Sanofi's Rilzabrutinib Approval: World's First Autoimmune BTK Inhibitor Fills ITP Treatment Gap
On August 29, 2025, Sanofi announced that its BTK inhibitor rilzabrutinib (Wayrilz) was approved for marketing by the US FDA.
On August 29, 2025, Sanofi announced that its BTK inhibitor rilzabrutinib (Wayrilz) received U.S. FDA approval for the treatment of adult patients with persistent or chronic immune thrombocytopenia (ITP) who have not responded adequately to previous treatment. As the first BTK inhibitor approved globally for this indication, rilzabrutinib uses an oral, reversible mechanism of action to achieve multi-immunomodulatory effects, targeting diverse immune pathways to address the underlying pathology of ITP, offering a novel therapeutic approach for this autoimmune blood disease.
This approval was based on data from the pivotal Phase III LUNA 3 study, which enrolled 202 adult patients and compared the efficacy of rilzabrutinib to placebo. Results showed that the platelet response rate in the rilzabrutinib group reached 64% at 12 weeks (compared to 32% in the placebo group), and the sustained response rate at 25 weeks was 23% (compared to 0% in the placebo group). Furthermore, the initial platelet response in the rilzabrutinib group was only 36 days, and the duration of response was extended to 7 weeks, significantly outperforming the placebo group. Furthermore, patients' health-related quality of life scores improved by 10.6 points, and the drug was generally well tolerated, demonstrating its clinical value.
Regarding its presence in China, the CDE accepted its import registration application for rilzabrutinib in December 2024 (acceptance number JXHS2400121). Sanofi is also simultaneously advancing multiple clinical trials for autoimmune diseases, including a Phase III study in ITP (CTR20220447) and a Phase IIb study in warm autoimmune hemolytic anemia (CTR20212864). The drug originated from Principia Biopharma, which Sanofi acquired for US$3.68 billion in 2020. Its approval marks a breakthrough for BTK inhibitors in the autoimmune field and will bring new options to more than 25,000 ITP patients in the United States and Chinese patients worldwide.