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Safety and acceptability of cellulose sulfate as a vaginal microbicide in HIV-infected women
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"....this study demonstrated that CS gel is a suitable candidate for continued development as a vaginal microbicide. The demonstration of its safety and acceptability in HIV-infected individuals is important in planning for its further assessment in clinical trials with larger number of participants....."
AIDS: Volume 20(8) 12 May 2006 p 1109-1116
[BASIC SCIENCE]
El-Sadr, Wafaa Ma,b; Mayer, Kenneth Hc,d; Maslankowski, Lisae; Hoesley, Craigf; Justman, Jessicab,g; Gai, Fangh; Mauck, Christinei; Absalon, Juditha,b; Morrow, Kathleenc; Masse, Benoith; Soto-Torres, Lydiaj; Kwiecien, Antoniak; for the HIV Prevention Trials Network (HPTN) 049 Protocol Team
From the aHarlem Hospital Center, New York, USA
bColumbia University, New York, USA
cMiriam Hospital, Brown Medical School, Providence, Rhode Island, USA
dFenway Community Health, Boston, Massachusetts, USA
eUniversity of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
fThe University of Alabama at Birmingham, Alabama, USA
gBronx Lebanon Hospital Center, Bronx, New York, USA
hFred Hutchinson Cancer Research Center, Seattle, Washington, USA
iCONRAD, Arlington, Virginia, USA
jNational Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA
kFamily Health International, Arlington, Virginia, USA.
Abstract
Objectives: Few studies of topical microbicides have assessed their safety in HIV-infected women. We conducted this study to evaluate the safety and acceptability of 6% cellulose sulfate (CS) gel as a vaginal microbicide in sexually abstinent and active HIV-infected women.
Methods: Fifty-nine HIV-infected women were enrolled in a randomized double-blind placebo-controlled study comparing 6% CS to placebo gel used for 14 days. Sexually abstinent women applied gel once or twice daily and sexually active women used gel once daily.
Results: CS gel was safe with no reported severe or life-threatening adverse events (AE). Thirty-nine (66%) of the participants experienced urogenital AE judged as probably or possibly related to gel. The majority (51%) of these participants reported only mild events. Fewer women (62%) who used CS experienced urogenital AE than those assigned to placebo gel (70%) (P = 0.59). Eleven (19%) women experienced intermenstrual bleeding judged to be probably or possibly related to gel use (four in the CS and seven in the placebo gel group). There was no increase in AE by frequency of gel use or sexual activity with the exception of abdominal/pelvic pain which was noted more frequently with twice daily use among sexually abstinent women. Women and men found the gel highly acceptable.
Conclusions: This Phase I study demonstrated that CS vaginal gel was safe, well tolerated and acceptable by HIV-infected women and their male partners. Thus, further development of CS is warranted as a potential method to prevent HIV transmission and acquisition.
Introduction
The global HIV epidemic has had a particularly severe impact on women. In countries with the highest global HIV seroprevalence rates, up to 60% of HIV-infected adults are women [1,2]. Microbicides have tremendous promise as a method for prevention of HIV transmission and acquisition as women are often unable to negotiate condom use with their male partners [3-6]. Several products have been evaluated in early studies and there are ongoing Phase II/III studies [7,8].
Cellulose sulfate (CS) is an antifertility agent with antimicrobial activity in vitro against a variety of organisms [9-11]. Although anticoagulant activity has been noted in vitro, there has been no evidence of bleeding in vivo [9,12]. In a Phase I safety and acceptability study comparing CS gel to K-Y jelly and nonoxynol-9 in women without HIV infection, CS was well tolerated [13]. Similar findings have been reported in other multi-center Phase I studies [14,15]. In a study of CS gel in men, only one of 24 men reported genital irritation [16]. While these results support the promise of CS as a vaginal microbicide, all the studies were conducted in HIV uninfected women and men. Should an effective microbicide become available, it is likely to be used unknowingly or knowingly by HIV-infected women. Thus, the HIV Prevention Trials Network conducted this Phase I study to evaluate the safety and acceptability of 6% CS gel in HIV-infected women and their seroconcordant male sexual partners.
Discussion
This study is the first to focus solely on the safety and acceptability of a candidate microbicide in HIV-infected women. It is likely that vaginal microbicides will be used by HIV-infected women who may or may not be aware of their HIV status. The results of this study demonstrate that 6% CS gel as used vaginally was well tolerated by the HIV-infected women, although the number of sexually active study participants was limited.
