Shares of Eli Lilly and Co. and Biogen Inc. fell in midday trading following studies on potential Alzheimer's disease treatments that left investors with few answers on the viability of the treatments.
On Wednesday, Eli Lilly reported that an experimental medication might slow mild Alzheimer's if people take it early enough. But, the new findings don't prove that the drug, solanezumab, really works. A larger study is underway that won't end until late 2016.
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Eli Lilly shares slipped 8 cents to $85.49 in midday trading after trading as high as $86.80 earlier in the day.
Meanwhile, Biogen released the results of a small, early-stage study showing that its drug candidate Aducanumab appeared to slow cognitive decline in some patients when given in higher doses. The results confirmed data from last spring that focused on several doses.
Biogen shares fell $13.71, or 3.4 percent, to $395.79 in midday trading.
The development of Alzheimer's disease treatment has been fraught with false starts and failures, leaving investors and patients waiting for a treatment. In 2012, Eli Lilly's solanezumab failed to meet treatment goals in two studies.
Roche stopped a late-stage study of its drug candidate Gantenerumab in December because it failed to meet treatment goals of stemming cognitive decline in patients. That drug is being tested in two additional studies involving higher doses.