Rilzabrutinib active, safe in immune thrombocytopenia
Rilzabrutinib induced rapid and durable clinical activity in previously treated patients with immune thrombocytopenia. he analysis included 60 patients (median age, 50 years; range, 19-74; 57% women) with platelet counts of less than 30 × 103/mm3 on two occasions no less than 7 days apart within 15 days before trial entry. Patients received a median four previous immune thrombocytopenia therapies and had a history of a response to at least one of those therapies, but not to the previous or concomitant therapy maintained at baseline. Patients had a median platelet count of 15 × 103/mm3 at baseline and median disease duration of 6.3 years.

Researchers used intrapatient dose escalation of oral rilzabrutinib (Sanofi) over 24 weeks, with a lowest starting dose of 200 mg (once daily) and higher starting doses of 400 mg (once daily), 300 mg (twice daily) and 400 mg (twice daily). Safety and platelet response served as primary endpoints.

Results showed that after a median 167.5 days of treatment (range, 4-293), 24 of 60 patients (40%) overall and 18 of the 45 patients (40%) starting rilzabrutinib treatment at the highest dose met the primary endpoint of platelet response.

Researchers reported a median time of 11.5 days to the first platelet count of at least 50 × 103/mm3. Additionally, they noted a 65% mean percentage of weeks with a platelet count of at least 50×103/mm3 among patients with a primary platelet response.