Toward early safety alert endpoints: exploring biomarkers suggestive of microbicide failure.

Several microbicides, including nonoxynol-9 (N-9) and cellulose sulfate (CS), looked promising during early trials but failed in efficacy trials. We aimed to identify Phase I mucosal safety endpoints that might explain that failure. In a blinded, randomized, parallel trial, 60 healthy premenopausal sexually abstinent women applied Universal HEC placebo, 6% CS or 4% N-9 gel twice daily for 13½ days. Endpoints included immune biomarkers in cervicovaginal lavage (CVL) and endocervical cytobrushes, inflammatory infiltrates in vaginal biopsies, epithelial integrity by naked eye, colposcopy, and histology, CVL anti-HIV activity, vaginal microflora, pH, and adverse events. Twenty women enrolled per group. Soluble/cellular markers were similar with CS and placebo, except secretory leukocyte protease inhibitor (SLPI) levels decreased in CVL, and CD3(+) and CD45(+) cells increased in biopsies after CS use. Increases in interleukin (IL)-8, IL-1, IL-1RA, and myeloperoxidase (MPO) and decreases in SLPI were significant with N-9. CVL anti-HIV activity was significantly higher during CS use compared to N-9 or placebo. CS users tended to have a higher prevalence of intermediate Nugent score, Escherichia coli, and Enterococcus and fewer gram-negative rods. Most Nugent scores diagnostic for bacterial vaginosis were in N-9 users. All cases of histological inflammation or deep epithelial disruption occurred in N-9 users. While the surfactant N-9 showed obvious biochemical and histological signs of inflammation, more subtle changes, including depression of SLPI, tissue influx of CD45(+) and CD3(+) cells, and subclinical microflora shifts were associated with CS use and may help to explain the clinical failure of nonsurfactant microbicides.

Crossover studies with survival outcomes.

Crossover designs are well known to have major advantages when comparing the effect of two treatments which do not interact. With a right-censored survival endpoint, however, this design is quickly abandoned in favour of the more costly parallel design. Motivated by human immunodeficiency virus (HIV) prevention studies which lacked power, we evaluate what may be gained in this setting and compare parallel with crossover designs. In a heterogeneous population, we find and explain a substantial increase in power for the crossover study using a non-parametric logrank test. With frailties in a proportional hazards model, crossover designs equally lead to substantially smaller variance for the subject-specific hazard ratio (HR), while the population-averaged HR sees negligible gain. Its efficiency benefit is recovered when the population-averaged HR is reconstructed from estimated subject-specific hazard rates. We derive the time point for treatment crossover that optimizes efficiency and end with the analysis of two recent HIV prevention trials. We find that a Cellulose sulphate trial could have hardly gained efficiency from a crossover design, while a Nonoxynol-9 trial stood to gain substantial power. We conclude that there is a role for effective crossover designs in important classes of survival problems.

L-selectin and P-selectin are novel biomarkers of cervicovaginal inflammation for preclinical mucosal safety assessment of anti-HIV-1 microbicide.

A major obstacle thwarting preclinical development of microbicides is the lack of a validated biomarker of cervicovaginal inflammation. Therefore, the present study aims to identify novel noninvasive soluble markers in a murine model for assessment of microbicide mucosal safety. By performing cytokine antibody array analysis, we identified two adhesion molecules, L-selectin and P-selectin, which significantly increased when mucosal inflammation was triggered by nonoxynol-9 (N9), an anti-HIV-1 microbicide candidate that failed clinical trials, in a refined murine model of agent-induced cervicovaginal inflammation. We found that patterns of detection of L-selectin and P-selectin were obviously different from those of the two previously defined biomarkers of cervicovaginal inflammation, monocyte chemotactic protein 1 (MCP-1) and interleukin 6 (IL-6). The levels of these two soluble selectins correlated better than those of MCP-1 and IL-6 with the duration and severity of mucosal inflammation triggered by N9 and two approved proinflammatory compounds, benzalkonium chloride (BZK) and sodium dodecyl sulfate (SDS), but not by two nonproinflammatory compounds, carboxymethyl celluose (CMC; microbicide excipients) and tenofovir (TFV; microbicide candidate). These data indicated that L-selectin and P-selectin can serve as additional novel cervicovaginal inflammation biomarkers for preclinical mucosal safety evaluation of candidate microbicides for the prevention of infection with HIV and other sexually transmitted pathogens.

Female genital tract secretions and semen impact the development of microbicides for the prevention of HIV and other sexually transmitted infections.

