Prospects for the highly anticipated new class of cholesterol-lowering drugs, the PCSK9 inhibitors, took a wild roller coaster ride this week. The publication of new lipid guidelines by the American Heart Association and the American College of Cardiology led many observers to think that the promising new drugs under development by Regeneron (in partnership with Sanofi), Amgen, and Pfizer might suffer significant delays.
The guidelines delivered a strong statement questioning the increasingly controversial theory that LDL lowering by itself is beneficial. “We found that non-statin therapies really didn’t provide an acceptable risk reduction benefit compared to their potential for adverse effects in the routine prevention of heart attack and stroke,” said the co-chair of the guideline. This led many observers to think that the FDA would likely require the developers of PCSK9 inhibitors to complete cardiovascular outcome trials before getting US approval. This decision would delay approval for several years.
Then, on Thursday, the companies developing PCSK9 inhibitors received some apparent good news. Bloomberg News reported that an FDA official said that the drugs “will only have to meet the U.S. Food and Drug Administration’s existing standards for clearance, including whether they cut cholesterol and reduce blood pressure or inflammation.”
But then the FDA added one other very important caveat. Here’s how they phrased it to me: