Sanofi’s Rilzabrutinib granted orphan drug designation for two rare diseases with no approved medicines

The US FDA has granted orphan drug designation to rilzabrutinib, an investigational, novel, advanced, oral, reversible Bruton’s tyrosine kinase inhibitor, for two rare diseases, warm autoimmune hemolytic anemia and IgG4-related disease. There is still a significant unmet medical need for these two rare diseases, and neither have any currently approved medicine.

Karin Knobe, MD, PhD
Global Head of Development, Rare Diseases
“Orphan drug designation for these two rare, immune-mediated conditions validates our ongoing commitment to pursuing potential first- and best-in-class medicines for diseases that affect small populations but persist with unmet medical need. Our continued exploration of rilzabrutinib across multiple indications speaks to our belief in its potential for multi-immune modulation, as well as our belief in supporting treatment options, no matter how rare a condition.”

Rilzabrutinib is currently under regulatory review in the US, the EU, and China for its potential use in immune thrombocytopenia (ITP). The target action date for the FDA regulatory decision for ITP, which was granted fast track designation, is August 29, 2025. Rilzabrutinib also received orphan drug designation for ITP in the US, EU, and Japan.

In IgG4-RD patients, results from a phase 2a study showed treatment with rilzabrutinib for 52 weeks led to reduction in disease flare, other disease markers, and glucocorticoid sparing. More detailed results will be shared at a forthcoming medical meeting.

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rilzabrutinib, Sanofi