Sanofi Receives Orphan Drug Designation in Japan for Rilzabrutinib to Treat IgG4 Related Disease

(IN BRIEF) Sanofi has obtained orphan drug designation in Japan for rilzabrutinib as a treatment for IgG4-related disease, a rare immune-mediated condition with limited treatment options. The designation from Japan’s Ministry of Health, Labour and Welfare is supported by positive phase 2 clinical trial results showing reduced disease flares and decreased need for glucocorticoid treatment. Rilzabrutinib is currently being evaluated in a phase 3 study for IgG4-RD and is also under investigation for several other rare immune-mediated diseases. The therapy has already been approved for immune thrombocytopenia in multiple regions and remains under regulatory review in Japan.

(PRESS RELEASE) PARIS, 2-Mar-2026 — /EuropaWire/ — Sanofi has received orphan drug designation in Japan for rilzabrutinib as a potential treatment for IgG4-related disease (IgG4-RD). The designation was granted by Japan’s Ministry of Health, Labour and Welfare and reflects the need for new treatment options for this rare and progressive immune-mediated condition. The decision marks the third orphan designation awarded globally for rilzabrutinib in IgG4-RD and reinforces Sanofi’s focus on therapies for rare immune-related diseases.

IgG4-related disease is a chronic disorder in which immune system activity leads to inflammation and damage in multiple organs and tissues. Available treatment options remain limited in Japan, creating a need for new therapeutic approaches. The orphan drug designation program is intended to support the development of medicines for rare diseases that currently lack sufficient treatment alternatives.

The designation is supported by findings from a phase 2 clinical study (NCT04520451) evaluating rilzabrutinib in patients with IgG4-RD. Results presented at the European Alliance of Associations for Rheumatology 2025 congress showed that treatment over a 52-week period reduced disease flare-ups and improved clinical indicators while decreasing reliance on glucocorticoid therapy. The safety results were consistent with earlier clinical experience in other conditions, and no new safety concerns were identified. Adverse events reported in more than ten percent of patients included diarrhea, COVID-19 infection, dizziness, dry mouth, and nausea.

Rilzabrutinib is currently being further studied for IgG4-RD in the ongoing RILIEF phase 3 clinical trial (NCT07190196).

The therapy is under investigation across several rare immune-mediated conditions. In 2025, rilzabrutinib was approved for the treatment of immune thrombocytopenia in the United States, the European Union, and the United Arab Emirates. Regulatory review for immune thrombocytopenia is ongoing in Japan. The medicine has also received multiple expedited regulatory designations worldwide for conditions including IgG4-related disease, warm autoimmune hemolytic anemia, and sickle cell disease. Apart from the approved indications for immune thrombocytopenia in the United States, European Union, and United Arab Emirates, other uses remain investigational and have not yet been approved by regulatory authorities.

About rilzabrutinib
Rilzabrutinib, Wayrilz where approved, is a novel, oral, reversible covalent BTK inhibitor that has the potential to be an effective new medicine for several rare immune-mediated or inflammatory diseases by working to restore immune balance via multi-immune modulation. BTK, expressed in B cells, macrophages, and other innate immune cells, plays a critical role in multiple immune-mediated disease processes and inflammatory pathways. With the application of the TAILORED COVALENCY® technology, rilzabrutinib can selectively inhibit the BTK target. Rilzabrutinib is now approved for the treatment of immune thrombocytopenia (ITP) in the US, the EU, and the UAE. Regulatory review for use in ITP is currently ongoing in Japan.

About IgG4-RD
IgG4-RD is a progressive, relapsing, chronic immune-mediated rare disease, which can manifest in almost every organ and can lead to organ damage and irreversible dysfunction with a sometimes fatal outcome. People with IgG4-RD experience flare-ups of the condition characterized by periods of exacerbated symptoms. Due to its rarity and challenges with diagnosis, the global prevalence of IgG4-RD is unknown.

About Sanofi
Sanofi is an R&D driven, AI-powered biopharma company committed to improving people’s lives and delivering compelling growth. We apply our deep understanding of the immune system to invent medicines and vaccines that treat and protect millions of people around the world, with an innovative pipeline that could benefit millions more. Our team is guided by one purpose: we chase the miracles of science to improve people’s lives; this inspires us to drive progress and deliver positive impact for our people and the communities we serve, by addressing the most urgent healthcare, environmental, and societal challenges of our time.

Sanofi is listed on EURONEXT: SAN and NASDAQ: SNY

Sanofi forward-looking statements
This press release contains forward-looking statements within the meaning of applicable securities laws, including the Private Securities Litigation Reform Act of 1995, as amended. Forward-looking statements are statements that are not historical facts. These statements include projections and estimates and their underlying assumptions regarding the marketing and other potential of the product; regarding potential future events and revenues from the product. Words such as “expect,” “anticipate,” “believe,” “intend,” “estimate,” “plan,” “can,” “contemplate,” “could,” “is designed to,” “may,” “might,” “potential,” “objective,” “attempt,” “target,” “project,” “strategy,” “strive,” “desire,” “predict,” “forecast,” “ambition,” “guideline,” “seek,” “should,” “will,” “goal,” or the negative of these and similar expressions are intended to identify forward-looking statements. Although Sanofi’s management believes that the expectations reflected in such forward-looking statements are reasonable, investors are cautioned that forward-looking information and statements are subject to various risks and uncertainties, many of which are difficult to predict and generally beyond the control of Sanofi, that could cause actual results and developments to differ materially from those expressed in, or implied or projected by, the forward-looking information and statements. These risks, uncertainties and assumptions include among other things, unexpected regulatory actions or delays, or government regulation generally, that could affect the availability or commercial potential of the product, the fact that product may not be commercially successful; authorities’ decisions regarding whether and when to approve a product candidate; political pressure in the United States to mandate lower drug prices including “most favored nation” pricing for State Medicaid programs; the uncertainties inherent in research and development, including future clinical data and analysis of existing clinical data relating to the product, including post marketing, unexpected safety, quality or manufacturing issues; competition in general; risks associated with intellectual property and any related pending or future litigation and the ultimate outcome of such litigation, and volatile economic and market conditions, and the impact that global crises may have on us, our customers, suppliers, vendors, and other business partners, and the financial condition of any one of them, as well as on our employees and on the global economy as a whole. The risks and uncertainties also include the uncertainties discussed or identified in the public filings with the SEC and the French Markets Authority (AMF) made by Sanofi, including those listed under “Risk Factors” and “Cautionary Statement Regarding Forward-Looking Statements” in Sanofi’s annual report on Form 20-F for the year ended December 31, 2025 or contained in our periodic reports on Form 6-K. Other than as required by applicable law, Sanofi does not undertake any obligation to update or revise any forward-looking information or statements. In light of these risks, uncertainties and assumptions, you should not place undue reliance on any forward-looking statements contained herein.

Sanofi Receives Orphan Drug Designation in Japan for Rilzabrutinib to Treat IgG4 Related Disease

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