Biogen Accelerated Approval for ALS Drug

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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.

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) 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.”

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