FDA Pushes Biogen’s ALS Drug Approval Date Back Three Months

After the FDA granted Biogen’s amyotrophic lateral sclerosis (ALS) drug, tofersen, Priority Review through the accelerated approval pathway in July, the regulatory agency announced it would need additional time to review the drug following information requests. The updated approval decision date is April 25, 2023. 

Tofersen’s Journey So Far

Biogen partnered with Ionis Pharmaceuticals in 2018 to develop tofersen, an antisense drug that targets superoxide dismutase 1 (SOD1) ALS. Since its inception, the two companies remained firm in their belief that the drug has the potential to treat ALS, which has very few approved treatment options.

ALS is a rare neurodegenerative disease that kills nerve cells that control voluntary movement. Over time, patients lose the ability to walk, chew, talk, and eventually breathe. After symptoms develop, patients’ survival time is usually between two and five years. 

The pivotal Phase 3 clinical trial, VALOR, studying the safety and efficacy of tofersen, has had ups and downs itself, though. In October 2021, Biogen announced that the drug did not show any statistical improvements in the functional status of the participants compared to the placebo, failing to meet the study’s primary endpoint. 

Following the disappointing data, Biogen pursued an open-label extension (OLE) to combine with data from the VALOR trial. With extra data to bolster tofersen’s long-term potential in SOD1-ALS patients, the FDA granted the drug Priority Review under the accelerated approval pathway in July this year, with an approval decision date set for January 25 next year.

In September, the New England Journal of Medicine published the combined VALOR trial and OLE data. According to the article and Biogen, tofersen demonstrated a slower rate of decline in clinical and respiratory function, strength, and quality of life. 

Now, with even more data available, the FDA requested more information from Biogen, which the company provided. The FDA considers the data a Major Amendment to the approval process, so it will take an extra three months to analyze and deliberate, moving the approval decision date back to April 25 next year. 

Related Article: Amylyx’s ALS Drug Nabs FDA Nod After Rare Regulatory Reversal

Competition in the ALS Space

ALS is an incredibly complicated disease with very few treatment options for patients. Currently, there are only three FDA-approved treatments, all of which aim to lengthen and improve quality of life, not cure the disease.

In September, Amylyx’s Relyvrio gained FDA approval after an FDA committee reversed its vote, deciding that the drug’s clinical trial data demonstrates positive results in ALS patients. Relyvrio’s approval marked the third-ever FDA-approved ALS treatment. 

Other companies have also struggled in the clinic, finding ALS treatments difficult to harness. Last month, Biohaven announced that its ALS-targeting candidate, Verdiperstat, did not perform statistically better than the placebo.

After putting so much work into tofersen’s development, the three-month delay is just another small hiccup in the drug’s development. Biogen hopes that with the additional data, the FDA will approve the drug through the accelerated approval pathway. April 25, 2023, is the day to see if tofersen becomes the fourth-approved ALS treatment.

Author

Reed Slater