GSK snags first-in-class FDA nod for Rukobia to treat HIV patients who have few options

Despite the many HIV drugs on the market, some patients still can’t be successfully treated due to resistance. Now, they have a new option.

Thursday, the FDA approved GlaxoSmithKline subsidiary ViiV Healthcare’s Rukobia, used in combination with other existing antiretroviral therapies, for patients resistant to multiple HIV drugs.

The med, also known as fostemsavir, is the first in a new class called attachment inhibitors. By latching onto the gp120 protein on the surface of HIV, it blocks the virus from entering and infecting immune cells.

Heavily pretreated HIV patients need drugs with new mechanisms given cross-resistance, where resistance to one drug may mean resistance to other drugs within the same class. In 2018, the FDA ended more than 10 years of drought for a novel HIV drug class by approving Taiwanese firm TaiMed Biologics’ Trogarzo, a post-attachment inhibitor, for multidrug-resistant HIV.

Rukobia’s efficacy was proven in the phase 3 Brighte study. In the randomized part of the study with 272 patients resistant to multiple drugs, 60% who got twice-daily oral Rukobia on top of an investigator-selected background therapy achieved successful virologic suppression at week 96, an increase from 53% after 24 weeks. Bear in mind these patients have taken many different drug combinations to fight their HIV; about 85% had tried—but failed—at least five different regimens.

Besides quashing viral loads, the regimen also helped boost patients’ immune systems, with a mean increase of CD4+ T-cell counts by 205 cells/mm3 at week 96. Patients with low CD4 counts are more vulnerable to other infections. A normal CD4 count for a healthy person ranges from 500 cells/mm3 to 1,500 cells/mm3.

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GSK’s ViiV got its hands on Rukobia from Bristol Myers Squibb in 2015 when the latter sold off all its R&D programs in HIV for $350 million upfront.

Heavily treatment-experienced patients only account for about 6% of the entire HIV population on medicaton. It’s a small group, but ViiV still decided to spend more than $20 million to build two manufacturing facilities dedicated to making Rukobia at its Parma, Italy, site mainly due to its complex manufacturing process.

ViiV’s priority these days includes establishing its two-drug HIV regimens as the new standard of care, winning back FDA’s heart for recently rejected long-acting injection Cabenuva, and getting its proposed long-acting cabotegravir across the regulatory finish line as a new PrEP option.

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All those projects have rival Gilead Sciences in mind. The Big Biotech is leading the HIV market with three-drug therapy Biktarvy, which raked in nearly $2 billion in the first four full quarters since its FDA go-ahead in February 2018. Combined 2019 sales of ViiV’s dual-drug regimens—Juluca and Dovato—came in at £422 million ($528 million).

Meanwhile, Gilead’s also working on its own potential first-in-class drug: long-acting capsid inhibitor lenacapavir (GS-6207). New data presented at this year’s ongoing International AIDS Conference showed the med has potential given once every six months. Merck & Co. has islatravir (MK-8591), a first-in-class nucleoside reverse transcriptase translocation inhibitor that the New Jersey pharma predicts could work as a one-year implant.