A Phase 1 pharmacokinetic study of a single-dose bioadhesive clindamycin 2% gel for bacterial vaginosis.

OBJECTIVES: To evaluate pharmacokinetics (PK) of a single dose of an investigational 2% clindamycin phosphate vaginal gel in healthy women by assessment of plasma and vaginal clindamycin concentrations over 7 days, and assess safety. METHODS: Single-centre, Phase 1, single-dose PK study. Blood and vaginal samples were collected daily and safety was evaluated through to Day 7. RESULTS: Twenty-one subjects were enrolled; 20 completed the study. Plasma clindamycin concentrations demonstrated quantifiable values in all subjects through to 24 h post-dose, remaining above the limits of quantification (LOQ) through to 48 h for the majority of subjects. Systemic exposure (AUC0-t) was 1179 (range 62-3822) h·ng/mL. Arithmetic mean AUC0-24 was 818 (range 51-3287) h·ng/mL. Vaginal clindamycin phosphate levels were relatively high 24 h following administration in 15/21 subjects (6 subjects had values >400 µg/g and 9 had values of 100-400 µg/g). The levels dropped in most participants to below the LOQ 2 days following dosing. In a few participants, levels remained elevated for several days. Maximal amounts of vaginal clindamycin occurred on Day 2 with a mean value of 30.3 µg. One treatment-emergent adverse event (TEAE) of moderate-severity headache not related to study drug was reported and resolved on Day 1. No TEAEs were related to physical examinations, pelvic examinations, laboratory values or vital signs. CONCLUSIONS: The vaginal concentrations of clindamycin phosphate plus the clindamycin plasma profile over time are consistent with release of drug from the investigational gel over 24 to 72 h. A single dose was well tolerated.

The postcoital test in the development of new vaginal contraceptives†.

Postcoital tests (PCTs) have been used for over a century in the clinical evaluation of infertile couples, and for nearly 70 years in the evaluation of new vaginal contraceptive products. PCTs have been largely replaced by more modern methods in the study of infertility, but they remain the most useful way to obtain preliminary data on the effectiveness of vaginal contraceptive products. The World Health Organization has described important aspects of the procedure. It involves collection of cervical mucus at a certain time point after intercourse and the counting and characterization of sperm found in the mucus. A wide range of progressively motile sperm (PMS) has been associated with pregnancy rates in infertility studies. Eligibility for contraceptive trials includes the requirement that couples achieve a certain threshold number of PMS per high power field at midcycle in a baseline cycle without the test product. The primary endpoint, or definition of a satisfactory result in test cycles, is predefined. A literature review identified 10 PCT studies of vaginal contraceptives involving nine test products. Phase II trials of vaginal contraceptives have not been deemed feasible in the development of any vaginal contraceptive to date. A PCT study of a test product can be predictive of contraceptive efficacy, although ultimate contraceptive effectiveness is influenced by the ease of use of the product, along with patient compliance. PCT results similar to results seen with products that later showed satisfactory performance in efficacy trials is the best indicator of likely success of a test product.

Comparison of self-reported female condom failure and biomarker-confirmed semen exposure.

OBJECTIVE: To investigate whether rates of self-reported Woman's Condom (WC) clinical failure and semen exposure from a functionality study are comparable to results from a contraceptive efficacy substudy. STUDY DESIGN: We structured our comparative analysis to assess whether functionality studies might credibly supplant contraceptive efficacy studies when evaluating new female condom products. Couples not at risk of pregnancy in the functionality (breakage/slippage/invagination/penile misdirection) study and women in the contraceptive efficacy study completed condom self-reports and collected precoital and postcoital vaginal samples for up to four uses of the WC. Both studies used nearly identical self-report questions and the same self-sampling procedures and laboratory for prostatic specific antigen (PSA), a well-studied semen biomarker. We compared condom failure and semen exposure proportions using generalized estimating equations methods accounting for within-couple correlation. RESULTS: Ninety-five (95) efficacy substudy participants used 334 WC and 408 functionality participants used 1572 WC. Based on self-report, 19.2% WC (64 condoms) clinically failed in the efficacy substudy compared to 12.3% WC (194 condoms) in the functionality study (p=.03). Of the 207 WC efficacy uses with evaluable postcoital PSA levels, 14.5% (30 uses) resulted in semen exposure compared to 14.2% (184 uses) of the 1293 evaluable WC functionality study uses. CONCLUSIONS: When evaluating the ability of an experimental condom to prevent semen exposure, the rate of clinical condom failure reported by participants risking pregnancy in an efficacy substudy was significantly higher than the rate reported by participants not risking pregnancy in a functionality study. The rate of semen exposure, assessed by an objective biomarker was nearly identical for the two studies. IMPLICATIONS: Our results suggest that an objective marker of semen exposure in functionality studies could provide a reasonable alternative to contraceptive efficacy studies in evaluating risk of unintended pregnancy and inferring protection from sexually transmitted infection than condom failure rates based on self-report.

Use of contraceptive depot medroxyprogesterone acetate is associated with impaired cervicovaginal mucosal integrity.

BACKGROUND: Injectable depot medroxyprogesterone acetate (DMPA) is one of the most popular contraception methods in areas of high HIV seroprevalence. Evidence is accumulating that use of DMPA might be associated with an increased risk of HIV-1 acquisition by women; however, mechanisms of this association are not completely understood. The goal of this study was to gain insight into mechanisms underlying the possible link between use of DMPA and risk of HIV-1 acquisition, exploring transcription profiling of ectocervical tissues. METHODS: Healthy women received either DMPA (n = 31) or combined oral contraceptive (COC), which has not been linked to an increased risk of HIV acquisition (n = 32). We conducted a comparative microarray-based whole-genome transcriptome profiling of human ectocervical tissues before and after 6 weeks of hormonal contraception use. RESULTS: The analysis identified that expression of 235 and 76 genes was significantly altered after DMPA and COC use, respectively. The most striking effect of DMPA, but not COC, was significantly altered expression (mostly downregulation) of many genes strategically involved in the maintenance of mucosal barrier function; the alterations, as indicated by Ingenuity Pathway Analysis (IPA), were most likely due to the DMPA-induced estrogen deficiency. Furthermore, IPA predicted that transcriptome alterations related to ectocervical immune responses were in general compatible with an immunosuppressive effect of DMPA, but, in some women, also with an inflammatory-like response. CONCLUSION: Our results suggest that impairment of cervicovaginal mucosal integrity in response to DMPA administration is an important mechanism contributing to the potential increased risk of HIV-1 acquisition in DMPA users. TRIAL REGISTRATION: ClinicalTrials.gov NCT01421368. FUNDING: This study was supported by the United States Agency for International Development (USAID) under Cooperative Agreement GPO-A-00-08-00005-00.

A phase I randomized postcoital testing and safety study of the Caya diaphragm used with 3% Nonoxynol-9 gel, ContraGel or no gel.

OBJECTIVES: The Caya® Diaphragm is a newly approved single-size, nonlatex diaphragm. Contragel® is a personal lubricant containing lactic acid approved in Europe and other countries for use with vaginal barrier devices. This study assessed the effectiveness in preventing sperm from penetrating midcycle cervical mucus of Caya with Contragel, Caya with 3% nonoxynol-9 (N-9) and Caya alone. STUDY DESIGN: Phase I multicenter, single-blind, randomized, crossover, nonsignificant risk study at two sites: Eastern Virginia Medical School, Norfolk, VA, USA, and Profamilia, Santo Domingo, Dominican Republic. Healthy, sexually active women 18-45years old, not at risk for pregnancy due to tubal occlusion, were eligible. Each participant was seen in nine visits, completing a baseline cycle (without product use) followed by three test cycles (sequence determined by randomization), each consisting of a cervical mucus check visit and a postcoital test visit. To proceed to test cycles, the baseline postcoital test had to show adequate cervical mucus and >5 progressively motile sperm per high power field (PMS/HPF). RESULTS: All women had an average of <5 PMS/HPF during the test cycle of each study arm, the primary endpoint. Caya with ContraGel and Caya with N-9 reduced the average number of PMS/HPF from 22.5 to 0. Caya alone reduced the average number of PMS/HPF from 22.5 to 0.4. There were two possibly product-related mild adverse events. CONCLUSION: This study supports that Caya with ContraGel is safe and functions as well as Caya with N-9 in preventing PMS from reaching midcycle cervical mucus. IMPLICATIONS: A single-size diaphragm used with a personal lubricant gel containing lactic acid appears to be safe and to function as well as the same diaphragm used with N-9 in preventing PMS from reaching midcycle cervical mucus.

