Phase I randomized safety study of twice daily dosing of acidform vaginal gel: candidate antimicrobial contraceptive

Reversible female contraceptives: historical, current, and future perspectives†

Contraception is a practice with extensive and complicated social and scientific histories. From cycle tracking, to the very first prescription contraceptive pill, to now having over-the-counter contraceptives on demand, family planning is an aspect of healthcare that has undergone and will continue to undergo several transformations through time. This review provides a comprehensive overview of current reversible hormonal and non-hormonal birth control methods as well as their mechanism of action, safety, and effectiveness specifically for individuals who can become pregnant. Additionally, we discuss the latest Food and Drug Administration (FDA)-approved hormonal method containing estetrol and drospirenone that has not yet been used worldwide as well as the first FDA-approved hormonal over-the-counter progestin-only pills. We also review available data on novel hormonal delivery through microchip, microneedle, and the latest FDA-approved non-hormonal methods such as vaginal pH regulators. Finally, this review will assist in advancing female contraceptive method development by underlining constructive directions for future pursuits. Information was gathered from the NCBI and Google Scholars databases using English and included publications from 1900 to present. Search terms included contraceptive names as well as efficacy, safety, and mechanism of action. In summary, we suggest that investigators consider the side effects and acceptability together with the efficacy of contraceptive candidate towards their development.

Lactic acid, citric acid and potassium bitartrate non-hormonal prescription vaginal pH modulator (VPM) gel for the prevention of pregnancy

INTRODUCTION

A non-hormonal prescription vaginal pH modulator (VPM) gel (Phexxi®), with active ingredients lactic acid, citric acid and potassium bitartrate, has recently been approved for prevention of pregnancy in the United States. The objective of this review is to compile the evidence available from published preclinical and clinical trials to support its use.

AREAS COVERED

PubMed was searched for published literature on VPM gel. Two Phase III trials were found on clinicaltrials.gov database. The results demonstrated that VPM gel is safe, with minimal side effects, and effective (cumulative 6-7 cycle pregnancy rate of 4.1-13.65%, (Pearl Index 27.5) as a contraceptive. Microbicidal effects suggest potential for the prevention of sexually transmitted infections (STIs); currently a Phase III clinical trial is being conducted to evaluate prevention of chlamydia and gonorrhea.

EXPERT OPINION

Non-hormonal reversible contraceptive options have been limited to the highly effective copper-releasing intrauterine device that requires insertion by a trained clinician, and less effective coitally-associated barrier and spermicide options which are typically available over-the-counter. Spermicides, which improve efficacy of barrier devices, may increase the risk of HIV/STIs. VPM gel provides a new safe, effective non-hormonal contraceptive option, with potential for prevention of STIs.

EVO100 prevents chlamydia and gonorrhea in women at high risk of infection

BACKGROUND

According to the Centers for Disease Control and Prevention, rates of infection for Chlamydia trachomatis and Neisseria gonorrhoeae are increasing in the United States. EVO100 is an investigational antimicrobial, pH-modulating, vaginal gel with active ingredients L-lactic acid, citric acid, and potassium bitartrate that is being evaluated for the prevention of sexually transmitted infections.

OBJECTIVE

The objective of this phase 2B/3 study was to assess the efficacy and safety of EVO100 for the prevention of chlamydia and gonorrhea.

STUDY DESIGN

AMPREVENCE was a double-blinded, placebo-controlled, multicenter study based in the United States conducted over approximately 16 weeks in women at the age of 18 to 45 years who were at risk of urogenital chlamydia and gonorrhea infection. Enrolled women had been diagnosed as having and treated for chlamydia or gonorrhea ≤16 weeks before enrollment. Women received either EVO100 or placebo vaginal gel and were instructed to apply the study drug immediately before or up to 1 hour before each act of vaginal sexual intercourse. The primary and secondary endpoints were the prevention of urogenital chlamydia and gonorrhea, respectively. Exploratory outcomes include women's overall satisfaction with EVO100.

