A major Alzheimer's drug just failed a key trial

A key drug to treat Alzheimer's disease failed a late-stage clinical trial, Eli Lilly and Company said Wednesday.

The drug, solanezumab, wasn't able to slow down cognitive decline in patients with Alzheimer's compared with those who took a placebo.

"The results of the solanezumab Expedition3 trial were not what we had hoped for and we are disappointed for the millions of people waiting for a potential disease-modifying treatment for Alzheimer's disease," Lilly CEO John Lechleiter said in a release.

Lilly's shares were down by 13% Wednesday morning.

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(Markets Insider)

The results weren't totally unexpected by analysts. Bernstein's Tim Anderson noted that he had thought the program was likely to fail, and hadn't built solanezumab into its Lilly forecast.

Only four approved drugs are in use to treat Alzheimer's; on average about 99% of all drugs in clinical trials never actually make it to approval.

Solanezumab was going after the "amyloid hypothesis," or the idea that targeting beta amyloid deposits in the brain to clear them out was the way to go about treating the disease. Biogen, another company that is going after the same hypothesis, was down 6% Wednesday.

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