Amgen notches another PhIII win for its PCSK9 blockbuster hopeful

Amgen's ($AMGN) promising PCSK9 candidate cleared another Phase III hurdle, this time in statin-intolerant patients, as the company piles up positive data with hopes of taking the lion's share of what could be a multibillion-dollar market.

In top-line results from a study on 307 high-cholesterol patients who can't take statins, Amgen's evolocumab met its co-primary endpoints of lowering baseline and mean LDL cholesterol rates over 12 weeks, the company said. Amgen is keeping specific results to itself for the time being, but the study, dubbed GAUSS-2, was consistent with an earlier Phase II trial in which evolocumab cut LDL cholesterol by up to 51% on its own and 63% when paired with Merck's ($MRK) Zetia, according to the company.

Those numbers put Amgen right in line with Pfizer ($PFE), Sanofi ($SNY) and Regeneron ($REGN), its top competitors in the race to commercialize PCSK9-blocking drugs and cash in on a market analysts say could top out at $10 billion a year. GAUSS-2 is one of 13 pivotal studies Amgen is running in its far-reaching Phase III program for evolocumab, and the company is planning to enroll more than 28,000 patients with multiple types of high cholesterol.

Meanwhile, partners Sanofi and Regeneron are executing a 12-study effort of their own, and Pfizer is planning to spend big on a 22,000-patient outcomes program to demonstrate the long-term benefits of its RN316. At stake is the lead role in the expected-to-boom market for drugs that block PCSK9, a protein that hampers the liver's ability to get bad cholesterol out of blood.

But despite all the excitement over the promise of a new class of cardio drug, some market watchers worry that the uptake for PCSK9 therapies may not be so swift thanks to skeptical payers who prefer tried, true and cheap statins. The FDA accepts reductions in LDL cholesterol and blood pressure as surrogate endpoints for long-term cardiovascular benefit, but the powers that be in reimbursement may well hold out for data from time-consuming outcomes studies.

GAUSS-2 is the third Phase III readout for Amgen's drug, formerly known as AMG 145.

- read the results