Reduced Intensity Allogeneic Transplantation for Non-Hodgkin’s Lymphoma: Extended Follow-Up of an Alemtuzumab-Containing Regimen.

Allogeneic transplantation with reduced intensity conditioning is increasingly being used in patients with non-Hodgkin’s Lymphoma (NHL) who fail standard therapy. We report extended follow-up on 121 patients with NHL, who underwent allogeneic transplantation with reduced intensity conditioning at 8 UK centres. Conditioning was with fludarabine 150mg/m2, melphalan 140mg/m2 and alemtuzumab (60–120mg). Cyclosporin A was administered at 3mg/kg from day-1, and stem cell source was bone marrow or PBSC. Diagnoses were in 3 categories: low grade follicular NHL (n=50), mantle cell lymphoma (n=21), and high-grade NHL (n=50, including transformed low grade disease n=15). Donors were HLA-matched siblings in 75 (62%), and unrelated in 46 (38%), of whom 18 were HLA-mismatched at up to 3/10 loci. 48% of patients had failed previous autologous transplantation. Median follow-up was 35 months (1–78). For the group with low grade follicular NHL (n=50), estimated overall survival (OS) was 76% at 1yr and 67% at 4yrs, and non-relapse mortality (NRM) was 16% at 4yrs. Disease relapse or progression occurred in 12 patients, of whom 8 received donor lymphocyte infusions (DLI), with responses in 6. Current progression-free survival (cPFS) is 68% at 4yrs. For the group with mantle cell lymphoma (n=21), estimated OS was 83% at 4yrs, NRM was 11% at 4yrs and relapse or progression occurred in 6 patients. Three patients received DLI, with non-sustained responses in 2. Current PFS is 43% at 4yrs. For high-grade NHL (n=50), estimated OS was 52% at 1yr and 45% at 4yrs. Prior autologous transplantation was common in this group (72%), and NRM was higher at 34% at 1yr and 40% at 4yrs. Progression/relapse occurred in 15 patients, of whom 10 received donor lymphocytes, with responses in 5. Current PFS is 48% at 1yr and 43% at 4yrs. These results, from patients who were often heavily pre-treated, including having failed autologous transplantation, provide encouraging evidence to support the application of reduced intensity allogeneic transplants in NHL. NRM in low grade follicular or mantle cell lymphoma is low, consistent with the use of T cell depletion, and graft-versus-lymphoma effects can be induced with DLI in a subset of cases. The data in follicular lymphoma, in particular, supports consideration of this therapy earlier in the disease. In high-grade disease, NRM appears to be higher, but durable remissions are attainable in a proportion of patients.