Sanofi's First Oral Autoimmune BTK Inhibitor Wayrilz (Rilzabrutinib) Receives FDA Approval for Chronic Immune Thrombocytopenia

On August 29, Sanofi announced that the U.S. FDA had approved Wayrilz (rilzabrutinib) for the treatment of adults with persistent or chronic immune thrombocytopenia (ITP) who have had an insufficient response to prior therapy. This approval is based on pivotal Phase 3LUNA 3 ClinicalThe study, in which Wayrilz achieved both primary and secondary endpoints, had a positive impact on sustained platelet counts and other ITP symptoms. By applying Sanofi's TAILORED COVALENCY® technology, Wayrilz can selectively inhibit the BTK target.

Sanofi initially set its sights five years ago when it acquired its partner Principia Biopharma for $3.7 billion.BTK Inhibitortolebrutinib, while another BTK inhibitorrilzabrutinibThen it was the first to receive approval from the U.S. FDA for marketing. Sanofi expectsWayrilz'sSales peak can reach 2 to 5 billion euros.

Caroline Kruse, President and Chief Executive Officer of the Platelet Disorder Support Association, stated:"The burden of immune thrombocytopenia can be both physical and emotional, accompanied by significant yet often overlooked symptoms that impact all aspects of daily life. We are pleased to have a new treatment option that can help alleviate the ongoing stress of managing the disease for patients and their families."

As a novel oral and reversible Bruton's tyrosine kinase (BTK) inhibitor, Wayrilz can help address the root cause of ITP by modulating the immune system through various pathways.

Brian Foard, Executive Vice President of Sanofi, stated:"With its differentiated mechanism of action, Wayrilz has the potential to become the preferred treatment for patients with immune thrombocytopenia who have not responded to prior therapies. Its multi-immunomodulatory approach shows promise in addressing the key drivers of immune thrombocytopenia, aligning with Sanofi's commitment to tailor and advance therapeutic solutions to help meet ongoing unmet patient needs. This approval underscores Sanofi's expertise and ambition in the intersection of rare diseases and immunological conditions."

The LUNA Phase 3 study, presented at the 66th American Society of Hematology Annual Meeting and Exposition, evaluated the efficacy and safety of Wayrilz versus placebo in adults (n=202) with persistent or chronic ITP. Patients achieving a platelet count response at 12 weeks were eligible to continue through the entire 24-week double-blind period (64% of patients in the Wayrilz group and 32% in the placebo group). Compared to patients on placebo, those taking Wayrilz experienced the following:

A statistically significant durable platelet response at Week 25 (23% of patients in the Wayrilz group vs. 0% in the placebo group; p<0.0001)

Faster initial platelet response time (36 days in the Wayrilz group, not reached in the placebo group; p<0.0001)

The duration of platelet response was longer (least squares mean of 7 weeks in the Wayrilz group vs. 0.7 weeks in the placebo group).

According to the Immune Thrombocytopenia Patient Assessment Questionnaire (a clinical tool designed to measure ITP symptoms), patients receiving Wayrilz treatment showed an overall improvement of 10.6 percentage points across nine health-related quality of life indicators, compared to a 2.3 percentage point increase in the placebo group. The results of this analysis are descriptive and not statistically significant. The most common adverse reactions (incidence ≥10%) were diarrhea, nausea, headache, abdominal pain, and COVID-19.

Wayrilz was approved in the United Arab Emirates in June 2025 for the treatment of adult patients with persistent or chronic ITP who have had an inadequate response to or are intolerant of prior therapies. Wayrilz is currently undergoing regulatory review for ITP in the EU and China.Recently, the FDA granted Wayrilz ODD for the treatment of three additional rare diseases, including warm autoimmune hemolytic anemia (wAIHA), IgG4-related disease (IgG4 RD), and sickle cell disease (SCD).