Impact of rituximab maintenance on survival of patients with mantle cell lymphoma: A north Indian tertiary care center experience.

e19047 Background: Mantle cell lymphoma (MCL) is an aggressive variant of non-Hodgkin lymphoma. Indian data is scarce owing to its rarity in south-east Asia. Till now, studies have not shown overall survival benefit with rituximab maintenance (RM). Our study aims to assess if RM improves overall survival of MCL patients. Methods: We retrospectively analysed clinicopathological data of 90 transplant-ineligible MCL patients treated between January’2013-December’2023 at Institute Rotary Cancer Hospital - All India Institute of Medical Sciences, New Delhi, India. Rituximab-based induction chemotherapy was used in all patients as per institutional protocol. RM was used in twenty-eight (31.0%) patients due to financial constraints. Primary outcome was overall survival (OS). Secondary outcomes were event free survival (EFS) and factors affecting OS, EFS. OS was defined as time from treatment initiation to demise from any cause or last follow-up. EFS was defined as time from treatment initiation to disease progression or relapse or demise from any cause. Response was assessed by modified Cheson’s lymphoma response evaluation criteria. STATA 13.0 was used to assess survival by Kaplan-Meier analysis and log rank test. Factors affecting survival were assessed by multivariate analysis (Cox proportional hazards model) and expressed as adjusted hazard ratio (aHR). p value < 0.05 defined statistical significance. Results: Median age was sixty years; male-female ratio 3:1. Thirty-five (39.0%) had one or more co-morbidities, 79(88.0%) generalised lymphadenopathy, 72(80.0%) extra-nodal involvement, 49(54.0%) B symptoms, 84(93.0%) advanced stage (III/IV), 49(54.0%) high risk MCL international prognostic index (MIPI). Clinical and tumor characteristics, response rates after initial induction were similar in both maintenance and non-maintenance groups. Overall, 52(58.0%) patients were alive with median follow-up of 63.0 months (inter-quartile range 37.0-90.0 months). Median OS was 37.5 months in non-maintenance group and did not reach in maintenance group. Estimated 1.0-, 2.0, 3.0-year OS were 100.0%, 91.0%, 81.0% vs 75.0%, 63.0%, 55.0% respectively in maintenance vs non-maintenance group. RM was significantly associated with better OS aHR (95% confidence interval): 0.31 (0.13-0.75), p=0.01. Advanced stage, Eastern Co-operative Oncology Group performance status (ECOG PS) ≥2 at presentation were also significant factors for poor OS. Median EFS was significantly lower in non-maintenance group 14.0 vs 42.5 months; aHR (95% confidence interval): 0.34 (0.18-0.64), p=0.001. Advanced stage, anemia, high risk MIPI at presentation were also significant factors for poor EFS. Conclusions: This was the first study from south-east Asia demonstrating impact of rituximab maintenance in MCL. Rituximab maintenance significantly improved OS and EFS of MCL patients.