RESULTS

In total, 860 women were randomized 1:1 to receive EVO100 (n=426) or placebo (n=434), and 764 women (EVO100, n=376; placebo, n=388) were documented as using the study drug at least once. Baseline characteristics were similar between treatment arms. Overall, women had a mean age of 27.7 years (standard deviation, 6.9) and body mass index of 28.9 kg/m² (standard deviation, 8.0). Most women were of White (54.3% [467 of 860]) or African American (41.6% [358 of 860]) race and of non-Hispanic/Latina ethnicity (67.1% [577 of 860]). The chlamydia infection rate in EVO100 users was 4.8% (14 of 289) compared with 9.7% (28 of 290) among placebo users (P=.0256), representing a relative risk reduction of 50%. For gonorrhea, the infection rate was 0.7% (2 of 280) in the EVO100 arm compared with 3.2% (9 of 277) in the placebo arm (P=.0316), representing a relative risk reduction of 78%. Increased efficacy was observed with increased adherence, and chlamydia infection rates were significantly reduced with increased adherence in the EVO100 group compared with placebo. Across both arms, there were similar rates of all-cause adverse events (EVO100, 21.3% [80 of 376]; placebo, 20.4% [79 of 388]) and treatment-related adverse events (EVO100, 7.2% [27 of 376]; placebo, 7.5% [29 of 388]). The most common adverse events in the EVO100 arm were vulvovaginal candidiasis (5.1% [19 of 376]), vaginal discharge (3.2% [12 of 376]), and urinary tract infection (3.2% [12 of 376]) and, in the placebo arm, bacterial vaginosis (4.6% [18 of 388]), urinary tract infection (2.6% [10 of 388]), and vaginal discharge (2.6% [10 of 388]). Few women discontinued owing to adverse events in either arm (EVO100, 1.1% [4 of 376]; placebo, 1.5% [6 of 388]). No treatment-related serious adverse events were reported. Most EVO100 users (88%) were satisfied or very satisfied with EVO100 after 16 weeks of use.

CONCLUSION

EVO100 significantly reduced the risk of chlamydia and gonorrhea infections in women at high risk of Chlamydia trachomatis and Neisseria gonorrhoeae infection and was well tolerated, with observed adverse events consistent with its known safety profile.

Multipurpose Prevention Technologies: Oral, Parenteral, and Vaginal Dosage Forms for Prevention of HIV/STIs and Unplanned Pregnancy

There is a high global prevalence of HIV, sexually transmitted infections (STIs), and unplanned pregnancies. Current preventative daily oral dosing regimens can be ineffective due to low patient adherence. Sustained release delivery systems in conjunction with multipurpose prevention technologies (MPTs) can reduce high rates of HIV/STIs and unplanned pregnancies in an all-in-one efficacious, acceptable, and easily accessible technology to allow for prolonged release of antivirals and contraceptives. The concept and development of MPTs have greatly progressed over the past decade and demonstrate efficacious technologies that are user-accepted with potentially high adherence. This review gives a comprehensive overview of the latest oral, parenteral, and vaginally delivered MPTs in development as well as drug delivery formulations with the potential to advance as an MPT, and implementation studies regarding MPT user acceptability and adherence. Furthermore, there is a focus on MPT intravaginal rings emphasizing injection molding and hot-melt extrusion manufacturing limitations and emerging fabrication advancements. Lastly, formulation development considerations and limitations are discussed, such as nonhormonal contraceptive considerations, challenges with achieving a stable coformulation of multiple drugs, achieving sustained and controlled drug release, limiting drug-drug interactions, and advancing past preclinical development stages. Despite the challenges in the MPT landscape, these technologies demonstrate the potential to bridge gaps in preventative sexual and reproductive health care.

Topical microbicides for preventing sexually transmitted infections

BACKGROUND

This is a updated version of our Cochrane Review published in Issue 6, 2012. Sexually-transmitted infections (STIs) continue to rise worldwide, imposing an enormous morbidity and mortality burden. Effective prevention strategies, including microbicides, are needed to achieve the goals of the World Heath Organization (WHO) global strategy for the prevention and control of these infections.

OBJECTIVES

To determine the effectiveness and safety of topical microbicides for preventing acquisition of STIs, including HIV.

SEARCH METHODS

We undertook a comprehensive search of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, LILACS, CLIB, Web of Science, ClinicalTrials.gov, WHO International Clinical Trials Registry Platform, and reference lists of relevant articles up to August 2020. In addition, we contacted relevant organisations and experts.

