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October 31, 2010

FDA and CONRAD Chart U.S. Regulatory Path for 1% Tenofovir Gel for HIV Prevention

CONRAD: "The U.S. Food and Drug Administration (FDA) held an end-of-Phase II meeting to determine the next steps required for U.S. licensure of 1% tenofovir gel, a microbicide product recently found to be effective at reducing the rate of HIV and herpes infection in women when used before and after sex.

"The meeting, held on October 20, 2010, was requested by CONRAD, a division of the Eastern Virginia Medical School in Norfolk, VA. CONRAD was one of the partners in the Phase II study, “CAPRISA 004,” which evaluated 1% tenofovir gel in prevention of male-to-female HIV transmission in 889 women in South Africa. USAID provided funding for the trial, conducted by the Centre for Programme Research for AIDS in South Africa and U.S. based FHI, which was the first study to show that a vaginal gel can reduce the risk of HIV and herpes infection in women. CONRAD manufactured and provided the tenofovir gel for the study.

"Tenofovir gel was found to be 39% effective in reducing a woman’s risk of becoming infected with HIV during sex and 51% effective in preventing genital herpes infections in the women participating in the trial. Results of the CAPRISA 004 clinical trial were reported in July 2010 and represent the first “proof of concept” for a vaginal microbicide."

Comment (by JSJ): This is great news. But it could be better. 39% reduction means that 61% of the infections were not stopped.

Is there a good case for a higher dose, e.g. 2%? If yes, the 1% approvaL should still proceed, and a (vastly smaller and vastly less expensive) safety trial with higher dose(s) should be done as well. Moving toward approving the 1% is how regulators act, which is how scientists and companies then act, so it may be the best we can expect from the conventional wisdom.

But if the obstacle is that there isn't money any more for big efficacy trials to get "ideal" dose information, people still need to be empowered to make intelligent decisions using all the information to protect themselves and others, and reduce or end the epidemic.

Perhaps test safety of the standard gel with more tenofovir mixed in, so that countries or pharmacists could more easily prepare a higher dose formulation before it becomes standard.

Or maybe test safety of adding a standard tenofovir pill to the post-sex use of the gel? No reformulation needed.