Anti-FLT3 Monoclonal antibody, clone B3G20 [PE]

One hundred and eight consecutive acute myeloid leukemia (AML) patients aged 60 or less treated with two different induction regimens were retrospectively analyzed. Induction regimen for the first 50 consecutive patients was DA3+7, and the following 58 patients received cladribine 5 mg/m(2) on days 1 through 5 in addition to DA3+7 (DAC). There were no significant differences in the median age and the proportion of patients with unfavorable characteristics between the two groups. Remission after induction chemotherapy was achieved in 30/50 (60%) patients in DA3+7 and in 46/58 (79%) in DAC group (p = 0.028). The median survival in the DA3+7 group was 18 months, while in the DAC group it was not reached (p = 0.034). We confirmed results from other research groups by demonstrating improved remission induction rate and overall survival of AML patients aged 60 years or less treated with DAC induction compared with standard DA3+7 induction chemotherapy.

Acute myeloid leukemia (AML) is a clonal hematologic neoplasm characterized by rapid, uncontrolled cell growth of immature myeloid cells (blasts). There are numerous genetic abnormalities in AML, many of which are prognostic, but an increasing number are targets for drug therapy. One of the most common genetic abnormalities in AML are activating mutations in the FMS-like tyrosine kinase 3 receptor (FLT3). As a receptor tyrosine kinase, FLT3 was the first targetable genetic abnormality in AML. The first generation of FLT3 inhibitors were broad-spectrum kinase inhibitors that inhibited FLT3 among other proteins. Although clinically active, first-generation FLT3 inhibitors had limited success as single agents. This led to the development of a second generation of more selective FLT3 inhibitors. This review focuses on quizartinib, a potent second-generation FLT3 inhibitor. We discuss the clinical trial development, mechanisms of resistance, and the recent FDA decision to deny approval for quizartinib as a single agent in relapsed/refractory AML.