French healthcare company Sanofi S.A. (Euronext Paris:SAN) (Nasdaq:SNY) announced on Tuesday that the US Food and Drug Administration (FDA) has granted orphan drug designation to rilzabrutinib, an oral reversible Bruton's tyrosine kinase inhibitor, for the treatment of sickle cell disease.

The designation supports its potential to reduce inflammation-driven vaso-occlusive crises in patients with this rare condition.

This marks the fourth orphan drug designation for rilzabrutinib. In addition to sickle cell disease, rilzabrutinib has received orphan drug designation for immune thrombocytopenia (ITP) in the United States, the European Union, and Japan, for warm autoimmune haemolytic anaemia (wAIHA) in the US and the EU, and for IgG4-related disease (IgG4-RD) in the US.

Rilzabrutinib is currently under regulatory review for immune thrombocytopenia in the US, the EU, and China, with an FDA decision expected by 29 August 2025.

Preclinical data presented at ASH 2024 demonstrated rilzabrutinib's ability to reduce blood vessel blockage and inflammation in mouse models of sickle cell disease.