Introduction
In refractory or relapsed acute leukemia the achievement of a complete remission by a salvage therapy and the performance of an allogeneic hematopoietic stem cell transplantation (HSCT) is in most cases the only treatment by which long term disease-free survival can be accomplished. With current salvage regimens a 5 year overall survival rate of 29% is obtained in children with relapsed acute myeloid leukemia (AML) and a 10 year overall survival rate of 36% in children with relapsed acute lymphoblastic leukemia (ALL) 3,5. It has to be considered that children with relapsed leukemia have been exposed to high dose chemotherapy, especially if hematopoietic transplantation and thus intensive conditioning regimens have already been performed. Therefore a low toxicity regimen is needed. Melphalan is an alkylating drug with myeloablative and anti-tumour effect, which has been used in conditioning regimens prior to stem cell transplantation in different hematologic and non-hematologic malignancies 6-8. The dose-limiting toxicity of melphalan is its bone marrow suppression, the extramedullary toxicity is low including mucosal damage, increase of liver enzymes and the development of interstitial pneumonia6. Cytarabine is an analogue of deoxycytidine. It is known to cause myelosuppression and gastrointestinal toxicity, fever and elevation of hepatic enzymes, neuronal toxicity and cardiac arrhythmia4,9.
In Germany first line treatment for relapsed ALL and AML is conducted with an induction polychemotherapy, followed by consolidation therapy and an allogeneic stem cell transplantation in intermediate and high risk cases of relapsed ALL and in the majority of cases of relapsed AML according to the ALL-REZ-BFM 2002 protocol and the International Registry AML Relapse 2009 4,10. In case of second or third relapse an individualized chemotherapy with the introduction of new drugs is recommended 4.
In this restrospective case cohort analysis we investigated the outcome of a salvage therapy with melphalan and cytarabine in refractory or relapsed acute leukemia in children.