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

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.

A CCR5 antagonist-based HIV entry inhibitor exhibited potent spermicidal activity: Potential application for contraception and prevention of HIV sexual transmission

B07 is a small-molecule CCR5 antagonist-based HIV-1 entry inhibitor that is being developed as an anti-HIV microbicide for preventing sexual transmission of HIV. Here we evaluated its spermicidal and contraceptive potential, including sperm motility, plasma membrane integrity, and contraceptive efficacy tested in rabbits. We found that B07 inhibited sperm motility and movement patterns in a concentration- and time-dependent manner. Within 30 min, B07 induced sperm immobilization with the minimum 100% effective concentration and median effective concentration of 640.0 and 64.4 μg/mL, respectively. The hypo-osmotic swelling test showed that plasma membranes of B07-treated sperms exhibited slight disruption, as verified by electron micrographs. In both B07 gel and N-9 gel groups, not a single implantation site or embryo was observed based on the contraceptive efficacy test in rabbits, indicating that B07 could effectively block the potential of sperm to reach and/or fertilize oocytes. The safety profile of B07 in vivo was evaluated by use of an optimized rabbit vaginal irritation test. While the pathological scores of the N-9 gel group was 14.67 ± 1.21, those of the blank control and B07 gel groups were 2.17 ± 0.76 and 4.00 ± 0.89, respectively, which were within the clinically acceptable range (<8). The proportion of inflammatory cells and CD45⁺ cells in the cervicovaginal lavages of the B07 gel group showed no significant change compared to those of the control group. Therefore, our results confirmed that B07 exhibited significant spermicidal and contraceptive effects, suggesting its potential for development as a microbicidal spermicide for contraception and prevention of HIV sexual transmission.

The use of biomarkers of semen exposure in sexual and reproductive health studies

Biomarkers of semen exposure have been used in studies investigating the safety and efficacy of barrier methods of contraception. They have been used as objective indicators of semen exposure when studying sexual behaviors and in human immunodeficiency virus/sexually transmitted infection research interventions where participants are advised to avoid unprotected sex. Semen biomarkers have also been used to assess or validate self-reported sexual behaviors or condom use in reproductive health settings. Prostate-specific antigen (PSA) and Y chromosome DNA (Yc-DNA) have each been evaluated in the past as semen biomarkers and are the most widely used in the field. While both are considered reliable for evaluating exposure to semen, each has unique characteristics. In this report, we summarize the literature and provide some considerations for reproductive health researchers who are interested in using PSA or Yc-DNA as semen biomarkers. We also synthesize our previous published work on the optimal conditions of collecting and storing specimens and assay performance in the presence of other vaginal products that may influence various assays. Semen biomarkers are innovative and promising tools to further study and better understand women's reproductive and sexual health and behavior. More research is needed to better understand the strengths, limitations, and optimal performance conditions of specific assays in vivo.