ViiV files first-in-class HIV drug in Europe

ViiV Healthcare has filed its new HIV drug fostemsavir for approval in Europe, a few weeks after the US, as a rescue therapy for people who can’t control their infection with current drugs.

The HIV specialist – which is majority-owned by GlaxoSmithKline – is seeking approval from the EMA of fostemsavir as an add-on to other antiretroviral therapy (ART) drugs in adults with multidrug resistant HIV.

The first-in-class HIV attachment inhibitor – which binds to glycoprotein 120 (gp120) on the envelope of HIV and stops the virus latching on to host cells – will be targeted at patients for whom an effective virus-suppressing regimen can’t be selected because of “resistance, intolerance or safety considerations.”

Its mechanism of action means there is no cross-resistance to other classes of  ART drug, according to ViiV.

HIV’s notorious ability to mutate and develop resistance to current drugs means that while most people with HIV can expect long-term suppression with drug therapy, some experience treatment failures that progressively limit the drugs they can use to control the infection.

“Although these individuals make up a small percentage of the total number of people who live with HIV, their unmet treatment needs are life-threatening and we are committed to addressing them,” said ViiV’s chief executive Deborah Waterhouse.

The FDA filing is based on the phase 3 BRIGHTE study, which showed that fostemsavir was significantly better than placebo when added on to current therapy at reducing viral load in this hard-to-treat patient population. 

Fostemsavir is just one of a series of new drugs that ViiV is hoping will help it compete in the coming years with Gilead Sciences, the market leader in HIV treatment and its arch-rival in the category.

It’s not expected to be a massive earner for the company – analysts have predicted peak sales could be around $400 million a year – but its clinical importance to patients starting to lose control of their infection is profound.

ViiV’s new generation of two-drug oral therapies like Juluca (dolutegravir/rilpivirine) and long-acting injectable ART therapies are the key to its battle with Gilead, which is in ascendency at the moment with its single-tablet three-drug product Biktarvy (bictegravir/emtricitabine/tenofovir alafenamide fumarate).

Launched in 2018, Biktarvy made almost $3.2 billion in sales in the first three quarters of 2019, becoming Gilead’s top-selling HIV therapy ahead of four-drug combo Genvoya (elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide fumarate).

Meanwhile, ViiV suffered a setback last month when the FDA rejected its once-monthly injectable Cabenuva, based on integrase inhibitor cabotegravir and Johnson & Johnson’s non-nucleoside reverse transcriptase inhibitor (NNRTI) rilpivirine, after finding fault with manufacturing data for the drug.

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