Gilead's blockbuster HIV combo hopeful "Quad" clears PhIII hurdle

Gilead's four-drug "Quad" pill for HIV--its planned successor to the blockbuster Atripla and the lynchpin to its strategy to remain perched on top of the HIV market--cleared an important hurdle today as researchers reported the new combo proved non-inferior to the marketed drug in a new study. The data leave Gilead on track to a planned marketing application in early 2012.

Just days ago Gilead won FDA approval for Complera, a once-daily HIV pill that combines its Truvada with J&J's Edurant. Analysts don't hold out high hopes for Complera on the marketplace, though. They've been waiting to see if the Quad can finish late-stage testing this year and go on to achieve blockbuster status as the preferred therapy for HIV. Atripla earned $822 million in the second quarter alone and some analysts have estimated peak sales of Quad at $4 billion.

According to Gilead, the primary endpoint analysis for the non-inferiority study indicated that 88% of patients in the Quad arm compared to 84% in the Atripla arm achieved a viral load of less than 50 copies/mL through week 48. That wasn't a surprise to analysts, leaving Gilead on track to an approval if another late-stage study also proves promising later this quarter. The Quad contains four Gilead compounds in a once-daily tablet: elvitegravir, an investigational integrase inhibitor; cobicistat, a "boosting" agent designed to boost blood levels of HIV medicines; and Truvada (emtricitabine/tenofovir disoproxil fumarate).

"Achieving non-inferiority to the current standard of care in HIV therapy is a major developmental milestone for our Quad regimen," said Norbert Bischofberger, Gilead's CSO. "We are very pleased with these results, which are in line with our expectations and allow us to begin preparations for a U.S. regulatory filing in the first quarter of 2012."

Non-inferiority on efficacy isn't enough to make the Quad a success, though. Jefferies found in a new survey that Atripla could still be preferred, unless the Quad proved to have a better safety profile with fewer side effects. And the Quad did come out of the survey better than Dolutegravir/GSK572, according to analysts.

Gilead didn't have much to say about safety in its release today. The biotech noted that the "frequency of Grade 3-4 adverse events and laboratory abnormalities was similar between the Quad-treated and the Atripla-treated arms. Discontinuation rates due to adverse events were comparable in both arms of the study." Details will have to wait on a scientific conference early next year.

- here's the Gilead release