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Biogen’s ALS drug gets partial backing from FDA panel

Signage is displayed in front of Biogen headquarters in Cambridge.Bloomberg/Photographer: Bloomberg/Bloomber

A Biogen drug that targets a rare form of ALS got partial support from a panel of US Food and Drug Administration advisers Wednesday, paving the way for a possible accelerated approval.

If it’s approved, the medication, tofersen, would be the first drug targeting a specific genetic cause of the incurable paralysis disease to get the regulatory green light.

Biogen and its partner Ionis Pharmaceuticals have faced some challenges in the development of tofersen. The drug failed to clearly slow the disease in a phase 3 trial. But Biogen applied for so-called accelerated approval on the basis that the drug reduces levels of a blood protein associated with nerve-cell injury.


Doctors on the FDA’s Peripheral and Central Nervous System Drugs Advisory Committee agreed in a 9-0 vote that this reduction is a likely sign patients are being helped. But separately the panel voted 5-3 with one abstention the company hadn’t fully proved the drug is effective.

The second vote means the drug may not get full approval if the FDA agrees with the panel’s conclusions.

The committee heard testimony about tofersen over a daylong hearing, including testimony from patients who spoke in favor of the drug. Tofersen aims to treat people with certain genetic mutations that can lead to a form of amyotrophic lateral sclerosis, a disease in which the nerve cells that control most muscles progressively die.