Hematopoietic stem cell transplantation in relapsed ALK+ anaplastic large cell lymphoma in children and adolescents: a study on behalf of the SFCE and SFGM-TC.

Allogeneic hematopoietic stem cell transplantation (allo-SCT) is a treatment option for relapsed anaplastic large cell lymphoma (ALCL) in children, but reports on its efficacy in this disease are still limited. We analyzed data concerning 34 patients under 18 years of age prospectively registered in the French SFGM-TC database, who had undergone an allo-SCT for the treatment of ALK+ ALCL between 1993 and 2011. At transplant, 28 patients (82.4%) were in CR, whereas 6 exhibited detectable disease. Conditioning regimens were mostly myelo-ablative (n=31). With a median follow-up of 6 years, 5-year overall and event-free survival rates were 70% (SE=8%) and 58% (SE=9%), respectively. The 5-year cumulative incidence of relapse and treatment-related mortality was 18% (SE=7%) and 24% (SE=8%), respectively. Six patients had relapsed (median time, 141 days (35-235)). A durable CR had been obtained in 4/6 patients after injection of donor lymphocytes (n=1) or vinblastine-corticosteroid therapy (n=3). Ten patients had died, eight due to transplant toxicity and two due to progressive disease. Allo-SCT is an efficient treatment for pediatric patients with high-risk relapsed ALK+ ALCL. However, the overall morbidity of allo-SCT raises questions about its place, given the efficacy of targeted agents currently under development in this disease.