First-line patients fared well on ibrutinib, a Bruton’s tyrosine kinase inhibitor, according to the findings.
Courtesy ASH
Dr. Martin Dreyling
“Based on the results so far ... at least for the majority of patients, ibrutinib early will become the new standard,” said study lead author Martin Dreyling, MD, associate professor of medicine at Ludwig Maximilian University (LMU) Munich. Dr. Dreyling spoke in a news briefing and at a separate presentation at the annual meeting of the American Society of Hematology. “It might well be that specific subsets of patients may benefit from autologous transplant.”
MCL is a rare form of non-Hodgkin’s lymphoma that strikes cells in the mantle zone of lymph nodes. It is usually diagnosed in older men and often presents at an advanced stage. Multiple available treatments include rituximab/bendamustine, CAR-T cell therapy, stem cell transplants, and Bruton’s tyrosine kinase inhibitors. Ibrutinib is approved by the Food and Drug Administration only for refractory/relapsed cases, however.
Dr. Dreyling was a pioneer in confirming benefit from stem-cell transplants for MCL. “However,” he said, “no one likes autologous transplant because it also has side effects.”
For the new open-label study, Dr. Dreyling and colleagues in the European MCL Network in 2016 began recruiting patients with newly diagnosed, advanced stage II-IV MCL. The patients were younger than 65.
The subjects were randomly assigned to three trial arms: Standard treatment (high-dose cytarabine followed by autologous stem cell transplant and rituximab maintenance, n = 288), the standard treatment plus ibrutinib (n = 292), and ibrutinib without stem cell transplant (n = 290). The median age was 57, and 76% of patients were male.
The primary endpoint was failure-free survival at 31 months. Standard therapy was not superior to the ibrutinib without transplant group (72% vs. 86%, respectively, P = .9979). However, standard therapy with ibrutinib was superior to the standard therapy group (88% vs. 72%, respectively, P = .0008). The researchers haven’t finished their analysis of standard therapy with ibrutinib vs. ibrutinib without transplant.
Subjects in the standard therapy plus ibrutinib arm had more grade 3-5 adverse events than did the standard therapy and ibrutinib without transplant groups: Neutropenia, 44%, 17%, and 23%, respectively; leukopenia, 4%, 2%, and 2%; febrile neutropenia, 6%, 3%, and 3%; infections and infestations, 25%, 13%, and 19%; and cardiac disorders, 3%, 1%, 4%. P values were not provided.
In an interview, Ohio State University hematologist Narendranath Epperla, MD, MS, who was not involved in the study, said that this research reflects efforts to understand how novel agents such as ibrutinib and cellular therapies fit into MCL treatment. “We are trying to incorporate them in the frontline setting with either chemo backbone or with other targeted agents to improve outcomes and minimize toxicity. We are also trying to understand in whom auto-HCT can be precluded.”
The results of the new study appear promising, Dr. Epperla said, but he questioned the primary endpoint (failure-free survival instead of progress-free survival) and the short duration of the trial.
“I would like to see how the patients with high-risk features such as TP53 mutation, complex cytogenetics, and blastoid/pleomorphic variants did on the three arms,” Dr. Epperla said. “And I would like to see longer follow-up data before adapting this – [addition] of ibrutinib to the chemotherapy backbone without auto-HCT – into clinical practice.”
What’s next? Dr. Dreyling said that upcoming data will provide further insight into ibrutinib vs. stem-cell transplantation. And “within the next half year or so,” he said, “there will be a next generation of studies challenging chemotherapy overall in mantle cell lymphoma and substituting targeted treatment, hopefully achieving much better tolerability.”
Funding information was not provided. Dr. Dreyling disclosed ties with Lilly/Loxo, AstraZeneca, Novartis, Amgen, Roche, Janssen, Gilead/Kite, BMS/Celgene, Bayer, Abbvie, and Beigene. The other study authors reported various disclosures. Dr. Epperla disclosed a relationship with Pharmacyclics.