Merck's Cholesterol Trial Win Puzzles as FDA Filing Uncertain

(Bloomberg) -- An experimental cholesterol drug developed by Merck & Co. succeeded in reducing heart risks in a late-stage trial, a surprise win for a class of treatments that has failed numerous times in the past.

But the drugmaker said it hasn’t decided whether it would file for approval with the U.S. Food and Drug Administration, puzzling doctors and analysts alike. In a two-paragraph statement on the study Tuesday, Merck did point out that the drug can build up in fat cells -- a potential issue, though consistent with earlier findings that the medicine may persist for years after people stop taking it.

“The fact that they are saying they aren’t sure if they will file a new drug application suggests the benefit may be small or there may be some adverse effects here that are concerning,” said Steven Nissen, head of cardiology at the Cleveland Clinic and the lead researcher on two medicines in the same class that previously failed.

Lack of Details

The study of 30,000 patients showed adding Merck’s drug, anacetrapib, to cholesterol-lowering pills known as statins significantly cut the risk of having a heart attack, requiring an artery-clearing procedure or dying from heart disease, when compared to patients on other cholesterol-lowering regimens. Merck didn’t release more details on the results, saying the full results would be presented at the European Society of Cardiology meeting in August.

There’s no downside risk for Merck in filing for FDA approval given it has already spent the money conducting its drug trial, said Evercore ISI analyst Umer Raffat. But he expressed caution over the lack of detail in Merck’s release and warned there could be a safety risk for the drug.

Shares of Kenilworth, New Jersey-based Merck were little changed at $65.96 at as of 1:26 p.m. in New York.

Anacetrapib is a so-called CETP inhibitor, a class of medicine designed to raise good cholesterol, used to ferry fats out of the body. It works differently than existing cholesterol pills, including statins, that help lower the levels of bad cholesterol. While naturally high levels of good cholesterol have been shown to protect against heart disease, the pharmaceutical industry has struggled to come up with treatments that create the same benefit by boosting good cholesterol. 

Drugmakers like Pfizer Inc., Roche Holding AG and Eli Lilly & Co. have all failed in the development of their CETP inhibitors. Pfizer spent almost $1 billion developing one that it hoped would replace its blockbuster drug Lipitor, at the time the biggest-selling drug in history. But Pfizer halted work on the treatment in 2006 after it was tied to deaths. Roche and Lilly’s products didn’t prove effective in trials.

Heart disease is the No. 1 killer in the U.S., responsible for about one in four deaths each year.