Contraceptive efficacy, safety, fit, and acceptability of a single-size diaphragm developed with end-user input.

OBJECTIVE: To estimate contraceptive efficacy, safety, acceptability, and fit of a single-size diaphragm used with contraceptive gel. METHODS: We conducted a multicenter trial in which 450 couples used the single-size diaphragm, 300 randomized to acid-buffering gel and 150 to nonoxynol-9, for at least 190 days and six menstrual cycles. Visits were at enrollment and after menstrual cycles 1, 3, and 6. Study outcomes included pregnancy probability, safety, acceptability, and fit. Pregnancy and safety were compared with an historical control group who used a standard diaphragm with these gels. RESULTS: Most (439/450 [98%]) women could be fitted with the single-size diaphragm. A total of 421 of 450 (94%) provided follow-up. The 35 study pregnancies yielded 6-month Kaplan-Meier cumulative typical use pregnancy probabilities per 100 women with 95% confidence intervals (CIs) of 10.4 (6.9-14.0) for all users and 9.6 (5.5-13.6) and 12.5 (5.4-19.5) with acid-buffering gel and nonoxynol-9, respectively. Historical control analysis yielded a propensity score-adjusted estimate of this pregnancy probability for the single-size diaphragm of 11.3 compared with 10.7 per 100 women for the standard diaphragm ([rounded] difference 0.7, 95% CI -3.6 to 4.9). Approximately half (51%) reported at least one urogenital event but compared favorably to the standard diaphragm in historical control analysis. Most (282/342 [82%]) liked the diaphragm. Results suggest that if provided by a clinician, 94% (95% CI 92-96%) could insert, correctly position, and remove the diaphragm. CONCLUSION: The single-size diaphragm was safe, as effective as a standard diaphragm, and acceptable when used with contraceptive gel. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00578877.

Does tenofovir gel or do other microbicide products affect detection of biomarkers of semen exposure in vitro?

OBJECTIVES: There is currently no information on whether products evaluated in HIV microbicide trials affect the detection of the semen biomarkers prostate-specific antigen (PSA) or Y chromosome DNA. STUDY DESIGN: We tested (in vitro) dilutions of tenofovir (TFV), UC781 and the hydroxyethylcellulose (HEC) placebo gels using the Abacus ABAcard and the quantitative (Abbott Architect total PSA) assays for PSA and Y chromosome DNA by real-time polymerase chain reaction. RESULTS: TFV gel and the HEC placebo adversely affected PSA detection using the ABAcard but not the Abbott Architect total PSA assay. UC781 adversely affected both the ABAcard and Abbott Architect total PSA assays. While there were some quantitative changes in the magnitude of the signal, none of the products affected positivity of the Y chromosome assay. CONCLUSIONS: The presence of TFV or HEC gels did not affect quantitative PSA or Y chromosome detection in vitro. Confirmation of these findings is recommended using specimens obtained following use of these gels in vivo. IMPLICATIONS: Researchers should consider the potential for specific microbicides or any products to affect the particular assay used for semen biomarker detection. The ABAcard assay for PSA detection should not be used with TFV UC781, or HEC.

Effect of lubricants and a vaginal spermicide gel on the detection of prostate specific antigen, a biomarker of semen exposure, using a quantitative (Abbott ARCHITECT) assay.

