Clinical Outcomes in Patients with Mantle Cell Lymphoma Who Received Autologous Stem Cell Transplant in the Second Line Setting

Background: Mantle cell lymphoma (MCL) is an aggressive B-cell lymphoma with a variable clinical outcome. The standard of care for transplant-eligible patients has been to employ autologous stem cell transplant (ASCT) in first remission and this strategy is currently being tested in the NCTN trial EA4151. The utilization and outcomes of ASCT in second line (2L) treatment is unclear and this knowledge is important for those in the non-transplant control arm in EA4151. In this report, we studied the outcomes of patients who received ASCT in 2L for relapsed/refractory (R/R) MCL.

Methods: Patients with newly diagnosed MCL between August 2002 and April 2015 were enrolled in the Mayo Clinic/University of Iowa Lymphoma SPORE Molecular Epidemiology Resource (MER) prospective cohort study. Patients who received ASCT at 2L, or at 1L as a reference group, were included in this study. Clinical characteristics and treatment details were abstracted from MER and by additional chart review. Event-free Survival (EFS) was defined as time from ASCT to progression, retreatment, or death due to any cause, and overall Survival (OS) was defined as time from ASCT to death due to any cause. Survival rates were generated using the Kaplan-Meier method in Rv4.1.2.

Results: Among a total of 343 patients with MCL enrolled in the MER, 177 had disease progression or relapse following 1L therapy and had complete 2L treatment information available. Eighteen patients were considered for ASCT as part of 2L therapy. Two (11%) patients did not have an adequate response to 2L induction therapy, and 1 (6%) patient did not meet criteria due to failure of the stem cell mobilization and harvest. Therefore, 15 (83%) patients went on to receive ASCT at the 2L.

For the 15 patients who received ASCT at 2L, 1L therapies were R-CHOP (N=9, 60%), rituximab and bendamustine (R-bendamustine, N=2, 13%), rituximab and cladribine (N=3, 20%); 1 (7%) received surgical intervention. All 15 patients were considered for ASCT at 1L. Eight (53%) did not proceed due to inadequate response or progression of disease in the 1L setting; 2 (13%) were treated on clinical trials at 1L that precluded ASCT (one with R-CHOP with ⁹⁰Yibritumomab tiuxetan and the other with R-Bendamustine); 2 (13%) were considered low risk for relapse and deferred ASCT, and 1 (7%) decided not to proceed (patient decision); the reason was unclear in 2 (13%) other patients. The median time from diagnosis to 1L disease progression/relapse was 6.4 months (range 1.1-35.8).

Of the 15 patients who received ASCT as 2L therapy, the median age at time of ASCT was 58 years old, 14 (93%) were male, 13 (87%) had stage III/IV disease, and MCL international prognostic index (MIPI) score was low in 5 (63%) and intermediate in 3 (38%) (MIPI missing in 7 patients). Induction therapy at 2L prior to ASCT included R-CHOP alternating with R-DHAP (N=1, 7%), Hyper-CVAD (N=2, 13%), R-CHOP (N=3, 20%), R-DHAP (N=2, 13%), R-EPOCH (N=1, 7%), ROAD (N=1, 7%), R-ICE (N=1, 7%), R-bendamustine (N=3, 20%), and ibrutinib (N=1, 7%).

At a median follow-up of 6.3 years from transplant for patients receiving ASCT at 2L, 9 patients had disease progression or relapse, and 8 patients died (3 without known progression or relapse). The median EFS was 3.8 years and the 2-year EFS rate was 59% (CI 38-91%) and 5-year EFS rate was 37% (CI 18-73%). The 2-year OS rate was 73% (CI 54-99%) and 5-year OS rate was 60% (CI 41-91%).

As a reference, 113 patients in the MER received ASCT in the 1L setting. The median EFS from date of ASCT was 5.2 years and the 2-year EFS rate was 77% (CI 70-85%) and the 5-year rate was EFS 54% (CI 45-64%). The 2-year OS rate was 86% (CI 80-93%) and 5-year OS rate was 79% (CI 72-87%).

Conclusion: ASCT consolidation after salvage therapy in the 2L setting appeared feasible in select patients with R/R MCL. The PFS and OS outcomes following 2L appeared reasonable. In the evolving landscape of R/R MCL treatment, it is unclear whether ASCT will still have a role. It is possible that select patients with R/R MCL would still benefit from ASCT. Larger studies, although likely limited to retrospective setting, are needed to further evaluate the feasibility, outcomes, and prognostic factors of ASCT at 2L and beyond.

Maurer:Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; BMS: Research Funding; GenMab: Membership on an entity's Board of Directors or advisory committees, Research Funding; Morphosys: Research Funding; Roche/Genentech: Research Funding. Cerhan:BMS/Celgene: Research Funding; Genentech: Research Funding; GenMab: Membership on an entity's Board of Directors or advisory committees, Research Funding; NanoString: Research Funding; Protagonist: Membership on an entity's Board of Directors or advisory committees. Ansell:SeaGen: Research Funding; Takeda: Research Funding; Bristol Myers Squibb: Research Funding; Regeneron: Research Funding; Affimed: Research Funding; Pfizer: Research Funding; ADC Therapeutics: Research Funding. Ayyappan:beigene: Membership on an entity's Board of Directors or advisory committees; Fate therapeutics: Membership on an entity's Board of Directors or advisory committees; Intellisphere: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle genetics: Membership on an entity's Board of Directors or advisory committees; TG therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Total CME: Speakers Bureau; Astrazeneca: Membership on an entity's Board of Directors or advisory committees; abbvie: Membership on an entity's Board of Directors or advisory committees. Witzig:Karyopharm: Other: Clinical Trail Support; ADC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Curio Science: Honoraria; Kura Oncology: Other: Clinical Trail Support. Nowakowski:Bantam Pharmaceutical: Consultancy; Blueprint Medicines Corporation: Consultancy; Celgene Corporation/Bristol Myers Squibb: Consultancy, Research Funding; Curis, Inc.: Consultancy; Daiichi Sankyo Inc: Consultancy; F. Hoffmann-La Roche Ltd: Consultancy, Research Funding; Genentech, Inc: Consultancy, Research Funding; Incyte: Consultancy; Karyopharm: Consultancy; Kite Pharma Inc.: Consultancy; Kymera Therapeutics: Consultancy; MorphoSys US Inc: Consultancy; NanoString: Research Funding; Ryvu Therapeutics: Consultancy; Selvita: Consultancy; TG Therapeutics: Consultancy; Zai Lab: Consultancy. Farooq:MorphoSys: Consultancy, Membership on an entity's Board of Directors or advisory committees; Kite, a Gilead Company: Honoraria; Caribou pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees; Checkmate Pharma: Research Funding. Wang:Eli Lilly and Company: Membership on an entity's Board of Directors or advisory committees; Genmab: Research Funding; MorphoSys: Research Funding; Genentech: Research Funding; Novartis: Research Funding; Loxo@Lilly: Membership on an entity's Board of Directors or advisory committees, Research Funding; InnoCare: Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; Kite Pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees.