David Kuter, MD, DPhil, Professor of Medicine at Harvard Medical School, Massachusetts General Hospital, discusses treatment with rilzabrutinib in patients with immune thrombocytopenia (ITP).
ITP is an autoimmune bleeding disorder characterized by too few platelets in the blood. Symptoms may include bruising, nosebleeds or bleeding in the mouth, bleeding into the skin, and abnormally heavy menstruation.
Recently, new data from the phase 3 LUNA clinical trial (NCT04562766) was presented at the 2025 American Society of Hematology Annual Meeting (ASH 2025). Rilzabrutinib is an oral, reversible, covalent, selective Bruton tyrosine kinase inhibitor that acts through multi-immune modulation.
As of April 1, 2025, 69 of 202 patients had entered the long term extension and 57 were ongoing in the long term extension. A total of 43 patients had completed 12 months or more of follow-up in the long term extension. Median duration of ITP was 9.6 years, median number of unique prior therapies was 4, and 97% of patients had received corticosteroids (CS). Median baseline platelet count was 18×10 9 /L. Median platelet count at long term extension entry was 113×10 9 /L and median counts at long term extension follow-up visits ranged from 83-168×10 9 /L through 33 months of extension.
During the first 12 months of the extension, patients had platelet counts 50×10^9 /L or greater or between 30-50×10^9 /L and at least doubled from baseline for an average of 88% of visits. Of patients who received rilzabrutinib monotherapy or rilzabrutinib and concomitant CS and/or thrombopoietin-receptor agonists, median platelet counts at extension entry were 78×10^9 /L and 115×10^9 /L, respectively, and ranged from 78-270×10^9 /L and 90- 160×10^9 /L, respectively, through 33 months.
In the extension, 20% of patients received rescue medication. Among 49% of patients who entered the extension on concomitant CS, 29% discontinued CS use, 6% reduced their CS 50% or greater from baseline, and 18% reduced their CS dose to less than 5 mg. Median platelet counts before and after CS discontinuation at last available visit were 148×10^9 /L and 178×10^9 /L, respectively.
Improvements in fatigue scores and bleeding symptoms were generally maintained during the extension. 19% of patients had treatment-emergent adverse events that were assessed as related by the investigator. The most common were nausea, diarrhea, and upper abdominal pain. Two patients had grade 2 or greater related treatment-emergent adverse events of infection. However, there were no related grade 2 or greater bleeding events, serious adverse events, or deaths.
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To learn more about ITP and other rare hematological disorders, visit https://checkrare.com/diseases/hematologic-disorders/