Gamma no-go

The safety signals seen in Eli Lilly and Co.'s Phase III trials of semagacestat for Alzheimer's disease lend support to researchers who believe antagonizing gamma secretase is not the right approach to AD. However, the setback doesn't mean that it's curtains for approaches that modulate the target or for the broader goal of blocking beta amyloid production to treat the disease.

Gamma secretase is a proteolytic complex that helps convert amyloid precursor protein (APP) into beta amyloid, the protein fragment that forms the amyloid plaques in AD. The theory has been that blocking gamma secretase would reduce production of beta amyloid and thus prevent neuronal toxicity caused by the amyloid plaques...