Favorable Influence of Pretransplant Rituximab but Not of High-Dose Ara-C in Upfront Autologous Stem Cell Transplantation (SCT) for Mantle Cell Lymphoma (MCL).

Recent data suggests that the prognosis of MCL might be improved by administration of rituximab and high-dose ara-C (HA) prior to upfront SCT. In order to investigate the relative contributions of rituximab and HA, respectively, we retrospectively analyzed 98 patients who received SCT as part of 1^st-line treatment of advanced-stage MCL. Patients (median age 55 (29–67)) with stage II–IV MCL were treated with a sequential therapy comprising 2–8 cycles of CHOP or CHOP-like regimens +/− rituximab for remission induction, DexaBEAM (49%) or HA-containing chemotherapy (39%) for further consolidation and mobilization of stem cells, and high-dose therapy with SCT. 22% were mobilized with CHOP alone. High-dose regimens were TBI/CY (38%), TBI/CY + rituximab (R-TBI/CY; 35%), or BEAM (27%).

Results: With a median follow-up of 35 (1–135) months, estimated median progression-free survival (PFS) of all 98 patients was 95 months from diagnosis and 82 months from SCT(median overall survival not reached). Pretransplant rituximab was given to 40 patients and improved PFS (3-year PFS from SCT 93% (95%CI 83–100%) vs 67% (54–79%) although this was still not statistically significant (hazard ratio (HR) .37; p .07). In contrast, pretransplant HA had no impact on PFS even after adjusting for rituximab (HR 1.9; p .61). PFS after R-TBI/CY tended to be superior to that after TBI/CY only if the 58 patients without pretransplant rituximab were considered (HR .39; p .07). Age, sex, time from diagnosis, and remission status after cytoreduction or immediately prior to SCT did not affect PFS.

Conclusions: Pretransplant rituximab but not high-dose ara-C seems to improve the outcome of early SCT for MCL. Addition of rituximab to myeloablative treatment with TBI/CY might be beneficial only in the absence of pretransplant rituximab. Pretransplant rituximab with upfront SCT provides long-term disease control in a large proportion of patients with MCL.