PCSK9 INHIBITORS

Pfizer, Amgen Inc and a partnership of Regeneron Inc and French drugmaker Sanofi SA are racing to develop the PCSK9 inhibitors, all deemed by Wall Street capable of generating annual sales in the billions of dollars.

The injectable drugs have generated excitement in mid-stage trials by slashing levels of LDL cholesterol 60 percent beyond reductions achieved with statins alone, without a pattern of serious side effects.

The companies are now conducting late-stage trials of the drugs, which work by blocking a protein called PCSK9, whose natural function is to maintain the presence of LDL in the bloodstream.

The drugmakers are hoping the U.S. Food and Drug Administration will approve their PCSK9 inhibitors on the basis of their ability to lower LDL. In the meantime, they are conducting their own outcomes studies to eventually prove to regulators that their medicines actually lower the risk of heart attack and stroke.

Mark Schoenebaum, an analyst with ISI Group, said the new heart-protection guidelines “appear to raise the bar for cholesterol-lowering drugs” that are not statins. He said use of Amgen’s PCSK9 inhibitor, called AMG 145 or evolocumab, if it is approved, could be slowed until data from the drug’s outcomes trial arrives in late 2017 or early 2018.

Moreover, Schoenebaum said it remains to be seen whether the new guidelines, formulated by the American Heart Association and the American College of Cardiology, will affect the willingness of U.S. and European regulators to approve the new class of cholesterol fighters.

“These new drugs may be very helpful in getting cholesterol under control, but we’re setting the bar high,” said Stone. “We’re saying show us that in addition to lowering cholesterol that you reduce the risk of heart attack and stroke.”

Schoenebaum said Wall Street has been expecting the Amgen drug to generate sales of $1.1 billion in 2018. For now, he said he is sticking to his own sales forecast of $500 million that year and more than $1.4 billion in 2020.

“Given the (heart) guidelines, we remain comfortable with our estimates for now but will monitor how the guidelines are perceived by the wider medical community,” Schoenebaum said in a research note.

Analysts said sales of Crestor were unlikely to get a big boost from the new guidelines because most doctors would reach instead for less costly generic Lipitor.

Shares of Regeneron fell 3.4 percent, those of Amgen rose 0.7 percent and Amarin was unchanged, all on the Nasdaq. Pfizer rose 1.6 percent, Merck dropped 0.5 percent and AbbVie gained 0.8 percent, all on the New York Stock Exchange. Sanofi fell 0.8 percent in Paris, and AstraZeneca shares slipped 0.5 percent in London.

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(Reporting by Ransdell Pierson and Bill Berkrot; Editing by Marguerita Choy and Steve Orlofsky)