A randomized phase II study comparing consolidation with a single dose of 90Y ibritumomab tiuxetan vs. maintenance with rituximab for two years in patients with newly diagnosed follicular lymphoma responding to R-CHOP. Long-term follow-up results.

This is a randomized phase-2 trial aimed to compare consolidation vs. maintenance in untreated patients with follicular lymphoma (FL) responding to induction. 146 patients were enrolled from 25 Spanish institutions (ZAR2007; ClinicalTrials.gov #NCT00662948). Patients in PR or CR/CR[u] after R-CHOP were randomized 1:1 to 90Y-ibritumomab-tiuxetan 0.4 mCi/kg (arm A) vs. rituximab 375 mg/m2 every 8 weeks for 2 years (arm B). After a median follow-up of 10.55 years, 53 patients eventually progressed with a 10-year PFS of 50% vs. 56% for patients in arm A and B, respectively (HR = 1.42; p > 0.1). No significant differences were seen in OS (10-year OS 78% vs. 84.5%; HR = 1.39, p > .1). Patients receiving 90Y-ibritumomab-tiuxetan showed higher incidence of second neoplasms than those in arm B (10-year cumulative incidence 18.5 vs. 2%, respectively; p = .038). In conclusion, in FL patients responding to R-CHOP, no significant differences were found between consolidation and maintenance, although with higher late toxicity for consolidation.