Novel Therapies for Relapsed ALL
The outcome of salvage therapy for relapsed acute lymphoblastic leukemia (ALL) remains poor. Salvage therapy mimics regimens with activity in newly diagnosed ALL. Novel strategies under investigation as monotherapy or in combination with chemotherapy improve the treatment of relapsed disease. For some ALL subsets, specifi c therapies are indicated.The addition of targeted therapy in Philadelphia chromosome–positive ALL has improved responses in relapsed patients without resistance to available tyrosine kinase inhibitors. Nelarabine demonstrates
activity as monotherapy in T-cell ALL and is approved by the US Food and Drug Administration.Clofarabine, a second-generation purine analogue approved in pediatric leukemia, has shown activity in adult acute leukemias including ALL and acute myeloid leukemia. The role of pegaspargase in adult ALL requires further investigation. The benefi t of matched related-donor allogeneic stem cell transplantation is signifi cant for standard-risk ALL but not for high-risk ALL. Development of new drugs and agents tailored to subset-specific cytogeneticmolecular characteristics remains vital to success in treating adult ALL.