Post-allogeneic stem cell transplant FLT3- targeted maintenance therapy: updates and considerations for clinical practice

Acute myeloid leukemia (AML) is characterized by multiple molecular and cytogenetic abnormalities, with increasing data to support clinical and prognostic implications to guide clinical decision making. One of the most well described mutations involves fms-like tyrosine kinase 3 (FLT3) that results in a constitutively active tyrosine kinase and is generally associated with poor prognosis involving shorter overall survival and higher rates of relapse. Advancements in targeted therapies have greatly influenced available treatment options in a landscape that has remained largely unchanged for the past five decades. Tyrosine kinase inhibitors (TKI), specifically FLT3-targeted therapies, are now integral treatment options for patients with this targetable mutation. As allogeneic hematopoietic cell transplant (alloHCT) remains the primary curative therapy for most adult AML patients, the goal is for eligible patients to proceed to transplant. However, post-alloHCT relapse remains exceedingly high even in patients achieving deep responses to therapy. Limited evaluation of FLT3-targeted TKIs as post-alloHCT maintenance therapy in FLT3-positive patients suggest improved outcomes and tolerable safety profiles, with ongoing studies further investigating second-generation agents. Thus, this commentary aims to review the role of post-alloHCT FLT3-targeted maintenance therapy and considerations for clinical practice.