Pfizer Inc said today that it is ceasing the clinical development of sumanirole, a compound under investigation for the treatment of Parkinson's disease and Restless Leg Syndrome.

The decision is based on results of recent studies that failed to sufficiently distinguish sumanirole from currently available therapies.

While the compound may still prove effective in these conditions, it did not meet Pfizer's criteria for continued development.

Today's statement is an update to the company's second quarter business performance conference call with financial analysts and media on July 21, 2004.