OBJECTIVES: Little is known about the effects of commonly used lubricants on detection of biomarkers of semen exposure. We investigated the in vitro effect of Gynol®, K-Y Jelly®, Replens®, Astroglide®, Carbopol, and Silicorel on quantitative detection of prostate specific antigen (PSA). STUDY DESIGN: A predetermined concentration of each of the gels was added to serially diluted semen samples. Additionally, serial dilutions of each of the gels were added to three different semen dilutions (high, medium, or low). The resulting samples were tested for PSA on the Abbott ARCHITECT System. RESULTS: When using the Abbott ARCHITECT system, the only products that inhibited PSA detection were Gynol® and Replens®. The inhibition caused by Gynol® was dose-dependent, but that of Replens was dose-independent. K-Y Jelly®-spiked samples had higher PSA values than controls. CONCLUSIONS: Caution is warranted when using the Abbott quantitative assay for PSA detection as a biomarker of semen exposure in settings where Gynol®, Replens® or K-Y Jelly® might also have been used. Neither Astroglide® nor Silicorel inhibited PSA detection. Additional studies evaluating other vaginal products, including microbicides, and their effects on other assays, are needed. In vivo studies will be especially important to optimize PSA detection from clinical samples. IMPLICATIONS: Researchers should consider the potential for specific lubricants or any vaginal products to affect the particular assay used for semen biomarker detection. The Abbott ARCHITECT's total PSA assay should not be used with the product Replens. Caution is warranted when using the assay in settings where Gynol or K-Y jelly may have been used.

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.

Effect of topical vaginal products on the detection of prostate-specific antigen, a biomarker of semen exposure, using ABAcards.

BACKGROUND: Prostate-specific antigen (PSA) is a biomarker of recent semen exposure. There is currently only limited information on whether topical vaginal products affect PSA assays. We investigated this question using various dilutions of several vaginal products (lubricants and spermicides) and the Abacus ABAcard for PSA detection. STUDY DESIGN: Pooled semen controls and various dilutions of nonoxynol-9 (N9), carboxymethyl cellulose (CMC), Replens, Gynol 2, K-Y jelly, Astroglide, Surgilube, combined with pooled semen dilutions, were tested for PSA using the Abacus ABAcard. RESULTS: N9 (2% with saline) and CMC did not appear to affect the results of testing with the ABAcard, but not all semen dilutions were tested. The other products (including Replens and Gynol, which is 2% N9 with propylene glycol, K-Y, Astroglide and Surgilube) at some of the dilutions tested either affected or gave invalid results with PSA testing using the ABAcard. Both Gynol 2 and K-Y at 1:10 dilution gave false-positive results. CONCLUSIONS: Some vaginal products affect PSA results obtained by using the semiquantitative ABAcard. In vivo confirmation is necessary to further optimize PSA detection when topical vaginal products are present.

Twice-daily application of HIV microbicides alter the vaginal microbiota.

UNLABELLED: Vaginal HIV microbicides offer great promise in preventing HIV transmission, but failures of phase 3 clinical trials, in which microbicide-treated subjects had an increased risk of HIV transmission, raised concerns about endpoints used to evaluate microbicide safety. A possible explanation for the increased transmission risk is that the agents shifted the vaginal bacterial community, resulting in loss of natural protection and enhanced HIV transmission susceptibility. We characterized vaginal microbiota, using pyrosequencing of bar-coded 16S rRNA gene fragments, in samples from 35 healthy, sexually abstinent female volunteer subjects (ages 18 to 50 years) with regular menses in a repeat phase 1 study of twice-daily application over 13.5 days of 1 of 3 gel products: a hydroxyethylcellulose (HEC)-based "universal" placebo (10 subjects), 6% cellulose sulfate (CS; 13 subjects), and 4% nonoxynol-9 (N-9; 12 subjects). We used mixed effects models inferred using Bayesian Markov chain Monte Carlo methods, which showed that treatment with active agents shifted the microbiota toward a community type lacking significant numbers of Lactobacillus spp. and dominated by strict anaerobes. This state of the vaginal microbiota was associated with a low or intermediate Nugent score and was not identical to bacterial vaginosis, an HIV transmission risk factor. The placebo arm contained a higher proportion of communities dominated by Lactobacillus spp., particularly L. crispatus, throughout treatment. The data suggest that molecular evaluation of microbicide effects on vaginal microbiota may be a critical endpoint that should be incorporated in early clinical assessment of microbicide candidates. IMPORTANCE: Despite large prevention efforts, HIV transmission and acquisition rates remain unacceptably high. In developing countries, transmission mainly occurs through heterosexual intercourse, where women are significantly more vulnerable to infection than men. Vaginal microbicides are considered to be one of the most promising female-controlled products, in that women themselves insert the microbicides into the vagina to prevent HIV transmission during sexual intercourse. The failure of several microbicides in clinical trials has raised questions concerning the low in vivo efficacy of such anti-HIV molecules. This study was designed to gain insights into the failures of two microbicides by testing the hypothesis that the microbicides negatively affect a critical line of defense against HIV, the vaginal microbiota. The results suggest that in the early assessment of candidate microbicides, culture-independent evaluation of their effect on the vaginal microbiota should be considered and may constitute a critical endpoint.

Colposcopy: still useful in microbicide safety trials?

BACKGROUND: Colposcopy is used to evaluate vaginal microbicides, but its link to risk of HIV is unknown. This reanalysis of 9 safety studies determined the impact of omitting colposcopy on the number of findings detected and assessed whether colposcopy was useful in identifying nonoxynol-9 (N-9) as an unsafe product in one study. METHODS: Product-related findings seen with naked eye and colposcopy or by colposcopy alone were evaluated. Using data from one study, the ratio of findings in N-9 users to those in hydroxyethylcellulose (HEC) users was compared for findings seen by naked eye and colposcopy versus findings detected only by colposcopy. RESULTS: Of the 403 finding observations in the 9 studies, 173 (43%) would have been missed without colposcopy. Data from the N-9/HEC study showed that without colposcopy, there would have been 7 times as many observations in the N-9 group as in the HEC group (63 vs. 9). With colposcopy, the N-9/HEC ratio was 13:9 or 1.4. Considering epithelial integrity, finding type, and size showed similar patterns, except that among the smallest findings (<5 mm), the N-9/HEC ratio was 1.2 by naked eye and nearly the same at 1.4 by colposcopy. CONCLUSION: Colposcopy was not helpful in identifying an unsafe product: the conclusions reached using naked eye examination alone were more alarming regarding the safety of N-9 than reached by including colposcopy. Recommendations include: (1) naked eye examinations should be continued in microbicide studies; (2) colposcopy may be considered for early studies, such as first-in-human studies, but has no place in large studies; and (3) colposcopy should be replaced as soon as possible with a more objective validated biomarker of HIV risk.

Baseline variation and associations between subject characteristics and five cytokine biomarkers of vaginal safety among healthy non-pregnant women in microbicide trials.

Interleukins (IL)-8, IL-1α, IL-1ß, and IL-1 receptor antagonist (IL-1RA) have emerged as indicators of vaginal inflammation and HIV-1 transmission risk. We provide values and factors of normal variation of these immune mediators in premenopausal women to allow their wider clinical application as biomarkers of vaginal health. Cross-sectional analyzes (Kruskal-Wallis and Wilcoxon exact tests) of cytokine concentrations in relation to sociodemographic variables and Nugent score were performed on baseline (prior to product) cervicovaginal lavage from two Phase I randomized microbicide trials. All women in the analysis had regular menstrual cycles, 72 h abstinence, normal blood and Pap tests, and absence of genitourinary infections, study-relevant allergies, antibiotics use and history of substance abuse. Cytokine norms were defined as the values among those with Nugent score <4. Among women with normal Nugent score (n=92), IL-8 and IL-1ß were lowest in those using abstinence as compared to hormonal contraceptives or male/female sterilization as their primary method for birth control. No difference was found by age, prior pregnancy, or education, and also by race after controlling for contraceptive method. Women with abnormal (>7) and borderline (4-6) Nugent scores had elevated IL-1α and/or IL-1ß although their IL-1RA-to-IL(α+ß) ratio remained within the normal range due to higher IL-1RA. Women with borderline Nugent scores had IL-8 levels above the normal range. IL-8 and the IL-1RA-to-IL-1 ratio can be used as independent biomarkers of vaginal immune balance. More studies must determine the role of sexual activity, contraceptive method, and borderline Nugent scores, which normally are not exclusion criteria for enrollment in microbicide trials but may affect product tolerability and HIV-1 risk due to the aberrant cytokine levels.

