Sanofi's MS drug candidate, tolebrutinib, failed to reduce relapse rates but delayed disability progression in late-stage trials.

Sanofi's MS drug candidate, tolebrutinib, failed to reduce relapse rates in two late-stage trials for relapsing forms of the disease but successfully delayed disability progression in a trial for non-relapsing secondary progressive MS. The company plans to seek regulatory approval by late 2024. Despite setbacks, tolebrutinib is considered a potential breakthrough in treating progressive MS, which currently lacks effective therapies.