The following article features coverage from the American Society of Clinical Oncology 2019 meeting. Click here to read more of Hematology Advisor’s conference coverage.

Extended treatment with ibrutinib may be feasible in patients with relapsed or refractory chronic lymphocytic leukemia (CLL), according to research presented at the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, Illinois.

In the phase 3 RESONATE trial (ClinicalTrials.gov Identifier: NCT01578707), 391 patients with relapsed or refractory CLL or small lymphocytic leukemia (SLL) were randomly assigned to receive 420 mg oral ibrutinib daily (195 patients) or intravenous ofatumumab at varied intervals (196 patients); 68% of patients in the ofatumumab arm ultimately crossed over to the ibrutinib arm. Researchers presented a final analysis of data from a median follow-up of 64 months in the ibrutinib arm.

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Median ibrutinib treatment duration was 41 months, and 41% of patients received treatment with ibrutinib for more than 4 years. The overall response rate was 88% in the ibrutinib arm, with 11% of patients experiencing complete remission with or without incomplete count recovery (CRi).

Patients receiving ibrutinib experienced significantly improved progression-free survival (44.1 vs 8.1 months; hazard ratio [HR], 0.15; 95% CI, 0.11-0.20; P <.0001) and overall survival (HR, 0.64; 95% CI, 0.42-0.98) compared with patients receiving ofatumumab.

In the ibrutinib arm, 86% of patients were considered to be at high genomic risk (defined as harboring del(17)p, del(11)q, TP53 mutations or unmutated IGHV). In the ofatumumab arm, 79% of patients were considered to be at high genomic risk. In genomic high-risk patients, median PFS was 44.1 months in the ibrutinib arm and 8.0 months in the ofatumumab arm (HR, 0.11; 95% CI, 0.08-0.15).

All-grade and grade 3 or higher hypertension occurred in 21% and 9% of patients in the ibrutinib arm, respectively. All-grade and grade 3 or higher atrial fibrillation occurred in 12% and 6% of patients receiving ibrutinib, respectively. Major hemorrhage occurred in 10% of patients receiving ibrutinib. Disease progression (37%) and adverse events (16%) were the most common reasons for discontinuation of ibrutinib.

The authors concluded that ibrutinib demonstrated sustained efficacy and a tolerable safety profile in patients with relapsed or refractory CLL.

Reference

1.     Barr PM, Munir T, Brown JR, et al. Final analysis from RESONATE: Six-year follow-up in patients (pts) with previously treated chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL/SLL) on ibrutinib. Poster presentation at: 2019 ASCO Annual Meeting; June 3, 2019; Chicago, IL. Abstract 7510.