FCR (Fludarabine, Cyclophosphamide, Rituximab) regimen followed by 90yttrium ibritumomab tiuxetan consolidation for the treatment of relapsed grades 1 and 2 follicular lymphoma: A report of 9 cases

Background: This retrospective analysis is focused on the efficacy and safety of radioimmunotherapy (RIT) with Zevalin® in nine patients with recurrent follicular lymphoma (FL) who were treated in a consolidation setting after having achieved complete remission or partial remission with FCR. Methods. The median age was 63 yrs (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/m²x 3 days), C (1 gr/m ² day 1) and R (375 mg/m² day 4) for 4 cycles. Who achieved at least a partial remission, with <25% bone marrow involvement, was treated with ⁹⁰Yttrium Ibritumomab Tiuxetan 11.1 or 14.8 MBq/Kg up to a maximum dose 1184 MBq, at 3 months after the completion of FCR. The patients underwent a further restaging at 12 weeks after ⁹⁰Y-RIT with total body CT scan, FDG-PET/CT and bilateral bone marrow biopsy. Results: Nine patients have completed the treatment: FCR followed by ⁹⁰Y-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 ⁹⁰Y-RIT two patients in PR converted to CR 12 weeks later. With median follow up of 34 months (range 13-50) the current analysis has shown that overall survival (OS) is 89% at 2 years, 76% at 3 years and 61% at 4 years. The most common grade 3 or 4 adverse events were hematologic, one patient developed herpes zoster infection after 8 months following valacyclovir discontinuation; another patient developed fungal infection. Conclusions: Our experience indicate feasibility, tolerability and efficacy of FCR regimen followed by ⁹⁰Y-RIT in patients relapsed with grades 1 and 2 FL with no unexpected toxicities. A longer follow up and a larger number of patients with relapsed grades 1 and 2 FL are required to determine the impact of this regimen on long-term duration of response and PFS.