FDA says PCSK9 inhibitors may not require outcomes studies for approval

The FDA indicated that PCSK9 inhibitors, being developed by companies including Amgen, Pfizer and Sanofi, could gain approval based on their ability to lower LDL cholesterol levels rather than requiring results from outcomes studies. The concerns recently emerged after the American Heart Association and the American College of Cardiology recommended a move away from an emphasis on specific targets for lowering LDL cholesterol levels to focus on risk reduction.

Eric Colman, the FDA's deputy director of the division of metabolism and endocrinology products, said that PCSK9 inhibitors will only have to meet the agency's existing standards for approval, including whether they cut cholesterol and reduce blood pressure or inflammation. Colman indicated that the regulator will review PCSK9 inhibitors "based on the compound’s effects on the entire lipoprotein lipid panel, particularly LDL-cholesterol, its effects on other markers of potential cardiovascular risk," such as blood pressure, as well as its safety profile.

Analysts predict that if approved, PCSK9 inhibitors will generate sales of $2 billion in 2018. Other companies developing the injectable antibodies include Alnylam Pharmaceuticals, Eli Lilly, Merck & Co., Regeneron Pharmaceuticals and Roche. Amgen and Regeneron have said that late-stage results will be available next year showing whether their drugs reduce cholesterol to levels beyond what patients can achieve on statins, with outcomes trials scheduled to finish around two to three years later.

Colman noted that while the FDA is sticking with its current guidelines, results from the IMPROVE-IT trial comparing Merck & Co.'s Vytorin (ezetimibe/simvastatin) to Zocor (simvastatin) may change the agency's outlook. "Looking ahead, the results of the [study]...will provide important insight into the incremental effect on risk for major adverse cardiovascular events of adding a non-statin, LDL-cholesterol lowering drug to subjects receiving background statin therapy," Colman said. The trial is expected to conclude in September next year.

For related analysis, see ViewPoints: New treatment guidelines reshape the cardiovascular market opportunity; provide another challenge for the much touted PCSK9 inhibitor class and Physician Views Poll Results – Awareness of PCSK9 inhibitors could be higher, but physicians ready to prescribe in hard-to-treat cardiovascular patients.

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