Merck & Co. to start new Phase III trial of BACE inhibitor MK-8931 in Alzheimer's disease

Merck & Co. said Tuesday that it will initiate a new Phase III study of its experimental BACE inhibitor MK-8931 in patients with amnestic mild cognitive impairment due to Alzheimer's disease. In October, the company identified the development of the drug as a priority under its plan to sharpen its commercial and R&D focus.

The drugmaker indicated that the APECS study will enrol 1500 patients who will be randomised to receive MK-8931 once daily at one of two doses or placebo. The study will assess the change from baseline in the Clinical Dementia Rating Scale-Sum of Boxes (CDR-SB) score following 104 weeks of treatment as its primary outcome. In March, Merck entered an agreement with Luminex to develop a companion diagnostic device to help identify suitable patients for studies of MK-8931.

Merck added Tuesday that the data monitoring committee (DMC) for its ongoing Phase II/III EPOCH study of MK-8931 in patients with mild to moderate Alzheimer's disease recommended that the trial continue to recruit patients. The DMC issued its recommendation after a planned analysis of interim safety data for 200 patients who received the BACE inhibitor for a minimum of three months. The trial is designed to enrol up to 1960 patients and has main goals of change from baseline in Alzheimer's Disease Assessment Scale Cognitive Subscale (ADAS-Cog) score and the change from baseline in the Alzheimer's Disease Cooperative Study – Activities of Daily Living (ADCS-ADL) score following 78 weeks of treatment.

"We are pleased to receive the DMCs recommendation and look forward to continuing the clinical development programme for MK-8931," remarked David Michelson, vice president of Neuroscience at Merck Research Laboratories. Darryle Schoepp, head of neuroscience at Merck, said "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. Schoepp noted that in previous studies, MK-8931 cut the production of amyloid beta peptide by 79 percent.

However, J.P.Morgan analyst Chris Schott indicated that expectations remained "low" for BACE inhibitors following Eli Lilly's decision in July to halt a mid-stage study of its experimental therapy LY2886721 due to abnormal liver biochemical tests. Schott suggested that if approved, Merck's drug could generate annual sales of more than $5 billion.

For related analysis, read ViewPoints: Second Phase III study in earlier-stage patients likely to be key for Merck & Co.'s Alzheimer's disease hopes and Spotlight On: Scrutiny increases on Merck & Co.'s R&D capabilities as company receives three analyst downgrades.

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