Glaxo's two-drug HIV bet looks good in phase 3 studies—and turns up the heat on Gilead

GSK logo building
GlaxoSmithKline's two-drug HIV combo performed as well as three- and four-drug cocktails did in a pair of phase 3 studies.

GlaxoSmithKline’s HIV drug unit, ViiV Healthcare, has placed a risky development bet on two-drug regimens. But on Monday, the company announced some data that so far affirms its approach.

Two phase 3 studies showed that a combo of GSK’s dolutegravir—already marketed solo as quick-launching Tivicay—and Johnson & Johnson compound rilpivirine measured up to three- or four-drug cocktails in the efficacy department, the company said. Glaxo will roll out more details at a medical meeting next year, and it’s also planning to apply for regulatory approval in 2017.

GSK’s approach is a departure from the three-med combos rival Gilead Sciences is cooking up, and some industry watchers say a two-drug success could help the British pharma giant poach share from its market-leading nemesis. Taking one drug out of the picture reduces the side-effect burden patients bear, and it may also result in cost savings potential payers like the sound of.

At least one analyst isn’t worried about Gilead ceding its lead, though. Jefferies’ Brian Abrahams sees “little incentive to switch” from a Gilead regimen to a potential GSK one-two punch. “We believe most patients on older regimens, … if they were going to switch, likely already switched to an integrase-based regimen like Gilead’s Genvoya or Stribild, or to ViiV’s Triumeq,” he wrote in a Monday note to clients.

Plus, the Big Biotech has a line of new-and-improved trios on the market that are already less toxic than their predecessors thanks to component med TAF. Those cocktails “already improve upon some of the long-term side effects that were concerning for patients with longer treatment durations,” Abrahams noted.

As for the potential for payers to get involved—and cut down Gilead’s pricing power? It’s “worth keeping an eye on,” he suggested. While they’ve so far stayed “relatively hands-off” in the HIV arena, “with each potentially competitive regimen offering a feasible alternative, we would monitor whether payers become more aggressive vying for discounts in the space.”