GlaxoSmithKline gambles against Gilead with risky bet on two-drug HIV combos

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GlaxoSmithKline ($GSK) may be able to surge ahead of HIV rival Gilead Sciences ($GILD), if a bet on two-drug regimens pays off. But that's a big if--and the stakes are high.

The British drugmaker is looking to upend the standard, three-med approach to HIV treatment with a two-drug combo centered on Tivicay, the latest pill from Glaxo’s ViiV Healthcare unit.

The pharma giant has embarked on a number of hefty clinical trials aiming to demonstrate that pairing Tivicay with just one other HIV-fighter can get the job done just as well as a triple therapy can, The Wall Street Journal reports. In one set of studies, GSK is examining Tivicay in tandem with Edurant from Johnson & Johnson’s Janssen unit; in another, Tivicay is joining forces with the long-used generic med 3TC.

And more two-drug trials on the way. GSK intends to launch a late-stage trial fusing an injectable version of Tivicay with Edurant, which has already proven itself as effective as a three-drug medley in patients whose virus had previously been suppressed by lead-in period of triple therapy. 

So far, Glaxo has reason to be hopeful, the Journal notes. In one small, 48-week study, the Tivicay-3TC one-two punch suppressed HIV levels in 18 of 20 previously untreated sufferers.

If the company does succeed, it’ll have both safety and cost-effectiveness on its side, which could propel ViiV ahead of Gilead in market-share within three years, UBS analysts predict.

Nixing one drug from the mix reduces the side-effect burden patients bear. And switching just one quarter of patients currently taking triple therapies to a Tivicay-3TC regimen would save more than $3 billion on HIV treatment over a 5-year stretch, one Harvard Medical School professor predicts. Payers, which have put the squeeze on Gilead in hepatitis C, may look fondly on figures like those.

But if Glaxo’s two-drug dreams don’t come true? Its Big Biotech rival, which is working on a Tivicay competitor of its own, could keep steamrolling with successful triple therapies as it siphons off Tivicay sales.

Even if GSK can come through with a one-two punch, doctors may not feel the need to switch most patients away from Gilead’s meds, now that the California company has a line of new-and-improved trios on the market. Those products are already less toxic than their predecessors, thanks to a component med dubbed TAF.

- get more from the WSJ (sub. req.)

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