The U.S. Food and Drug Administration issued a complete response letter for Sanofi’s tolebrutinib application in non-relapsing secondary progressive multiple sclerosis, citing serious safety concerns. During pivotal Phase 3 trials, investigators recorded six instances meeting Hy’s Law criteria for severe drug-induced liver injury, including one fatality that required a liver transplant. The agency concluded that neither efficacy data nor safety findings supported a favorable benefit-risk profile in any patient subgroup, effectively halting Sanofi’s efforts to bring this Bruton’s tyrosine kinase inhibitor to market for SPMS.

In a strategic investment, Sanofi has agreed to inject $30 million into Enable Injections to expand production of the enFuse® On-Body Delivery System. This capital infusion will fund the build-out of a 90,000-square-foot Manufacturing Center of Excellence in Springdale, Ohio, enhance supply-chain resilience and support commercial launches with pharmaceutical partners. Enable’s OBI technology, used in subcutaneous formulations of Sanofi’s Sarclisa in multiple myeloma studies presented at ASCO 2025, is currently under regulatory review as part of Sanofi’s broader oncology portfolio.

The FDA has accepted Sanofi’s supplemental biologics license application for Tzield, extending its use to children as young as one year old who are at high risk of progressing to type 1 diabetes. The agency assigned a six-month priority review timeline, reflecting the potential to delay autoimmune β-cell destruction. Tzield demonstrated a 25% reduction in C-peptide decline over 18 months in adolescents during the pivotal trial, and Sanofi projects up to 15,000 pediatric patients could become eligible for early intervention if approved.