Sanofi Granted Orphan Drug Designation in Japan for Rilzabrutinib
Sanofi has received orphan drug designation from the Japanese Ministry of Health for rilzabrutinib in the treatment of IgG4-related disease. This recognition comes as the company continues to evaluate the compound in various rare immune-mediated diseases.
Orphan Drug Status Awarded for IgG4-Related Disease
Rilzabrutinib, an oral and reversible inhibitor of Bruton's tyrosine kinase (BTK), has been granted orphan drug designation in Japan for IgG4-related disease, a rare, progressive, and chronic immune-mediated condition in which the immune system attacks various tissues and organs. The Japanese Ministry of Health grants this designation to drugs treating rare diseases with unmet medical needs. In Japan, IgG4-related disease has limited treatment options and an unmet medical need.
Evaluation of Rilzabrutinib in IgG4-Related Disease
The evaluation of rilzabrutinib in IgG4-related disease is based on a phase 2 study, the results of which were presented at the 2025 Congress of the European Alliance of Rheumatology Associations. In patients treated for 52 weeks, the compound led to a reduction in disease flares and other disease markers, minimizing the need for glucocorticoid treatment. The safety profile observed was consistent with that of previous studies in other indications. Rilzabrutinib is currently being evaluated in the phase 3 RILIEF study. Elsewhere, rilzabrutinib was approved in 2025 for immune thrombocytopenia in the United States, the European Union, and the United Arab Emirates, with regulatory review ongoing in Japan for this indication. The compound is also subject to accelerated designations by several regulatory authorities for other rare immune-mediated or inflammatory diseases.
