Merck Issues Update on Phase III Trial for Preladenant

Merck (NYSE: MRK), known as MSD outside the United States and Canada, todayprovided an update on the clinical program for preladenant, Merck'sinvestigational adenosine A2[A ]receptor antagonist for the treatment ofParkinson's disease (PD). An initial review of data from three separate PhaseIII trials did not provide evidence of efficacy for preladenant compared withplacebo.Based on these results, Merck is taking steps to discontinue the extensionphases of these studies and no longer plans to pursue regulatory filings forpreladenant. The decision to discontinue these studies is not based on anysafety finding. The results of these studies will be presented at an upcomingscientific meeting and will be submitted for publication in a peer-reviewedjournal.“While these results are disappointing, this program is an important exampleof Merck's continued commitment to pursue promising science with the goal ofbringing forward medicines that address important unmet medical needs,” saidDavid Michelson, M.D., vice president, clinical research, Neuroscience andOphthalmology at Merck Research Laboratories. “Parkinson's disease is verycomplex, making it difficult to treat patients and develop novel therapeuticapproaches. We are committed to neuroscience research and will be conductingfurther analyses of the data to inform the scientific community's efforts infinding new approaches to treat this debilitating disease. We thank theinvestigators and importantly the Parkinson's patients who participated in thepreladenant clinical program.”The Phase III clinical program for preladenant included three randomized,controlled clinical trials to evaluate safety and efficacy. Two of thesestudies assessed preladenant when added to levodopa therapy in patients withmoderate-to-severe PD, and one assessed preladenant as monotherapy in earlyPD. More information about the preladenant Phase III clinical trials isavailable on www.clinicaltrials.gov.