FDA Issues CRL to SNY's Regulatory Filing for Multiple Sclerosis Drug

Core Insights - Sanofi's new drug application (NDA) for tolebrutinib, a Bruton's tyrosine kinase (BTK) inhibitor for treating non-relapsing secondary progressive multiple sclerosis (nrSPMS), received a complete response letter (CRL) from the FDA [1] Regulatory Developments - The FDA's CRL for tolebrutinib was anticipated, as the review timeline had already been extended twice earlier this year [2] - The initial decision date of September 28, 2025, was pushed to December 28, 2025, due to Sanofi's submission of additional analyses deemed a major amendment [3] - Following the submission of an expanded access protocol at the FDA's request, the review date was revised again, with further guidance expected by the end of Q1 2026 [4] Market Performance - Over the past six months, Sanofi's shares have increased by 1.1%, while the industry has seen a rise of 20.4% [5] International Approvals - Tolebrutinib received provisional approval in the UAE for treating nrSPMS and slowing disability accumulation in adults [6] - A regulatory filing for a similar indication is currently under review in the European Union [6] Clinical Study Outcomes - The phase III PERCEUS study for tolebrutinib in primary progressive multiple sclerosis (PPMS) did not meet its primary endpoint [10] - Sanofi has decided not to pursue further development of tolebrutinib in PPMS, which represents 10% of the overall MS patient population [11] - In 2022, the FDA placed a partial clinical hold on phase III studies for tolebrutinib due to identified cases of drug-induced liver injury [11] Other Regulatory Approvals - The European Commission approved Wayrilz (rilzabrutinib) for immune thrombocytopenia (ITP) in adult patients refractory to other treatments [13] - The approval was based on data from the phase III LUNA 3 study, which met both primary and secondary endpoints [14]