Results of a safety and feasibility study of the diaphragm used with ACIDFORM Gel or K-Y Jelly.

BACKGROUND: New strategies are needed for preventing HIV infection in women. One potential approach is female-initiated use of an effective topical microbicidal gel in combination with a cervical barrier such as the diaphragm. STUDY DESIGN: Randomized, placebo-controlled safety and feasibility trial of diaphragm with vaginal gel during 6 months of use among 120 HIV-negative sexually active women in Johannesburg, South Africa. RESULTS: Pelvic event rates were 338.3 and 247.1 per 100 women-years in the ACIDFORM gel (plus diaphragm) and K-Y(R) Jelly (plus diaphragm) groups, respectively, with a rate ratio of 1.37 (95% CI: 0.89-2.11). Most women found diaphragm with gel use acceptable. CONCLUSION: There was a trend towards more safety events in the ACIDFORM plus diaphragm group, although no primary comparisons achieved statistical significance. Adding an effective microbicidal gel to a mechanical barrier may still prove to be an important and acceptable combination method to help prevent pregnancy and HIV/sexually transmitted infection transmission.

Biomarkers of semen exposure.

Biomarkers of semen exposure have historically played their most important role in forensics, i.e., determining whether ejaculation took place in the course of a crime. However, it is becoming increasingly recognized that biomarkers of semen exposure can be useful in the development of new vaginal methods of HIV/sexually transmitted infections (STI) prevention and contraception. This review is based on the presentations of Drs. Michael Coppola (ContraVac, Inc.), Maurizio Macaluso (Centers for Disease Control and Prevention), Andrezej Kulczycki (University of Alabama at Birmingham), Christine Mauck (CONRAD), Robin Maguire (Population Council), and the subsequent discussion led by Drs. Susan Ballagh (CONRAD) and Johan Melendez (Johns Hopkins University) during a session entitled "Biomarkers of semen exposure" held during the conference entitled "Biomarkers for evaluation of vaginal microbicides and contraceptives: Discovery and early validation," organized by CONRAD and the Alliance for Microbicide Development in November of 2006.

Biomarkers for evaluating vaginal microbicides and contraceptives: discovery and early validation.

A biomarker has been defined as "a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes, pharmacological responses to a therapeutic intervention." Biomarkers can reduce the costs and time required to get a drug from discovery to market. Topical microbicides are new drugs designed to prevent HIV and other sexually transmitted infections (STIs). Biomarkers that may be important in microbicide development include biomarkers of semen exposure, biomarkers of cervicovaginal inflammation, and biomarkers of HIV and STIs. The development of biomarkers for use in microbicide development is a high priority. This supplement reports on a meeting entitled "Biomarkers for Evaluating Vaginal Microbicides and Contraceptives: Discovery and Early Validation," held in Reston, VA on November 16 to 17, 2006. It was sponsored by CONRAD and the Alliance for Microbicide Development with funding from the Bill and Melinda Gates Foundation and the United States Agency for International Development (USAID). The meeting was convened to look at the ways in which biomarkers could be used to attenuate the challenges alluded to above. Availability of key biomarkers could expedite the development of microbicides, for which there is a pressing need, especially in developing countries where combinations of cultural and socioeconomic pressures on women constrain their ability to protect themselves from STIs. Although the meeting was held 2 years ago, the material reviewed and conclusions drawn are still relevant.