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PDF Comments on Halted Research of Experimental A2A Treatment for Parkinson's

Merck, the company testing the potential of an experimental treatment for Parkinson's disease, has announced that it is halting its research and further development of the drug called preladenant. According to Merck, large, late stage clinical trials, called Phase III trials, failed to show that the drug is more effective for people living with Parkinson's disease than those who took a placebo.

Preladenant is one of several similar drugs in trials for PD, which are broadly called adenosine A2A antagonists. They work like caffeine but in a specific way, by targeting the part of the brain affected by PD.  Unlike other PD drugs, A2A antagonists do not affect the dopamine system. Thus, many in the Parkinson's community have hoped that these drugs may have great potential for improving PD symptoms.

James Beck, Ph.D., Director of PDF Research Programs, commented on the news,

"It is disappointing to learn that Merck's investigational drug, preladenant, did not demonstrate efficacy even after several large Phase III clinical trials.

"While we await to hear the full results of the trial as well as possible conclusions as to why this compound was not effective, I believe there is still hope that these A2a-antagonists may yet be effective for treating Parkinson's disease.  Several other pharmaceutical companies are still funding clinical research in this area and we hope to see results of those efforts be announced in the next few years."

Merck Ends Further Studies On Preladenant For Treatment Of Parkinson's Disease

Merck (MRK: Quote) Thursday announced the discontinuation of the extension phases of its studies on investigational adenosine A2A receptor antagonist for the treatment of Parkinson's disease, as initial review of data from three Phase III trials did not provide evidence of efficacy for preladenant compared with placebo.

Issuing an update on the clinical program for preladenant, Merck said it no longer plans to pursue regulatory filings for preladenant. The decision to discontinue 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. The remaining one assessed preladenant as monotherapy in early PD.

David Michelson, vice president, clinical research, Neuroscience and Ophthalmology at Merck Research Laboratories, said, ''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."

MRK closed up 1.3 percent at $47.33 on Thursday.

Source Date: May 23 2013
Source Publication: RTT News
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