US approves first-ever pill for HIV prevention
By Kerry Sheridan, AFP
July 18, 2012, 12:06 am TWN
Participants were selected at random to take a daily dose of Truvada — a combination of 200 milligrams of emtricitabine and 300 milligrams of tenofovir disoproxil fumarate — or a placebo.
Those in the study who took the drug regularly had almost 73 percent fewer infections. Across the entire study, including those who had not been as diligent in taking Truvada, there were 44 percent fewer infections than in those who took a placebo.
A second study on 4,758 heterosexual couples in which one partner was infected with HIV and the other was not, showed that Truvada reduced the risk of becoming infected by 75 percent compared with a placebo.
Experts have described the results as game changing and the first demonstration that an already approved oral drug could decrease the likelihood of HIV infections.
Common side effects were the same as experienced by people with HIV who were taking Truvada, and included diarrhea, nausea, abdominal pain, headache, and weight loss.
However, adherence rates — meaning how often people in the study actually took the drug daily — were low in the study of men who have sex with men, just 30 percent, Birnkrant said.
In the study of heterosexual partners, adherence was much higher, between 80 and 90 percent.
Therefore, the drug label must include special instructions for health care providers on how to counsel potential users of the drug.
The drugmaker must also include a warning that Truvada for PrEP "must only be used by individuals who are confirmed to be HIV-negative prior to prescribing the drug and at least every three months during use."
Gilead Sciences is also required to collect samples from people who test positive for HIV while taking the drug and analyze them for signs of drug resistance.
As to concerns about whether the pill might boost risky sex practices and lead people to abandon condoms as a first line of protection, Birnkrant said the studies have not shown that so far.