RB but not R- HCVAD is a feasible induction regimen prior to auto- HCT in frontline MCL: results of SWOG Study S1106.

Aggressive induction chemotherapy followed by autologous haematopoietic stem cell transplant (auto- HCT) is effective for younger patients with mantle cell lymphoma ( MCL). However, the optimal induction regimen is widely debated. The Southwestern Oncology Group S1106 trial was designed to assess rituximab plus hyper CVAD/ MTX/ ARAC (hyperfractionated cyclophosphamide, vincristine, doxorubicin and dexamethasone, alternating with high dose cytarabine and methotrexate) ( RH) versus rituximab plus bendamustine ( RB) in a randomized phase II trial to select a pre-transplant induction regimen for future development. Patients had previously untreated stage III, IV, or bulky stage II MCL and received either 4 cycles of RH or 6 cycles of RB, followed by auto- HCT. Fifty-three of a planned 160 patients were accrued; an unacceptably high mobilization failure rate (29%) on the RH arm prompted premature study closure. The estimated 2-year progression-free survival ( PFS) was 81% vs. 82% and overall survival ( OS) was 87% vs. 88% for RB and RH, respectively. RH is not an ideal platform for future multi-centre transplant trials in MCL. RB achieved a 2-year PFS of 81% and a 78% MRD negative rate. Premature closure of the study limited the sample size and the precision of PFS estimates and MRD rates. However, RB can achieve a deep remission and could be a platform for future trials in MCL. [ABSTRACT FROM AUTHOR]