Biogen Shares Seesaw on Uncertainty About Alzheimer’s Drug

Biogen Inc. shares reversed gains after concerns about the safety of an experimental drug for Alzheimer’s disease crushed earlier optimism about its potential.

The stock’s seesawing Friday reflects the amount of uncertainty that surrounds the search of a treatment for a disease that’s one of the leading causes of death in the U.S., as investors digest data presented at the annual Clinical Trials on Alzheimer’s Disease meeting in San Diego.

Biogen fell as much as 2.7 percent after slides from a presentation at the meeting showed that one patient on an extension study of its drug, aducanumab, had a therapy-related seizure and loss of pulse. The shares had earlier risen as much as 6 percent as data from a failed trial by Eli Lilly & Co. presented the previous night was seen as a sign that aducanumab was a stronger drug, and may have a greater shot at changing the course of the illness.

As of 2:41 p.m., Biogen’s stock was down 0.4 percent to $288.76.

Lilly’s announcement last month that it would stop a study for its treatment, called solanezumab, was a major setback for patients and the industry, sending stocks of companies developing related drugs plunging.

The detailed results of the failed trial presented by Lilly Thursday show that solanezumab had little effect in lowering the brain’s levels of beta amyloid, a protein thought to play a role in the disease. Biogen’s study suggests its treatment is more effective in targeting the protein.

Alzheimer’s has grown into the sixth-biggest cause of death in the U.S., and rate of deaths linked to the condition rose about 16 percent between 2014 and 2015, according to the Centers for Disease Control and Prevention. More than 100 compounds have failed to slow or prevent the condition, which robs patients of their minds and eventually their lives.

    Before it's here, it's on the Bloomberg Terminal.