Ibrutinib Yields Long-Term Activity in Patients With Previously-Treated WM
Long-term findings from a multi-center trial of ibrutinib therapy for patients with previously-treated Waldenstrom macroglobulinemia (WM) shows that ibrutinib promotes long-term disease control and remains highly active in this setting (J Clin Oncol. 2020 Sep 15. Epub ahead of print).
The study was conducted by Steven P. Treon, MD, PhD, Director of the Bing Center for Waldenström's Macroglobulinemia Research, Dana-Farber Institute, Boston, Massachusetts, and colleagues. Enrollment for this study began in May 2012 and closed June 2013, with the last patient evaluation and update in September 2018.
A total of 63 symptomatic patients who received a median of 2 prior therapies were included in the study, 40% of whom had disease refractory to their previous therapy. Patients received ibrutinib 420 mg daily and were permitted dose reductions for toxicity.
Patients were followed-up with for a median of 59 months. Among the 63 patients, overall and major response rates were 90.5% and 79.4%, respectively. At best response, the median serum immunoglobulin M declined from 3,520 mg/dL to 821 mg/dL, bone marrow disease involvement declined from 60% to 20%, and hemoglobin rose from 10.3 g/d to 14.2 g/d (P <.001).
Grade ≥3 adverse events included neutropenia (15.9%), thrombocytopenia (11.1%), and pneumonia (3.2%). Furthermore, 8 (12.7%) patients had atrial arrhythmia, 7 of whom continued therapy with medical management.
“These findings supported the regulatory approval of ibrutinib for the treatment of symptomatic WM,” wrote Dr Treon et al.—Alexandra Graziano
