A phase II trial of short course fludarabine, mitoxantrone, rituximab followed by ⁹⁰Y-ibritumomab tiuxetan in untreated intermediate/high-risk follicular lymphoma

BACKGROUND: A prospective, single-arm, open-label, multicenter, nonrandomised phase II trial to evaluate efficacy and safety of short fludarabine, mitoxantrone, and rituximab (FMR) induction followed by radioimmunotherapy, in untreated, intermediate/high-risk follicular non-Hodgkin's lymphoma (NHL) patients. PATIENTS AND METHODS: Fifty-five patients were treated using a sequential treatment schedule of four induction cycles of FMR chemoimmunotherapy, and a subsequent consolidating single administration of (90)Y-ibritumomab tiuxetan ((90)Y-IT), 8-14 weeks later. Patients were eligible for radioimmunotherapy if at least in partial response (PR) after induction, with normal platelet and granulocyte counts and a bone marrow infiltration ≤ 25%. Primary study end points were response rate and hematologic toxic effects; secondary end points were overall survival (OS) and progression-free survival (PFS). RESULTS: All the 55 patients received four induction cycles with an overall response rate of 96% (38 complete responses [CR] and 15 PR). Fifty-one patients (38 in CR and 13 in PR) received (90)Y-IT. By the end of the treatment, 49/55 patients achieved a CR. With a median follow-up of 21 months, the estimated 3-year PFS was 81% and the 3-year OS 100%. CONCLUSIONS: This study has established feasibility, tolerability, and efficacy of a regimen composed by short FMR induction with (90)Y-IT consolidation in untreated intermediate/high-risk follicular NHL patients.