Merck halts Phase III trial of AD candidate

Merck & Co. Inc. (NYSE:MRK) stopped the Phase III APECS trial of verubecestat (MK-8931) to treat prodromal Alzheimer’s disease after an external DMC said it was unlikely the trial would establish a positive benefit-risk profile for the candidate. Merck spokesperson Ian McConnell told BioCentury the company plans to conduct a detailed analysis of the data and present them at a medical meeting.

The placebo-controlled trial’s primary endpoint evaluated the effect of two dose levels of once-daily oral verubecestat on Clinical Dementia Rating Scale-Sum of Boxes (CDR-SB) score after 104 weeks. Last year, Merck halted the Phase II/III EPOCH trial of verubecestat to treat mild to moderate AD after an external DMC determined the study had "virtually no chance of finding a positive clinical effect” (see BioCentury Extra, Feb. 14, 2017).

According to a Nov. 7 SEC filing, verubecestat is the company’s only AD candidate in Phase II testing or later. McConnell said Merck does not disclose specifics on early internal candidates. The product is a beta-site APP-cleaving enzyme 1 (BACE1) inhibitor.

Last year, Teijin Pharma Ltd. (Tokyo, Japan) granted Merck exclusive, worldwide rights to develop and commercialize a preclinical anti-microtubule-associated protein tau (tau; MAPT; FTDP-17) antibody. Also last year, Bionomics Ltd. (ASX:BNO; OTCQX:BNOEF) received a $10 million milestone payment from Merck under a 2014 deal after Bionomics started a clinical trial of an undisclosed candidate for cognitive dysfunction associated with AD.