While 62% of the women assigned to CS developed at least one urogenital AE judged probably or possibly related to gel, the majority of women reported events that were mild in nature, none were serious or life-threatening and the number of AE did not differ by CS or placebo use, frequency of use or sexual activity. The high prevalence of AE is consistent with findings in other Phase I microbicide studies and may reflect intense participant monitoring [13,18-21]. In addition, an observational study of women that included daily recording of vaginal symptoms noted a high prevalence of symptoms in the absence of any gel use [22]. The use of a placebo gel in this study was invaluable in demonstrating that many of the AE were unrelated to the active moiety in the CS gel.
Abdominal/pelvic pain was more commonly reported among women assigned to twice daily versus once daily use. It is of interest that none of the sexually active women reported this symptom, possibly due to loss of gel from the vagina during sex.
Intermenstrual bleeding or metrorraghia has been previously reported in studies of vaginal microbicides for unclear reasons. In a study of the use of PRO 2000, it was hypothesized that this might be due to a local anticoagulant effect [18]. While 19% of the women participating in this study experienced intermenstrual bleeding judged possibly or probably related to study gel, most of the episodes occurred with use of placebo gel. It is reassuring that CS gel use was not associated with prolongation of coagulation parameters or with intermenstrual bleeding.
Although the women who participated in the study were highly selected, 32% had colposcopic evidence of erythema, petechiae/ecchymosis or abrasion at baseline. Studies conducted among women at low risk and not known to be HIV-infected have shown a substantial prevalence of colposcopic findings at baseline [13]. This may reflect the protocol-mandated documentation of all findings, including common and asymptomatic ones.
At follow-up, 22% of women (21% in the CS group and 23% in the placebo group) had at least one of the following findings on colposcopy: erythema, petechaie/ecchymosis, or abrasion whereas only one woman in each of the CS and placebo groups had disruption of blood vessels and epithelium. These findings were not associated with frequency of gel use or sexual activity. In a previous study that compared CS to nonoxynol-9 and K-Y jelly in women without HIV infection, colposcopic findings were noted in 13% and 25% of women assigned to the CS and K-Y jelly, respectively [13]. In another study in women without HIV infection, 10% of women who used CS had colposcopic findings at follow-up [14]. In our study, a higher percentage of women assigned to CS had findings at both baseline and follow-up than in previous studies; which may be related to underlying HIV infection. Notably, though, more women using placebo gel had colposcopic findings at follow-up compared to CS users.
Adherence with use of the gel was higher among the sexually active compared to sexually abstinent women, suggesting that it may be easier for women to use the gel in conjunction with sex rather than on a specified daily schedule or that male partners reminded the women to use it.
Participants found the CS gel acceptable and indicated willingness to utilize it, if available. Notably, although participants reported leaking of the gel during sex, this did not appear to have a negative impact on sexual pleasure. Prior studies have noted that use of a product by men is influenced by its effect on sexual pleasure [23]. It should be noted that the women indicated preference for a vaginal microbicide that would not be noticed by their partners.
The study has some limitations. It was conducted at four sites which may have led to variability in AE assessment. The inability to complete recruitment prevented the full assessment of CS gel in sexually active women. The women enrolled met multiple eligibility criteria and, thus, may not reflect the broader HIV-infected population. Finally, utilizing interviewer-administered acceptability questionnaires may have elicited socially desirable responses.
The strengths of this study are that it was placebo-controlled and focused on HIV-infected individuals including assessment of effect of gel on plasma and CVL HIV RNA levels, two safety parameters in this population. Intensive training and quality assurance ensured rigorous data collection. Finally, the high patient retention and adherence ensured an appropriate gel exposure to allow for safety determination.
In conclusion, this study demonstrated that CS gel is a suitable candidate for continued development as a vaginal microbicide. The demonstration of its safety and acceptability in HIV-infected individuals is important in planning for its further assessment in clinical trials with larger number of participants.
Results
Study participants
A total of 195 women were screened and 59 HIV-infected women were enrolled, with 29 assigned to the CS and 30 assigned to the placebo gel group. Table 3 demonstrates the distribution of women in cohorts and by study arm, their demographic and HIV disease characteristics. Overall, baseline characteristics were well balanced across arms and cohorts. Three women were terminated from the study; two could not be located and one did not adhere to study procedures (all three in CS group).