Pharmacologic strategies for the prevention of HIV include vaccines, post-exposure prophylaxis with antiretroviral therapy, and topical microbicides. Vaginal microbicides have the potential to augment innate defenses in the genital tract but may also disrupt endogenous protection and increase HIV acquisition risk, as observed in clinical trials of nonoxynol-9. The initially disappointing results of microbicide clinical trials stimulated the development of more sensitive and comprehensive pre-clinical safety studies, which include dual-chamber culture systems to model the epithelial barrier and post-coital studies to evaluate the effects of semen and sexual intercourse on microbicide efficacy. This review discusses the key factors that contribute to a healthy female genital tract environment, the impact of semen on mucosal defense, and how our understanding of these mediators informs the development of effective vaginal microbicides.

Potential acceptability of microbicides in HIV prevention in stable marital relationships in Malawi.

BACKGROUND: The XVII International Conference on AIDS held in Mexico City in August 2008 emphasised the importance of dual prevention using both vaccines and microbicides in the fight against HIV and AIDS. Microbicides are important because they constitute one of the potentially important female-controlled methods of HIV and sexually transmitted infection prevention, especially in Malawi where the use of the female condom has not yet been fully embraced. METHODS: A qualitative study utilising focus group discussions was used to assess the acceptability of the microbicide nonoxynol-9 (N-9) as part of the ongoing Preparatory AIDS Vaccine Evaluation (PAVE) studies. RESULTS: The study observed that men oppose the use of N-9, and that although women consider themselves at risk for HIV they caution against the unintended consequence of altering the vaginal environment with the use of microbicides, which can interfere with the men's preference for dry sex. DISCUSSION AND CONCLUSIONS: Although N-9 did not produce the desired results, these can inform the development of other promising microbicide candidates. The study concludes that it is important to pay attention to how new microbicides are formulated rather than just concentrating solely on an individual product's effectiveness.

SILCS diaphragm: postcoital testing of a new single-size contraceptive device.

BACKGROUND: This study was conducted to compare the effectiveness of a new, single-size silicone contraceptive diaphragm used with either spermicide [2% nonoxynol-9 (N-9)] or lubricant in preventing sperm from penetrating midcycle cervical mucus. STUDY DESIGN: A crossover postcoital test (PCT) in healthy, sexually active women not at risk for pregnancy due to tubal occlusion was conducted. Couples had a baseline PCT without a device to verify normal fertility parameters. Qualified couples underwent up to two test cycles using the SILCS diaphragm with a metal spring. A subgroup of couples underwent a third test cycle with the SILCS polymer spring diaphragm used with N-9 gel. RESULTS: Fifteen couples completed a baseline cycle and were randomized to order of study gel. Of these, 14 couples completed a baseline cycle and at least one test cycle, 12 couples completed a baseline cycle and two test cycles and 8 couples completed a third test cycle with the polymer spring prototype. Sperm was detected in the vaginal pool in all completed test cycles. The SILCS metal spring diaphragms used with N-9 gel reduced the average number of progressively motile sperm per high power field in the cervical mucus from a baseline of 12.5 to 0, while use of this device with lubricant reduced the number to 0.5. The SILCS polymer spring diaphragm used with N-9 performed the same as the metal spring used with N-9. CONCLUSION: The SILCS diaphragm used with N-9 gel performed well. It is likely that the SILCS diaphragm will give acceptable results in a contraceptive effectiveness study but that adjunctive use of a chemical barrier such as N-9 gel will be necessary for it to be most effective.

Update on nonoxynol-9 as vaginal spermicide.

Nonoxynol-9 (N-9) is a typical surfactant. For more than 30 years that very property of N-9 has been successfully exploited for its spermicidal action. It is available as an over-the-counter, locally acting vaginal spermicide. The suitability of N-9 as a spermicide is elaborated in this article. The reasons why N-9 may fail as a contraceptive are discussed. In spite of many drawbacks, which are mentioned in the article, N-9 is still often resorted to as a locally acting contraceptive. The review ends with suggestions to alter the molecular structure of N-9 and to adjust the dosages.

Over-the-counter vaginal contraceptive and spermicide drug products containing nonoxynol 9; required labeling. Final rule.

