transfection systems to determine anti-HCV and anti-HBV activities.
Results: We showed that CB-DNJ and CN-DNJ have similar EC50 and CC50 than NB-DNJ and NN-DNJ against BVDV, HBV and HCV, while displaying slightly reduced EC90. As previously shown, we confirmed that the antiviral effect was not due to the inhibition of genome synthesis, but was rather due to the inhibition of morphogenesis, secretion and infectivity of viruses. The reduced EC90 of CB-DNJ and CN-DNJ derivatives over parental molecules was due to a reduced inhibition of ER-glucosidases in cellulo.
Conclusion: We have evaluated in cell culture the anti-HBV and anti-HCV properties of new glucosidase inhibitors that have different selectivity patterns against GI-related osidases compared to previously studied DNJ derivatives. The new molecules were found slightly less active than parental molecules.. This was due to lower inhibition of ER-glucosidases. The research of novel glucosidase inhibitors with improved selectivity towards ER glucosidases should be pursued.
PK/PD ASSESSMENT OF A PHASE 1 HEALTHY VOLUNTEER STUDY WITH ANA773, AN ORAL PRODRUG OF A TLR7 AGONIST FOR THE TREATMENT OF HCV
S. Fletcher, L. Bauman, B. Eam, M. Sergeeva, O. Khatsenko, T. Harding, M. Rahimy, J. Freddo, J. Appleman Anadys Pharmaceuticals, San Diego, CA, USA
Background ANA773 is an oral prodrug of a small-molecule TLR7-selective agonist discovered at Anadys Pharmaceuticals. Based on preclinical studies with ANA773 demonstrating pharmacologic activity that supports the potential utility of ANA773 in HCV, a clinical study was conducted to investigate the pharmacokinetics (PK), pharmacodynamics (PD) and safety of ANA773 in healthy volunteers.
Methods: ANA773 was investigated in a double-blind, placebo-controlled, dose escalation study composed of five dose groups (200, 400, 800, 1200 and 1600 mg). In each group, 6 subjects received oral ANA773 and 2 received placebo. Subjects typically received a single dose of ANA773, followed by a 14-18 day rest period, and were then dosed with ANA773 every other day for 7 days (4 doses).
Results: ANA773 was rapidly converted to the active metabolite with the Cmax of the latter occurring typically within 1.5 hours after administration. Plasma exposure of the active metabolite was approximately dose proportional and, consistent with its short t1/2, there was no evidence of accumulation. There were dose-related increases in various markers of interferon-α (IFN-α) response after administration of ANA773. Notably, significant induction of oligoadenylate synthetase (OAS) activity, neopterin and whole blood OAS1 and ISG15 mRNA levels were observed in most subjects receiving 800 mg or greater. In contrast, substantial levels of circulating IFN-α were seen in only a few subjects confined to the 1200 mg and 1600 mg groups. Importantly, the pharmacologic response to ANA773 continued on off-dosing days and was of comparable magnitude following each dose during the multi-dose phase. ANA773 was generally well tolerated with adverse events (AEs) increasing in frequency and intensity with increasing dose. Mild to moderate AEs were reported, with a few subjects reporting flu-like symptoms in the higher dose groups. No serious AEs were reported.
Conclusions: Oral ANA773 was efficiently converted to the active metabolite, induced a dose-related IFN-dependent response and was typically well tolerated in healthy volunteers. These findings, in conjunction with pharmacologic and toxicologic data from animal studies, justify clinical exploration with ANA773 in patients with chronic HCV infection. Accordingly, a trial with ANA773 in HCV infected patients is currently in progress.