SELECTION CRITERIA

We included randomised controlled trials of vaginal microbicides compared to placebo (except for nonoxynol-9 because it is covered in related Cochrane Reviews). Eligible participants were sexually-active non-pregnant, WSM and MSM, who had no laboratory confirmed STIs.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened and selected studies, extracted data, and assessed risks of bias in duplicate, resolving differences by consensus. We conducted a fixed-effect meta-analysis, stratified by type of microbicide, and assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included eight trials from the earlier version of the review and four new trials, i.e. a total of 12 trials with 32,464 participants (all WSM). We did not find any eligible study that enrolled MSM or reported fungal STI as an outcome. We have no study awaiting assessment. All 12 trials were conducted in sub-Saharan Africa, with one having a study site in the USA, and another having a site in India. Vaginal microbicides tested were BufferGel and PRO 2000 (1 trial, 3101 women), Carraguard (1 trial, 6202 women), cellulose sulphate (2 trials, 3069 women), dapivirine (2 trials, 4588 women), PRO 2000 (1 trial, 9385 women), C31G (SAVVY) (2 trials, 4295 women), and tenofovir (3 trials, 4958 women). All microbicides were compared to placebo and all trials had low risk of bias. Dapivirine probably reduces the risk of acquiring HIV infection: risk ratio (RR) 0.71, (95% confidence interval (CI) 0.57 to 0.89, I² = 0%, 2 trials, 4588 women; moderate-certainty evidence). The other microbicides may result in little to no difference in the risk of acquiring HIV (low-certainty evidence); including tenofovir (RR 0.83, 95% CI 0.68 to 1.02, cellulose sulphate (RR 1.20, 95% CI 0.74 to 1.95, BufferGel (RR 1.05, 95% CI 0.73 to 1.52), Carraguard (RR 0.89, 95% CI 0.71 to 1.11), PRO 2000 (RR 0.93, 95% CI 0.77 to 1.14), and SAVVY (RR 1.38, 95% CI 0.79 to 2.41). Existing evidence suggests that cellulose sulphate (RR 0.99, 95% CI 0.37 to 2.62, 1 trial, 1425 women), and PRO 2000 (RR 0.95, 95% CI 0.73 to 1.23) may result in little to no difference in the risk of getting herpes simplex virus type 2 infection (low-certainty evidence). Two studies reported data on tenofovir's effect on this virus. One suggested that tenofovir may reduce the risk (RR 0.55, 95% CI 0.36 to 0.82; 224 participants) while the other did not find evidence of an effect (RR 0.94, 95% CI 0.85 to 1.03; 1003 participants). We have not reported the pooled result because of substantial heterogeneity of effect between the two studies (l² = 85%). The evidence also suggests that dapivirine (RR 1.70, 95% CI 0.63 to 4.59), tenofovir (RR 1.27, 95% CI 0.58 to 2.78), cellulose sulphate (RR 0.69, 95% CI 0.26 to 1.81), and (Carraguard (RR 1.07, 95% CI 0.75 to 1.52) may have little or no effect on the risk of acquiring syphilis (low-certainty evidence). In addition, dapivirine (RR 0.97, 95% CI 0.89 to 1.07), tenofovir (RR 0.90, 95% CI 0.71 to 1.13), cellulose sulphate (RR 0.70, 95% CI 0.49 to 0.99), BufferGel (RR 0.97, 95% CI 0.65 to 1.45), Carraguard (RR 0.96, 95% CI 0.83 to 1.12), and PRO 2000 (RR 1.01, 95% CI 0.84 to 1.22) may result in little to no difference in the risk of acquiring chlamydia infection (low-certainty evidence). The evidence also suggests that current topical microbicides may not have an effect on the risk of acquiring gonorrhoea, condyloma acuminatum, trichomoniasis, or human papillomavirus infection (low-certainty evidence). Microbicide use in the 12 trials, compared to placebo, did not lead to any difference in adverse event rates. No study reported on acceptability of the intervention.  AUTHORS' CONCLUSIONS: Current evidence shows that vaginal dapivirine microbicide probably reduces HIV acquisition in women who have sex with men. Other types of vaginal microbicides have not shown evidence of an effect on acquisition of STIs, including HIV. Further research should continue on the development and testing of new microbicides.

Lactic acid-containing products for bacterial vaginosis and their impact on the vaginal microbiota: A systematic review

Objective

The vaginal microbiota in bacterial vaginosis (BV) typically has low abundance of lactic acid producing lactobacilli. Lactic acid has properties that may make it effective for treating BV and/or restoring an optimal lactobacillus-dominated vaginal microbiota. We conducted a systematic review to describe the effect of intravaginal lactic acid-containing products on BV cure, and their impact on vaginal microbiota composition (PROSPERO registration: CRD42018115982).

Methods

PubMed, Embase and OVID were searched from inception to November 2019 to identify eligible studies. Included studies evaluated an intravaginal lactic acid-containing product and reported BV cure using established diagnostic methods, and/or vaginal microbiota composition using molecular methods. Studies were independently screened and assessed, and the proportion of women cured post-treatment was calculated. Study results were described in a qualitative manner.

Results

We identified 1,883 articles and assessed 57 full-texts for eligibility. Seven different lactic acid-containing products were evaluated and differed with respect to excipients, lactic acid concentration and pH. Most studies had medium or high risk of bias. Three trials compared the efficacy of a lactic acid-containing product to metronidazole for BV cure. One study found lactic acid to be equivalent to metronidazole and two studies found lactic acid to be significantly inferior to metronidazole. Two studies included a control group receiving a placebo or no treatment. One reported lactic acid to be superior than no treatment and the other reported lactic acid to be equivalent to placebo. Lactic acid-containing products did not significantly impact the vaginal microbiota composition.

