Media Update: New data for tolebrutinib, Sanofi’s investigational brain- penetrant BTK inhibitor, showed significant effect on CNS immune mediators that drive MS disease progression

New data for tolebrutinib, Sanofi’s investigational brain-penetrant BTK inhibitor, showed sign i ficant effec t on CNS immune mediators that drive MS disease progression Findings to be presented at ACTRIMS Forum 2023 showed significant impact of tolebrutinib on neuroinflammatory biomarkers in the central nervous system (CNS) associated with MS disease progression, reinforcing the potential of tolebrutinib to address disability accumulation – a significant unmet need in MS treatment Additional research includes Phase 2 trial design for SAR443820, Sanofi’s investigational oral receptor-interacting protein kinase 1 (RIPK1) inhibitor Paris , February 23 , 2023 . New data for tolebrutinib, Sanofi’s investigational oral Bruton’s tyrosine kinase (BTK) inhibitor for the treatment of multiple sclerosis (MS), showed a significant effect on key immune mediators that may drive disease progression within the CNS. In the study, researchers measured proteomic changes in the cerebrospinal fluid of MS patients treated with tolebrutinib, compared to patients receiving either no treatment or the B-cell depleting therapy, ocrelizumab. These findings stem from a collaborative research and development partnership with the National Institute of Neurological Disorders and Stroke (NINDS) and will be presented at the Americas Committee for Treatment and Research in Multiple Sclerosis (ACTRIMS) Forum 2023. Tim Turner, PhD Global Project Head for Tolebrutinib, Sanofi “Delivering therapies across the tightly controlled blood-brain barrier to reach disease targets thought to be responsible for driving smoldering neuroinflammation within the central nervous system has been a tremendous hurdle in advancing innovation in multiple sclerosis. D ata being presented at this year’s ACTRIMS Forum 2023 support the unique disease-mod i f y ing potential of tolebrutinib to target inflammation both in the periphery and directly in the central nervous system and, more broadly, reflect Sanofi’s long-standing commitment to advancing research that hold s promise for truly transforming the way multiple sclerosis is treated.” Additional presentations include an evaluation of the CNS penetrability of tolebrutinib in human participants at bioactive levels, as measured by drug concentration in the cerebrospinal fluid of healthy volunteers, as well as the Phase 2 MS trial design for SAR443820, Sanofi’s investigational oral RIPK1 inhibitor. A bstracts accepted for presentation at ACTRIMS 2023 include: Tolebrutinib Evaluating Large Scale Proteomic Changes in Cerebrospinal Fluid of Multiple Sclerosis Patients Treated with Tolebrutinib Poster: #P019 Feb. 23, 7:00-7:30 p.m. PST Tolebrutinib Demonstrates Cerebrospinal Fluid Exposure at Bioactive Levels in a Single-Ascending Dose Study in Healthy Volunteers Poster: #P151 Feb. 23, 7:00-7:30 p.m. PST SAR443820 Effect of RIPK1 Inhibitor, SAR443820, on Serum Neurofilament Light Chain Levels in Patients with Multiple Sclerosis: A Phase 2 Trial Design Poster: #P072 Feb. 23, 6:30-7:00 p.m. PST About tolebrutinib Tolebrutinib is an investigational brain-penetrant and bioactive Bruton’s tyrosine kinase (BTK) inhibitor that achieves CSF concentrations predicted to modulate B lymphocytes and microglial cells. Tolebrutinib is being evaluated in Phase 3 clinical trials for the treatment of relapsing forms of MS (RMS), non-relapsing secondary progressive MS (nrSPMS), and primary progressive MS (PPMS) and its safety and efficacy have not been evaluated by any regulatory authority worldwide. For more information on tolebrutinib clinical trials, please visit www.clinicaltrials.gov . About Sanofi We are an innovative global healthcare company, driven by one purpose: we chase the miracles of science to improve people’s lives. Our team, across some 100 countries, is dedicated to transforming the practice of medicine by working to turn the impossible into the possible. We provide potentially life-changing treatment options and life-saving vaccine protection to millions of people globally, while putting sustainability and social responsibility at the center of our ambitions. Sanofi is listed on EURONEXT: SAN and NASDAQ: SNY Media Relations Sandrine Guendoul | + 33 6 25 09 14 25 | [email protected] Sally Bain | + 1 617 834 6026 | [email protected] Kate Conway | + 1 508 364 4931 | [email protected] Investor Relations Eva Schaefer-Jansen | + 33 7 86 80 56 39 | [email protected] Arnaud Delépine | + 33 6 73 69 36 93 | [email protected] Corentine Driancourt | + 33 6 40 56 92 21 | [email protected] Felix Lauscher | + 1 908 612 7239 | [email protected] Tarik Elgoutni| + 1 617 710 3587 | tarik.e [email protected] Nathalie Pham | + 33 7 85 93 30 17 | [email protected] Sanofi Forward-Looking Statements This press release contains forward-looking statements as defined in the Private Securities Litigation Reform Act of 1995, as amended. Forward-looking statements are statements that are not historical facts. 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