Alzheimer's drug shows promise in early trial

Experimental agent similar to medicines already used to ease symptoms, but more study needed.

19  july 2012--Researchers say an investigational drug helped improve memory, language, attention and other mental skills in people with early Alzheimer's disease.

The study was funded by EnVivo Pharmaceuticals, which is developing the drug, dubbed EVP-6124. The results are to be presented Wednesday at the annual meeting of the Alzheimer's Association in Vancouver.

The study involved 409 patients with mild to moderate Alzheimer's disease who were either being treated with the drugs donepezil (Aricept) or rivastigmine (Exelon) or were receiving no treatment.

During the six-month, phase 2 trial, patients took either a placebo or one of three different doses of EVP-6124.

After 23 weeks of treatment, the patients in the high-dose group showed statistically significant benefits on tests of mental function compared to those taking the dummy pill. Some patients in the medium- and high-dose groups did experience mild to moderate gastrointestinal side effects, the team added.

"In our study, EVP-6124 provided significant benefits for people with mild to moderate Alzheimer's whether they were on currently approved therapy or not," Dr. Dana Hilt, senior vice president of clinical development and chief medical officer of EnVivo, said in an Alzheimer's Association news release.

The authors explain that EVP-6124 belongs to a family of drugs called alpha-7 nicotinic agonists, which amplify the effects of acetylcholine, a brain chemical that's essential for normal brain and memory function. People with Alzheimer's disease have greatly reduced levels of acetylcholine.

Currently, there are no effective treatments to fight Alzheimer's disease, although certain drugs may temporarily ameliorate symptoms.

For that reason, the new study "is potentially interesting, as there is a need for better symptomatic treatment of Alzheimer's disease," said Peter Davies, director of the Litwin Zucker Research Center for the Study of Alzheimer's Disease at the Feinstein Institute for Medical Research in New Hyde Park, N.Y.

He pointed out that the mechanism behind the new drug is not altogether novel. "Treating the deficiency of acetylcholine is the basis for the already approved drugs Aricept, Exelon and Razodyne," Davies said. "This drug does the same thing, but in a different way. The other drugs act to reduce the breakdown of acetylcholine: this drug mimics the effect of acetylcholine at one of the receptors for this compound."

He said that there are hints that this approach might do more than just ease symptoms, and might attack the underlying illness. But that remains speculative and "further studies do seem to be warranted," Davies said.

Another expert agreed.

"These promising effects are 'symptomatic' (the drug does not slow progression of disease), and the study is relatively small in size," noted Stephen Ferris, director of the Alzheimer's Disease Center and the clinical trials program at NYU Langone Medical Center's Comprehensive Center on Brain Aging in New York City.

Like Davies, Ferris stressed that "if the results can be confirmed in a larger trial, the drug would be an important addition to current Alzheimer treatments."

Findings presented at medical meeting are typically considered preliminary until published in a peer-reviewed journal.