Upfront Consolidation Combining Yttrium-90 Ibritumomab Tiuxetan and High-Dose Therapy with Stem Cell Transplantation in Poor-Risk Patients with Diffuse Large B Cell Lymphoma

Abstract

We evaluated the safety and efficacy of standard-dose yttrium-90 (Y90) ibritumomab tiuxetan combined with high-dose BEAM (carmustine, etoposide, cytarabine, and melphalan) after first-line induction treatment in young patients with poor prognoses diffuse large B cell lymphoma (DLBCL) (clinicaltrials.gov: NCT00689169). Seventy-five high-risk (≥2 International Prognostic Index [IPI] factors) consecutive DLBCL patients (≤65 years old) in complete remission (CR) or partial remission (PR) after rituximab chemotherapy were treated with Y90 ibritumomab tiuxetan and BEAM regimen followed by autologous stem cell transplantation (ASCT). The median follow-up was 34 months. Of the 75 patients, 71 underwent ASCT and were eligible for analysis. Median time to reach a neutrophil count of >500/μL and platelet count of >20,000/μL was 11 days. Mucositis ≥3 (51%) occurred in most patients. Other adverse events were similar to those seen with BEAM alone. The overall response rate was 86%; 59 patients (83%) achieved a CR or unconfirmed CR. The 2-year event-free survival (EFS), overall survival (OS), and disease-free survival were 79%, 83%, and 91%, respectively. Disease status (CR/PR) and positron emission tomography (PET) findings before transplantation did not predict treatment failure. The IPI (2 versus >2) and maximum tumor diameter of ≥10 cm at diagnosis appeared to be prognosis factors for OS but not for EFS. Adding Y90 ibritumomab tiuxetan to BEAM is safe and does not increase transplantation-related toxicity. First-line consolidation with Y90 ibritumomab tiuxetan and high-dose chemotherapy induced high rates of EFS and OS in poor-prognosis patients with DLBCL, regardless of PET status after induction treatment and warrants a randomized study.