Conclusion

There is a lack of high-quality evidence to support the use of lactic acid-containing products for BV cure or vaginal microbiota modulation. However, adequately powered and rigorous randomised trials with accompanying vaginal microbiota data are needed to evaluate the efficacy of lactic acid as a BV treatment strategy.

Development of multipurpose technologies products for pregnancy and STI prevention: update on polyphenylene carboxymethylene MPT gel development†

Current modern contraceptives rely heavily on the use of hormones. These birth control drug products, including pills, patches, injections, and IUDS, have been extremely beneficial to millions of women and their families over the past 50 years. But a surprisingly high number of women abandon such modern methods, many because they cannot tolerate the side effects and others because they have medical issues for which hormonal methods are contraindicated. In addition, modern hormonal methods are simply not available to many women. The extent of this problem is steadily becoming more apparent. We present the case for developing simple nonhormonal vaginal products that women can use when needed, ideal products that are multipurpose and offer both contraception and sexually transmitted disease protection. Gel-based vaginal products are particularly well suited for this purpose. Gels are easy to use, highly acceptable to many women, and can be safely formulated to enhance natural vaginal defenses against infection. However, the development of a new chemical entity for this application faces significant technical and regulatory hurdles. These challenges and our solutions are described for polyphenylene carboxymethylene (PPCM), a novel topical drug in a vaginal gel nearing human clinical trials. We have advanced PPCM from benchtop to IND-enabling studies and provide a brief description of the complex development process. We also describe a simple lab assay which can be used as a biomarker for contraceptive activity to enable pharmacodynamic studies in vaginal contraceptive development, both preclinically and in early human clinical trials.

A novel vaginal pH regulator: results from the phase 3 AMPOWER contraception clinical trial

Objective

The objective was to evaluate the contraceptive effectiveness, safety, and acceptability of a novel vaginal pH regulator over seven cycles of use.

Study design

A single-arm, open-label, phase 3 study was conducted across 112 sites in the United States in sexually active 18–35-year-old women at risk of pregnancy. Women administered the study treatment ≤ 1 h before each episode of intercourse. Women recorded use of study drug, coital information, and any symptoms experienced in electronic diaries. The primary outcome was the seven-cycle cumulative pregnancy rate as calculated using the Kaplan–Meier methodology; secondary outcomes included safety. Overall satisfaction was assessed via written questionnaires.

Results

A total of 1384 women were enrolled in the study from July 2017 to November 2018. Mean age was 27.7 ± 4.4 years; most women were white (69.0%). The seven-cycle cumulative pregnancy percentage was 13.7% [95% confidence interval (CI): 10.0%–17.5%], meeting the prespecified primary endpoint of having the upper bound 95% CI ≤ 21%. Most common adverse events (AEs) occurring in ≥ 2% of women were vulvovaginal burning sensation, vulvovaginal pruritus, urinary tract infection, vulvovaginal pain, mycotic infection, bacterial vaginosis, and nasopharyngitis. Of 1330 women who used the study drug at least once, fewer than 2% of women discontinued due to any AEs, and < 1% of women discontinued due to genitourinary symptoms. Overall, > 80% of women reported being “very satisfied” or “satisfied” with study treatment.

Conclusions

In this phase 3 study, the novel vaginal pH regulator demonstrated 86.3% contraceptive effectiveness, was safe and well tolerated, and was highly acceptable.

Implications

This novel vaginal pH regulator is a safe, nonhormonal, woman-controlled method of contraception that expands women's options.

Biomaterials and Contraception: Promises and Pitfalls

The present state of reproductive and sexual health around the world reveals disparities in contraceptive use and effectiveness. Unintended pregnancy and sexually transmitted infection transmission rates remain high even with current prevention methods. The 20th century saw a contraceptive revolution with biomedical innovation driving the success of new contraceptive technologies with central design concepts and materials. Current modalities can be broadly categorized according to their mode of function: reversible methods such as physical/chemical barriers or hormonal delivery devices via systemic (transdermal and subcutaneous) or localized (intrauterine and intravaginal) administration, and nonreversible sterilization procedures such as tubal ligation and vasectomy. Contraceptive biomaterials are at present dominated by well-characterized elastomers such as polydimethylsiloxane and ethylene vinyl acetate due to their favorable material properties and versatility. Contraceptives alter the normal function of cellular components in the reproductive systems to impair fertility. The purpose of this review is to highlight the bioengineering design of existing methods, explore novel adaptations, and address notable shortcomings in current contraceptive technologies.

