Sanofi’s Rilzabrutinib Receives Orphan Drug Status for IgG4-Related Disease
Tuesday, March 03, 2026
Sanofi has announced that Japan’s Ministry of Health, Labour and Welfare (MHLW) has granted orphan drug designation to rilzabrutinib for the treatment of IgG4-related disease (IgG4-RD).
IgG4-RD is a rare, progressive and immune-mediated condition occurs when the immune system attacks various tissues and organs, which can result in serious and lasting damage. Treatment options in Japan remain limited, highlighting a clear unmet medical need. The MHLW grants orphan status to medicines intended for rare diseases that require new therapeutic approaches. The disorder is chronic and relapsing, may affect almost any organ, and in severe cases can become life-threatening. Due to its rarity and the difficulty in diagnosis, the global prevalence remains uncertain.
Rilzabrutinib is an oral, reversible covalent Bruton’s tyrosine kinase (BTK) inhibitor. It was evaluated in a Phase II study (NCT04520451), with results presented at the European Alliance of Associations for Rheumatology 2025 Congress. After 52 weeks of treatment, patients experienced a reduction in disease flares and other markers of disease activity, along with a reduced need for glucocorticoids. The safety profile was consistent with earlier studies in other conditions, and no new safety concerns were reported. The most common treatment-emergent adverse events, seen in more than 10% of patients, included diarrhoea, COVID-19, dizziness, dry mouth and nausea.
Marketed as Wayrilz where approved, the therapy is designed to help restore immune balance through multi-immune modulation. By selectively inhibiting BTK, a key protein involved in immune cell signalling, it aims to address the underlying causes of several immune-mediated and inflammatory diseases.
The medicine is currently being further evaluated in the Phase III RILIEF study (NCT07190196) for IgG4-RD. It is also under investigation for several other rare immune-mediated conditions. In 2025, rilzabrutinib received approval for immune thrombocytopenia (ITP) in the United States, the European Union and the United Arab Emirates, and it is presently under regulatory review for ITP in Japan.
Apart from the approved use in ITP in the US, EU and UAE, other indications remain investigational and have not yet been approved by regulatory authorities.
Source: sanofi.com