PK-PD MODELING OF VIRAL KINETICS DURING TREATMENT WITH DEBIO-025 PLUS PEGYLATED INTERFERON ALPHA-2A IN TREATMENT-naive HCV PATIENTS
E. Herrmann1, A. Kafer1, R. Flisiak2, V. Nicolas-Metral3, S. Zeuzem4, R. Crabbe3 1Institute of Biostatistics and Mathematical Modeling, Department of Medicine, J.W. Goethe-University Frankfurt, Frankfurt/Main, Germany, 2Department of Infectious Diseases, Medical University of Bialystok, Bialystok, Poland,3Debiopharm SA, Lausanne, Switzerland, 4Department of Internal Medicine I, J.W. Goethe Univeristy Hospital, Frankfurt/Main, Germany
Background Debio 025 is an oral cyclophilin inhibitor with a potent anti-HCV activity in vitro and in vivo. Its effect on HCV viral load in combination therapy with pegylated interferon alfa-2a (Peg-IFN) was investigated in a randomized, double-blind, placebo-controlled phase II study in 90 treatment-naive HCV patients.
Methods: Patients received Peg-IFN plus placebo or Debio 025 with doses ranging from 200 to 1000 mg/day or Debio 025 1000 mg/day monotherapy. Debio 025 was administered BID for 1 week then QD for 3 weeks. Detailed pharmacokinetics of Peg-IFN and Debio 025 was available in 46 and 50 patients, respectively, whereas for the others pharmacokinetics was predicted from trough levels. Viral kinetics was then analysed using a full PK-PD model approach of antiviral efficiency of both, PEG-IFN and DEBIO 025, to assess mean and maximum efficiency of both compounds besides other viral kinetic parameters..
Results: Viral kinetics revealed a significant dose-dependent additive anti-viral effect of Debio 025 which enhanced overall mean and maximum treatment efficiency (p=0.004 and p< 0..001, see Figures). Furthermore, time during 4 weeks of treatment with antiviral efficiency greater than 90% and greater than 95% increased from 62% to 78% and from 42% to 73%, respectively, in Peg-IFN+Placebo arm to the Peg-IFN + Debio 025 1000 mg arm (p=0.008 and p=0.002). Viral kinetics does not indicate upcoming resistance against Debio 025.
Conclusions: Debio 025 showed an important dose-dependent additive anti-viral effect in combination with Peg-IFN in treatment-naive HCV patients.
A NEWLY SYNTHESIZED SERINE PALMITOYLTRANSFERASE INHIBITOR, NA 808, HAS THE STRONG EFFECT TO HEPATITIS C VIRUS IN VITRO AND IN VIVO
Y. Hirata1,2, M. Sudoh3, T. Tsukuda3, K. Ikeda4, R. Taguchi4, K. Inoue2, M. Yoshiba2, M. Kohara1 1Department of Microbiology and Cell Biology, The Tokyo Metropolitan Institute of Medical Science, Tokyo, 2Department of Gastroeterology, Showa University Fujigaoka Hospital, Yokohama, 3Kamakura Research Laboratories, Chugai Pharmaceutical Co., Ltd., Kamakura, 4Department of Metabolome, The University of Tokyo, Tokyo, Japan
There are many anti-hepatitis C(HCV) drugs under the clinical development. But almost all targets are viral factors, hence these drugs produce the emergence of resistance mutations. To discover new anti-HCV agents, we focused on host factors as the target of anti-HCV agents, which contribute to HCV replication.
We identified serine palmitoyltransferase (SPT) inhibitor as anti-HCV agent through high through-put screening program using HCV replicon cells. Now, we synthesized NA808, a new SPT inhibitor, toward clinical development. Moreover, we evaluated the anti-HCV effect of NA808 in vivo using humanized chimeric mice infected with HCV genotype 1a or 2a. In HCV genotype 1a, NA808 led to rapid decline in serum HCV-RNA of about 1-2.5 log within 14 days, while PEG-IFNα-2a dosing at 30ug/kg twice a week achieved less than 1log for 14 day. Furthermore, the combination therapy of NA808 and PEG-IFN achieved over 4 log reduction in serum HCV-RNA. In HCV genotype 2a, NA808 led to rapid decline in serum HCV-RNA of about 3log within 14 days. Also we confirmed the decline of HCV-RNA and the level of HCV core protein in the liver was consistent with the serum level.
Finally, we investigated the mechanism of anti-HCV effect of NA808. It has been reported that sphingolipids and cholesterol compose the lipid raft, in which the replication of HCV occur. We evaluated the influence of NA808 to lipid raft. The analysis proved that NA808 decrease NS5B in lipid raft via decline of sphingomyelin.
