Zenyaku Kogyo and Chugai win MHLW approval for Rituxan (rituximab) in autoimmune hemolytic anemia (AIHA). Details on new indication, AIHA types, and B-cell therapy benefits
Edited and Written By: Pharmacally Medical News Desk
Assisted By: Pavan Kumar Chikkula PharmD
Reviewed By: Pharmacally Editorial Team
Zenyaku Kogyo Co., Ltd. and Chugai Pharmaceutical Co., Ltd. announced that Japan’s Ministry of Health, Labour and Welfare (MHLW) has approved an additional indication for Rituxan® (rituximab, genetic recombination), their co-marketed anti-CD20 monoclonal antibody. Available as intravenous injections of 100 mg and 500 mg, Rituxan now targets autoimmune hemolytic anemia (AIHA), expanding its role in treating this challenging condition.
The approval stemmed from development requests by the Japanese Society of Hematology and the Japanese Society of Pediatric Hematology/Oncology. Evaluated at the 64th Evaluation Committee on unapproved or off-label drugs with high medical needs on July 4, 2025, and confirmed by the Pharmaceutical Affairs Council’s First Committee on Drugs on July 31, 2025, the indication qualified for a public knowledge-based application. Zenyaku submitted this on August 29, 2025, leading to today’s approval.
AIHA encompasses immune-mediated destruction of red blood cells due to autoantibodies targeting membrane antigens, drastically shortening red cell lifespan. Designated as intractable disease No. 61 by the Japanese government, it divides into warm AIHA (autoantibodies active near 37°C) and cold AIHA, including cold agglutinin disease (CAD) and paroxysmal cold hemoglobinuria (PCH). Triggers often involve infections, immunodeficiency, immune dysregulation, hormones, drugs, or tumors.
Treatment varies by type. About 80% of warm AIHA cases respond initially to adrenocortical steroids, but relapses are common, often requiring long-term use or splenectomy for refractory patients. CAD focuses on warmth maintenance, yet severe anemia, transfusion needs, and circulatory issues persist.
Both Japanese and international guidelines recommend Rituxan for these scenarios. PCH, rarer and mostly post-viral in children, typically uses warmth and steroids, with Rituxan showing promise in chronic or steroid-refractory cases.
Rituxan binds CD20 on B cells (sparing stem cells and plasma cells), triggering immune-mediated depletion. In autoantibody-driven diseases like AIHA, autoreactive B cells likely drive plasma cell production of harmful antibodies. Though AIHA’s exact pathogenesis remains unclear, autoantibodies’ presence across types supports Rituxan’s B-cell targeting efficacy.
Reference
Anti-CD20 Monoclonal Antibody Rituxan® Approved for Treatment of Autoimmune Hemolytic Anemia, 19 February 2026, Feb 19,2026 | Anti-CD20 Monoclonal Antibody Rituxan® Approved for Treatment of Autoimmune Hemolytic Anemia | News | CHUGAI PHARMACEUTICAL CO., LTD.