Merck announced last month that it is moving ahead with MK-8931, an experimental BACE inhibitor drug designed to slow the production of amyloid beta protein in the brain, one of the hallmarks of Alzheimer’s disease.
Beta secretase (BACE) inhibitors work by interfering with the process that creates amyloid beta protein in the first place, in the theory that halting production of amyloid beta will vastly reduce the chances of Alzheimer’s disease.
Patient safety in Merck’s Phase 2 & 3 clinical trials should be closely monitored. In addition to controlling the formation of amyloid beta protein in the brain, BACE is also involved in the development of myelin sheathes — the “insulation” surrounding the long axons of nerves throughout the human body.
The possibility of serious unintended consequences can happen when drugs tinker with a basic process that controls several important functions, in addition to the one it happens to target, in this case halting the process of amyloid beta production.
Another unanswered question is whether amyloid beta toxicity in the brain is the actual cause of Alzheimer’s disease, or if it is simply a robust biomarker (or evidence trail) of disease progression.
Stay tuned for updates on Alzheimer’s drug trial progress.