Vytorin Update: Cancer Risk, Generic Challenge

VytorinA couple pieces of news today on Merck’s big cholesterol drug Vytorin, which has seen its share of trouble in the past couple years but remains widely prescribed:

The FDA said it’s “unlikely” that Vytorin or Zetia, another Merck drug, increase the risk of cancer. But “an association cannot be definitively ruled out,” the agency said. Vytorin is a combination of two drugs — Zetia and a statin called simvastatin. It’s clear that simvastatin doesn’t raise cancer risk, the FDA said, but there’s not enough data to “definitively rule out” a cancer link for Zetia (known generically as ezetimibe).

The uncertainty comes from a study that found there were more cancers and cancer-related deaths in patients who took Vytorin, compared with those who received placebo. But other studies of the drug have not shown similar risk. Animal studies have not shown a cancer link. And the cancer risk found in the study came from combining several types of cancer together. “It is biologically less likely that a single drug increases the risk of a wide variety of cancer types,” the FDA said.

Mylan, a big generics shop, said it had been sued by a Merck subsidiary for patent infringement because it applied to sell a generic version of Vytorin.

This is is the kind of lawsuit generic drug makers wear like a badge of honor these days. In its statement today, Mylan said it believes it is the first generic company to file this sort of application for Vytorin; if the company is correct, it will get a six-month window during which it’s the only generics company allowed to compete against Merck for sales of the drug.

An exclusivity period on a big drug like Vytorin — and it’s still a very big drug, despite the troubles it’s had — means a windfall for a company like Mylan.