An overview of properties of Amphora (Acidform) contraceptive vaginal gel

INTRODUCTION

Although only a minority of contracepting women rely solely on spermicides, they may soon be the only ongoing female method available without a prescription in the United States. Spermicides are also combined with other methods for additional pregnancy protection and/or lubrication. Nonoxynol-9 (N-9), the active ingredient in most spermicides, is cytotoxic and may increase risk of transmission of HIV and other sexually transmitted infections, especially in high-risk women. Amphora (previously called Acidform) is a noncytotoxic spermicide composed of a series of generally regarded as safe compounds, which maintains the acidity of the vagina following coitus to immobilize and kill sperm. Amphora is currently Food and Drug Administration-approved as a vaginal lubricant. Amphora is currently being tested in a multicenter Phase III contraceptive trial.

AREAS COVERED

This paper describes key properties of Amphora, including its acid-buffering abilities, viscosity, stability, bioadhesiveness, and tolerability.

EXPERT OPINION

Amphora is a nontoxic spermicide that maintains the pH within the vagina at levels less than 5.0 for hours, which immobilizes and kills sperm as well as many sexually transmitted pathogens. If the current clinical trial demonstrates safety, efficacy, and tolerability of Amphora as a contraceptive, it would represent a viable alternative to N-9. Its potential as a microbicide warrants further investigation.

Vaginal lactic acid elicits an anti-inflammatory response from human cervicovaginal epithelial cells and inhibits production of pro-inflammatory mediators associated with HIV acquisition

Inflammation in the female reproductive tract (FRT) is associated with increased HIV transmission. Lactobacillus spp. dominate the vaginal microbiota of many women and their presence is associated with reduced HIV acquisition. Here we demonstrate that lactic acid (LA), a major organic acid metabolite produced by lactobacilli, mediates anti-inflammatory effects on human cervicovaginal epithelial cells. Treatment of human vaginal and cervical epithelial cell lines with LA (pH 3.9) elicited significant increases in the production of the anti-inflammatory cytokine IL-1RA. When added simultaneously or prior to stimulation, LA inhibited the Toll-like receptor agonist-elicited production of inflammatory mediators IL-6, IL-8, TNFα, RANTES, and MIP3α from epithelial cell lines and prevented IL-6 and IL-8 production by seminal plasma. The anti-inflammatory effect of LA was mediated by the protonated form present at pH≤3.86 and was observed with both L- and D-isomers. A similar anti-inflammatory effect of LA was observed in primary cervicovaginal cells and in an organotypic epithelial tissue model. These findings identify a novel property of LA that acts directly on epithelial cells to inhibit FRT inflammation and highlights the potential use of LA-containing agents in the lower FRT as adjuncts to female-initiated strategies to reduce HIV acquisition.

Evaluation of immunological markers of ovine vaginal irritation: Implications for preclinical assessment of non-vaccine HIV preventive agents

The presence of genital inflammatory responses and a compromised vaginal epithelial barrier have been linked to an increased risk of HIV acquisition. It is important to assure that application of candidate microbicides designed to limit HIV transmission will not cause these adverse events. We previously developed high resolution in vivo imaging methodologies in sheep to assess epithelial integrity following vaginal application of a model microbicide, however characterization of genital inflammation in sheep has not been previously possible. In this study, we significantly advanced the sheep model by developing approaches to detect and quantify inflammatory responses resulting from application of a nonoxynol-9-containing gel known to elicit vaginal irritation. Vaginal application of this model microbicide resulted in foci of disrupted epithelium detectable by confocal endomicroscopy. Leukocytes also infiltrated the treated mucosa and the number and composition of leukocytes obtained by cervicovaginal lavage (CVL) were determined by differential staining and flow cytometry. By 18h post-treatment, a population comprised predominantly of granulocytes and monocytes infiltrated the vagina and persisted through 44h post-treatment. The concentration of proinflammatory cytokines and chemokines in CVL was determined by quantitative ELISA. Concentrations of IL-8 and IL-1β were consistently significantly increased after microbicide application suggesting these cytokines are useful biomarkers for epithelial injury in the sheep model. Together, the results of these immunological assessments mirror those obtained in previous animal models and human trials with the same compound and greatly extend the utility of the sheep vaginal model in assessing the vaginal barrier and immune microenvironment.

Non-Antiretroviral Microbicides for HIV Prevention

Non-antiretroviral microbicide candidates were previously explored as a female-controlled method of preventing sexual transmission of HIV. These products contained non-HIV specific active compounds that were ultimately found to disrupt the vaginal epithelium, cause increased immune activation in the female genital tract, disturb vaginal flora, and/or cause other irritation that precluded their use as vaginal microbicides. Due to the failure of these first-generation candidates, there was a shift in focus to developing HIV pre-exposure prophylaxis and microbicides containing small-molecule antiretrovirals. Even with the limited success of the antiretroviral-based microbicides in clinical evaluations and no commercially available products, there has been significant progress in microbicide research. The lessons learned from previous trials have given rise to more rigorous preclinical evaluation that aims to be better at predicting microbicide efficacy and safety and to novel formulation and delivery technologies. These advances have resulted in renewed interest in developing non-antiretroviral-based microbicides, such as broadly neutralizing antibodies (for example, VRC01) and anti-viral proteins (for example, Griffithsin), as options for persons not wanting to use antiretroviral drugs, and for their potential to prevent multiple sexually transmitted infections.