Baseline genital tract findings
At baseline, the median vaginal pH was 5.0 ± 0.7 and 15% of the women had asymptomatic bacterial vaginosis (as defined by modified Amsel criteria, i.e. pH > 4.5, positive whiff test and > 20% clue cells). Colposcopic findings of erythema, petechiae/ecchymoses, and abrasion were noted in 19 (32%) of women; nine (31%) and 10 (33%) of women assigned CS and placebo gel, respectively. Erythema was noted in five and eight women; petechiae/ecchymoses in five and six women; and abrasions in two and one woman in the CS and placebo groups, respectively.
At baseline, 35 (59%) of the women had plasma HIV RNA ≥ 50 copies/ml and seven (20%) of these women had bleeding, erosion/ulceration or erythema. In comparison, these findings were noted in 10 (42%) of the 41% women with HIV RNA < 50 copies/ml; (P = 0.09). HIV RNA assays on CVL specimens demonstrated that 57 (97%) of the women had levels < 400 copies/ml.
Urogenital adverse events during follow-up
Table 4 shows product-related AE during follow-up by cohort and treatment group. During the course of the study, 62% of the women assigned to CS and 70% of those assigned placebo gel experienced at least one urogenital AE judged to be possibly or probably gel related; none were considered definitely gel related and none were severe or life threatening. The majority, (30 women) reported only mild urogenital AE. The most frequently reported symptoms were abdominal/pelvic pain (15 women) and genital pruritus (15 women). Abdominal/pelvic pain was reported by nine women in the CS gel and six women in the placebo group (P = 0.38). Genital itching was reported by eight women and seven women in the CS and placebo groups, respectively (P = 0.77). Abdominal/pelvic pain was more commonly reported by sexually abstinent women who used gel twice daily compared to once daily users (P = 0.06). None of the sexually active women reported abdominal/pelvic pain. Vulvovaginal candidiasis was noted in one CS user and two placebo users, and bacterial vaginosis was noted in one placebo user.
Metrorraghia or intermenstrual bleeding, judged to be probably or possibly related to study product, was noted in 11 women, four in the CS gel and seven in the placebo group (P = 0.51). All were mild in nature and lasted 4 days or less. One woman in the placebo group with intermenstrual bleeding had mild prolongation of prothrombin time (also noted at enrollment).
Colposcopic findings of erythema, petechiae/ecchymoses, and abrasion were noted in 13 (22%) of women at follow-up; six (21%) and seven (23%) of women in the CS and placebo groups, respectively. Erythema was noted in three women in the CS and four women in the placebo groups; petechiae/ecchymoses in three women in the CS and five in the placebo group; and abrasions in one woman in the CS and two in the placebo group (Table 4). Only one woman in each group had disruption of both blood vessels and epithelium (data not shown). None of these findings was thought to be clinically significant.
There was no significant association between pelvic/colposcopic findings and change in plasma HIV RNA or CVL HIV RNA from baseline to follow-up (data not shown).
Laboratory findings during follow-up
Five (8%) of women (three in CS and two in placebo gel) experienced at least one laboratory AE that was judged as possibly or probably related to gel. None were definitely related to the gel and all were graded as mild (Grade I). One woman in the CS group had mild anemia and another had mildly prolonged activated partial thromboplastin time (33.3 s with an upper limit of normal of 33 s). One woman in the placebo group had mild prolongation of prothrombin time and two (one in each of the treatment groups) had mildly increased gamma-glutamyltransferase.
Plasma HIV RNA levels remained similar from baseline through follow up. No difference was noted in the proportion of women with plasma HIV RNA > 50 copies/ml at follow up by treatment group. One woman in the placebo group had a change in CVL HIV RNA from < 400 at baseline to ≥ 400 copies/ml at follow-up.
Adherence
Adherence to product use as per protocol definition was noted in 69% of the women in the CS group and 70% in the placebo group. In the sexually abstinent women, 77% of those assigned to once daily gel use and 52% of those assigned to twice daily gel use were adherent (P = 0.12) while 91% of the sexually active women were adherent. Eighty-seven percent of the expected CS doses and 96% of the placebo doses were used by the women. Ninety nine percent of expected doses were used by sexually active women compared to 90% of expected doses in the sexually abstinent women.
Acceptability
Table 5 indicates behavioral assessment at enrollment and the follow-up acceptability assessment. Women assigned to the CS gel were less likely (77%) to report liking the gel than those assigned to the placebo gel (87%) (P = 0.49). All of the men liked the gel overall, though one reported disliking the consistency of the placebo gel.
