FDA advisors reject Biogen's ALS drug for rare and aggressive form.

The FDA's independent panel of advisors voted against the effectiveness of Biogen's investigational ALS drug, Tofersen, for a rare and aggressive form of the disease. The drug failed to meet the primary and secondary endpoint in a phase three clinical trial, but the panel voted unanimously that the drug could have a clinical benefit in reducing a protein associated with disease severity. The FDA will make a final decision on April 25. ALS is a progressive and fatal neuromuscular disease that causes nerve cells in the brain and spinal cord to waste away over time.