Allogeneic Stem Cell Transplantation for Hodgkin's Disease From Sibling and Unrelated Donors: The German Cooperative Transplantation Study Group Experience.

Although modern chemotherapy regimens achieve a high cure rate in primary Hodgkin's disease and relapsed patients can be salvaged by high dose chemotherapy with autologous stem cell transplantation there remains a subgroup of patients with early relapse despite high dose chemotherapy. The prognosis of these patients is dismal with further chemotherapy. Allogeneic transplantation has the potential to exert an alloimmune response against lymphoma cells and has therefor been offered to patients with relapsed or refractory Hodgkin's disease, in particular when a matched sibling donor was available. However only limited information on the feasability of allogeneic transplantion from an unrelated donor is available.

We performed a retrospective analysis of allogeneic transplants for Hodgkins disease within the German Cooperative Transplantation Study Group. 18 centres have provided data on patient and donor characteristics, transplant procedure and outcome. Survival data were analysed by Kaplan-Meier and tested for differences by log rank test. Cumulative incidences for relapse, non-relapse mortality and graft-versus-host-disease were calculated in a competing risk model.

79 patients with a median age of 30 years (range 14-59) were included. 65 (82%) patients had failed a previous autologous transplantation 582 days (median) before allotransplantation. Disease status at transplantation was CR in 17.6%, PR in 54.0%, stable disease in 9.5%, PD in 12.2%, and untreated relapse in 6.8%. Donors were matched related in 33%, mismatched related in 5%, matched unrelated in 42% and mismatched unrelated in 20%. With a median follow up of 19 months for surviving patients the median overall survival (OS) after allotransplant was 42 months with a 2 year survival of 51%. Non-relapse mortality was 21.1% after 12 and 24 months. The median progression-free survival was 14.6 months with a 2 year PFS of 42.0%. Patients relapsing after an autologous transplantation had a significantly better OS (median 53.7 vs 8.4 months, p=0.029) and PFS (22.0 vs 7.5 months, p=0.039) than patients without a prior autograft. No significant difference was seen for OS or PFS regarding the use of related or unrelated donors or disease status at transplant.

Allogenic transplantation is a feasible option for high-risk patients with relapsed or refractory Hodgkins disease in particular after failing an autograft. Non-relapse mortality appears to be acceptable in view of the intensive prior treatment. Probabilities for overall survival and progression-free survival were similar after transplantation from a related or unrelated donor. Further optimisation strategies have to focus on on efforts to reduce the high relapse-rate after transplantation, thereby potentially increasing overall and progression free survival.

No relevant conflicts of interest to declare.