Rituximab monotherapy with eight weekly infusions for relapsed or refractory patients with indolent B cell non‐Hodgkin lymphoma mostly pretreated with rituximab: A multicenter phase II study

Information regarding rituximab monotherapy with eight weekly infusions for relapsed or refractory indolent B cell non‐Hodgkin lymphoma (B‐NHL), in particular for patients pretreated with rituximab, is limited. To evaluate the efficacy and safety of eight doses of rituximab monotherapy, 52 patients with relapsed or refractory indolent B‐NHL were enrolled in the present study. Forty of 45 eligible patients (89%) had follicular lymphoma and 24 (53%) were at intermediate or high risk group according to the Follicular Lymphoma International Prognostic Index. The median number of prior chemotherapy regimens was 1 (range 1–7). At the median follow‐up of 12.2 months, the overall response rate (ORR), complete response rate (%CR), and median progression‐free survival (PFS) were 69% (95% confidence interval [CI] 53%–82%), 47% (95% CI 32%–62%), and 15.6 months (95% CI 10.6– months), respectively. In the 33 patients pretreated with rituximab, the ORR, %CR, and median PFS were inferior compared with values for the 12 patients who had not received rituximab previously (64%vs 83% for ORR; 39%vs 67% for %CR; and 13.8 vs 17.5 months for median PFS, respectively). All mild‐to‐moderate infusion‐related toxicities were reversible. Grade 3/4 non‐hematologic adverse events occurred in six of the 52 patients. Two patients developed Grade 4 late‐onset neutropenia and a decrease (>50%) in serum immunoglobulin was observed in six patients. In conclusion, rituximab monotherapy with eight weekly infusions is effective in relapsed patients with indolent B‐NHL, with acceptable toxicities, including in patients pretreated with rituximab; however, careful monitoring is recommended for infections associated with late‐onset neutropenia and hypogammaglobulinemia. (University Hospital Medical Information Network no. UMIN000002974.) (Cancer Sci 2011; 102: 1698–1705)