Johannesburg - Gilead Sciences, the US biotechnology company that produces antiretroviral (ARV) treatment tenofovir, is waiting for the Medicines Control Council (MCC) to rule on its application to allow the use of the ARV drug for the prevention of HIV transmission through sexual intercourse.

Researchers at the Centre for the Aids Programme of Research in SA (Caprisa) had obtained evidence that encouraged them to look at the use of ARV drugs as an additional technology for the prevention of HIV transmission through sex, Caprisa associate scientific director Abdool Karim told the 16th International Congress on Infectious Diseases in Cape Town yesterday.

Different studies analysed by Caprisa had all shown a pattern of decreasing HIV transmission where ARV treatment coverage increased.

Gilead Sciences submitted its application to the MCC about eight months ago.

Karim said under perfect usage of the drug, where there was maximum adherence to the dosage guidelines, the topical gel version of tenofovir had 74 percent effectiveness in preventing transmission of the virus. The oral version, which has to be taken every day, had 82 percent effectiveness in perfect usage.

“[Gilead Sciences] has also got agreements in place for low-cost availability. The cost of the drug is not a problem at all,” Karim said.

The tenofovir oral drug is already used in South Africa’s ARV treatment combination and is available in retail pharmacies on prescription but it is not licensed for prevention purposes. Tenofovir gel is not yet available in South Africa.

Karim noted that of the technologies developed to reduce the spread of HIV, South Africa was only using ARVs to stop mother-to-child transmission.

“We do not have a single new technology to reduce transmission due to sexual spread,” he said.

The research carried out by Caprisa showed that if South Africa just continued with its current HIV treatment trajectory, which was already showing a steady decline in the number of new HIV infections, the benefits of that decline would continue to increase.

However, if ARVs were used for prevention, and if there was increased acceptance of male circumcision and more people were put on ARV treatment early, the drop in HIV transmission would be much quicker.

“We have seen now, for the first time, empirical evidence that if you scale up antiretroviral treatment, that as you increase antiretroviral coverage, you get a steady decline in the HIV transmission rate.”

This evidence was obtained from two scientific studies conducted in a rural community in northern KwaZulu-Natal.

Karim said researchers had reached a stage in HIV control that they had never seen to date and described this point in fighting the epidemic as a “tipping point”.

For instance, there were two new drugs using nanotechnology: GSK744, an investigational drug from GlaxoSmithKline, and Rilpivirine tmc278, which was being developed by Tibotec.

With these technologies, HIV patients would potentially need to come for four injections once a year and could have a viral load test installed on a little gadget that fitted on a cellphone, Karim added.

Up to July 2010, the world had used behavioural strategies like condoms and male circumcision to prevent the transmission of HIV through sexual intercourse.

Later in 2010, technologies using microbicides, topical ARVs for women for pre-exposure prevention, emerged.

“All these together showed us the potential value of using ARVs for prophylaxis. But it is really the additional value we have seen on the potential of treatment to provide prevention as one of its outcomes.” - Business Report