Our results indicate that the new SPT inhibitor has strong efficacy to suppress of HCV via affecting the replication machinery.
SILIBININ INHIBITS HCV REPLICATION IN VITRO
I. Najera1, M. Mc Cown1, V. Leveque1, J. Hang1, H. Ma1, S. Rajyaguru1, A. Fung1, Y. Yang1, Y. Liu1, S. Kular1, N. Cammack1, P. Ferenci2, K. Klumpp1 1Roche, Palo Alto, CA, USA, 2Medical University of Vienna, Vienna, Austria
Background Intraveneous Legalon-silibinin (SIL) was recently reported as a potent antiviral agent in HCV infected persons. SIL monotherapy at 20 mg/kg resulted in significant viral load reduction in prior non-responders to pegylated interferon and ribavirin therapy (VL reduction of 3.0 ± 1.0 log IU/ml after 7 days). Antiviral potency of SIL was further increased in combination with pegylated interferon and ribavirin (VL reduction of 4.8 ±0.9 log IU/ml after 7 days).. The mechanism of action of SIL remained unresolved.
Methods: We determined the inhibitory activity of SIL and structurally related analogs in a number of HCV in vitro assay systems including subgenomic replicon, GT-1a infectious virus replication (HCVcc), HCV entry (HCVpp), RNA polymerase, protease and helicase. In addition, in vitro selection of SIL resistant replicons was performed.
Results: SIL inhibited HCV replication in the genotype 1a and 1b replicon systems with similar potency and IC50 values in the low micromolar range. SIL was not cytotoxic (CC50 >100 µM) or cytostatic (3H-Thy iincorporation IC50 >100 µM) at these concentrations. SIL also inhibited HCV replication in the GT 1a infectious virus assay assay (H77-HCVcc), but did not inhibit HCV entry in either the genotype 1a or 1b cell HCVpp systems, consistent with SIL targeting HCV replication. Among the HCV replication targets, HCV protease and helicase activity were not affected by SIL, whereas RNA-dependent RNA polymerase NS5B was moderately sensitive to inhibition by SIL (IC50 = 50 ± 7.6 µM). SIL interfered with NS5B-RNA interaction, whereas preformed NS5B-RNA complexes were resistant to inhibition by SIL, a profile different from that obtained with most current non-nucleoside inhibitors of NS5B. Characterization of SIL analogs suggested structural features important for HCV replication inhibition. Results from the in vitro selection of SIL resistant replicon variants will be available and discussed at the time of presentation.
Conclusions: HCV replication was identified as a target of SIL. The ability of SIL to inhibit HCV RNA synthesis by HCV polymerase NS5B was consistent with inhibition of HCV replicon and HCV infectious virus replication in vitro, whereas HCV entry was not affected by the presence of SIL.
INTRAVENOUS SILIBININ AS "RESCUE TREATMENT" FOR ON TREATMENT NONRESPONDERS TO FULL DOSE OF PEGINTERFERON / RIBAVIRIN COMBINATION THERAPY
K. Rutter1, S. Beinhardt1, H... Kerschner2, T.M. Scherzer1, H.. Hofer1, T. Popow-Kraupp2, P. Steindl-Munda1, P. Ferenci1
1Internal Medicine III, Dpt of Gastroenterology and Hepatology, Medical University of Vienna, 2Clinical Virology, Medical University of Vienna, Vienna, Austria
Background Silibinin (SIL) given intravenously at a dose of 20 mg/kg/day for 14 days had marked antiviral properties in nonresponders to full dose of peginterferon/ribavirin (SOC) combination therapy with chronic hepatitis C (Ferenci et al, Gastroenterology 2008). This confirms the in vitro findings that SIL inhibited viral replication. In this study we extended this treatment approach to on treatment nonresponders, defined as having detectable HCV-RNA after at least 24 weeks of SOC.
Methods: Nine patients HCV-RNA on treatment with 180 µg peginterferon-alfa2a (Pegasys®) and 1000-1200 mg ribavirin (Copegus®)/d who were still HCV-RNA positive after 24 weeks (mean age: 53 ± 6.6 years; male/female: 5/4; genotype 1:7, 3a:1, 4:1; liver fibrosis F4:6, F3:1, n.a.:2) were investigated. Seven patients were treatment naive, 2 had a previous therapy (one nonresponder, one patient had relapsed twice after 24 weeks therapy). After completing at least 24 weeks of SOC therapy patients received additionally 20 mg/kg/d Silibinin (Legalon-SIL®, Rottapharm-Madaus, Monza, Italy) intravenously for 15 days. Thereafter peginterferon/ribavirin was continued. At the time of writing, all 9 patients are still on therapy. HCV-RNA was quantified by TaqMan® (Roche Diagnostics, USA) at monthly intervals on standard treatment and weekly after starting SIL treatment.
Results: On peginterferon/ribavirin HCV-RNA was quantifiable with a median log drop of 2.3 (range 0.4-5.7) at week 24. Two patients had a detectable but unquantifiable HCV-RNA (< 15 IU/mL). After 15 days of intravenous SIL therapy HCV-RNA decreased in all patients and 7 out of the 9 patients had undetectable HCV-RNA. After the end of SIL administration patients were followed for at least 12 weeks.. In one patient HCV-RNA increased to 100 IU/ml, and a second course of intravenous SIL for 15 days was given. HCV-RNA became negative again and remained negative so far. All patients are still on standard of care treatment. Treatment was well tolerated.
Conclusion: Intravenous silibinin is an effective "rescue treatment" for on treatment nonresponders to full dose of peginterferon/ribavirin combination therapy..
2'-DEOXY-NUCLEOSIDE ANALOGS AS POTENT DUAL INHIBITORS OF HCV AND HIV REPLICATION, WITH SELECTIVITY AGAINST OTHER VIRAL AND HUMAN POLYMERASES
K. Klumpp1, G. Su2, J. Deval1, V. Leveque1, A.. Jekle1, S. Rajyaguru1, P. Gee1, Y. Li1, J. Hang1, H.. Ma1, N. Inocencio1, G. Kalayanov3, A. Winqvist3, D. Smith1, N. Cammack1, N.G.. Johansson3, G. Heilek1, I. Najera1 1Roche, Palo Alto, 2Rigel Pharmaceuticals, South San Francisco, CA, USA, 3Medivir AB, Huddinge, Sweden
Background HCV polymerase and HIV reverse transcriptase (RT) have both been shown to accept modified deoxynucleoside analogs as substrates, suggesting the possibility that nucleoside analogs may be designed that inhibit both the RNA polymerase of HCV and the DNA polymerase of HIV-RT, while retaining high selectivity against human RNA and DNA polymerases. Such compounds may provide specific benefit in HCV/HIV co-infected persons by reducing the overall drug burden in combination therapies.
Methods: Nucleoside analogs were tested for antiviral activity and cytotoxicity using Con1 HCV subgenomic replicon in Huh-7 cells, HXB2 HIV-1 in MT-4 cells and Dengue virus replication in Huh-7 cells. Nucleoside triphosphate analogs were tested as inhibitors of viral and human RNA and DNA polymerases including HCV NS5B, Dengue and West Nile virus NS5, HIV-1 reverse transcriptase, CMV DNA polymerase and human mitochondrial DNA polymerase gamma.
Results: Screening of a series of nucleoside analog inhibitors ofHCV replication for inhibition of HIV-1 replication identified novel cytidine analogs with superior anti-HIV potency as compared to reference compounds 3TC (IC50 = 2.5 ± 1.2 µM), FTC (IC50 = 0.43 ± 0..17 µM) and AZT (IC50 = 0.095 ± 0.028 µM). The most potent compound RO-0622 inhibited HCV replicon replication (IC50 = 24 ± 3.0 nM) and was thus 50-fold more potent than R1479 (4'-azido-cytidine). RO-0622 inhibited HIV-1 replication in MT-4 cells with an antiviral IC50 of 0.4 ± 0.1 nM, and was therefore more than 6000-fold more potent than 3TC. RO-9187 also inhibited both HCV (IC50 = 171 ± 12 nM) and HIV-1 replication (IC50 = 49 ± 27 nM). Both compounds were not cytotoxic or cytostatic in HCV replicon cells and protected HIV-1 infected cells from HIV-induced cell death. The corresponding nucleoside triphosphates were competitive inhibitors of HCV and HIV polymerases, but were highly selective against human polymerases as well as other viral polymerases, consistent with low toxicity in cell culture.
