Longer-Term Use, Early Initiation of Biogen's Experimental Drug For Inherited Rare Disease Slows Disease Progression

Biogen Inc BIIB announced that The New England Journal of Medicine (NEJM) had published detailed results from the Phase 3 VALOR study of tofersen for superoxide dismutase 1 (SOD1) amyotrophic lateral sclerosis (ALS).
The journal also published the combined analysis of VALOR and its open-label extension (OLE) study.
Data from the combined analysis were included within Biogen's marketing application for tofersen, which was recently accepted for priority review by the FDA, with a Prescription Drug User Fee Act action date of January 25, 2023.
As reported in October 2021, VALOR did not meet the primary endpoint. However, trends of reduced disease progression across multiple secondary and exploratory endpoints were observed.
The combined VALOR and OLE 12-month data showed sustained reductions in SOD1 protein (a marker of target engagement) and neurofilament (neurodegeneration marker). It also slowed the decline in clinical function, respiratory function, strength, and quality of life with earlier initiation of tofersen.
The most common adverse events (AEs) were procedural pain, headache, pain in the arms or legs, falls, and back pain. Most AEs in both VALOR and the OLE were mild to moderate in severity. Serious neurologic events were reported in 6.7% of participants receiving tofersen in VALOR and its OLE.
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