Phase 2 results demonstrate rilzabrutinib rapidly reduced itch severity and significantly improved disease activity in adults with chronic spontaneous urticaria

• Late-breaking data at 2024 AAAAI showed rilzabrutinib, an oral BTK inhibitor, significantly reduced weekly itch severity score (ISS7) as early as the first week of treatment in adults with moderate to severe CSU
• Data form the basis for the Phase 3 CSU and prurigo nodularis programs to start in 2024
• Pivotal Phase 3 readout in immune thrombocytopenia and Phase 2 readouts in asthma, IgG4-related disease and warm autoimmune hemolytic anemia expected in 2024
• Rilzabrutinib is one of 12 potential blockbusters in Sanofi’s leading immunology pipeline

Paris, February 24, 2024. Positive results from the Phase 2 study RILECSU showed that rilzabrutinib significantly improved itch, hives and urticaria in adults with moderate-to-severe chronic spontaneous urticaria (CSU), whose symptoms are not adequately controlled by H1 antihistamines. These results were presented today in a late-breaking poster at the 2024 American Academy of Allergy, Asthma and Immunology (AAAAI) Annual Meeting in Washington, DC and form the basis for the Phase 3 program which is on track to start in 2024.

Professor Marcus Maurer, M.D.Professor of Dermatology and Allergy, Executive Director of the Institute of Allergology at the Charité Berlin“People with CSU are living with debilitating symptoms such as intensely itchy recurrent hives, swelling, or both which can have a high impact on their day-to-day lives. These data are promising news for patients that cannot be controlled with standard-of-care antihistamines – the possibility of controlling itch rapidly with an oral medicine would offer an important advancement in the treatment of this disease.”

Naimish Patel, M.D.Head of Global Development, Immunology and Inflammation, Sanofi“These data reinforce the potential of rilzabrutinib as a treatment option for patients with moderate-to-severe CSU and we believe that the rapid improvement of itch could make a meaningful difference in alleviating the physical and psychosocial burden these patients suffer from. Based on these data, later this year we will advance rilzabrutinib into Phase 3 development in both CSU and prurigo nodularis, another skin disorder characterized by relentless itching. We also look forward to data readouts for rilzabrutinib in 2024 with the opportunity to further demonstrate its potential impact across multiple immune-mediated diseases.”

Key Results In this dose-ranging study, different doses of rilzabrutinib were evaluated: 400 mg once every evening (QPM), 400 mg twice a day (BID), 400 mg three times a day (TID).

In the intent-to-treat (ITT) population which included either patients who were previously naïve or incomplete responders to omalizumab, Rilzabrutinib 400 mg TID demonstrated:

• Significant reduction from baseline in weekly itch severity score (ISS7) at Week 12, a key symptom of the disease, [least squares mean (LSM) -9.58 vs -6.31, respectively; p=0.0181]. Significant changes in ISS7 were seen as early as Week 1.
• Significant reduction from baseline to week 12 in weekly urticaria activity score (UAS7) [LSM -17.95 vs -11.20, respectively; p=0.0116].
• Significant reduction from baseline to week 12 in weekly hives severity score (HSS7) [LSM -8.31 vs -4.89; p