Murdoch University Research Repository

Welcome to the Murdoch University Research Repository

The Murdoch University Research Repository is an open access digital collection of research
created by Murdoch University staff, researchers and postgraduate students.

Learn more

Rilzabrutinib, an Oral BTK Inhibitor, in Immune Thrombocytopenia

Kuter, D.J., Efraim, M., Mayer, J., Trněný, M., McDonald, V., Bird, R., Regenbogen, T., Garg, M., Kaplan, Z., Tzvetkov, N., Choi, P.Y., Jansen, A.J.G., Kostal, M., Baker, R., Gumulec, J., Lee, E-J, Cunningham, I., Goncalves, I., Warner, M., Boccia, R., Gernsheimer, T., Ghanima, W., Bandman, O., Burns, R., Neale, A., Thomas, D., Arora, P., Zheng, B. and Cooper, N. (2022) Rilzabrutinib, an Oral BTK Inhibitor, in Immune Thrombocytopenia. New England Journal of Medicine, 386 (15). pp. 1421-1431.

Link to Published Version:
*Subscription may be required



Rilzabrutinib, an oral, reversible covalent inhibitor of Bruton’s tyrosine kinase, may increase platelet counts in patients with immune thrombocytopenia by means of dual mechanisms of action: decreased macrophage (Fcγ receptor)–mediated platelet destruction and reduced production of pathogenic autoantibodies.


In an international, adaptive, open-label, dose-finding, phase 1–2 clinical trial, we evaluated rilzabrutinib therapy in previously treated patients with immune thrombocytopenia. We used intrapatient dose escalation of oral rilzabrutinib over a period of 24 weeks; the lowest starting dose was 200 mg once daily, with higher starting doses of 400 mg once daily, 300 mg twice daily, and 400 mg twice daily. The primary end points were safety and platelet response (defined as at least two consecutive platelet counts of ≥50×103 per cubic millimeter and an increase from baseline of ≥20×103 per cubic millimeter without the use of rescue medication).


Sixty patients were enrolled. At baseline, the median platelet count was 15×103 per cubic millimeter, the median duration of disease was 6.3 years, and patients had received a median of four different immune thrombocytopenia therapies previously. All the treatment-related adverse events were of grade 1 or 2 and transient. There were no treatment-related bleeding or thrombotic events of grade 2 or higher. At a median of 167.5 days (range, 4 to 293) of treatment, 24 of 60 patients (40%) overall and 18 of the 45 patients (40%) who had started rilzabrutinib treatment at the highest dose met the primary end point of platelet response. The median time to the first platelet count of at least 50×103 per cubic millimeter was 11.5 days. Among patients with a primary platelet response, the mean percentage of weeks with a platelet count of at least 50×103 per cubic millimeter was 65%.


Rilzabrutinib was active and associated with only low-level toxic effects at all dose levels. The dose of 400 mg twice daily was identified as the dose for further testing. Overall, rilzabrutinib showed a rapid and durable clinical activity that improved with length of treatment. (Funded by Sanofi; number, NCT03395210. opens in new tab; EudraCT number, 2017-004012-19. opens in new tab.)

Item Type: Journal Article
Publisher: Massachusetts Medical Society
Copyright: © 2022 Massachusetts Medical Society.
Item Control Page Item Control Page