The Food and Drug Administration (FDA) is issuing a final rule establishing new warning statements and other labeling information for all over-the-counter (OTC) vaginal contraceptive drug products (also known as spermicides, hereinafter referred to as vaginal contraceptives or vaginal contraceptives/spermicides) containing nonoxynol 9 (N9). These warning statements will advise consumers that vaginal contraceptives/spermicides containing N9 do not protect against infection from the human immunodeficiency virus (HIV), the virus that causes acquired immunodeficiency syndrome (AIDS), or against getting other sexually transmitted diseases (STDs). The warnings and labeling information will also advise consumers that use of vaginal contraceptives and spermicides containing N9 can irritate the vagina and rectum and may increase the risk of getting the AIDS virus (HIV) from an infected partner. This final rule is part of FDA's ongoing review of OTC drug products. FDA is issuing this final rule after considering public comments on its proposed regulation, and all relevant data and information on N9 that have come to our attention.

Awareness and attitudes regarding microbicides and Nonoxynol-9 use in a probability sample of gay men.

A household probability sample of 879 adult gay and other men who have sex with men in San Francisco underwent phone interviews. Approximately, half reported recent unprotected anal intercourse (UAI). Yet, lubricant use was high, a behavior that may facilitate future adoption of topical microbicide delivered by a lubricant gel. Despite warnings against Nonoxynol-9 (N-9), 26% of respondents reported still using it. Microbicide awareness was higher among men reporting UAI than among consistent condom users. Scenarios presenting microbicides "as effective as condoms," "nearly as effective," or "less effective but better than nothing" produced wide variability in willingness to use them, which may have implications for microbicide acceptability. HIV-infected men and those who reported UAI showed greater microbicide acceptance.

Mucosal transmission of HIV-1: first stop dendritic cells.

Worldwide the heterosexual route is the prevalent mode of transmission of HIV, increasing the demand for measures that block the sexual spread of HIV infection. Vaccines designed to prevent mucosal transmission of HIV should be considered a component of vaccine strategies against HIV (in addition to cytotoxic T cells required for clearance and to prevent viral dissemination) and include antibodies, which are capable of blocking HIV entry at mucosal epithelial barriers, and prevent initial infection of target cells in the mucosa. However, in the interim and in the absence of an effective vaccine, the development of microbicides, topical preparations that block the early steps of HIV infection and transmission, may represent a more viable alternative to condom use in many HIV infected regions of the world especially by empowering women. To date there has been some success with antiviral antibodies applied as a microbicide capable of preventing SIV infection in macaques and reports of vaccines capable of preventing intravaginal and intrarectal inoculated SIV. However, for such success in humans a much greater understanding of the mechanisms involved in the very early stages of mucosal transmission in HIV infection are required. These may lead to additional strategies to inactivate or inhibit viral uptake and replication before a potentially life threatening acute infection develops. Such measures will lead to the development of effective microbicides and vaccines that will diminish the global spread of HIV.

Nonoxynol-9 vaginal pessary: a preliminary Indian experience.

BACKGROUND: Barrier methods of contraception do not have systemic effects and allow the user complete control over their use. For women, the ease of use of a contraceptive is often more important than its efficacy. Hence, barrier methods could be offered as a useful alternative method of contraception. Nonoxynol-9 (a spermicide) is a locally acting, non-hormonal method free from systemic side-efforts. It is a woman-controlled, reversible method which is to be used before intercourse. There are little data available on its efficacy, side-effects and acceptability among Indian women. METHODS: The vaginal pessary nonoxynol-9 was offered as a contraceptive option to 3200 women attending the Family Planning clinics at 31 Human Reproduction Research Centres (HRRCs) of the Indian Council of Medical Research. The other contraceptives offered included an intrauterine device, oral pills, condoms, Norplant, tubal sterilization and vasectomy using the cafeteria approach. Those who accepted nonoxynol-9 were followed up to assess the rates of continuation, failure and side-effects. RESULTS: The nonoxynol-9 pessary was accepted by 541 women who were followed up for 3470 woman-months of use. The reasons given for acceptance were that it was user-controlled and/or they did not wish to use other methods because of the side-effects or contraindications of these methods. The overall continuation rates were 41.2% and 33% at 9 and 12 months of use, respectively. Most women (31.3%) discontinued its use due to personal reasons such as husband dissatisfaction, desire for further pregnancy, irregular use of pessary and difficulty in insertion. Twenty-nine women became pregnant during the study period (15 due to method failure and 14 due to user failure) giving a use-effectiveness of 8.8% at 12 months. The method failure rate was 4.3% at 12 months of use. The failure rates were lower compared with the reported failure rates of barrier contraceptives (1%-30% at 1 year of use) and the side-effects were minimal. CONCLUSION: Nonoxynol-9 had low acceptability (16.9%) and overall continuation rates--41.2% and 33% at 9 and 12 months of use. It could be offered to women looking for a short term, user-controlled contraceptive.

