8 February 2021 - - The European Marketing Authorisation of Rukobia (fostemsavir) 600mg extended-release tablets, for use in combination with other antiretroviral therapies for the treatment of adults with multidrug-resistant HIV-1 infection, for whom it is otherwise not possible to construct a suppressive anti-viral regimen, UK-based specialist HIV company ViiV Healthcare said.

ViiV Healthcare is majority owned by British pharmaceutical company GlaxoSmithKline plc (NYSE: GSK), with Pfizer Inc. (NYSE: PFE) and Shionogi Ltd. as shareholders.

Fostemsavir is a first-in-class HIV attachment inhibitor; it works by targeting the first step of the HIV lifecycle and shows no cross-resistance to other currently licensed antiretroviral classes, offering a new option to this group of people who are multidrug-resistant and at risk of disease progression and death.

The Marketing Authorisation Application for fostemsavir is supported by data from the pivotal phase III BRIGHTE study, which evaluated the safety and efficacy of fostemsavir in combination with an optimised background therapy in heavily treatment experienced adults living with multidrug-resistant HIV, many of whom had advanced HIV disease at study entry. In the randomised cohort, 60% (n=163/272) of individuals who received fostemsavir in addition to an investigator-selected OBT achieved undetectable HIV viral load and clinically significant improvements to CD4+ T-cell count through Week 96.2

The most commonly seen treatment emergent adverse reactions were diarrhoea, headache, nausea, rash, abdominal pain, and vomiting.

The most common adverse events leading to discontinuation were related to infections. The most serious adverse reaction was immune reconstitution inflammatory syndrome.

Fostemsavir, under the brand name Rukobia, was licensed by the US Food and Drug Administration on 2 July 2020, and further regulatory applications have been submitted worldwide.

As the only pharmaceutical company solely focused on HIV and AIDS, ViiV Healthcare is working to deliver a range of treatments that meet the needs of a wide variety of people living with HIV (PLHIV).

The company continues to invest in R and D programmes that push the boundaries to provide a portfolio of innovative treatment options that will help make a difference to the lives of PLHIV.

Fostemsavir is a first-in-class HIV-1 attachment inhibitor.

After oral administration, fostemsavir is converted to temsavir, which is then absorbed and exerts antiviral activity by attaching directly to the glycoprotein 120 (gp120) subunit on the surface of the virus, thereby blocking HIV from attaching to host immune system CD4+ T-cells and preventing the virus from infecting those cells and multiplying.

As fostemsavir is the first ARV therapy to target this step of the viral cycle, there is no demonstrated resistance to other classes of ARVs, which may help patients whose HIV infection has become resistant to most other medicines.

The BRIGHTE trial is an international, phase III, partially-randomised, double-blind, placebo-controlled study 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 ARV medications remaining at baseline due to resistance, intolerability, contraindication, or other safety considerations.

Trial participants were enrolled in either a randomised or nonrandomised cohort defined as follows:

Within the randomised cohort (n = 272), participants had 1, but no more than 2, fully active and available ARV agent(s) at screening, which could be combined as part of an efficacious background regimen.

Randomised 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, randomised participants received open-label fostemsavir 600 mg twice daily plus an investigator-selected optimised background therapy. The randomised cohort provides primary evidence of efficacy of fostemsavir.

Within the nonrandomised cohort (n = 99), participants had no fully active and licensed ARV agent(s) available at screening. Nonrandomised 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 optimised background therapy was permitted in the nonrandomised cohort.

The primary endpoint analysis, based on the adjusted mean decline in HIV-1 RNA from Day 1 at Day 8 in the randomised cohort, demonstrated superiority of fostemsavir to placebo (0.79 vs. 0.17 log10 copies/mL decline, respectively; P