AIDS drug pushed for prevention

As the U.S. Food and Drug Administration weighs approval of a radical new method of AIDS prevention – a prescription pill taken once a day – advocates say the results of experimental trials in sub-Saharan Africa argue strongly for the drug’s adoption in the United States.

The pill was developed to treat people already infected with HIV. But studies published Wednesday by the New England Journal of Medicine demonstrate that it can also prevent heterosexual transmission of HIV, the most common mode of contagion in Africa.

A growing number of doctors in the U.S. are already prescribing the drug to uninfected high-risk patients as an off-label use, and some insurers are covering the considerable expense.

The blue tablets, which are sold under the brand name Truvada, contain a combination of two antiretroviral drugs called tenofovir and emtricitabine. Researchers began studying Truvada’s ability to prevent the spread of HIV to uninfected gay men and heterosexual men and women several years ago; the FDA has said it will make a determination on the drug’s use for HIV prevention by Sept. 14.

Publication of the Africa drug trials comes less than two weeks before the International AIDS Conference convenes in Washington, D.C. The results, as well as the FDA’s deliberations, are likely to be hot-button issues there, since advocates and critics of using Truvada for prevention have found ammunition for their views in the studies’ findings.

Most notably, the Los Angeles-based AIDS Healthcare Foundation is vehemently opposed to the drug’s approval as a prophylaxis in the U.S. because it says the pill is dangerous, overly expensive and will detract from proven methods of AIDS prevention, such as condom use.

In each of the trials published Wednesday, test subjects were given Truvada or a placebo. They also received counseling on HIV risk reduction, condom use and other contraceptives.

The study that showed the highest rate of success involved 4,747 married couples in Kenya and Uganda. In each case, one of the spouses had HIV and the other was uninfected. Truvada reduced transmission of the virus by up to 75 percent, according to the report; the medication was deemed so effective that the study ended early and people on the placebo switched to the drug.

However, a related study that focused exclusively on healthy women in Kenya, South Africa and Tanzania – some married, some unmarried – was discontinued early because Truvada failed to significantly reduce infection rates. Although 95 percent of test subjects told researchers they were taking the pills regularly, blood tests suggested that less than 40 percent of the women actually did so.

“We hypothesize that the women’s perception that they were at low risk for HIV infection may have contributed to the poor adherence,” wrote the study authors, who were from the U.S., South Africa, Kenya, Britain and Belgium. Daily pill regimens may have also posed a difficulty for some of the women, though the researchers weren’t sure why.