Rilzabrutinib LUNA 3 phase 3 study met primary endpoint in immune thrombocytopenia

Positive results from the LUNA 3 phase 3 study demonstrated that rilzabrutinib 400 mg twice daily orally achieved the primary endpoint of durable platelet response in adult patients with persistent or chronic immune thrombocytopenia (ITP). The safety profile of rilzabrutinib was consistent with that reported in previous studies.

LUNA 3 study met its primary endpoint demonstrating a significantly higher proportion of patients receiving rilzabrutinib achieved the primary endpoint of durable platelet response versus placebo. This clinically and statistically significant result was achieved in a population of patients with primary ITP that had been refractory to prior therapy. Overall, study participants had a median of four prior ITP therapies and a median baseline platelet count of 15,000/μL (normal platelet count levels typically range from 150,000-450,000/μL). Positive results on key secondary endpoints also underscore the potential for rilzabrutinib to deliver clinically meaningful benefits for patients living with persistent and chronic ITP.

Rilzabrutinib was granted Fast Track Designation by the US Food and Drug Administration (FDA) for the treatment of ITP in November 2020 and was previously granted Orphan Drug Designation.

Houman Ashrafian
Executive Vice President, Head of Research and Development, Sanofi
“The results of this study reinforce rilzabrutinib’s potential to be a first-in-class oral, reversible BTK inhibitor that can provide clinically meaningful improvements for people living with severe immune-mediated diseases like ITP. These pivotal results are a testament to our commitment and expertise in rare blood diseases and ability to build a portfolio of next-generation small-molecule inhibitors that are both more selective and optimized to deliver robust efficacy and safety outcomes as compared to existing therapies.”

ITP is a serious, acquired autoimmune blood disorder characterized by autoantibody-mediated platelet destruction and impaired platelet production, leading to thrombocytopenia (low platelet counts of less than 100,000/μL) and an increased risk of life-threatening bleeding episodes (like intracranial hemorrhage). In addition, patients with ITP often experience significant quality-of-life impairments such as fatigue and cognitive dysfunction. With its dual mechanisms of action that reduce production of pathogenic autoantibodies and decrease macrophage mediated platelet destruction, rilzabrutinib could address the underlying mechanisms responsible for a wide range of ITP complications.