This randomized phase III trial assessed whether intensification of rituximab (R) during the first 4 cycles of R-CHOP can improve outcome of diffuse large B-cell lymphoma (DLBCL) patients compared with standard R-CHOP. Patients in complete remission (CR) after induction treatment were randomized between rituximab maintenance and observation. Intensification of rituximab was not more effective than standard R-CHOP, showing same CR-rates and progression free survival after induction (ASCO 2016 # 7504). Here, we report the results of the second randomization for rituximab maintenance therapy.
To assess in a prospective, multicenter, randomized phase III study in patients with DLBCL the efficacy of maintenance treatment with rituximab in comparison to no further treatment on disease free survival.
Patients in CR after R-CHOP were randomized between 24 months of rituximab maintenance 375 mg/m2 intravenous every 8 weeks (n = 199) or observation (n = 199). CT scans were performed at 6, 12, 18 and 24 months in both arms. The primary endpoint was disease free survival (DFS) from maintenance randomization. Secondary endpoints were overall survival (OS) and adverse events (AEs). (www.trialregister.nl NTR1014).
Median age was 65 years (range 31–80), 48% were 66 years or older and 49% were male. The majority of patients (54%) had a high-intermediate or high aa-IPI score. After a median follow-up of 79.9 months (maximum 125.7 months), the 5-year DFS rate was 79% for rituximab maintenance versus 74% for observation. This difference was not statistically significant, with a hazard ratio of 0.83 (95% confidence interval 0.57–1.19, p = 0.31, adjusted for age and aa-IPI). The secondary endpoint OS was also not significantly different (85% versus 83% at 5 years). No clinical subgroup benefited from rituximab maintenance. Toxicity was mild. Among patients who received rituximab maintenance CTCAE grade 3 and 4 AEs were reported in 17% and 6% of patients, respectively. Infection was the most frequent AE, a grade 3 infection occurred in 6% of patients. Neutropenia was seen in 1% (grade 3) and 3% (grade 4) of patients.
Rituximab maintenance therapy provides no additional benefit for DLBCL patients in first CR after R-CHOP.