The New Drug Application (NDA) for fostemsavir (ViiV Healthcare), a first-in-class HIV-1 attachment inhibitor for the treatment of HIV-1 infection, has been submitted to the Food and Drug Administration (FDA).

Fostemsavir, an investigational prodrug of temsavir, works by binding directly to the glycoprotein 120 (gp120) subunit on the surface of the virus. This blocks HIV from attaching to host immune system CD4+ T-cells and other immune cells and prevents the virus from infecting cells and multiplying.

The NDA submission was based on data from the phase 3, double-blind, placebo-controlled, 2-cohort BRIGHTE study that evaluated the efficacy and safety of fostemsavir in heavily treatment-experienced adults with multidrug-resistant HIV-1 infection (N=371). Patients were enrolled in either a randomized (n=272) or nonrandomized cohort (n=99). The primary end point was the mean change in log10 HIV-1 RNA from Day 1 at Day 8 in the randomized cohort.

  • In the randomized cohort, patients who had to have 1 but no more than 2 fully active antiretroviral agents, received either fostemsavir 600mg twice daily (n=203) or placebo (n=69) in addition to their current failing regimen for 8 days. After Day 8, patients received fostemsavir 600mg twice daily plus an investigator-selected optimized background therapy (OBT).
  • In the nonrandomized cohort, patients received fostemsavir 600mg twice daily plus OBT from Day 1. 

Results showed that treatment with fostemsavir in the randomized cohort met the primary end point demonstrating superiority to placebo (0.79 vs. 0.17 log10 copies/mL decline, respectively; P <.0001, Intent-to-Treat-Exposed [ITT-E] population). Moreover, at Weeks 24, 48, and 96, HIV-1 RNA <40 copies/mL was achieved in 53%, 54%, and 60% of patients in the randomized cohort, respectively. Patients also showed continued improvement in mean changes in CD4+ cell count from baseline up to Week 96 (90 cells/mm3 at Week 24, 139 cells/mm3 at Week 48, and 205 cells/mm3 at Week 96).

With regard to safety, the most common adverse reactions were nausea and diarrhea.

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“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 […] We look forward to working with the FDA to make fostemsavir available to the people in the US who need it,” said Deborah Waterhouse, CEO of ViiV Healthcare, said: 

The FDA previously granted Fast Track and Breakthrough Therapy designations to fostemsavir.

For more information visit viivhealthcare.com.