Conclusions: Novel nucleosides have been identified that can inhibit both HCV and HIV replication with higher potency as compared to reference compounds 3TC, FTC, AZT or R1479, while retaining selectivity against human and other viral polymerases.
NO EVIDENCE OF R7128 DRUG RESISTANCE AFTER UP TO 4 WEEKS TREATMENT OF GT 1, 2 AND 3 HEPATITIS C VIRUS INFECTED INDIVIDUALS
S. Le Pogam1, A. Seshaadri1, A. Kosaka1, S. Hu1, A. Beard2, S. Julian1, C. Nick1, I. Najera1 1Roche Palo Alto LLC, Palo Alto, CA, 2Pharmasset, Princeton, NJ, USA
Background and aims: R7128, a prodrug of PSI-6130, has demonstrated antiviral efficacy after 2 weeks' monotherapy in treatment-experienced HCV GT-1-infected patients and after 4 weeks therapy in combination with pegylated interferon alpha 2a and ribavirin in GT-1 infected treatment-naive patients and in GT-2/3 infected treatment-experienced patients. The aim of the study was to i) monitor the emergence of drug resistance to R7128 in vivo, ii) determine whether the NS5B S282T substitution exists in the patient's quasispecies at low frequency (clonal analysis), iii) determine the frequency of S282T in a patient's quasispecies necessary to observe a decrease in PSI-6130 sensitivity.
Methods: Viral resistance monitoring was performed by sequence (population and clonal studies) and phenotypic analysis of the NS5B gene from isolates at baseline and at on-treatment time points. The S282T mutation was introduced into NS5B clinical isolates at different ratios of wild-type / S282T replicons to determine their effect on PSI-6130-sensitivity.
Results: Population sequence analysis of the NS5B region revealed no evidence of the S282T resistance mutation. NS5B quasispecies sequence information from 42 GT-1 infected patients (3400 NS5B sequences from untreated patients and 800 from patients undergoing R7128 treatment) showed no S282T variants. All NS5B isolates from on-treatment time points were sensitive to inhibition by PSI-6130. In vitro studies showed that NS5B S282T confers a low replication capacity and a low level of resistance regardless of the genetic background it is engineered into. Mutant S282T needs to be present at a high proportion in the viral population in order to observe a decrease in PSI-6130 sensitivity.
Conclusions: No evidence for the development of viral resistance to R7128 after 2 weeks or 4 weeks of therapy was observed. No S282T variants were found in any treatment-naive or R7128 treated patients at population or quasispecies level, confirming clinically the high genetic barrier of this nucleoside polymerase inhibitor in short-term studies. Given the low replication capacity of the S282T in vitro engineered mutant, and the low level of phenotypic resistance it confers, it is likely that S282T variants must become predominant in the viral population to observe a clinically-relevant decrease in PSI-6130 sensitivity.
GENOTYPIC AND PHENOTYPIC ANALYSIS OF HCV NS5B VARIANTS SELECTED FROM PATIENTS TREATED WITH VCH-916
O. Nicolas, I. Boivin, A. Berneche-D'Amours, P. Fex, F. Denis, S. Selliah, J. Bedard Virology, ViroChem Pharma Inc., Laval, QC, Canada
Background VCH-916 is a orally bioavailable non-nucleoside inhibitor of HCV NS5B. In genotype 1 subjects, a ≥ -1.2 log in HCV RNA was obtained at 200 mg tid for 14 days or at 300 and 400 mg bid for 3 days. An initial rapid reduction of viral load was observed in all subjects receiving VCH-916 except in the 100 mg tid (14-day dosing) regimen. No viral rebound was observed in the 300 and 400 mg bid groups whereas a subset of the 200 mg tid cohort experienced viral breakthrough. The aim of this study was to genotypically and phenotypically characterize selected resistant variants and to investigate potential viral kinetics correlation.
