Risks and Benefits of Rituximab Maintenance in Elderly Patients with Advanced Follicular Lymphoma

Introduction: Based on the PRIMA trial (Lancet 2010; 377: 42-51), rituximab maintenance following induction rituximab-based chemotherapy is the standard of care in patients with advanced follicular lymphoma (FL) because it extended the 3-year progression free survival (PFS) from 58% to 75%, with a low rate of infection (<5%). However, this study was conducted in young patients (median age 57 years old) and the benefits and risks of the maintenance are unknown in elderly patients.

Methods: We reviewed the clinical characteristics, outcome and complications of 62 advanced FL patients selected based on having successfully completed induction chemotherapy and initiated maintenance rituximab at the Jewish General Hospital between 2007 and 2014. The age cut off of ≥75 years old at the time of treatment was defined as "elderly". We compared characteristics of the two groups using the χ² test and calculated PFS using the Kaplan-Meier method and log-rank test.

Results: In total, 9/62 (15%) patients were "elderly" and 53/62 (85%) were "young", with median ages of 79 (75-87) and 55 (30-74) years old, respectively. Elderly patients had more adverse prognostic features compared to younger patients: B symptoms (4/9 vs 7/53, p=0.023), elevated lactate dehydrogenase (5/9 vs 9/51, p=0.013), lower hemoglobin (5/9 vs 3/52, p<0.001) and poor performance status (3/9 vs 1/53, p<0.001). The mean PFS was lower in elderly patients (25 months vs 65 months, p=0.05). The 3-year PFS in the young group was 80%. Toxicities were higher in the elderly group: grade 3-4 neutropenia (3/9 vs 5/53, p=0.05) and infections (5/9 vs 13/52, p=0.063).

Conclusion: Elderly patients had more adverse prognostic factors and a significantly inferior PFS with rituximab maintenance compared to younger patients. The rates of infections were higher than those reported in the PRIMA trial. Maintenance rituximab may not benefit elderly patients with advanced FL.