An update on multipurpose prevention technologies for the prevention of HIV transmission and pregnancy

INTRODUCTION

Multipurpose Prevention Technologies (MPTs) are designed to address two or more indications from a single product. The overall goal is to prevent unintended pregnancy and transmission of one or more STIs including HIV-1.

AREAS COVERED

The topics covered herein are advances in over the past three years. Advances include development of novel intravaginal rings capable of releasing microbicides to prevent transmission of HIV-1 and unintended pregnancy. These rings include the potential to prevent transmission of more than one STI and unintended pregnancy. There are also gels that can potentially accomplish the same thing. Finally, combination of a drug and barrier device are also covered.

EXPERT OPINION

There has been considerable advance in this field over the past three years. There is one ring currently in a Phase I clinical trial and others are soon to follow. Some of these drug delivery systems are by necessity rather complicated and hence could be prohibitively expensive in the developing world. Conducting multiple clinical trials to support regulatory approval of two or more indications represents a significant barrier. It remains unclear that women will be more motivated to use MPT products than has been observed in recent microbicide-only clinical trials. Despite these challenges, the need for MPTs remain acute hopefully ensuring they will continue to be developed over the coming years.

Multipurpose prevention technologies for reproductive and sexual health

Global statistics on unplanned pregnancies, abortions and STIs show that unprotected sex is still widely practised. More needs to be done to provide women and men with a wider choice of convenient protective options. To address this need, international efforts are focusing on developing multipurpose prevention technologies (MPTs) that address two or more indications simultaneously. These technologies would have significant advantages over single-indication products. They include inter alia novel barrier devices, drugs administered either as oral tablets or vaginal/rectal gels, drugs used in combination with medical devices, and genetically engineered organisms which secrete antimicrobial substances. As an example of progress in the MPT field, this paper describes an on-demand contraceptive/antimicrobial vaginal gel, Amphora (previously known as Acidform), now in an advanced stage of development. Clinical trials are currently being planned to find out whether this product's promising antimicrobial profile translates into protective and preventive choices.

Loss of Innate Host Defense Following Unprotected Vaginal Sex

BACKGROUND

Multiple host defense mechanisms protect the female genital tract from pathogens, but the impact of sexual intercourse on defense is unknown.

METHODS

As part of a hypothesis-generating study, 17 women provided cervicovaginal lavage (CVL) specimens at baseline (all had abstained from sexual intercourse, masturbation, and vaginal product use for 72 hours prior to screening), 2-6 hours and 10-14 hours after vaginal intercourse with a male condom, and 2-6 hours and 10-14 hours after vaginal intercourse without a male condom (5 visits total, including the baseline visit). Vaginal pH, concentrations of immune molecules, and antimicrobial activity at postcoital visits were compared to baseline values.

RESULTS

Vaginal pH and the transforming growth factor β1 level increased, but human beta-defensin 2 (HBD-2), HBD-3, and interleukin 8 levels decreased after unprotected sex. Median Escherichia coli inhibitory activity in CVL specimens decreased significantly from baseline at the visit 2-6 hours after unprotected sex (63% [range, -34% to 99%] vs 5% [range, -51% to 100%]; P = .02) and remained low at the visit 10-14 hours after unprotected sex (6% [range, -19% to 92%]; P = .02). Pooled human seminal plasma enhanced E. coli growth in vitro in a dose-dependent manner and, when added to CVL samples with high anti-E. coli activity, reversed the inhibition.

CONCLUSIONS

Unprotected vaginal sex results in a reduction in endogenous anti-E. coli activity, which may reflect, in part, enhancement of bacterial growth by seminal plasma. This finding may contribute to the risk of E. coli vaginal colonization following sexual intercourse.

Recent advances on anti-HIV vaginal delivery systems development

A review of the recent outcomes regarding technologies to prevent vaginal transmission of HIV, mainly by using antiretroviral (ARV) drugs formulated as microbicides. An introduction about the HIV transmission mechanisms by the vaginal route is included, together with the recent challenges faced for development of successful microbicide products. The outcomes of clinical evaluations are mentioned, and the different formulation strategies studied to-date, with the requirements, advantages, disadvantages and limitations of each dosage-form type, are presented. Finally, the recent attempts to apply various types of nanotechnologies in order to develop advanced microbicide-products and overcome existing limitations, are discussed.

