Merck sues to block Impax version of Vytorin

Merck (NYSE: MRK) is fighting back against an Impax Laboratories bid to cut in on its cholesterol drug Vytorin. The drugmaker has sued the generics firm to protect the blockbuster med, to which it gained full rights in last year's acquisition of Schering-Plough.

Impax filed last week for FDA approval of its version of the combo pill, which comprises the statin drug Zocor (simvastatin) and another cholesterol-fighter, Zetia. The drug brought in $2.1 billion in 2009 global sales. Merck is trying to protect Vytorin until a key patent expires in 2017. It's already fighting generic copycats from Mylan and Teva Pharmaceutical Industries.

Vytorin's sales have suffered after a series of setbacks, including the much-touted Enhance trial, which suggested that the combo pill was no better at treating artery-hardening than Zocor alone. Despite the negative reports, the drug is still a blockbuster.

- read the Morning Call piece