Sanofi’s Wayrilz Receives FDA Approval as First BTK Inhibitor for Immune Thrombocytopenia

The US FDA approved Wayrilz (rilzabrutinib) on August 29, 2025, marking it as the first Bruton’s tyrosine kinase (BTK) inhibitor for adults with persistent or chronic immune thrombocytopenia (ITP) who have had an insufficient response to prior treatment1235.

Approval was based on the Phase 3 LUNA 3 study, which demonstrated rapid and durable platelet response, improved ITP symptoms, and a manageable safety profile for Wayrilz compared to placebo135.

Rilzabrutinib’s novel mechanism targets BTK—a key protein in inflammatory immune pathways—in B cells, macrophages, and other immune cells, providing multi-immune modulation and addressing root immune dysregulation in ITP235.

ITP is a rare autoimmune disorder characterized by low platelet counts (below 100,000/μL), leading to increased risk of bleeding, bruising, and severe events like intracranial hemorrhage; it can also cause fatigue, cognitive impairment, and emotional symptoms23.

More than 25,000 US adults could benefit from advanced treatment options like Wayrilz, which represents a significant innovation for patients with ongoing disease despite current therapies15.

Sources:

1. https://www.sanofi.com/en/media-room/press-releases/2025/2025-08-29-21-50-18-3141825

2. https://www.ajmc.com/view/rilzabrutinib-becomes-first-fda-approved-btk-inhibitor-for-itp

3. https://www.pharmacytimes.com/view/rilzabrutinib-becomes-first-approved-btk-inhibitor-for-immune-thrombocytopenia

5. https://www.pharmexec.com/view/fda-approves-sanofi-wayrilz-persistent-chronic-immune-thrombocytopenia