Abstract
BACKGROUND: The authors examined the "real-world" effectiveness of rituximab (R) maintenance therapy (R-maintenance) compared with observation after R-based induction therapy in patients with previously untreated follicular lymphoma (FL) in the United States. METHODS: The National LymphoCare Study is a prospective, multicenter, observational study that enrolled > 2700 untreated patients with FL diagnosed from 2004 to 2007 at 265 sites in the United States. Among these, patients who achieved at least stable disease after R-based induction therapy were eligible for the current analysis. Patients who initiated R-maintenance within 215 days of completing induction therapy were categorized as the R-maintenance group, and those who did not initiate therapy during this period were categorized as the observation group. The objective of the current study was to determine the effect of R-maintenance on progression-free survival (PFS), time to next treatment (TTNT), and overall survival (OS). RESULTS: A total of 1439 patients completed R-based induction therapy, 1186 of whom met all inclusion criteria (541 patients received R-maintenance and 645 patients were observed). Characteristics that were found to be predictive of receiving R-maintenance were histology grade (1/2), Ann Arbor stage of disease (III/IV), geographic region (region other than the West), and practice setting (community practice). With a median follow-up of 5.7 years, R-maintenance was associated with superior PFS (hazards ratio [HR], 0.68; 95% confidence interval [95% CI], 0.56-0.84 [P = .0003]) and TTNT (HR, 0.66; 95% CI, 0.52-0.84 [P = .0007]). No significant difference in OS was observed (HR, 0.81; 95% CI, 0.58-1.14 [P = .23]). CONCLUSIONS: R-maintenance in patients with FL and at least stable disease after R-based induction therapy provided significantly longer PFS and TTNT in comparison with observation, but no significant difference in OS was observed with 5-years of follow-up. This comparative effectiveness study aligns with the results of randomized trials suggesting that similar outcomes occur with R-maintenance in FL with the treatment variations observed in clinical practice.