Impact Of Rituximab Maintenance Schedule On Prognosis In First Line Treatment Of Follicular Lymphoma. Retrospective Analysis From Czech Lymphoma Group (CLG) Database
Authors: Janikova Andrea , Bortlicek Zbynek , Campr Vit , Kren Leos , Belada David , Prochazka Vit , Pytlik Robert , Pirnos Jan , Matuska Milan , Papajik Tomas , Mocikova Heidi , Vokurka Samuel , Mayer Jiri , Trneny Marek 
Published: October 2019

Abstract

Introduction
Results of randomized studies showed benefit of maintenance therapy with monoclonal anti-CD20 antibody (rituximab) in terms of time to progression (PFS) and overall survival (OS) in follicular lymphoma (FL). General recommendation, based on large clinical trial, is to give 2 years of rituximab maintenance á 375mg/m2every 2 months (12 doses) in first line setting. On the other hand, there are various rituximab maintenance schedules; however, the clear comparison of clinical efficacy is missing. Our retrospective analysis compared two different schedule of rituximab maintenance in first-line treatment of FL used in university centers participating on CLG registry.

Methods
Data were recruited from 1702 FL patients registered in the prospectively maintained multicentric database (Czech Lymphoma Group; CLG). For the analysis, patients with stage II-IV of new diagnosed FL (grade 1-3a) responding (complete or partial remission) to 6-8 cycles first-line RCHOP (rituximab, cyclophosphamide, doxorubicine, vincristine and prednisone) followed with rituximab maintenance (RM) were included. Completed planned maintenance was inclusion criterion. Patients with previous watch and wait or additional first line therapy (radiotherapy, other chemotherapy, transplant therapy) were excluded.

Results
Totally, 168 evaluable FL patients with median age 57ys (range 28-82) including 70 (41.7%) men treated with RCHOP + RM were found in CLG database. 52/168 patients received totaly 8 doses of rituximab maintenance every 3 months for 2 years (RM8 arm), whereas 47/168 patients were treated with totaly 12 doses (RM12 arm) of rituximab maintenance every 2 months for 2 years. All patients in both subgroups completed planned RM therapy. There was no difference in distribution of age, gender, FLIPI, grade, B-symptoms, bone marrow involvement, performance status, LDH and beta2microglobuline level between both arms. Induction treatment in terms of administered cycles CHOP (6xCHOP in 41/52 and 35/45 pts., for RM8 and RM12 arm) and rituximab doses (8xR in 48/52 and 41/45 pts., for RM8 and RM12 arm) was similar between arms (ns). There were 4/52 (7.7%) and 5/47 (10.6%) relapses in subgroups RM8 and RM12, with no statistical significance. Median PFS was 3.8 (2.1-5.8) years vs. 3.9 (2.4-7.8) years in RM8 and RM12 arms (not significant), and median OS 3.91 (2.2-6.94) years vs. 3.1 (2.48-8.6) years also with no statistical significance.

Conclusion
Our results show, that rituximab maintenance given every 2 or every 3 months for two years in first line treatment brings similar benefit to the FL patients in terms of remission duration and overall survival. Despite the fact, that presented data are retrospective observation, this is the first report comparing two different rituximab maintenance regimens in FL. Further prospective study and longer follow up are needed to confirm our preliminary data.
This work was supported by grant NT/12193-5 and MHCZ-DRO (FNBr 65269705)

Disclosures:
Mayer: Roche: Consultancy, Research Funding; Glaxo: Consultancy, Research Funding. Trneny:Roche: Honoraria, Research Funding.