Merck updates on preladenant clinical program for treatment of Parkinson's disease

Merck (NYSE: MRK), known as MSD outside the United States and Canada, today provided an update on the clinical program for preladenant, Merck's investigational adenosine A2_A 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 compared with placebo.

“While these results are disappointing, this program is an important example of Merck's continued commitment to pursue promising science with the goal of bringing forward medicines that address important unmet medical needs”

Based on these results, Merck is taking steps to discontinue the extension phases of these 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.

"While these results are disappointing, this program is an important example of Merck's continued commitment to pursue promising science with the goal of bringing forward medicines that address important unmet medical needs," said David Michelson, M.D., vice president, clinical research, Neuroscience and Ophthalmology at Merck Research Laboratories. "Parkinson's disease is very complex, making it difficult to treat patients and develop novel therapeutic approaches. 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."

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.