UPDATE 1-Merck abandons one migraine drug, pursues another

CHICAGO, Sept 10 (Reuters) - Drugmaker Merck & Co Inc (MRK.N) on Thursday said it is abandoning an experimental drug to treat acute migraines because the drug caused elevated liver enzyme levels in some cases.

The drug, dubbed MK-3207, is an oral calcitonin gene-related peptide receptor antagonist. The drug was effective, Merck said, but caused liver test abnormalities after the drug was discontinued, and so the company will not pursue Phase III studies.

Merck said it is continuing development of its drug telcagepant, or MK-0974, for the treatment of acute migraines, which is in late-stage trials.

It said it will present new data from two Phase III clinical studies at the International Headache Congress. Data showed, among other things, that telcagepant was superior to placebo, or a dummy pill, for the treatment of multiple migraine attacks, Merck said.

Merck said it is preparing for discussions it plans to have with regulatory agencies later this year about telcagepant.

Merck in April said it scrapped plans to seek U.S. approval this year for telcagepant after some patients taking it in a clinical trial developed elevated liver enzyme levels. (Reporting by Debra Sherman, editing by Gerald E. McCormick)