Methods: Plasma was collected at day 1 (pre-dosing), day 15 (day after last dose), day 28, and 84, 140 and 196 (selected subjects) for the 100 and 200 mg tid groups. Samples from the 300 and 400 mg bid cohorts were collected at day 1 (pre-dosing), day 4 (day after last dose), and day 17. The NS5B region corresponding to the compound binding pocket (amino acids 340-539) was amplified, cloned, and sequenced. The drug susceptibility and fitness of the variants were performed using the HCV replicon system.
Results: Sequencing from the 100 mg tid cohort revealed a mixture of wild-type, L419M and M423T/V/I substitutions at days 15 and 28, whereas the L419S/M, M423T/V/I, I482L and V494A substitutions were found in the 200 mg tid group. These variants were associated with 6 to 62-fold increase in EC50 values vs wild-type replicon. All selected variants had a reduced replication capacity relative to wild-type in a transient replicon assay. No variants were detected from the 300 and 400 mg bid cohorts at days 4 and 17.
Conclusions: HCV variants conferring resistance were selected during the course of dosing with VCH-916 over a 14-day period. No variants were observed in the 300 and 400 mg bid regimens dosed over 3 days. This study illustrates that VCH-916 should be used in combination to maintain viral suppression and prevent emergence of resistance.
SAFETY AND A ANTIVIRAL ACTIVITY OF A MONOTHERAPY WITH A MP-424 FOR 24 WEEKS IN naive PATIENTS WITH CHRONIC HEPATITIS C VIRUS GENOTYPE 1B INFECTION
I. Ozeki Gastroenterology, Sapporo Kosei General Hospital, Sapporo, Japan
Background MP-424 (telaprevir) is a novel, highly selective inhibitor of HCV NS3/4A protease with potent antiviral activity. Prior studies have indicated that short-term dosing (14 days) with telaprevir can show a strong antiviral effect against the hepatitis C virus. This study is the first reported to extend dosing period to 24 weeks, allowing the assessment of safety, antiviral activity and clonal sequencing of NS3 protease domain.
Methods: 5 naive patients were treated with MP-424 monotherapy and received at 750 mg every 8 hours for up to 24 weeks. All patients had a chronic infection with HCV genotype 1b and baseline serum HCV RNA levels of at least 1x105IU/ml. Quantitative measurement of serum HCV RNA levels was performed with the Cobas TaqMan assay. Sequence analysis was performed using clonal sequencing method. We evaluated antiviral effects and observed evolutional substitutions at HCV NS3 protease domain. Patients who met the definition of viral breakthrough (>2-log increase in HCV RNA above nadir) discontinued MP-424 dosing.
Results: All patients had at least a 2-log10 decrease from baseline in HCV RNA during the first 2 days of dosing. At 8 week, two of the 5 patients achieved undetectable HCV RNA levels and complete dosing for 24 weeks. However, HCV RNA levels were detectable at end of dosing in all patients. The other 2 patients had met a viral breakthrough and discontinued MP-424 dosing at day 43 and 105. In the remaining 1 patient, discontinued due to a pruritic rash at day 43. In four patients, amino acid substitutions at the NS3 serine protease domain were detected at days of 8,15 and 169. The most common adverse events included rash, anemia, gastrointestinal events. After a withdrawal of MP-424, all patients were treated with peginterferon alfa-2b and ribavirin and is now evaluating for treatment outcomes.
Conclusions: MP-424 produced rapid reduction in HCV RNA levels. However, none of the patients showed a continued decline in HCV RNA levels toward the end of dosing.. The addition of other antiviral agents to MP-424 treatment may be necessary to achieve a sustained viral response.
