Subjects: Behavioral health
Last month, scientists reported that Truvada, Gilead’s once-a-day pill that is normally used to treat HIV infection, can be used to prevent HIV infection as well.
The report appeared in the New England Journal of Medicine. In the study, nearly 2,500 HIV-negative gay and bisexual men were randomized to receive either Truvada or a placebo. Study participants who received the anti-retroviral pill were 44% less likely to become HIV-positive during the 15 month follow-up than folks in the control group. The risk reduction was 73% among men who managed to take the pill every day or nearly every day.
The study results “represent a major advance in HIV research,” Kevin Fenton, the CDC’s HIV/AIDS czar told the Wall Street Journal. Even President Obama was moved to comment that the study, and those like it “could mark the beginning of a new era in HIV prevention.”
Truvada contains 2 drugs produced by Gilead: tenofovir and emtricitabine. Both drugs are reverse transcriptase inhibitors, which block replication of the AIDS virus in the human body. Normally, Truvada is combined with 2 other drugs to create a cocktail for the treatment of AIDS. This is the first time Truvada has been tested for its ability to prevent infection in the first place.
Gay and bisexual men comprise nearly half of the one million-or-so people who are HIV positive in this country. They are 44 times more likely to be HIV positive than other men.
Despite the apparently good news about Truvada, many public health officials raised concerns that people would not take the drug every day or fail to use condoms in a mistaken belief that the drug is, by itself, enough to prevent HIV infection. There were good reasons for this concern. Men in the study whose adherence to the once-a-day regimen was less than 90% experienced only a 21% reduction in infection risk.
It’s also not clear that Truvada will be similarly effective in IV-drug abusers or heterosexuals, since HIV enters the body via different routes in these people. Studies of Truvada’s prophylactic efficacy in these groups are underway.
The CDC plans to release guidelines for using Truvada to prevent HIV/AIDs in the near future. The drug hasn’t been approved for this purpose by the FDA, but physicians can prescribe drugs for off-label uses if they want.
By the way, Truvada costs just under $1,000 per month in the US. Also of note, the scientists responsible for the so-called Prep trial covered here are continuing to follow enrollees to look for drug resistance and long-term side effects. It’s something to keep in mind as the dust settles on this exciting finding.