Among the 11 sexually active women (data not shown), seven (64%) reported gel leaking during sex (two CS; five placebo). Only four (36%) of the male partners reported the same (one CS; three placebo). When asked whether the gel increased their sexual pleasure, all of the women and men either agreed or responded that the gel made no difference.
Almost all (96%) CS users, all placebo users and the men indicated that they would 'probably' or 'definitely' use the product, if available. The majority (61% women; 73% men) reported that they would prefer a product not noticeable by the male sex partner.
Methods
Study design
The study was a multi-center, randomized, double blind, placebo-controlled, frequency escalation study in sexually abstinent and sexually active HIV-infected women.
Study products
CS 6% gel (containing 60 mg CS/ml gel) was dispensed in an applicator containing 3.5 ml resulting in a dose of 210 mg of CS per dose. The placebo gel consisted of K-Y Jelly Personal Lubricant (Personal Products Company, Skillman, New Jersey). The gels were similar in appearance and were provided in identical pre-filled, single-dose disposable applicators.
Recruitment
The study was conducted at the University of Alabama at Birmingham (Birmingham, Alabama, USA); Harlem Hospital Center and Bronx-Lebanon Hospital Center (New York, USA); University of Pennsylvania (Philadelphia, Pennsylvania, USA); and The Miriam Hospital (Providence, Rhode Island, USA). All participants (including male sexual partners) signed a consent form approved by the corresponding institutional review boards.
Eligibility criteria
Eligibility criteria for the female and male study participants are listed in Table 1-
Study procedures
Women were instructed to apply the gel intravaginally for 14 intermenstrual days at the following frequency. Cohort 1: once daily (sexually abstinent women); cohort 2: twice daily (sexually abstinent women); cohort 3: once daily (sexually active women) up to 2 h prior to intercourse; cohort 4: twice daily (sexually active women). However, cohort 4 was not recruited due difficulty in identifying eligible HIV-infected monogamous couples.
Women were provided with non-spermicidally lubricated latex male condoms and a daily study record to report the date and timing of product use, vaginal intercourse (in the sexually active cohort) and any symptoms or signs.
Study visits
Eligible women underwent an assessment at screening and enrollment visits (scheduled 2-6 days after menstrual period) (Table 2). Colposcopy was performed by trained staff according to the CONRAD/WHO Manual for the Standardization of Colposcopy for the Evaluation of Vaginal Products, Update 2000. Upon confirmation of eligibility, the women were randomized to study arms.
Assessments were conducted on day 7 and 14 visits (Table 2). The daily record was reviewed to guide the assessments. All adverse events (AE) were graded as per toxicity tables (Division of AIDS Toxicity Tables).
HIV RNA determination
Plasma HIV RNA assessment was performed with the Roche Amplicor Monitor Ultrasensitive Assay, Version 1.5 (Roche Diagnostics, Branchburg, New Jersey, USA). HIV-1 RNA was extracted from 0.5 ml of cervico-vaginal lavage (CVL) using the Boom method [17].
Adherence assessment
Daily study records were reviewed for adherence to gel use, frequency and timing of sexual activity and condom use and number of applicators returned. Non-adherence was defined as 3 or more days of missed product out of 14 days (not due to AE). Non-adherence was also defined as less than two vaginal sex episodes per week in cohorts 3 and 4.
Acceptability assessments
At the enrollment visit, women completed a behavioral assessment questionnaire and at day 14 visit women completed an interviewer-administered acceptability questionnaire. Male sexual partners completed a similar acceptability questionnaire on or after the women's day 14 visit.
Statistical considerations and analysis
The study was designed to recruit 96 women (and 48 male partners) into four cohorts of 24 women each. The randomization assignment was equally balanced by cohort and study site and enrollment of cohorts was sequential.
The original study was powered to determine if the true rate of observing an AE is 5%, 12 women randomized to placebo gel and 12 women assigned to CS in a given cohort would provide 88% power to exclude AE rates greater than 35%. In addition, the upper bounds of the exact 95% confidence interval around safety endpoint rates were 26.5% and 38.5% if the observed number of endpoints in a cohort of 12 women was zero or one, respectively. The study was not designed to provide sufficient power for statistical comparisons between the CS and placebo gel arms. Means, medians, counts, and proportions were used to describe cohort characteristics at baseline and frequency of findings, AE, and symptoms at baseline and during follow-up.
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