ViiV’s Investigational HIV Drug Finds Success in Hard-to-Treat Patient Population

HIV patients who have gone through multiple treatment options but still have not kept their virus under control due to being multi-drug resistant may soon have a new therapy that will suit their medical needs for virologic suppression and immunologic response following the release of late-stage data at an AIDS Society conference.

ViiV Healthcare, the HIV-focused joint venture of GlaxoSmithKline, Pfizer and Shinogi Limited, said its Phase III BRIGHTE study hit its 96-week endpoints in heavily treatment-experienced adults with HIV-1 infection. The late-stage trial was assessing the investigational drug, fostemsavir, a first-in-class attachment inhibitor, used in combination with optimized background treatment (OBT) in this tough-to-treat population. Patients who have been unable to control their virus through standard antiretroviral treatments can see the development of selected mutations resistant to one or more antiretroviral medicines.

The results from the Phase III BRIGHTE study though show promise for these patients. At 96 weeks, 60% of patients receiving fostemsavir plus OBT in the randomized cohort achieved virologic suppression. That was a 6% increase over the 48-week results. At 96 weeks, the fostemsavir-dosed patients saw an increase in CD4+ T-cell counts, a mean change from baseline of +205 cells per microliter, ViiV said. Also at 96 weeks, ViiV said 67% of patients with a baseline CD4 of less than 200 cells per microliter increased to a CD4 greater than or equal to 200 cells per microliter. Also, 56% of patients with a baseline CD4 of less than 50 cells per microliter increased to a CD4 of greater than or equal to 200 cells per microliter.

ViiV plans to seek regulatory approval with the U.S. Food and Drug Administration for fostemsavir later this year, the company said.

Kimberly Smith, head of global research and medical strategy at ViiV, said the findings from the BRIGHTE trial reinforce fostemsavir as a potential treatment option for those heavily treatment-experienced patients. Of that patient population, Smith said they “have few options available to them due to the complexities of resistance, safety, tolerability, contraindications and prior treatment failure.” Now with the BRIGHTE study, those patients can see a potential for more successful treatment.

“We look forward to completing the necessary regulatory approval process to make this promising therapy available to the people living with HIV who need it,” Smith said in a brief statement.

Findings from the Phase III BRIGHTE trial were presented Monday at the 10th International AIDS Society Conference of HIV Science in Mexico City. While the BRIGHTE trial did achieve its endpoints at 96 weeks, ViiV noted that all of the patients who received fostemsavir experienced at least one adverse event. The most common adverse events were nausea, diarrhea and headache, respectively. ViiV said at least one serious adverse event was experienced by 38% of the total treated patients, the most common of which were attributed to infections or infestations. In all, 3% of serious adverse events were related to the study medication with 1% leading to discontinuation of study medication. ViiV noted that there were 29 deaths that occurred during the trial. Of those, seven were AIDS-related and 11 were acute infections, six were non-AIDS-related malignancies and the remaining five were due to other conditions. ViiV said that 79% of the deaths occurred in patients with baseline CD4+ T-cell counts of less than 50 cells per microliter. The median baseline CD4+ T-cell counts for all patients who died was 11 cells per microliter.

ViiV has been on a roll lately with its pipeline. Earlier this month, the company presented data that showed its combination of recently-approved Dovato (dolutegravir plus lamivudine) had similar success in maintaining viral suppression t 48 weeks as patients on a tenofovir alafenamide fumarate (TAF)-containing regimen of at least three drugs. Also this year, ViiV submitted a New Drug Application to the FDA for approval of its monthly injectable combination of ViiV’s cabotegravir and Janssen’s rilpivirine (Edurant) as a treatment of HIV-1 in adults whose viral load is suppressed and who are not resistant to cabotegravir or rilpivirine.