For older, unfit patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), first-line treatment with the all-oral combination of ibrutinib (Imbruvica) and venetoclax (Venclexta) was associated with superior progression-free survival, compared with chlorambucil and obinutuzumab (Gazyva), results of the phase 3 GLOW trial showed.
Among 211 patients with CLL/SLL who were 65 or older, or younger patients with a high comorbidity burden, the median progression-free survival (PFS) after 27.7 months of follow-up was not reached for patients treated with a fixed duration combination of ibrutinib plus venetoclax (I+V), compared with 21 months for patients who received chlorambucil plus obinutuzumab (Clb+O), reported Arnon P. Kater, MD, PhD, from Amsterdam University Medical Centers.
The oral combination was also associated with a higher rate of undetectable minimal residual disease (MRD) 3 months after the end of treatment, at 51.9% vs. 17.1% with Clb+O, he said in a late-breaking abstract presented during the European Hematology Association annual meeting (Abstract LB1902).
“Overall, the results from GLOW support a positive clinical profile of I+V as an all-oral, once-daily, fixed-duration regimen in older patients with newly diagnosed CLL,” he said.
A low bar
But the bar for success in the GLOW trial may have been set low, with the older combination of chlorambucil plus obinutuzumab used as the comparator, rather than a more contemporary regimen, said Clive S. Zent , MD, from the Wilmot Cancer Institute at the University of Rochester (New York) Medical Center, who was not involved in the study.
“Really, nobody in this country that I’m aware of, certainly not in academic medicine, would be using chlorambucil and obinutuzumab or rituximab for standard of care,” Dr. Zent said in an interview.
“This is like comparing a mule cart to a Tesla,” he said.
Apart from possibly providing a rationale for using ibrutinib and venetoclax in this population, the GLOW results do not add much beyond that already in the CAPTIVE MRD trial, he added.
“What we’re really interested in, is ibrutinib and venetoclax better than ibrutinib alone or venetoclax alone? And that has not been asked or answered yet,” he said.
Dr. Zent acknowledged that the combination works very well and is well tolerated, and the idea of fixed duration therapy is attractive, as are the long-term outcomes for many patients following cessation of therapy.
“But remember, if you take ibrutinib, you’ve got a 90% chance of going into remission, and an over 80% chance of being in remission 5 years later, so that’s pretty good as well,” he said.
Paolo P. Ghia, MD, from Univerista Vita-Salute San Raffaele in Milan, who has studied fixed-duration I+V in younger patients with CLL in the CAPTIVATE trial agreed that “in general, there is very little role for chemoimmunotherapy in CLL.”
But Dr. Ghia, who was not involved in the GLOW study, said in an interview that the results add to the growing body of evidence of the efficacy and safety of ibrutinib -venetoclax in a wide range of patients.
“Overall between the two studies [CAPTIVATE and GLOW] we have now over 400 patients who have been treated with the combination, and the message is rather similar in the two studies: you have a high frequency of undetectable MRD in peripheral blood and in the bone marrow, with a high concordance between the two tissues, and in particular we have a durability of the response,” he said.