Vaginal microbicides: detecting toxicities in vivo that paradoxically increase pathogen transmission.

BACKGROUND: Microbicides must protect against STD pathogens without causing unacceptable toxic effects. Microbicides based on nonoxynol-9 (N9) and other detergents disrupt sperm, HSV and HIV membranes, and these agents are effective contraceptives. But paradoxically N9 fails to protect women against HIV and other STD pathogens, most likely because it causes toxic effects that increase susceptibility. The mouse HSV-2 vaginal transmission model reported here: (a) Directly tests for toxic effects that increase susceptibility to HSV-2, (b) Determines in vivo whether a microbicide can protect against HSV-2 transmission without causing toxicities that increase susceptibility, and (c) Identifies those toxic effects that best correlate with the increased HSV susceptibility. METHODS: Susceptibility was evaluated in progestin-treated mice by delivering a low-dose viral inoculum (0.1 ID50) at various times after delivering the candidate microbicide to detect whether the candidate increased the fraction of mice infected. Ten agents were tested - five detergents: nonionic (N9), cationic (benzalkonium chloride, BZK), anionic (sodium dodecylsulfate, SDS), the pair of detergents in C31G (C14AO and C16B); one surface active agent (chlorhexidine); two non-detergents (BufferGel, and sulfonated polystyrene, SPS); and HEC placebo gel (hydroxyethylcellulose). Toxic effects were evaluated by histology, uptake of a 'dead cell' dye, colposcopy, enumeration of vaginal macrophages, and measurement of inflammatory cytokines. RESULTS: A single dose of N9 protected against HSV-2 for a few minutes but then rapidly increased susceptibility, which reached maximum at 12 hours. When applied at the minimal concentration needed for brief partial protection, all five detergents caused a subsequent increase in susceptibility at 12 hours of approximately 20-30-fold. Surprisingly, colposcopy failed to detect visible signs of the N9 toxic effect that increased susceptibility at 12 hours. Toxic effects that occurred contemporaneously with increased susceptibility were rapid exfoliation and re-growth of epithelial cell layers, entry of macrophages into the vaginal lumen, and release of one or more inflammatory cytokines (Il-1beta, KC, MIP 1alpha, RANTES). The non-detergent microbicides and HEC placebo caused no significant increase in susceptibility or toxic effects. CONCLUSION: This mouse HSV-2 model provides a sensitive method to detect microbicide-induced toxicities that increase susceptibility to infection. In this model, there was no concentration at which detergents provided protection without significantly increasing susceptibility.

"We have our protector": misperceptions of protection against HIV among participants in a microbicide efficacy trial.

OBJECTIVES: We examined perceptions of the effectiveness and acceptability of a candidate microbicide among 94 South African female sex workers who had participated in a phase 3 microbicide trial for HIV prevention. METHODS: Sixteen focus groups were conducted in 2001, 12 to 15 months after participants were informed that the candidate microbicide had been determined to be ineffective in preventing HIV and other sexually transmitted infections (STIs). RESULTS: Participants clearly indicated that they understood the experimental nature of the candidate microbicide, and they recognized that they had been informed after the trial that the product was ineffective. Nevertheless, most continued to believe that the candidate microbicide helped prevent HIV and other STIs, alleviated reproductive tract pain and STI symptoms, and helped to clean the vagina. CONCLUSIONS: These findings underscore the importance of understanding women's perceptions of the efficacy of candidate microbicides and the rationale for these beliefs. These issues need to be addressed in counseling throughout microbicide trials for HIV prevention. These results also demonstrate how desperate many women at high risk of HIV infection may be for new HIV prevention technologies.

Microbicides for prevention of transmission of sexually transmitted diseases.

