Emerging strategies for high-risk and relapsed/refractory acute myeloid leukemia: novel agents and approaches currently in clinical trials.

High-risk acute myeloid leukemia (AML) is defined by clinical and biologic features that predict for poor response to induction chemotherapy and high risk of relapse. Despite even the most aggressive and well-developed strategies for care, most patients succumb to the disease. No currently available treatment has demonstrated consistent efficacy in terms of remission induction or long-term survival. This review will highlight some of the emerging strategies to treat high-risk AML with an emphasis on clinical trials of novel strategies currently enrolling patients. Targeted molecular therapies, novel cytotoxics, and immune-based therapies are under investigation for the management of high-risk AML. Some of the agents covered include tyrosine kinase inhibitors targeted to AML specific oncoproteins, nanoparticle formulations of existing drugs, nucleoside analogs, monoclonal antibodies, chimeric antigen receptors, bispecific T-cell engaging antibodies, and vaccines. As our understanding of the biology of AML has improved, targeted therapy for AML has emerged, offering to change not only response rate, but also the nature of response. Differentiation, rather than necrosis or apoptosis, is often seen in response to targeted agents and may be seen more frequently in the future. Interventions that might be more widely used in the near future include FLT3 inhibitors and nanoparticle formulations of drugs already known to have activity in the disease. Long term immune therapy holds significant promise.