Panelists: Myron S. Czuczman, MD, Roswell Park; John C. Byrd, MD, Ohio State; Richard Furman, MD, Weill Cornell; Thomas J. Kipps, MD, UCSD; Shuo
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Approximately 6% of patients diagnosed with non-Hodgkin’s lymphoma have mantle cell lymphoma (MCL), which is typically associated with a bad prognosis. At this point, there is not a standard of care for MCL, and “optimal” treatment is dependent on where a patient is being treated, Myron S. Czuczman, MD, suggests.
In November 2013, the FDA approved ibrutinib as a treatment for patients with MCL who have received at least one prior therapy, based on a single-arm clinical trial demonstrating a durable improvement in overall response rates (ORR). Building on this approval, phase II findings for single-agent ibrutinib demonstrated promising responses in patients with MCL who progressed after rituximab-containing chemotherapy and bortezomib therapy. The ORR for evaluable patients was 62.7%, with a complete response rate of 20.9%. Additionally, this study also confirmed ibrutinib’s acceptable toxicity profile (Wang M, et al. Blood. 2014;124:4471).
The maintenance use of rituximab is an important evolving issue for patients with MCL, specifically in elderly patients, for whom high-dose combination chemotherapy is not appropriate, Shuo Ma, MD, PhD, comments. In this setting, rituximab has been shown to prolong progression-free survival (PFS).
In younger patients with MCL, treatment with R-DHAP as induction therapy followed by autologous stem cell transplant, and then rituximab maintenance was found to be efficacious versus observation. The preliminary results show that maintenance rituximab significantly improved both event-free survival and PFS (Le Gouill S, et al. Blood. 2014;124: abstract 146).
Another important question related to MCL is determining when mantle cells become highly proliferative, since this may cause patients to stop responding to newer agents, suggests Richard Furman, MD. Newer agents, such as ibrutinib, can be initiated earlier and long-term control can be obtained before the cells develop the transformative process, making them more aggressive. In some circumstances, Ki-67 can be used as a predictive factor for outcomes in MCL, Furman says, suggesting that Ki-67 could be more predictive than histology (Hoster E, et al. Blood. 2014;124: abstract 2977).