In the last 50 years, changes in cultural and scientific realities and customs have resulted in a worldwide epidemic of sexually transmitted diseases (STD). This is a multi-factorial problem resulting in part from: 1) an increased permissiveness in sexual attitudes in the Western world that results in earlier onset of intercourse and increased numbers of partners and types of sex acts; 2) a global transportation network that facilitates contacts and interactions between urban and rural areas as well as between countries resulting in migration and spread of infections; 3) an emergence of new and mutated forms of pathogens with increased capabilities to cause infections and for which there are no available vaccines or therapies; and, 4) at risk populations in developing countries who are susceptible to these pathogens while having societal infrastructures that lack basic health education and proper access to healthcare. Overwhelming examples of increasing and emerging STD pathogens exist in the early twenty-first century. These include human immunodeficiency virus type 1 (HIV-1), the causative agent of acquired immunodeficiency syndrome (AIDS), with over 42 million current cases of infection, 20 million deaths to date, and an estimated 500,000 deaths per year; human papillomavirus (HPV) infections, the causative agents of genital warts and cervical cancer, with approximately 1 in 4 women harboring virus DNA in genital epithelium, 1-3 percent of women showing symptoms of infection and 250,000 deaths per year in women worldwide from cervical cancer; and numerous others. Topical microbicides have been proposed as agents to break the chain of transmission in these infections by providing chemical, biological, and/or physical barriers to infection by blocking and/or inactivating pathogens at the mucosal surface where infection can occur. For many sexually transmitted infections, vaccines do not exist, and therapeutic agents are only partially effective, expensive, and difficult to distribute. In addition, female partners in many relationships do not control pregnancy or STD risk and may benefit from discrete methods, other than condoms, that would provide protection. Thus, microbicides should be valuable additions to preventing these diseases if they can be shown effective. Currently, 62 microbicides are in development with 6 entering Phase III clinical trials, 11 entering Phase I clinical trials, and 44 in pre-clinical development. In this review, we will describe many of the principles of microbicide mechanisms and give examples of major types of microbicides and their actions. Space precludes a complete description of all of the agents and their mechanisms of action. We will also put forth the argument for alkyl sulfate microbicides, including sodium dodecyl sulfate (SDS), agents that are in active development in our laboratories.

Nonoxynol 9 as an additive therapy in metronidazole-resistant cases of vaginal trichomoniasis.

The present study was conducted on 30 female patients with metronidazole resistant vaginal trichomoniasis to investigate the efficacy of nonoxynol 9 (N-9), a non hormonal contraceptive with spermicidal effect, as an additive therapy to metronidazole (MNZ). Study population were randomly divided into 3 groups according to treatment regimen: G.I: patients received high dose MNZ (2 g daily for 7 days) n = 10; G. II: patients received (100 mg N-9 vaginal suppository daily for 7 days) n = 10; G. III: patients receiving conventional MNZ dose (1 g daily for 7 days) plus (a 100 mg N-9 suppository for 7 days) n = 10. Clinical and parasitological evaluation of cure was performed at return visits 1, 2, 4 and 6 weeks post treatment. Negative T. vaginalis vaginal smears were ensured by direct microscopic visualization and In Pouch TV culture technique. Most of the patients were in the 30-39 years age group (60%) and burning was the most frequent symptom (96.67%). The cure rates were 70%, 40% and 90% for Gs I, II & III respectively, while adverse effects of treatment were recorded most frequently by patients of G.I. So, MNZ resistant trichomoniasis incidence seems to be on the rise. Topical therapy alone has a low cure rate while combined oral conventional doses of MNZ and intravaginal nonoxynol 9 treatment appears to be a good clinical trial with fairly good cure rate thus, avoiding the adverse side effects of high doses MNZ therapy and T. vaginalis health hazards potentiality.

Why nonoxynol-9 may have failed to prevent acquisition of Neisseria gonorrhoeae in clinical trials.

OBJECTIVES: To understand why clinical trials failed to demonstrate efficacy of nonoxynol-9 in preventing gonorrhea. GOAL: To test the hypothesis that nonoyxnol-9 failed to prevent acquisition of Neisseria gonorrhoeae because most isolates are resistant to killing by nonoyxnol-9 at the level attainable with intravaginal use. STUDY: The lowest concentrations of nonoxynol-9 required to kill or inhibit growth of clinical isolates of N gonorrhoeae and Lactobacillus were determined. RESULTS: Most strains (17 of 25) of N gonorrhoeae (68%) were resistant to the highest concentration of nonoxynol-9 tested (20%). L crispatus (100%), L jensenii (90%), and L iners (79%) were also resistant to nonoxynol-9. CONCLUSIONS: N gonorrhoeae and H2O2-producing strains of vaginal lactobacilli were not killed by nonoxynol-9 at concentrations greater than those achievable in vivo. Earlier studies that formed the basis for subsequent trials most likely did not detect resistance because too few isolates were evaluated. Large numbers of clinical isolates should be examined before the initiation of clinical trial using microbicidal products.