ViiV Healthcare submits New Drug Application to the FDA for fostemsavir, an investigational, first-in-class attachment inhibitor for the treatment of HIV in adults with few treatment options available

Antiretroviral medicines that can effectively suppress HIV have been instrumental in decreasing disease progression, HIV transmission, and AIDS-related deaths, but because of HIV’s ability to constantly change, some individuals can develop viral resistance to antiretroviral medicines, causing their treatment regimens to fail. Challenges with tolerability, safety, and drug-to-drug interactions may further decrease the number of acceptable antiretroviral therapies available to design effective treatment regimens. There remains an unmet need for these individuals who are considered heavily treatment-experienced and who are unable to successfully suppress their HIV.    

Deborah Waterhouse, CEO of ViiV Healthcare, said: “Fostemsavir may provide an important treatment option for the group of people living with HIV who, for a variety of reasons, are not able to suppress their virus with other medicines and could be left with few or no treatments available to them. In keeping with our mission of leaving no person with HIV behind, we have overcome many barriers to bring this important new medicine to people living with HIV, including investing in what is a very complex manufacturing process. We look forward to working with the FDA to make fostemsavir available to the people in the US who need it.”

About BRIGHTE
The efficacy of fostemsavir in heavily treatment-experienced adults with HIV-1 infection is based on 96-week data from the phase III, partially-randomized, international, double-blind, placebo-controlled BRIGHTE study (NCT02362503). 

The BRIGHTE trial was conducted in 371 heavily treatment-experienced adults living with HIV-1 infection with multidrug resistance. All trial participants were required to have a viral load ≥400 copies/mL and ≤2 classes of antiretroviral medications remaining at baseline due to resistance, intolerability, contraindication, or other safety concerns. Trial participants were enrolled in either a randomized or nonrandomized cohort defined as follows:

• Within the randomized cohort (n = 272), participants had 1, but no more than 2, fully active and available antiretroviral agent(s) at screening which could be combined as part of an efficacious background regimen. randomized participants received either blinded fostemsavir 600 mg twice daily (n = 203) or placebo (n = 69) in addition to their current failing regimen for 8 days of functional monotherapy. Beyond Day 8, randomized participants received open-label fostemsavir 600 mg twice daily plus an investigator-selected optimized background therapy.
• Within the nonrandomized cohort (n = 99), participants had no fully active and approved antiretroviral agent(s) available at screening. Nonrandomized participants were treated with open-label fostemsavir 600 mg twice daily plus OBT from Day 1 onward. The use of an investigational drug(s) as a component of the optimized background therapy was permitted in the nonrandomized cohort.

The primary endpoint analysis, based on the adjusted mean decline in HIV-1 RNA from Day 1 at Day 8 in the randomized cohort, demonstrated superiority of fostemsavir to placebo (0.79 vs. 0.17 log10 copies/mL decline, respectively; P<0.0001, Intent-to-Treat-Exposed [ITT-E] population). In the randomized cohort, HIV-1 RNA <40 copies/mL was achieved in 53%, 54%, and 60% of subjects at Weeks 24, 48, and 96, respectively (ITT-E, Snapshot algorithm). Mean changes in CD4+ cell count from baseline continued to increase over time (i.e., 90 cells/mm3 at Week 24, 139 cells/mm3 at Week 48, and 205 cells/mm3 at Week 96). The most common adverse reactions (incidence ≥5%, all grades) were nausea and diarrhoea. The proportion of participants who discontinued treatment with fostemsavir due to an adverse event was 7% at Week 96 (randomized: 5% and nonrandomized 12%).