Long-Term Follow-Up of Ibrutinib Monotherapy in Symptomatic, Previously Treated Patients With Waldenström Macroglobulinemia. Issue 6 (20th February 2021)

• Record Type: Journal Article
• Authors: Treon, Steven P.; Meid, Kirsten; Gustine, Joshua; Yang, Guang; Xu, Lian; Liu, Xia; Patterson, Christopher J.; Hunter, Zachary R.; Branagan, Andrew R.; Laubach, Jacob P.; Ghobrial, Irene M.; Palomba, M. Lia; Advani, Ranjana; Castillo, Jorge J.
• Is Part Of: Journal of clinical oncology. Volume 39:Issue 6(2021)
• Page Start: 565
• Page End: 575
• Publication Date: 2021-02-20
• Subjects: Oncology -- Periodicals; Cancer -- Periodicals; Oncology; Medical Oncology; Cancérologie -- Périodiques; Cancer -- Périodiques; Cancérologie; Cancer; Oncology; Oncologia; Càncer; Periodicals; 616.994
• DOI: 10.1200/JCO.20.00555
• Languages: English
• ISSNs: 0732-183X

Abstract

Abstract : PURPOSE: We report the long-term findings and final analysis of a pivotal multicenter trial of ibrutinib monotherapy in previously treated patients with Waldenström macroglobulinemia (WM). PATIENTS AND METHODS: Sixty-three symptomatic patients with median prior therapies of two (range, one to nine therapies), of whom 40% were refractory to their previous therapy, received ibrutinib at 420 mg/d. Dose reduction was permitted for toxicity. RESULTS: The median follow-up was 59 months, and overall and major response rates were 90.5% and 79.4%, respectively. At best response, median serum immunoglobulin M declined from 3, 520 to 821 mg/dL, bone marrow disease involvement declined from 60% to 20%, and hemoglobin rose from 10.3 to 14.2 g/dL ( P < .001 for all comparisons). Responses were impacted by mutated (Mut) MYD88 and CXCR4 status. Patients with MYD88 Mut, wild-type (WT) CXCR4 showed higher major (97.2% v 68.2%; P < .0001) and very good partial (47.2% v 9.1%; P < .01) response rates and a shorter time to major response (1.8 v 4.7 months; P = .02) versus patients with MYD88 Mut CXCR4 Mut . Conversely, four patients who had MYD88 WT disease showed no major responses. The median 5-year progression-free survival (PFS) rate for all patients was not reached, and was 70% and 38% for those with MYD88 Mut CXCR4 WT and MYD88 Mut CXCR4 Mut WM, respectively ( P = .02). In patients with MYD88 WT, the median PFS was 0.4 years ( P < .01 for three-way comparisons). The 5-year overall survival rate for all patients was 87%. Grade ≥ 3 adverse events in more than one patient at least possibly related included neutropenia (15.9%), thrombocytopenia (11.1%), and pneumonia (3.2%). Eight patients (12.7%) experienced atrial arrhythmia, and seven of the eight continued therapy with medical management. CONCLUSION: Ibrutinib is highly active and produces long-term disease control in previously treated patients with WM. Treatment is tolerable. Response depth, time to major response, and PFS are impacted by MYD88 and CXCR4 mutation status.