Poly(ethylene glycol) (PEG)-lactic acid nanocarrier-based degradable hydrogels for restoring the vaginal microenvironment

Women with bacterial vaginosis (BV) display reduced vaginal acidity, which make them susceptible to associated infections such as HIV. In the current study, poly(ethylene glycol) (PEG) nanocarrier-based degradable hydrogels were developed for the controlled release of lactic acid in the vagina of BV-infected women. PEG-lactic acid (PEG-LA) nanocarriers were prepared by covalently attaching lactic acid to 8-arm PEG-SH via cleavable thioester bonds. PEG-LA nanocarriers with 4 copies of lactic acid per molecule provided controlled release of lactic acid with a maximum release of 23% and 47% bound lactic acid in phosphate buffered saline (PBS, pH7.4) and acetate buffer (AB, pH4.3), respectively. The PEG nanocarrier-based hydrogels were formed by cross-linking the PEG-LA nanocarriers with 4-arm PEG-NHS via degradable thioester bonds. The nanocarrier-based hydrogels formed within 20 min under ambient conditions and exhibited an elastic modulus that was 100-fold higher than the viscous modulus. The nanocarrier-based degradable hydrogels provided controlled release of lactic acid for several hours; however, a maximum release of only 10%-14% bound lactic acid was observed possibly due to steric hindrance of the polymer chains in the cross-linked hydrogel. In contrast, hydrogels with passively entrapped lactic acid showed burst release with complete release within 30 min. Lactic acid showed antimicrobial activity against the primary BV pathogen Gardnerella vaginalis with a minimum inhibitory concentration (MIC) of 3.6 mg/ml. In addition, the hydrogels with passively entrapped lactic acid showed retained antimicrobial activity with complete inhibition G. vaginalis growth within 48 h. The results of the current study collectively demonstrate the potential of PEG nanocarrier-based hydrogels for vaginal administration of lactic acid for preventing and treating BV.

The evolving design and methods for trials evaluating the safety of candidate vaginal microbicides: a systematic review

Vaginal preexposure prophylaxis is a promising biomedical tool for HIV prevention. Although guidelines for the clinical assessment of microbicides are available, validated markers for product safety are lacking. To inform future microbicide and multipurpose vaginal product research, we reviewed the current and past safety methods used. We searched the Cochrane, EMBASE, and Ovid MEDLINE databases for clinical studies of vaginal products for the prevention of HIV that included safety evaluations. Ninety-seven clinical studies involving 21 products were identified: 63 lasted 14 days or less, 19 were longer in duration, and 15 were effectivess studies that included also safety as an outcome. Median sample size in the safety studies was 48 participants (range, 10-799). All studies reported on urogenital endpoint, 71% included colposcopy, and 67% assessed the vaginal microflora. Markers of vaginal epithelial inflammation, systemic absorption, and systemic toxicology assessments were evaluated in 29%, 26%, and 43% of studies, respectively. Excluding the effectiveness studies, these same assessments were done before 1998 in 33%, 7%, and 27% and after 2001 in 38%, 44%, and 60% of studies, respectively. Soluble inflammatory markers were introduced after 2001. Adverse event collection was reported in 73% of studies before 1998 and in 98% after 2001. In a previous review, we recommended that larger and longer safety studies were necessary to detect clinically important toxicities and to provide assurance that agents are ready for large-scale effectiveness trials. Here, we propose a stepwise clinical assessment that can be used for future guidance.

Cultivated vaginal microbiomes alter HIV-1 infection and antiretroviral efficacy in colonized epithelial multilayer cultures

There is a pressing need for modeling of the symbiotic and at times dysbiotic relationship established between bacterial microbiomes and human mucosal surfaces. In particular clinical studies have indicated that the complex vaginal microbiome (VMB) contributes to the protection against sexually-transmitted pathogens including the life-threatening human immunodeficiency virus (HIV-1). The human microbiome project has substantially increased our understanding of the complex bacterial communities in the vagina however, as is the case for most microbiomes, very few of the community member species have been successfully cultivated in the laboratory limiting the types of studies that can be completed. A genetically controlled ex vivo model system is critically needed to study the complex interactions and associated molecular dialog. We present the first vaginal mucosal culture model that supports colonization by both healthy and dysbiotic VMB from vaginal swabs collected from routine gynecological patients. The immortalized vaginal epithelial cells used in the model and VMB cryopreservation methods provide the opportunity to reproducibly create replicates for lab-based evaluations of this important mucosal/bacterial community interface. The culture system also contains HIV-1 susceptible cells allowing us to study the impact of representative microbiomes on replication. Our results show that our culture system supports stable and reproducible colonization by VMB representing distinct community state types and that the selected representatives have significantly different effects on the replication of HIV-1. Further, we show the utility of the system to predict unwanted alterations in efficacy or bacterial community profiles following topical application of a front line antiretroviral.

