Radioimmunotherapy with ¹³¹I‐rituximab for patients with relapsed or refractory follicular or mantle cell lymphoma

Abstract Aim This study aimed to evaluate the safety and efficacy of 131 I‐rituximab in patients with relapsed or refractory follicular or mantle cell lymphoma. Methods Twenty‐four patients with relapsed or refractory follicular or mantle cell lymphoma were administered unlabeled rituximab (70 mg) immediately before receiving a therapeutic dose of 131 I‐rituximab. Contrast‐enhanced 18F‐fluorodeoxyglucose positron emission tomography/computed tomography was used a month later to assess tumor response. Results This study enrolled 24 patients between June 2012 and 2022. Depending on how they responded to radioimmunotherapy (RIT), 131 I‐rituximab was administered one to five times. Of the 24 patients, 9 achieved complete response after RIT and 8 achieved partial response. The median progression‐free and overall survival was 5.9 and 37.9 months, respectively. During the follow‐up period of 64.2 months, three patients were diagnosed with a secondary malignancy. Among treatment‐related adverse events, hematologic toxicities were common, and grade 3–4 thrombocytopenia and neutropenia were reported in 66.6% of cases. Conclusion 131 I‐rituximab has an effective and favorable safety profile in patients with relapsed or refractory follicular lymphoma and mantle cell lymphoma. This suggests that RIT may also be considered a treatment option for patients with relapsed or refractory follicular lymphoma and mantle cell lymphoma.