Biogen's (BIIB) late breaking results for aducanumab and China's conditional approval of Shanghai Green Valley Pharmaceuticals' GV-971 were perhaps the two biggest surprises regarding Alzheimer's drug development this year. Aducanumab seems to slow down Alzheimer's disease for a longer period of time than Aricept in APOE4 carriers. By contrast, GV-971 appears to help stabilize the disease for at least 36 weeks.
Biogen updated slides for its Emerge and Engage trials provide some insight into what aducanumab actually does (although there is still a great deal of missing data). (source of chart, p. 15)