Long term efficacy and safety of Fludarabine, Cyclophosphamide and Rituximab regimen followed by 90 Y-ibritumomab tiuxetan consolidation for the treatment of relapsed grades 1 and 2 follicular lymphoma

Background In this retrospective study, we investigated the efficacy and safety of radioimmunotherapy with 90 Yttrium- ibritumomab tiuxetan ( 90 Y-RIT) in 9 patients with recurrent follicular lymphoma (FL) who were treated in a consolidation setting after having achieved complete (CR) or partial remission (PR) with Fludarabine, Cyclophosphamide and Rituximab (FCR). Methods The median age was 63 years (range 46–77). All patients were relapsed with histologically confirmed CD20-positive (grade 1 or 2) FL, at relapse they received FCR every 28 days: F (25 mg/m 2 x 3 days), C (1 gr/m 2 day 1) and R (375 mg/m 2 day 4) for 4 cycles. Those who achieved at least a PR with <25 % bone marrow involvement were treated with 90 Y-RIT 11.1 or 14.8 MBq/Kg, at 3 months after completing FCR. Patients underwent a further restaging at 12 weeks after 90 Y-RIT with a total body CT scan, FDG-PET/CT and bilateral bone marrow biopsy. Results Nine patients completed the treatment: FCR followed by 90 Y-RIT (6 patients at 14.8 MBq/Kg, 3 patients at 11.1 MBq/Kg). After FCR, 7 patients obtained CR and 2 PR; after 90 Y-RIT 2 patients in PR converted to CR 12 weeks later. With a median follow up of 95 months (range 20–114) since FCR and 88 months (range 13–104) since 90 Y-RIT 3 deaths were not related to lymphoma; all 3 deceased patients obtained CR before 90 Y-RIT and died still in CR. The median overall (OS) and progression free survival (PFS) have not been reached, in this analysis both OS or PFS are 67 % at 7.5 year. The most common grade 3 or 4 adverse events were hematologic. Conclusions These results confirm the long term efficacy and safety of 4 cycles of FCR followed by 90 Y-RIT in relapsed grades 1 and 2 FL and suggest that this regimen could be a therapeutic option for this setting of patients, specially at age of 60–75 with no unexpected toxicities.