Dr. Barr on Updated RESONATE Data in IGHV-Mutant CLL

Paul Barr, MD, medical director, Cancer Center Clinical Trials Office, and assistant professor, School of Medicine and Dentistry, University of Rochester, discusses the 6-year follow-up in patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) on ibrutinib (Imbruvica) as part of the RESONATE study.

This phase III study randomized patients to receive oral ibrutinib 420 mg daily until or intravenous ofatumumab (Arzerra) for up to 24 weeks. Of the 391 patients randomized to receive ibrutinib (n = 195) or ofatumumab (n = 196), 86% and 79%, respectively, were in the genomic high-risk population. Of patients randomized to ofatumumab, 68% switched to ibrutinib.

Patients with unmutated IGHV status seem to respond to ibrutinib just as well as patients with mutated IGHV status, according to Barr. Patients with other high-risk features, such as 11q deletion, 17p deletion, and TP53 mutations responded nearly as well as patients with more favorable risk factors. Patients with 11q deletion responded exceptionally well with a median PFS approaching 60 months. Overall, patients on the ibrutinib arm had a median PFS of 44.1 months. Approximately, 40% of patients are without progression and still alive after five years.

The RESONATE study helped researchers understand how durable the responses to ibrutinib are in this patient population, according to Barr. After 6 years of follow-up, extended ibrutinib treatment showed sustained efficacy in patients with relapsed/refractory CLL, including patients with high-risk genomic features. These results demonstrate long-term benefit and tolerability for continuous ibrutinib treatment in patients with relapsed/refractory CLL.