CLAG-GO for Patients With Persistent, Relapsed or Refractory AML

This is a single-arm, two-stage phase II trial of cladribine, cytarabine, granulocyte colony stimulating factor and gemtuzumab ozogamicin (CLAG-GO) in adult patients with acute myeloid leukemia (AML) who are either have persistent disease after initial induction chemotherapy or are in first relapse, with early stopping for unacceptable toxicity. The trial will be conducted at the University of Maryland Greenebaum Comprehensive Cancer Center (UMGCCC), with a target enrollment of 39 patients if the trial proceeds to the second stage. Eligible patients will receive induction chemotherapy with CLAG-GO at the doses detailed below. In the first stage of the trial, a sequential boundary is used to monitor induction mortality and halt accrual if this mortality is significantly above 10%. If more than 6 responses are seen in the initial 19 patients, 20 additional patients will be enrolled in the 2nd stage. Responders may proceed to allogeneic hematopoietic stem cell transplantation (alloHSCT) at any time after induction, and these patients will be monitored for at least 30 days post-transplantation for veno-occlusive disease. Responding patients will also have the option of having a single cycle of consolidation therapy using the same CLAG-GO regimen, followed by maintenance with GO monotherapy for up to 8 additional cycles. Responses will be categorized according to the European LeukemiaNet (ELN) response criteria for AML. Assessment of measureable residual disease (MRD) will be conducted with bone marrow aspirate samples and changes in immunophenotype will be evaluated. In addition, single nucleotide polymorphism (SNP) analysis and sialylation status of CD33, along with sialidase activity of myeloblasts will be evaluated and correlated with responses and survival times. Safety and toxicity will be evaluated continuously, and event-free survival, and overall survival as well as the proportion of patients proceeding to receive alloHSCT will be estimated.