European MCL Network: An Update on Current First Line Trials.

Background: Conventional chemotherapy achieves only short term remission despite high initial response rates of 70%–80%. In the current study generation, the European MCL Network investigates the impact of various combined immuno-chemotherapy regimens. Additionally, in elderly patients the role of rituximab maintenance is being evaluated, whereas in younger patients dose-intensified regimens with implementation of high dose cytarabine are investigated based on the excellent results of the HyperCVAD regimen.

Methods: In MCL elderly, patients are initially randomized between 8 cycles of R-CHOP or 6 cycles of R-FC (experimental arm). Patients who achieve either an PR or CR, receive subsequently either interferon maintenance (standard arm) or a single rituximab dose every 2 months. In MCL younger, the standard arm (R-CHOP induction followed by myeloablative consolidation: 12 Gray TBI, 2x 60mg/kg cyclophosphamide) is compared to the implementation of high dose cytarabine into induction (R-CHOP/R-DHAP) and consolidation (10 Gray TBI, 4x1,5 g/m2 Ara-C, 140mg/m2 melphalan).

Results: In MCL elderly, 222 of 263 patients were evaluable based on the annual interim analysis. Median age was 70 years with 66% of patients displaying an intermediate high/high risk IPI. Induction was well tolerated with mainly hematological toxicity (grade III/IV in R-CHOP/R-FC): Leukocytopenia 62/72%, thrombocytopenia 13%/40%, but only rare febrile neutropenia (23%/7%) or infections (19%/23%). Despite the poor risk profile, combined immuno-chemotherapy (total group) achieved a remarkable 84% response rate (51% CR/CR_u). Although the impact of maintenance is not yet evaluable, both progression-free and overall survival were encouraging with 77% and 86% at 12 months, respectively. In MCL younger, 247 of 271 patients were evaluable. Again, toxicity (grade III/IV in R-CHOP/alternating R-DHAP) was mainly hematological: leukocytopenia 58/77%, thrombocytopenia 14%/74%, but only rare febrile neutropenia (11%/22%) or infections (5%/7%). Combined immuno-chemotherapy achieved a 93% response rate (60% CR/CR_u) before subsequent high dose consolidation. Again, both progression-free and overall survival are remarkable with both 90% at 12 months, respectively.

Discussion: Combined immuno-chemotherapy results in high response rates in two prospective international trials. Further recruitment and follow-up will determine the role of rituximab maintenance and high dose cytarabine in this distinct subtype of malignant lymphoma.