NEW YORK – Although optimal sequencing strategies in chronic lymphocytic leukemia are still unclear, real-world data suggest an alternate kinase inhibitor or venetoclax is the best approach for a patient who has received ibrutinib or idelalisib, according to John N. Allan, MD, of Cornell University, New York.
“I think for the most part, there’s enough evidence,” Dr. Allan said at the annual congress on Hematologic Malignancies held by the National Comprehensive Cancer Network.
“If you had one to two lines of therapy, it still favors the novel agents rather than the chemotherapy arms in all these studies,” said, referring to some of the pivotal trials supporting approval of novel agents in chronic lymphocytic leukemia (CLL). “The earlier we get to these drugs, I believe, the better.”
While venetoclax after ibrutinib is supported by multiple studies, “vice versa is unknown, but there’s seemingly no reason to think it wouldn’t work – different mechanisms of actions, different pathways,” Dr. Allan said.
What is clear, he added, is that retreating those patients with chemoimmunotherapy is not optimal.
In support of that, he cited a multicenter retrospective analysis, which is believed to be the largest real-world experience to date of novel agents in CLL looking at post–kinase inhibitor salvage strategies ().
Using an alternate kinase inhibitor or venetoclax resulted in superior progression-free survival versus chemoimmunotherapy at the time of initial kinase inhibitor failure in that study, which looked at treatment strategies and outcomes for 683 patients.
Ibrutinib appeared to be superior to idelalisib as a first kinase inhibitor, with significantly better progression-free survival in both frontline and relapsed/refractory settings, and in both complex karyotype and del17p patients, according to the report. Additionally, the response rate to venetoclax seemed superior to that of idelalisib in patients who discontinued ibrutinib because of progression or toxicity.
All of that supports the need for trials to test various sequencing strategies and establish clear treatment algorithms, according to Dr. Allan. “Optimal sequencing is unknown, but real-world data gives us some idea.”
For relapsed/refractory patients, ibrutinib, idelalisib, and venetoclax all have lengthened responses, improved survival, and are approved by the Food and Drug Administration, he added, noting that the toxicity profiles vary and must be understood when dosing and prescribing these agents.
More novel treatments are on the way. On Sept. 24, just days after Dr. Allan’s NCCN presentation, the FDA grantedto duvelisib for adults with relapsed or refractory CLL or small lymphocytic lymphoma following two or more previous lines of therapy.
Dr. Allan reported financial disclosures related to AbbVie, Acerta Pharma, Genentech, Pharmacyclics, Sunesis Pharmaceuticals, and Verastem Oncology.