Other Research

CONRAD has been spearheading the effort to find a biomarker of semen exposure suitable for use in contraceptive and microbicide efficacy trials.

Clinical Updates

Compliance and Adherence Studies

Biomarkers are increasingly used in all fields of medicine and are applicable for monitoring compliance.  CONRAD is conducting several  studies in this area:

Clinical Study of PSA, Yc-DNA and New Semen Biomarkers 

Primary Objective:  To characterize the vaginal residence time (decay time) of prostate-specific antigen (PSA), the sex determining region of the Y chromosome (Yc-DNA) using two different primers and protamine-2 in two groups of women who are exposed to semen via either inoculation or unprotected intercourse.  

Secondary Objectives:  To see whether collecting specimens at more time points results in depletion; to compare levels of markers between inoculation and unprotected intercourse; and to compare levels of markers obtained by clinical sampling vs. participant sampling at home.

Status:  17 out of the targeted 32 women have been enrolled.

 Interference of Semen Biomarker Detection by Vaginal Products

In a post-(delete dash and closeup)coital study of the SILCS diaphragm, nonoxynol-9 (N-9) appeared to interfere with detection of PSA. This was confirmed in the laboratory.  In addition, Replens interfered with PSA detection and Astroglide, KY, N-9 and Replens interfered with Yc-DNA detection.  Current plans include testing UC781, HEC and tenofovir in the laboratory and confirming results in the clinic.

Utility of PSA in Female Condom Studies

CONRAD convened a USAID-sponsored meeting in July 2008 to find a biomarker that could be validated against a biological endpoint, such as pregnancy or an STI, to augment slippage and breakage studies for approval of a new female condom.   The goal was to eliminate the need for the currently required contraceptive effectiveness trial. 

Results:  PSA is the best indicator of female condom performance and it is felt to be stronger evidence than pregnancy or STIs, given the extreme variability in fertility, timing of sex, partner infection, participant compliance and self-reporting of compliance expected in contraceptive and STI prevention studies. This information will be used in an upcoming study of the PATH Woman’s Condom and the Female Condom 2.  NIH will conduct a concurrent contraceptive efficacy study of the PATH Woman’s Condom.

Support of Xhale Project

An additional biomarker study will use proprietary technology developed for oral dosing to tag vaginal products and detect the taggants in the breath.

Learn more.

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Biomarkers

One of the strengths of our program is our capacity to take a novel biomarker from discovery to clinical validation. Biomarkers are biochemical substances that can be used to measure the progress of disease or the effects of treatment. In the area of vaginal product research, biomarkers could give early information about the safety and likely efficacy of both contraceptive and microbicide products, facilitating triage of less promising candidate products. In addition, biomarkers of sexual behavior and study product use could help with interpretation of study results. As examples, CONRAD is developing new biomarkers of cervicovaginal inflammation, indicating safety or lack of it, and new biomarkers of vaginal exposure to semen, indicating whether intercourse unprotected by condoms took place. 

If a biomarker of HIV transmission could be found that would give an early indication of the likely efficacy of a candidate microbicide before thousands of women are enrolled in a Phase III trial, the benefit to the microbicide field, and perhaps others, would be great. Because of this critical potential, work on biomarkers and surrogates of safety and efficacy is a priority action called for by the Microbicide Development Strategy produced under the aegis of the Microbicide Donors’ Committee with support from the Bill & Melinda Gates Foundation.

Read more about CONRAD's biomarker research.