INCIDENCE OF VIROLOGIC ESCAPE OBSERVED DURING ITMN-191 (R7227) MONOTHERAPY IS GENOTYPE DEPENDENT, ASSOCIATED WITH A SPECIFIC NS3 SUBSTITUTION, AND SUPPRESSED UPON COMBINATION WITH PEGINTERFERON ALFA-2A/RIBAVIRIN
C. Sarrazin1, J. Hong2, S. Lim2, X. Qin2, S. Susser1, B.. Bradford2, S. Porter2, S. Zeuzem1, S. Seiwert2 1J..W. Goethe Universitat, Frankfurt, Germany, 2Intermune, Inc., Brisbane, CA, USA
Background In a phase 1 multiple ascending dose study in genotype-1 chronic HCV patients, 14 day treatment with the NS3 protease inhibitor ITMN-191 alone was safe, well tolerated, and resulted in multi-log10 HCV viral load reductions. Combination of ITMN-191 with peginterferon alfa-2a/ribavirin (SOC) for 14 days resulted in HCV RNA below quantification (< 25 IU/mL) in the majority of all treated patients in q12h and q8h cohorts to date.
Methods: Virologic response (VR) patterns were defined by end of treatment (EOT) and nadir HCV RNA. NS3 protease domain was amplified and population sequenced. Amplicons were inserted into a novel NS3 phenotyping vector and used for clonal sequencing.
Results: Patients receiving ITMN-191 as monotherapy (n=40) displayed continuous decline, plateau, and breakthrough VR profiles. Genotype-1b patients experienced breakthrough less frequently than genotype-1a patients (4/24 or 17% vs. 10/16 or 63%, respectively). By population analysis, all 10 genotype-1a breakthrough patients carried R155K at EOT. R155K was observed in all 4 genotype-1b breakthrough patients, but in 3 the population analysis evidenced a complex R155 substitution pattern. Clonal sequencing in these patients indicated R155K was dominant, but R155Q and other less frequent R155 variants were present. NS3 substitutions observed in vitro were absent in breakthrough patients- with the notable exception of D168E in a single genotype 1b breakthrough patient who also displayed the most complex substitution pattern.. Importantly, virologic breakthrough was not observed in either genotype when ITMN-191 was combined with SOC.
Conclusions: The scope of NS3 substitutions allowing virologic escape appears to be largely restricted to R155K in patients receiving ITMN-191 monotherapy, which is consistent with previous in vitro studies and in contrast to the numerous paths to viral breakthrough associated with telaprevir monotherapy. The lower incidence of viral escape in genotype-1b patients compared to genotype-1a may relate to the higher genetic barrier to R155K in genotype-1b (2 rather than 1 nucleotide substitutions required). Of most clinical relevance, combination with SOC prevented viral breakthrough in all patients studied to date. Thus, while R155 substitution is observed in some patients receiving ITMN-191 monotherapy and is associated with virologic escape, combination with SOC abrogates virologic escape.
IDX184, A LIVER-TARGETED NUCLEOTIDE HCV POLYMERASE INHIBITOR: RESULTS OF A FIRST-IN-MAN SAFETY AND PHARMACOKINETIC STUDY
X.-J. Zhou, K. Pietropaolo, J. Sullivan-Bolyai, B. Kuca, W. Liu, L. Xu, B. Belanger, S. Khan, D. Mayers Idenix Pharmaceuticals, Inc., Cambridge, MA, USA
Background and aims: IDX184 is a liver-targeted nucleotide prodrug designed to enhance formation of its active triphosphate in the liver, while minimizing systemic exposure to the parent drug and its nucleoside metabolite (NM). Multilog viral load reductions were observed in HCV-infected chimpanzees receiving 10 mg/kg IDX184 for 3 days. This first-in-man study investigated single ascending dose safety and the pharmacokinetics of IDX184.
Methods: Single ascending oral doses of 5, 10, 25, 50, 75 and 100 mg IDX184 were administered sequentially to cohorts of 8 healthy subjects randomized 6:2, active:placebo. Plasma levels of IDX184 and NM were quantitated using a validated LC-MS/MS methodology.
