*Pathogenic variants (mutations) in the SOD1 gene are a known risk factor for ALS and contribute to about 1.5 to 7% of all ALS cases.
Long-term results for tofersen, now approved in Canada as Qalsody, continue to show ongoing benefits for people with SOD1-ALS.*
In the Phase 3 VALOR trial and its open label extension, people who started the drug six months early had a slower decline in clinical function (according to the ALSFRS-R score), respiratory function, muscle strength, and overall quality of life over almost three years. About 25% of early start participants even showed improvements in strength and function.
These findings support early treatment initiation, despite the fact that the study didn’t show a statistically significant difference between early- and delayed-start groups at the three-year point. For tofersen, this is likely a testament to it being an effective treatment, as a large difference would not be expected if individuals in the delayed-start group were benefitting for years, following only six months on placebo. Overall trends still favoured earlier treatment, and there is an expectation that the benefit of earlier intervention would be much more pronounced in individuals with faster progressing disease. This is being tested in a landmark, presymptomatic clinical trial called ATLAS, which is currently underway. In this study, both groups did better than what’s typically seen in SOD1-ALS.
Plasma NfL levels, a biomarker of nerve damage, dropped the most around 16 weeks after starting treatment. By about three years, NfL levels were still much lower than at the start: about 67% lower in the early-start group and 64% lower in the group that began treatment six months later.
The long-term safety profile remained consistent with earlier trials, and all the data together strongly support Qalsody as an effective long-term treatment option, especially when started early. Like any treatment, many people are thriving on Qalsody but side effects may occur in some individuals. Biogen published a separate paper on the potential safety risks of Qalsody as a commitment to transparency.
Watch the trailer for Another Tomorrow, a documentary coming up spring 2026 about Qalsody’s impact.