Staff Writer

Gilead Sciences Inc. said that its Quad regimen for treating HIV infection met its primary objective in a Phase II study, fueling hopes that the combination pill could diversify the company's pipeline as its blockbuster HIV drugs face a looming patent cliff.

The small, 71-patient Phase II study showed that at 24 weeks, the Quad pill was noninferior, or no worse than Gilead's Atripla.

Discontinuation rates due to adverse events were comparable in both arms of the study, and that may come as a relief to some investors. As Cowen & Co. analyst Phil Nadeau pointed out in a research note, "The lack of any apparent safety issues with the Quad pill at this juncture should alleviate some investor concerns."

Added Oppenheimer & Co. analyst Brett Holley, "We continue to see a good probability that the Quad pill will have an improved side effect profile vs. Atripla. . . . We believe the Quad pill is likely to be a viable alternative to Atripla."

But a clear picture of the Quad pill's safety profile probably won't emerge until a larger, Phase III study is conducted, Robert W. Baird analyst Thomas Russo told BioWorld Today.

He said that the good Phase II data puts it on track to enter Phase III testing around midyear.

Deutsch Bank analyst Mark Shoenebaum stated in a note issued ahead of the Phase II Quad data that he would be "keeping an eye out for any liver enzyme elevations" in light of a patient who dropped out from an earlier trial due to grade 3 liver enzyme elevation.

Since Gilead's HIV molecules face patent expirations between 2017 and 2021, investors are watching the Quad pill as a way to potentially extend the life of the company's HIV franchise. If the Quad pill is proven to work just as good as Gilead's Atripla and with fewer side effects, it could extend the life of the HIV franchise to the late 2020s, Russo said.

"This is a significant milestone in the development of the Quad, which could represent an important new treatment option for patients living with HIV," Gilead spokeswoman Erin Rau said of the Phase II results. "We look forward to advancing the clinical program."

The Quad pill is a fixed-dose combination of elvitegravir, Gilead's investigational boosting agent (GS 9350) and Truvada (emtricitabine and tenofovir disoproxil fumarate).

Atripla contains components of Gilead's Truvada (emtricitabine and tenofovir disoproxil fumarate) and Bristol-Myers Squibb Co.'s Sustiva (efavirenz). The pill essentially replaces the efavirenz component with the combination of elvitegravir and GS 9350, a boosting agent which is designed to increase blood levels of elvitegravir and other medicines. Efavirenz has been associated with serious psychiatric incidents such as severe depression, suicidal thoughts and nonfatal suicide attempts.

Gilead also reported positive data for its once-daily boosting agent, GS9350, which is being studied as a stand-alone boosting agent for other antiretrovirals, in particular, protease inhibitors.

That study is ongoing. GS9350, which was compared to ritonavir in that study as a boosting agent for atazanavir (Bristol-Myers' Reyataz), one of the most widely prescribed HIV protease inhibitors.

Cowen analyst Nadeau wrote that the favorable data for GS9350 "would be important for the ultimate adoption of the Quad combo pill.

Detailed data from both the Phase II Quad study and boosting agent likely will be presented next month at the Conference on Retroviruses and Opportunistic Infections in San Francisco, analysts said.

Leerink Swann analyst Joshua Schimmer wrote, "We wonder whether hitting noninferiority for the Quad relative to Atripla with such few patients means there was a trend to superiority, but [we] await the full dataset before drawing conclusions." He also noted that, "The GS9350 booster trial indicates similar efficacy to ritonavir but does not claim noninferiority."

Shares in Gilead (NASDAQ:GILD) were up $1.50, closing at $44.76.

Published  January 7, 2010