FDA Issues Guidance For HIV Prevention Drugs

A host of safe and effective HIV prevention drugs could be an invaluable tool in the fight against the spread of HIV/AIDS worldwide, but clinical research required to develop such products is a tricky terrain for scientists to navigate. With this in mind, the FDA has issued a guidance for vaginal microbicides which offers suggestions for the design of clinical trial and ethical concerns surrounding potential trial candidates.

According to the FDA, vaginal microbicides can take the form of gels, creams, tablets, films, or devices, which are designed to be self-administered and which prevent or reduce the risk of HIV transmission.

Unitaid, a non-profit organization, issued a comprehensive report in 2013 detailing the development of these preventative treatments and their importance. According to their report, the pipeline for HIV prevention products is active and strong, with many projected to enter the market in the next few years.

Despite active research, there is currently only one such product approved by the FDA: Gilead Sciences’ Truvada.

The Regulatory Affairs Professionals Society (RAPS) explains that clinical testing for these products is extremely risky. Some products have increased risk rather than reduced it, usually due to failures in patient adherence.

Because of these factors, scientists must take special considerations into the design of their clinical trials.

The FDA guidance suggests that researchers explain the importance of explaining risk and the importance of adherence and urge patients not to use the product as an excuse to engage in riskier behavior than is normal.

Furthermore, the FDA considers the promotion of condom-use in addition to the experimental product an “ethical imperative” in clinical study. Scientists may also offer the use of clinically proven products as part of the trial’s safety precautions.

The FDA points out the particular importance in long-term clinical study. The report explains, “Because usage rates of microbicide and/or other prevention methods as well as sexual behavior patterns are expected to fluctuate over time, and long term safety events may potentially reduce efficacy over time, longer term duration efficacy trials are preferred because they can capture the effect of these variables and are more likely to reflect the real world effects.”

The guidance also specifies that accelerated approval is not available for these products.

Though condoms remain the most effective method of preventing HIV transmission, the WHO reports that the development of vaginal microbicides is particularly advantageous for women because they are self-administered, do not require cooperation of a partner and give women some agency over their reproductive health.

According to Unitaid, 49 percent of HIV/AIDS patients worldwide are women, and the rate of infection is rapidly spreading. Unitaid’s studies indicate a woman is newly infected with the virus every minute.