Results: IDX184 was rapidly absorbed (median Tmax: 0.25-0.5 h) and eliminated (mean t1/2: 0..6-1 h). Plasma concentrations of NM increased gradually (median Tmax: 4-6 h). Plasma exposure of IDX184 and NM was low and dose-related: the respective mean Cmax values ranged from 1.1 to 17 and 1.7 to 19 ng/mL, and mean total AUC values ranged from 1.2 to 22.7 and 17.3 to 334 ng*h/mL. Mean NM plasma concentrations 24 h after dosing were 0.6-3 ng/mL for 25-100 mg doses. Mean t1/2 for NM ranged from 18 to 43 h for doses ≥ 25 mg.IDX184 was well tolerated with no discontinuations, SAEs, dose-limiting toxicities, or dose-dependence of AEs. Overall, the incidence of AEs and laboratory abnormalities was low and similar among subjects receiving IDX184 or placebo. Dizziness was the most common AE which occurred more frequently in placebo subjects. All AEs were mild to moderate and resolved at the end of study.
Conclusions: IDX184 appeared to be safe and well tolerated in this study.. Consistent with a liver-targeting approach, systemic exposure of parent drug and metabolite was low. Importantly, systemic levels of NM obtained with 25 to 100 mg doses of IDX184 in this study are comparable to those associated with potent antiviral effects in HCV-infected chimpanzees. The favorable safety and pharmacokinetic profiles warrant further clinical development of IDX184 in HCV-infected patients.
GENOTYPIC CHARACTERISATION OF HCV NS5B FOLLOWING 8-DAY MONOTHERAPY WITH THE POLYMERASE INHIBITOR PF-00868554 IN HCV-INFECTED SUBJECTS
P. Troke1, M. Lewis2, P. Simpson2, E. van der Ryst3, J. Hammond4, C. Craig1, M. Perros1, M. Westby1 1Antivirals, 2Experimental Biological Sciences, 3Clinical Development, Pfizer Global Research and Development, Sandwich, UK, 4Clinical Development, Pfizer Global Research and Development, New London, CT, USA
Background PF-00868554 is a novel, potent, non-nucleoside inhibitor of the HCV NS5B polymerase. PF-00868554 inhibits genotype 1 replicons in vitro (59 nM mean EC50). Changes at amino acid 423 were the predominant mutation encoded by resistant variants generated during in vitro passage experiments. Mean maximum reductions (log10) in HCV RNA of 0.97, 1.84, 1.74, and 2.13 were achieved in HCV-infected subjects following 8 days of monotherapy with PF-008686554 at doses of 100, 300 or 450 mg BID and 300 mg TID, respectively. Changes of NS5B genotype following short-term monotherapy are described.
Methods: Study A8121002 was a double-blind, placebo-controlled monotherapy study in subjects infected with genotype 1 HCV.. Four cohorts of 8 subjects were randomized (6:2) to receive oral doses of PF-00868554, or placebo, for 8 days. Plasma samples for virologic analysis were collected at Screening, Day 8 and Follow-Up (Day 28). The HCV NS5B region was sequenced and the derived translations aligned to reference sequences according to genotype (genotype 1a: H77, NC_004102; genotype 1b: Con1, AJ238799). Sequences obtained at Day 8 and Day 28 were compared with the Screening sample for each subject.
Results: Fifteen genotype 1a and sixteen genotype 1b subjects were enrolled in the study. All 31 subjects encoded wild-type M423 at screening. At Day 8, mutations at position 423 were identified in 11 of the 24 subjects dosed with PF-00868554, and 0 of 7 placebo subjects. Six subjects treated with PF-00868554 showed on-treatment viral load rebound of >0.5 log from NADIR to Day 8; virus from all 6 encoded M423 mutations at Day 8. At Follow-Up, 6 of the 11 subjects with 423 mutations at Day 8 had reverted back to methionine. One subject receiving 450 mg BID did not respond to PF-00868554. An uncommon variant, R422K, was identified in this subject at all timepoints. This mutation was also detected at Day 8 in another subject (300 mg TID), although this subject showed a continuous decline in viral load throughout dosing.
Conclusions: Consistent with previous findings in vitro, the predominant mechanism of resistance to PF-00868554 during 8 days monotherapy was through mutation at residue 423 (11/24).
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