Background: Radioimmunotherapy represents a potential option as consolidation after chemoimmunotherapy in patients with diffuse large B-cell lymphoma who are not candidates for transplantation. We aimed to assess activity and toxicity of fractionated radioimmunotherapy using anti-CD22 90Y-epratuzumab tetraxetan as consolidation after front-line induction chemoimmunotherapy in untreated elderly patients with diffuse large B-cell lymphoma.
Methods: We did a prospective, single-group, phase 2 trial at 28 hospitals in France, with patients recruited from 17 hospitals. Eligible patients were aged 60-80 years with bulky stage 2-3 or stage 3-4 CD20-positive diffuse large B-cell lymphoma, previously untreated, and not eligible for transplantation. Patients received six cycles of R-CHOP (rituximab [375 mg/m2], cyclophosphamide [750 mg/m2], doxorubicin [50 mg/m2], and vincristine [1·4 mg/m2, up to 2 mg] all on day 1, and prednisone [40 mg/m2] daily for 5 days), administered every 14 days. 6-8 weeks after R-CHOP, responders received two doses of 15 mCi/m2 (555 MBq/m2) 90Y-epratuzumab tetraxetan administered 1 week apart. The primary endpoint was 2 year event-free survival in all registered eligible patients who received at least 1 day of study treatment; the safety analysis was done in the same population. This trial is registered with ClinicalTrials.gov, number NCT00906841.
Findings: Between Oct 22, 2008, and Dec 16, 2010, we recruited 75 patients, of whom four (5%) were excluded after central pathology review; hence, 71 (95%) patients were included in the analysis. All patients started induction treatment; 57 (80%) received radioimmunotherapy. With a median follow-up of 37 months (IQR 30-44), the estimated 2 year event-free survival was 75% (95% CI 63-84). Radioimmunotherapy toxicity consisted of grade 3-4 thrombocytopenia in 48 (84%) of 57 patients and neutropenia in 45 (79%) of 57 patients. One patient developed myelodysplastic syndrome 28 months after receiving radioimmunotherapy and one patient developed acute myeloid leukaemia 5 months after receiving radioimmunotherapy.
Interpretation: Fractionated radioimmunotherapy with 90Y-epratuzumab tetraxetan might be appropriate for response consolidation after induction chemotherapy in older patients with advanced diffuse large B-cell lymphoma, but further comparative studies are needed.
Funding: Immunomedics, Amgen, Canceropôle Grand Ouest, the GOELAMS/LYSA group and the French National Agency for Research (Investissements d'Avenir).
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