Merck moves Alzheimer's drug into big trials after safety review Tue Dec 10, 2013 11:07am EST (Reuters) - Merck & Co said on Tuesday it will advance its experimental Alzheimer's drug into late-stage trials among patients with mild to moderate disease, after an independent monitoring board reviewed its safety and recommended the trial continue to recruit patients. The data monitoring committee gave its blessing to a Phase III trial involving up to 1,960 patients after examining interim safety data from a mid-stage trial of 200 patients who had been treated with the medicine, called MK-8931, for at least three months. The planned new study, called EPOCH, is expected to conclude in mid-2017, Merck said. The medicine works by blocking an enzyme called beta secretase, which is involved in production of beta-amyloid, a protein that creates brain plaques considered a major cause of the progressive memory-robbing disease. Such medicines are known as BACE inhibitors. Merck will also begin a separate Phase III trial of the drug, involving 1,500 patients, in so-called "prodromal" patients who do not yet have dementia. That study, called APECS, will enroll patients with mild cognitive problems and potential biomarkers for Alzheimer's, such as elevated levels of beta amyloid in the brain and of beta amyloid and the protein tau in spinal fluid. They will be treated for two years and then assessed for progression toward dementia. Oral drugs to block beta secretase, although still unproven, are considered one of the most promising new approaches to slowing progression of Alzheimer's after an injectable class of medicines meant to block beta amyloid directly last year failed or fell short in trials conducted by Pfizer Inc and Eli Lilly and Co. But safety of BACE inhibitors became a major concern in June, when Lilly pulled the plug on its own medication due to liver toxicity. Although data from Merck's mid-stage trial of MK-8931 remains blinded, or secret, the data monitoring committee was allowed to examine the data for hints of safety issues. Its green light could help ease safety concerns over the emerging new class of medicines. "There's good reason to hope that a BACE inhibitor might help patients, and ours is the first to get the go-ahead for Phase III" trials, Darryle Schoepp, head of neuroscience at Merck, said in an interview. The Merck drug in earlier trials cut production of a-beta peptide, the building block of beta amyloid plaque, by 79 percent, Schoepp said. J.P.Morgan analyst Chris Schott said expectations remained "low" for BACE inhibitors following termination of Lilly's product. But he said Merck's drug could generate annual sales of more than $5 billion if it succeeds in trials and is approved. An estimated 35 million people worldwide are believed to have dementia, including Alzheimer's disease, and those numbers are expected to rise as more people live longer. Merck shares slipped 0.7 percent to $49.21 in morning trading on the New York Stock Exchange, amid moderate declines for the drug sector. Reporting by Ransdell Pierson; Editing by Chizu Nomiyama and Dan Grebler