Before sex Aids pill trials to start

• Survey in Bondo intended to show that the drug can stop HIV infection

A new study to find out whether a single pill taken daily before sexual intercourse can prevent HIV infection is to be done among 700 virus-free women in Bondo District, Nyanza.

The study, beginning in May, will run alongside others in Botswana, Tanzania, Malawi, South Africa, the US, Thailand, Peru and Ecuador.

The trial drug, Truvada, which is registered in Kenya and is used as an anti-retroviral, prevents the virus from reproducing itself inside the cells of infected people. The new thinking is: Can it prevent infection in a negative person who becomes exposed to the virus?

According to Family Health International (FHI), a leading organisation in the proposed trials, studies have shown that using Truvada before being exposed to the virus provides significant protection to primates that have been repeatedly exposed to an HIV-like virus.

The Bondo study, called Female Pre-Exposure Prophylaxis, follows a similar one among 2,000 discordant couples in Kisumu, Thika, Eldoret and Nairobi by the universities of Nairobi and Washington.

The study on discordant couples — where one partner is HIV positive but does not infect the other — began last year and is scheduled to end in 2011. According to the Kenya Aids Indicator Survey 2007, about half of infected couples are discordant.

High exposure

“The key objective of the Bondo study is to determine the effectiveness and safety of a daily dose of Truvada in preventing transmission in HIV-negative women facing a high exposure rate through sexual intercourse,” says Dr Kawango Ogot, the principal investigator.

Dr Ogot, who has been involved in several HIV studies including the relationship between the virus and male circumcision, says the study has been granted the necessary government approvals.

During the study period, says FHI, all participants will be provided with standard HIV-prevention services like free condoms, counselling, screening and treatment for sexually transmitted infections.

The clinical trials will compare a group that receives standard prevention services plus Truvada to a second group that receives standard prevention services plus a placebo. A placebo is a dummy medicine containing no active ingredients.

Participants who become infected during the trial will receive counselling and agreements will be in place to provide referrals to medical and social services.

“If they are willing, the HIV-positive women will be monitored for disease progression and resistance to Truvada for at least 12 more months. These participants will be counselled to use all precautions to limit the transmission of the virus to others,” the researchers say.

Even as these studies are taking place, one of the key concerns is whether the virus will develop resistance to the ARVs being used.

“One of the key questions is whether individuals who get infected while on Truvada will acquire an HIV strain that is resistant to this medicine,” says Dr Ogot.

At the moment, she says, the most important thing is to find out whether taking the pill once a day will prevent HIV infection.

Dr Ogot says that if one becomes infected even after safety measures have been observed, administration of the drug will be discontinued immediately and any resistance to the drugs will be closely monitored.

Another challenge is the fact that the drug’s effects on the unborn child is not yet known. And as such, maintains Dr Ogot, all participants will be put on contraceptives prior to and during the study period.