FDA Accepts Sanofi's Filing for Multiple Sclerosis Drug Tolebrutinib (Revised)

Core Viewpoint - Sanofi's investigational BTK inhibitor tolebrutinib has received FDA acceptance for regulatory filing to treat non-relapsing secondary progressive multiple sclerosis (nrSPMS), with a priority review that shortens the review period by four months, leading to a final decision expected by September 28, 2025 [1][2][3]. Group 1: Clinical Data and Studies - The FDA filing is supported by data from three late-stage studies: HERCULES for nrSPMS and GEMINI 1 and 2 for relapsing MS (RMS). HERCULES data indicated that tolebrutinib delayed the onset of six-month confirmed disability progression compared to placebo, while GEMINI studies showed a delay in disability worsening compared to Aubagio (teriflunomide) [2]. - Tolebrutinib is positioned as the first and only brain-penetrant BTK inhibitor targeting both nrSPMS and RMS, potentially addressing a significant unmet need in multiple sclerosis by targeting smoldering neuroinflammation, a key driver of disability accumulation [3][4]. Group 2: Market Context and Stock Performance - Currently, there are no approved therapies for nrSPMS, highlighting the potential market opportunity for tolebrutinib if approved [4]. - Year to date, Sanofi's shares have increased by 16%, outperforming the industry growth of 6% [5]. Group 3: Future Developments - Sanofi is also evaluating tolebrutinib in a phase III study (PERSEUS) for primary progressive MS, with data expected in the second half of 2025 [7]. - A partial clinical hold was placed by the FDA on Sanofi's phase III studies for tolebrutinib in MS and myasthenia gravis (MG) due to cases of drug-induced liver injury, leading to the eventual discontinuation of MG studies [8][9].