A combination of the drugs raltegravir and lamivudine produced acceptable drug levels in both women and men, in rectal and vaginal tissues, suggesting that the two drugs could provide an effective alternative to tenofovir-based pre-exposure prophylaxis (PrEP), the 25th Annual Conference of the British HIV Association (BHIVA) heard in Bournemouth yesterday.
Dr Julie Fox of Guy’s and St Thomas’s Foundation Trust told the meeting that explant studies, in which cells from tissue biopsies from people treated with the drugs are exposed to HIV, showed that the drug combination completely suppressed viral replication in rectal tissues after just two days, and after eight days in vaginal tissues.
Dr Fox said that raltegravir (an integrase inhibitor) was researched because it was a very effective and well-tolerated drug and reached high levels quickly in the rectum, suggesting it could be used as PrEP, at least in gay men and for anal sex.
Lamivudine was chosen because the drug is very similar to emtricitabine and the World Health Organization has recommended it as a substitute in PrEP. However, data on it are sparse and this is one of the first studies to measure whether it reached protective levels in tissues.
Even with tenofovir alafenamide (TAF) now available, not everyone tolerates tenofovir, and having a second oral PrEP drug combination to offer would give doctors and users a choice.
Originally, she told aidsmap.com, one drug company had been proposing to co-formulate raltegravir and lamivudine in a combination pill, ideal for PrEP. They had decided not to proceed, but Dr Fox said that she hoped this study would encourage them to reconsider.