ViiV Healthcare’s investigational entry inhibitor fostemsavir has helped fully suppress HIV in a majority of those with virus so severely multidrug-resistant that they had only a maximum of two other antiretroviral (ARV) options, aidsmap reports.

Presenting their findings at the International Congress on Drug Therapy in HIV Infection (HIV Glasgow) in Scotland, researchers conducted a study, called BRIGHTE, that included 371 people with multidrug-resistant HIV. Ninety-two of them had no approved ARVs left that would work against their virus and 272 of them had either one or two workable ARVs remaining.

Those in the group that had one or two workable ARVs were randomized to receive fostemsavir (203 people) or a placebo for eight days (69 people), after which they all received fostemsavir on an open-label basis (meaning they knew they were taking the active drug) plus what is known as an optimized background regimen of ARVs.

The participants who had no approved ARVs left that would suppress their virus were all immediately put on fostemsavir and an optimized background regimen, which could include investigational drugs.

On average, participants began the study with a baseline viral load of 40,000. Three quarters of them had a CD4 count below 200, indicating an AIDS diagnosis.

Twenty participants died during the study, including eight members of the group that was randomized and 12 members of the group that received treatment immediately.

During the eight-day placebo-controlled period, those who received fostemsavir saw their viral load drop by 0.8 log10, or about 6.5-fold, compared with a 0.2 log10 drop among those who received the placebo.

After 48 weeks, 62 percent of those in the randomized group had a viral load below 40 and 86 percent had a viral load below 400. Of those in the immediate-treatment group, 48 percent had a viral load below 40 and 55 percent had a viral load below 400.

The randomized group experienced an average rise in CD4 count of 139, while the immediate-treatment group gained an average of 64 CD4s.

The treatment was generally relatively safe. The most common adverse health events were nausea, diarrhea and headache. One third of those in the randomized group and 44 percent of those in the immediate-treatment group had to stop treatment at some point.

To read a press release about the study, click here.

To read the aidsmap article, click here.