Allogeneic Transplantation after Myeloablative Rituximab/BEAM ± Bortezomib for Patients with Relapsed/Refractory Lymphoid Malignancies: 5-Year Follow-Up Results

Although bortezomib and rituximab have synergistic activity in patients with lymphoma and both can attenuate graft-versus-host disease (GVHD), the drugs have not been used together in patients undergoing allogeneic stem cell transplantation (alloSCT). In this phase I/II trial, we assessed the safety and activity of bortezomib added to the rituximab (R) plus BEAM (carmustine, etoposide, cytarabine, melphalan) regimen in patients with relapsed lymphoma undergoing alloSCT. Primary GVHD prophylaxis consisted of tacrolimus and methotrexate. Bortezomib (1 to 1.3 mg/m² per dose) was administered i.v. on days –13, –6, –1, and +2. We performed inverse probability weighting analysis to compare GVHD and survival results with an historical control group that received R-BEAM without bortezomib. Thirty-nine patients were assessable for toxic effects and response. The median age was 54 years. The most common diagnosis was diffuse large B cell lymphoma (41%). Twenty-two patients (56%) and 17 patients (44%) received their transplants from matched related and matched unrelated donors, respectively. The maximum tolerated bortezomib dose was 1 mg/m². The weighted cumulative incidences of grades II to IV and III or IV acute GVHD were 50% and 34%, respectively; these incidences and survival rates were not significantly different from those of the control group. Median survival was not reached in patients age ≤ 50 years and with a long follow-up time of 60.7 months. The R-BEAM regimen has a survival benefit in lymphoma patients age ≤ 50 years undergoing alloSCT. The addition of bortezomib has no impact on survival or incidence of GVHD.