ACIDFORM: a review of the evidence

OBJECTIVE

ACIDFORM is a candidate microbicide with spermicidal properties. A large Phase 3 trial is underway, and it is anticipated that this product will be approved for contraceptive use and marketed soon in the United States. The goal of this article is to critically review the evidence supporting the properties, safety profile and different uses of ACIDFORM gel.

STUDY DESIGN

We searched PubMed and Medline for any published literature on ACIDFORM.

RESULTS

ACIDFORM is an acidifying agent that works by lowering the vaginal pH to enhance the normal vaginal defenses. In addition to strong acid-buffering properties, ACIDFORM has high bioadhesive and viscosity-retaining properties. Several Phase 1 clinical trials have demonstrated the vaginal safety of ACIDFORM used alone or in combination with a diaphragm, although dose-dependent side effects appear to be present. Studies investigating the efficacy of ACIDFORM against sexually transmitted infections (STIs) are promising, but further trials are needed.

CONCLUSIONS

The properties of ACIDFORM offer many advantages for use, either alone or in combination with another active ingredient, such as Tenofovir. Potential applications for ACIDFORM include use as a personal lubricant, a vaginal contraceptive (alone or with a barrier method) and a microbicidal product or as a formulation vehicle for an active ingredient.

IMPLICATIONS

ACIDFORM is a candidate female-controlled vaginal preparation with microbicidal and spermicidal properties. A dual protection method could prevent unwanted pregnancies and reduce the risk of STI acquisition.

Use of the dye stain assay and ultraviolet light test for assessing vaginal insertion of placebo-filled applicators before and after sex

BACKGROUND

Applicator dye staining and ultraviolet (UV) light have been used in trials to measure adherence, but not in the setting of before and after sex gel dosing (BAT-24). This study was designed to determine if semen or presex gel dosing impacts the sensitivity and specificity of a dye stain assay (DSA) for measuring vaginal insertion of placebo-filled applicators with BAT-24 dosing.

METHODS

Healthy monogamous couples received Microlax-type applicators (Tectubes, Åstorp, Sweden) filled with hydroxyethylcelluose placebo gel. Women were instructed to vaginally insert 1 dose of gel before and a second dose after sex and to return applicators within 48 hours after sex. Applicators were stained to detect semen, followed by UV then DSA, and scored by 2 readers. Positive and negative controls were randomly included in applicator batches.

RESULTS

Fifteen couples completed the study. Each woman returned at least 6 applicators over a 30-day period. The sensitivity for insertion of postsex applicators was higher for UV (97%) compared with DSA (90%), and the specificity was similar (≥96%). For presex applicators, the sensitivity and specificity were higher for DSA (100%) compared with UV testing (87% sensitivity, 96% specificity). Among returned postsex applicators, 95% tested positive by UV compared with 87% by DSA. Agreement between readers was significantly better on the presex applicators for DSA than for UV, and for postsex readings, agreement was less than half that for UV, although the results were not statistically significant.

CONCLUSIONS

Applicator tests are feasible for measuring adherence in trials with gel dosing before and after sex.

Evaluation of 3 approaches for assessing adherence to vaginal gel application in clinical trials

BACKGROUND

Accurate measurement of adherence to product use is an ongoing challenge in microbicide trials.

METHODS

We compared adherence estimates using 2 applicator tests (a dye stain assay [DSA] and an ultraviolet light assay [UVA]), the Wisebag (an applicator container that electronically tracks container openings), and self-reported adherence (ability, frequency, and percent missed doses). Healthy, HIV-negative, nonpregnant US women aged 23 to 45 years received a Wisebag and 32 applicators filled with placebo gel were instructed to insert 1 applicator daily for 30 days, returned the Wisebag and all applicators, and completed an exit interview. Emptied applicators were tested by UVA and then DSA, and scored by 2 blinded readers. Positive and negative controls were randomly included in applicator batches.

RESULTS

Among 42 women enrolled, 39 completed the study. Both DSA and UVA yielded similar sensitivity (97% and 95%) and specificity (79% and 79%). Two participants had fully inoperable Wisebags, and 9 had partially inoperable Wisebags. The proportion of participants considered to have high adherence (≥80%) varied: 43% (Wisebag), 46% (UVA), 49% (DSA), and 62% to 82% (self-reports). For estimating high adherence, Wisebag had a sensitivity of 76% (95% confidence interval, 50%-93%) and a specificity of 85% (95% confidence interval, 62%-97%) compared with DSA. Although 28% of participants reported forgetting to open the Wisebag daily, 59% said that it helped them remember gel use.

CONCLUSIONS

Dye stain assay and UVA performed similarly. Compared with these tests, self-reports overestimated and Wisebag underestimated adherence. Although Wisebag may encourage gel use, the applicator tests currently seem more useful for measuring use in clinical trials.