Signs of cognitive slowing observed in small subset of trial participants
An experimental drug from Biogen lowered levels of the tau protein in the brains of people with early Alzheimer’s disease and appeared to slow cognitive decline in a small subset of participants, researchers reported Tuesday at the Alzheimer’s Association International Conference in London. The study of about 400 patients is the first to suggest that targeting tau, the second major Alzheimer’s protein after amyloid, may yield clinical benefit.
Two drugs now on the market, lecanemab and donanemab, work by clearing amyloid plaques from the brain and can modestly slow cognitive decline. But attempts to develop drugs that attack tau, which forms neurofibrillary tangles inside brain cells, have repeatedly failed until now.
Biogen’s drug, diranersen, lowered tau levels in the brain, and in one small subset of the trial, the reduction was associated with a slowing of cognitive decline comparable to what has been seen with amyloid-targeting therapies, the researchers said. Biogen is planning a larger Phase 3 trial to try to prove the drug’s benefit.
Jessica Langbaum, a researcher at the Banner Alzheimer’s Institute in Phoenix who was not involved with the study, said the results are “really quite promising if it were to hold up” in that next-step testing.