FDA Accepts New Drug Application for Tofersen as Treatment of SOD1-ALS

The FDA has accepted a new drug application (NDA) for tofersen (Biogen), an investigational drug that treats superoxide dismutase 1 (SOD1) amyotrophic lateral sclerosis (ALS).

The application has been granted priority review status and given a Prescription Drug User Fee Act date of January 25, 2023. The FDA has said that it currently plans to hold an advisory committee meeting for the application, but the date has not been determined yet.

Currently, there is no treatment targeted for SOD1-ALS, which has a life expectancy of 3 to 5 years from time of symptom onset, according to a statement released by Biogen.

“The available data show that tofersen has the potential to make a meaningful difference for [patients] with SOD1-ALS,” Priya Singhal, MD, MPH, head of Global Safety and Regulatory Sciences and interim head of Research and Development at Biogen, said in the statement. “Pursuing the FDA’s accelerated approval pathway offers the potential to make tofersen available to [individuals] living with this fatal, neurodegenerative disease as quickly as possible. If approved, tofersen will be the first treatment to target a genetic cause of ALS and we hope this will pave the way for further advances in this relentless disease.”

Biogen is seeking approval under the FDA’s accelerated approval pathway due to the use of neurofilament as a surrogate biomarker that is reasonably likely to predict clinical benefit.

Neurofilaments are a normal protein in healthy neurons that are increased in blood and cerebrospinal fluid when damage has been done to the neurons or their axons. They are a marker of neurodegeneration and, in ASL, higher levels of neurofilament shave been found to predict more rapid decline in measures of clinical and respiratory function, strength, and quality of life.

Biogen will be committed to ongoing data generation and finalizing the confirmatory data package with the FDA.

“The 12-month results showed that individuals with SOD1-ALS who started tofersen earlier experienced a slower rate of decline in clinical and respiratory function, strength and quality of life. These are critical measures for [individuals] living with this devastating disease,” said Timothy Miller, MD, PhD, principal investigator of VALOR and co-director of the ALS Center at Washington University School of Medicine, St. Louis, said in a statement. “For [patients] in my clinic living with SOD1-ALS, tofersen may meaningfully slow the rapid progression of their disease and the impact it has on their lives.”

The NDA for tofersen included results from a phase 1 study in healthy individuals, a phase 1/2 study evaluating ascending dose levels, the phase 3 VALOR study, and the open label extension study. Additionally, investigators included the most current 12-month integrated results from VALOR and the open label extension study, which were recently presented at the European Network to Cure ASL annual meeting.

While the VALOR study did not meet the primary endpoint of change from baseline to week 28 in the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale, trends of reduced disease progression across multiple secondary and exploratory endpoints were observed.

In the 12-month data, investigators saw that earlier initiation of tofersen led to sustained reduction in neurofilament. Adverse events of the VALOR and open label extension study were headache, procedural pain, fall, back pain, and pain in extremities, which were generally mild to moderate in severity.

Reference

FDA accepts Biogen’s new drug application and grants priority review of tofersen for a rare, genetic form of ALS. News release. Biogen. July 26, 2022. Accessed July 26, 2022. http://media.biogen.com/news-releases/news-release-details/fda-accepts-biogens-new-drug-application-and-grants-priority