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Small, Unrandomized Study Compares Pegasys to PegIntron
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Reported by Jules Levin
There have been several news reports in Reuters and other news services reporting on a study comparing Pegasys to PegIntron, leading readers to ask questions about this study and perhaps not understanding the study results. I was at EASL and here is a report on this study. You can read my EASL reports on other interesting studies from EASL including new drugs for HCV at
At the EASL liver conference in Berlin, Italian researchers (Chemello et al) reported results in a poster of a comparison between PegIntron and Pegasys. The study is small trial in which only 11 patients taking Pegasys were analyzed. The study is not randomized but is a report on consecutive patients seen in the clinic. The patients receiving Pegasys appear to have more advanced liver disease making it more difficult to compare responses for genotype 1 patients between the two drugs without identifying how many on each drug had early or later disease. The study reported end of treatment responses for patients but not sustained response rates, presumably because they don't have SVR data yet. This study is not related to the IDEAL Study, which is a trial sponsored by Schering Plough and compares Pegasys to PegIntron. The IDEAL Study is a large trial that is just starting and will take several years to be completed.
The poster from the conference said:
75 consecutive (not randomized) naive patients with biopsy proven chronic hepatitis C received:
-- 180 mg/once weekly of PEG-IFN alfa-2a (Pegasys)
or
-- 1.5 mg/kg/once weekly of PEG-IFN alfa-2b (PegIntron)
- both in combination with 15 mg/kg/daily of ribavirin (Rebetol).
Baseline characteristics between the groups were comparable.HCV-RNA levels were tested by qualitative PCR and quantitativebDNA in all patients at weeks 4, 12, 24 during therapy and at end oftherapy (EOT).
Mean body weight was 78.8 kg (173 lbs) for patients receiving Pegasys and 73.7 kg (162 lbs) for patients receiving PegIntron. Mean BMI was 26.3 for Pegasys recipients and 24.5 for PegIntron recipients. Mean ALT was 200 U/L for Pegasys recipients and 180 for PegIntron recipients. These differences don't appear to be very significant. These differences are important, but patients receiving Pegasys appear to have more advanced liver disease---Fibrosis stage (Ishak)—F1/F2/F3 0/6/5- (52%) for Pegasys patients vs 3/14/24 (79%) for PegIntron patients; F4/F5/F6- 6/4/2 (48%) for Pegasys patients vs 7/1/2 (20%) for PegIntron patients.
RESULTS
The study authors reported that of the 75 patients initially in the study who were genotype 1 or 4, 6/11 (55%) receiving Pegasys + RBV and 21/28 (75%) receiving PegIntron who were genotype 1 and 4 had undetectable viral load at the end of treatment. The study authors did not report sustained viral response rates.
For genotype 2/3 patients, the end of treatment response rates were 12/12 (100%) receiving Pegasys/RBV and 22/24 (92%) receiving PegIntron/RBV had undetectable viral load.
For patients with less Fibrosis (F1-F3) 8/11 (73%) receiving Pegasys/RBV and 36/41 (88%) receiving PegIntron had undetectable viral load at the end of treatment. For patients with later stage fibrosis (F4-F6), 10/12 (83%) receiving Pegasys/RBV and 6/10 (60%) receiving PegIntron/RBV had undetectable viral load.
Thus, the authors concluded Pegasys/RBV performed worse in genotype 1 and better in more advanced liver disease.
As well, the authors claimed PegIntron performed better in the first 4 weeks of therapy based on: 3/11 patients in early fibrosis receiving Pegasys/RBV being HCV negative and 21/41 receiving PegIntron/RBV being HCV negative; for genotype 1 patients 1/11 receiving Pegasys/RBV and 9/28 receiving PegIntron/RBV had negative HCV RNA at week 4. To support this claim 7/12 (58%) receiving Pegasys/RBV and 16/24 (67%) receiving PegIntron/RBV who had genotype 2/3 had negative HCV RNA at week 4.
In sum, several points need to be considered when interpreting the study results: the number of patients receiving Pegasys is small; the study is not randomized; the Pegasys patients had more advanced disease which complicates interpretation of the results for genotype 1 patients. End of treatment responses were reported but not sustained viral responses. This study is not related to the IDEAL Study.
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