FDA staff says safety issues with Biogen's ALS drug to not prevent approval

FILE PHOTO: A sign marks a Biogen facility in Cambridge

By Bhanvi Satija

(Reuters) -The U.S. health regulator's staff said on Monday safety issues with Biogen Inc's drug to treat an ultra-rare form of amyotrophic lateral sclerosis or ALS, also known as Lou Gehrig's disease, should not prevent its accelerated approval.

A panel of outside advisers to the U.S. Food and Drug Administration on Wednesday will closely scrutinize mixed efficacy data from the drug's late-stage trial and vote on the drug's effectiveness, and if reduction of a key protein related to the disease is enough to conclude that it may benefit ALS patients.

The drug, tofersen, failed to meet its main goal of reducing symptoms but reduced protein neurofilament levels during a late-stage study.

"Our regulations allow for regulatory flexibility to expedite the ... marketing of new therapies intended to treat persons with life-threatening and severely debilitating illnesses," the FDA's staff said in briefing documents.

The risks related to Biogen's drug, such as spinal cord inflammation and optic nerve swelling, observed in trial patients "are acceptable to the patient population", the staff said.

They added that a majority of these risks may be related to the way in which the drug is administered, rather than the drug itself.

Biogen has also submitted data from an extension study to support the drug's approval.

If approved under the FDA's accelerated approval pathway, the drug will have to show that it provides a clinical benefit in a confirmatory trial.

The company is seeking approval for the drug in ALS patients with mutation in a gene known as superoxide dismutase 1.

(Reporting by Raghav Mahobe and Bhanvi Satija in Bengaluru; Editing by Krishna Chandra Eluri and Shinjini Ganguli)