Sanofi's Rilzabrutinib Gains Orphan Drug Designation for Sickle Cell Disease in the US

Sanofi announced today that the U.S. FDA has granted orphan drug designation to rilzabrutinib for the treatment of sickle cell disease, marking its fourth orphan status for this investigational Bruton's tyrosine kinase (BTK) inhibitor. The oral, reversible BTK inhibitor targets immune system modulation and aims to reduce vaso-occlusive crises—a major source of pain and complications in sickle cell patients.

Rilzabrutinib is also under regulatory review in the US, EU, and China for immune thrombocytopenia (ITP), with an FDA decision expected by August 29, 2025. Previous designations include approvals for ITP, warm autoimmune hemolytic anemia (wAIHA), and IgG4-related disease.

Preclinical data presented at ASH 2024 demonstrated rilzabrutinib’s potential to reduce inflammation and blood vessel blockage in transgenic mouse models of sickle cell disease. Sanofi continues to advance its pipeline in rare immune-mediated and inflammatory conditions using its TAILORED COVALENCY® technology.