Once the MTD/MED for ALT-803 is determined, this cohort will be used in the extended phase. The primary goal of this extended phase is to study the potential efficacy of ALT-803 in this patient population. Efficacy will be measured using rates of remission induction. An optimal Simon's two-stage design will be used in this phase. Stage 1 will enroll 14 patients (including the 6 patients treated at the MTD/MED during the dose finding phase). If 3 or more of these 14 patients respond to ALT-803, the trial will move to stage 2 and enroll an additional 23 patients. If 2 or fewer respond, the study will terminate enrollment early.