Pfizer says PCSK9 study was a winner, boosting its chances in hectic R&D race

Pfizer says the Phase IIb study for its closely-watched PCSK9 cholesterol drug bococizumab (RN316) scored the primary endpoint on all doses, which should help steer a massive Phase III program that started out last fall with 22,000 patients.

The biggest impact on LDL-C was seen in patient groups receiving 150 mg for a twice monthly regimen and 300 mg for the once monthly regimen, according to Pfizer ($PFE). A total of 314 patients were recruited for the study and the adverse event profile in the drug groups matched the placebo arm.

Pfizer is one of a group of high-profile developers looking for new blockbusters among a wave of PCSK9 drugs in the clinic. Amgen ($AMGN) has already read out 6 of its 13 Phase III studies, all positive, while Regeneron ($REGN) and its partner Sanofi ($SNY) race ahead with their own late-stage program for a rival therapy.

Structure of the PCSK9 protein--Courtesy of Emw, Creative Commons BY-SA 3.0

While the efficacy data has been uniformly positive in this new class of therapies, the FDA managed to rattle investors recently with a warning about potential neurocognitive side effects, which have been tracked in statins as well. A few patients taking statins have experienced confusion and fuzzy thinking, which has been easily reversed once they stop taking the treatment. But regulators want all the developers to keep a sharp eye out specifically for these kinds of effects.

A sharp drop in LDL may convince the FDA to provide an approval, but developers will be facing an uphill climb with payers in the U.S. who have an assortment of cheap generic statins to choose from and may want to wait to see how these drugs influence health outcomes rather than a biomarker for disease.

"We are pleased with the outcome of this Phase IIb study and continue to maintain focus on delivering our Phase 3 program, which includes two CV outcome studies in populations at high risk from cardiovascular events," said Dr. Steven Romano, global medicines development lead for the Pfizer Global Innovative Pharmaceutical business. "Recent guidelines emphasize the reduction of CV risk as the primary goal of lipid therapy for patients at risk for CV events."

- here's the release