Merck hits the brakes on combo cholesterol drug

In an ongoing prioritization of its drug pipeline, drug giant Merck ($MRK) put on hold development of a combo pill for raising HDL or "good" cholesterol and lowering blood fat. The Whitehouse Station, NJ-based company revealed the decision from July on Wednesday among other updates to its closely watched drug candidates.

Merck cited "business reasons" as the justification for halting developing of MK-0524B, which combines extended-release niacin with the approved heart drug Zocor (simvastatin) and laropiprant. The candidate isn't to be confused with MK-0524A or Tredaptive--a combo of laropiprant and niacin--which the pharma powerhouse has shortlisted as one of 5 key drugs headed to the FDA for approval between now and 2013.

Tredaptive and the major HPS2-THRIVE trial for the combo cholesterol drug are on schedule, Merck says. As Dow Jones Newswires reports, the major clinical trial is expected to show whether the treatment, which is already approved outside the U.S., can impact cardiovascular outcomes such as numbers of heart attacks. Such tangible benefits have become crucial to gaining reimbursement for new cardio drugs as Pfizer's ($PFE) Lipitor and other meds become available as cheap generics.

While that program advances as planned, Merck said on Wednesday a delay in an 18,000-patient study for Vytorin (a Zetia and Zocor combo) in acute coronary syndrome, saying that large cardio outcomes study won't be completed until 2014 rather than next year. This could be setback for Merck, which has seen slow growth in its blockbuster sales of Vytorin and Zetia amid doubts about their effectiveness, Reuters reported.

- here's Merck's update from the SEC website
- check out the Dow Jones report
- and Reuters' article