BACE1 and Alzheimer disease: However, Merck no longer listed verubecestat in its research pipeline since verubecestat did not improve cognitive decline in AD patients and was associated with unfavorable side effects.95 Lanabecestat (AZD3293, AstraZeneca/Eli Lilly) is another BACE1 inhibitor that can lower CSF Aβ levels by up to 75%.