SIGNIFICANT EFFECT OF RITUXIMAB MAINTENANCE IN FIRST LINE TREATMENT IN MANTLE CELL LYMPHOMA

ABSSUB-3306

Background: Mantle cell lymphoma (MCL) is a relatively rare malignancy with unfavorable outcomes. Introduction of anti-CD20 rituximab maintenance (RM) treatment into therapeutic protocols should be beneficial.

Aims: To verify the importance of rituximab maintenance in MCL first line treatment.

Methods: Prospective single center observation of newly diagnosed MCL patients: n=57, median age 66 (47-82), 68% males, 84% Ann Arbor stage IV., prognostic MIPI index media 6 (2-10), 92% R-CHOP-like and 8% R-COP induction therapy protocol, 46% intensified with Autologous stem cells transplantation (SCT), 82% complete and 18% partial remissions prior to start of RM administration. Rituximab maintenance was administered as 375mg/m2 dose every 3 months for 2 years and the median number of administered doses was 7 (2-8), seven patients are still on treatment, eight patients discontinued the RM prematurely due to MCL relapse/progression, refusal of further treatment, or health insurance company obstacles. Progression free survival (PFS, time since diagnosis to relaps/progression ) was analyzed separately in a group of patients with and without Autologous SCT and in respect to RM administration.

Results: In a group of non-intensified patients without Autologous SCT the probability of 2-years PFS and median PFS was 26% and 20 months if RM was not given (n=16) versus 86% and median PFS not yet reached at the median follow-up of 37 (14-65) months if RM (n=15) was administered (p=0,01). In Autologous SCT patients the probability of 2-years PFS and median PFS  was 75% and 46 months if RM was not given (n=12) versus 95% and median PFS not yet reached at the median follow-up of 50 (22-82) months if RM (n=14) was administered (p=0,02). No statistically significant differences were observed when comparing age, gender, MCL stage, MIPI index, complete remission ratios prior to RM. RM administration was statistically significant predictor for prolonged PFS in the multivariable analysis.

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Summary/Conclusion: Even though the numbers of our analyzed patients are small, we can observe that in newly diagnosed MCL patients responding to the initial induction therapy (R-CHOP-like, R-COP), the administration of RM significantly prolongs PFS in both Autologous SCT treated patients and in those non-intensified. The data are not mature enough to asses the overall survival.

Keywords: Maintenance, Mantle cell lymphoma, Rituximab, Survival

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