Singapore: Merck, known as Merck Sharp & Dohme (MSD) outside the US and Canada, provided update on its clinical program for preladenant , which is an investigational adenosine A2A receptor antagonist for the treatment of Parkinson's disease (PD). An initial review of data from three separate phase III trials did not provide evidence of efficacy for preladenant as compared to the placebo.

Merck is taking steps to discontinue the extension phases of the studies and no longer plans to pursue regulatory filings for preladenant. The decision to discontinue these studies is not based on any safety finding. The results of these studies will be presented at an upcoming scientific meeting and will be submitted for publication in a peer-reviewed journal.

The phase III clinical program for preladenant included three randomized, controlled clinical trials to evaluate safety and efficacy. Two of these studies assessed preladenant when added to levodopa therapy in patients with moderate-to-severe PD, and one assessed preladenant as monotherapy in early PD.

Dr David Michelson, vice president, clinical research, Neuroscience and Ophthalmology, Merck Research Laboratories, said that, "Parkinson's disease is very complex, making it difficult to treat patients and develop novel therapeutic approaches."

He also said, "We are committed to neuroscience research and will be conducting further analyses of the data to inform the scientific community's efforts in finding new approaches to treat this debilitating disease. We thank the investigators and importantly the Parkinson's patients who participated in the preladenant clinical program."