A Prospective Phase II Comparison of Stem Cell Source Using Rituximab, Ifosfamide, Carboplatin, Etoposide (RICE) RE—Induction, Then High Dose Fludarabine, Busulfan (FLUBU) and Autologous (ASCT) or Allogeneic (AlloSCT) Hematopoietic Blood Stem Cell Transplantation for Mantle Cell (MCL) and Relapsed Low-Grade B-Cell Non-Hodgkin’s Lymphoma (NHL).

Introduction: A “genetically-randomized” prospective phase II study was designed to compare stem cell source following novel, uniform, and expected low toxicity re-induction and high dose chemotherapy for indolent B-cell NHL.

Patients and Methods: Pts with MCL in 1st remission or 1st relapse, or other indolent B-cell lymphoma in 1st or 2nd relapse were eligible providing adequate organ function and age <65 years. Pts received RICE (Rituximab 375mg/m² d1,8,15,22, Ifosfamide 1.67g/m² d16-18, Carboplatin AUC=5 d17, Etoposide 100mg/m² d16-18), with G-CSF d22-30, and apheresis d29-31 if ASCT, then FluBu (Fludarabine 50mg/m² d-6to-2, Busulfan 3.2 mg/kg IV daily d-5to-2) and SCT d0. GVHD prophylaxis for AlloSCT involved ATG 4.5mg/kg, MTX and CSA.

Results: The initial 43 pts accrued from 06/2001-03/2004 included Follicular=30, MCL=7, SLL=4, other histology=2. Disease status was 1st remission=2, 1st relapse=18, 2nd relapse=12, 1⁰ refractory=11. The median EFS following most recent prior chemotherapy was 7 mos. RICE resulted in an overall RR of 72%. Blood stem cell source was ASCT=27, donor SCT=16 (related=14, unrelated=1, syngeneic=1). For ASCT, a median of 5.9 (1–14.5) x10⁶ CD34+ cells/kg were collected from 1 (n=17) or 2 (n=10) 15-25L aphereses. Three pts required a second mobilization procedure. 16/24 pts converted from positive to negative marrow biopsies post-RICE. Two pts had NHL detected in the autograft. FluBu resulted in no acute Bearman grade 3-4 RRT(overall 100d non-relapse mortality (NRM)=0% for both ASCT and donor SCT). Median engraftment times were slightly longer post AlloSCT than ASCT (ANC>0.5 = 15 vs 11d, and platelets>20 = 12 vs 9d, respectively). Of 15 AlloSCT pts, grade 3–4 aGVHD occurred in 5 (33%), cGVHD occurred in 64%, and death from extensive cGVHD + infection occurred in 5 pts from 7-13mo post-AlloSCT (overall NRM=33% for AlloSCT). With a median follow-up of 22mo, the 2 year projected outcome of ASCT vs Allo/Syngeneic-SCT for relapse-free survival (RFS) was 64% vs 87% (logrank p=0.48), event-free survival (EFS) 63% vs 52% (logrank p=0.38), and overall survival (OS) 86% vs 46% (logrank p=0.0018), respectively. For relapsed follicular lymphoma only, the 2yr EFS was 61% vs 59% (logrank p=0.49) and OS 100% vs 51% (logrank p=0.0009) for ASCT (n=19) vs Allo/Syngeneic SCT (n=11), respectively.

Conclusion: These preliminary results suggest that RICE can "in-vivo" purge autografts but mobilizes blood stem cells only moderately well. RICE-FluBu/ASCT may result in prolonged EFS with significantly less NRM than AlloSCT.