Reduced-intensity allogeneic transplantation for lymphoma

Megadose 90Y-ibritumomab tiuxetan prior to allogeneic transplantation is effective for aggressive large B-cell lymphoma

Allogeneic hematopoietic cell transplantation (allo-HCT) can be curative for relapsed or refractory B-cell lymphomas (BCLs), although outcomes are worse in aggressive disease, and most patients will still experience relapse. Radioimmunotherapy using 90Y-ibritumomab tiuxetan can induce disease control across lymphoma subtypes in a dose-dependent fashion. We hypothesized that megadoses of 90Y-ibritumomab tiuxetan with reduced-intensity conditioning could safely produce deeper remissions in aggressive BCL further maintained with the immunologic effect of allo-HCT. In this phase 2 study, CD20+ BCL patients received outpatient 90Y-ibritumomab tiuxetan (1.5 mCi/kg; maximum, 120 mCi), fludarabine, and then 2 Gy total body irradiation before HLA-matched allo-HCT. Twenty patients were enrolled after a median of 4.5 prior lines of therapy, including 14 with prior autologous transplant and 4 with prior anti-CD19 chimeric T-cellular therapy. A median 90Y-ibritumomab tiuxetan activity of 113.6 mCi (range, 71.2-129.2 mCi) was administered, delivering a median of 552 cGy to the liver (range, 499-2411 cGy). The estimated 1- and 5-year progression-free survival was 55% (95% confidence interval [CI], 31-73) and 50% (95% CI, 27-69) with a median progression-free survival of 1.57 years. The estimated 1- and 5-year overall survival was 80% (95% CI, 54-92) and 63% (95% CI, 38-81) with a median overall survival of 6.45 years. Sixteen patients (80%) experienced grade 3 or higher toxicities, although nonrelapse mortality was 10% at 1 year. No patients developed secondary acute myeloid leukemia/myelodysplastic syndrome. Megadose 90Y-ibritumomab tiuxetan, fludarabine, and low-dose total body irradiation followed by an HLA-matched allo-HCT was feasible, safe, and effective in treating aggressive BCL, exceeding the prespecified end point while producing nonhematologic toxicities comparable to those of standard reduced-intensity conditioning regimens.

Therapies for relapsed Hodgkin lymphoma: transplant and non-transplant approaches including immunotherapy

Autologous stem cell transplant remains the standard of care for relapsed Hodgkin lymphoma (HL). Approximately 50% of patients with chemo-sensitive relapse will be cured with this approach. The optimal pretransplant salvage regimen is controversial, but less toxic combinations seem to be equivalent to more aggressive approaches. For patients with chemo-refractory disease at relapse and those failing autologous transplant, the long-term prognosis remains poor. New approaches such as reduced-intensity allogeneic transplant, monoclonal antibodies targeting the CD30 antigen, Epstein-Barr virus (EBV)-specific cytotoxic T-lymphocytes, and bortezomib are under investigation, but preliminary results are disappointing. New therapies are needed for patients with relapsed HL.