Merckx stopping trial of failing Alzheimer’s drug

Drug company Merck said Tuesday it stopped a clinical trial of an experimental Alzheimer's drug because it wasn't helping patients, the latest setback in the pharmaceutical industry's quest to find a better treatment for the brain disorder.

An outside committee monitoring the study of more than 2,000 patients with mild to moderate Alzheimer's concluded there was "virtually no chance of finding a positive clinical effect" of the drug, verubecestat, Merck said. The study, which was due to be completed around midyear, was testing whether verubecestat slowed declines in patients' cognition and daily functioning compared with a placebo.

"The benefit-risk profile no longer made any sense," Roger Perlmutter, president of Merck's research unit, said in an interview. He said there weren't major safety issues that on their own would justify stopping the study, but "it did not make sense to expose patients to any risk, whatever that may be, because the study would not succeed."

Merck said another study of its drug in patients with prodromal, or very early, Alzheimer's disease would continue with results expected by February 2019.

Blinded clinical trials use independent monitors to watch for any unexpected safety problems that may crop up. They can also recommend stopping a study early if it becomes clear that a drug is going to fail or if the data looks so compelling that it believes the treatment should be offered to those getting a placebo or other standard treatments.

Around 47 million people currently live with dementia worldwide, with Alzheimer's estimated to account for 60 to 80% of dementia cases. This figure is expected to double every 20 years to reach 131 million people in 2050, according to Alzheimer's Disease International.