Maintenance rituximab every 2 months is more toxic than every 3 months in patients with non-Hodgkin lymphoma.

Maintenance rituximab every 2 months is more toxic than every 3 months in patients with non-Hodgkin lymphoma The phase III PRIMA study of patients with previously untreated follicular lymphoma randomly assigned to maintenance rituximab (MR; every 8 weeks for 2 years) vs observation following rituximab-based immunochemotherapy (rituximab plus cyclophosphamide, vincristine, and prednisone [R-CVP], rituximab plus cyclophospha-mide, doxorubicin, vincristine, and prednisone [R-CHOP], or rituximab plus fludarabine, cyclophosphamide, and mitoxantrone [R-FCM]) demonstrated an improvement of 16.5% in 6-year progression-free survival (PFS) with MR (59.2% vs 42.7%; P , .001) as well as increased frequency of grade 3 to 4 adverse events (24% vs 17%; most commonly infections). 1,2 These results established MR as a standard-of-care option in such patients, and MR is now empirically generalized to accompany other rituximab-based induction regimens in treating indolent non-Hodgkin lymphomas and mantle cell lym-phoma. For example, the increasingly popular regimen of bendamus-tine and rituximab (BR) is often followed by MR every 2 months for 2 years. In our recent experience with BR, we noticed an apparently increased incidence of toxicities during maintenance that required delay or discontinuation of MR. We conducted a retrospective study to determine the predictors of MR toxicity. We hypothesized that the use of BR (vs R-CHOP/R-CVP) for induction and/or MR administered every 2 months (vs every 3 months) are associated with increased MR toxicity. We reviewed the medical records of all patients with B-cell indolent non-Hodgkin lymphoma or mantle cell lymphoma treated at our institution with R-CHOP/R-CVP or BR as first-line induction followed by MR (375 mg/m 2) every 2 months or every 3 months for a maximum of 2 years. A total of 148 patients who received their first dose of induction after January 1, 2006, and either completed or discontinued the planned maintenance were included (Table 1). The most common diagnosis was follicular lymphoma (82%), and approximately half the patients (44%) received BR. The planned maintenance schedule was every 2 months in 28% of patients and every 3 months in the remaining patients. The decision to offer one schedule of MR vs another was largely based on whether patients were treated before or after the PRIMA study. Toxicities attributed to MR occurred in 33 patients (22%) (76% grade 3-4, 18% grade 1-2, 6% grade unknown). Neutropenia (7%), infection (6%), or both (7%) accounted for 88% of all toxicities (supplemental Table 1). A delay/omission of at least 1 dose of MR …