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# Biogen Accelerated Approval for ALS Drug
- URL: https://www.fdaweb.com/biogen-accelerated-approval-for-als-drug/
- Published: 2023-04-25T12:00:00.000Z
- Updated: 2026-09-14T18:27:34.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5154292

FDA has granted Biogen accelerated approval for Qalsody (tofersen) to treat patients with amyotrophic lateral sclerosis (ALS) associated with superoxide dismutase 1 (SOD1) gene mutation, which in turn is linked with 20% of familial cases and about 2% of sporadic ALS cases. The antisense oligonucleotide, which is designed to target SOD1 mRNA to reduce the synthesis of SOD1 protein, was approved based on a reduction in plasma neurofilament light (NfL), a biomarker that assesses nerve injury and neurodegeneration, according to an [FDA release](https://www.fda.gov/drugs/news-events-human-drugs/fda-approves-treatment-amyotrophic-lateral-sclerosis-associated-mutation-sod1-gene?ref=fdaweb.com).

The approval was based on data from a placebo-controlled clinical study in 147 patients with weakness attributable to ALS and a SOD-1 mutation. “Patients receiving Qalsody had nominally significant reductions in plasma NfL concentration at Week 28 compared to the placebo arm,” the agency says. “The findings are reasonably likely to predict a clinical benefit in patients.” To confirm clinical benefit, a Phase 3 trial is ongoing in individuals who are carriers of the SOD1 genetic mutation who do not yet have symptoms, it adds.

The approval is in line with last month’s ([see story](https://www.fdaweb.com/panel-backs-accelerated-ok-consideration-of-biogens-als-drug/)) Peripheral and Central Nervous System Drugs Advisory Committee vote of 9 to 0 recommending accelerated approval. The company proposed the accelerated pathway after the drug’s primary study failed to show a statistically significant difference from placebo groups for the primary and secondary endpoints. A second question asked the panel whether the totality of data could support a traditional approval was met with significantly less support, with panel members voting 5 to 3 (one abstention) that the data do not justify such a move, mainly due to the primary trial missing the endpoints.

In voting yes for traditional approval, Abington Neurologic Associates Clinical Research Center director **David Weisman** said he agonized over his decision but the “odds are extremely high that this drug works. And I guess I really worry about the consequences of an accelerated approval, maybe as a neurologist, where payers will not cover this drug and consider it experimental, which I think would be a big problem clinically.”