Study of Fosciclopirox in Patients With Relapsed/Refractory Acute Myeloid Leukemia

This will be an open-label, Phase 1B/2A, study to characterize the efficacy, safety, PK, and pharmacodynamics of fosciclopirox administered alone and in combination with cytarabine in patients with R/R AML. There will be up to two cohorts used to confirm the efficacy (or futility) of fosciclopirox on the endpoint of disease response. Initially, 14 patients will be enrolled in Cohort 1a. If disease response to fosciclopirox alone IS observed in at least 4 of 14 patients, an additional 14 patients will be enrolled in Cohort 1b. If disease response to fosciclopirox alone IS NOT observed in at least 4 of 14 patients in the initial Cohort 1a, based on a review of all available data study data, the study may be terminated OR a second cohort (Cohort 2a) may be initiated using the combination of fosciclopirox and cytarabine. If disease response to fosciclopirox in combination with cytarabine IS observed in at least 4 of 14 patients in Cohort 2a, an additional 14 patients will be enrolled in Cohort 2b. If disease response to fosciclopirox in combination with cytarabine IS NOT observed in at least 4 of 14 patients in Cohort 2a, the study will be stopped for futility. If both Cohorts 1a and 2a are initiated, the minimum patient number will be 28 (i.e., treatment with fosciclopirox alone and in combination with cytarabine are futile). The maximum number of patients potentially evaluated is 42 (i.e., the first treatment is futile based upon observations in 14 patients (Cohort 1a), but treatment in Cohort 2a evaluated is positive \[14 patients\], and Cohort 2b \[14 patients\] is completed). Patients in Cohort 1a will initially be treated with fosciclopirox as a single agent. Patients who respond to this treatment, as defined below, may continue to receive treatment cycles of fosciclopirox alone until evidence of disease progression. Patients who do not respond to fosciclopirox alone, as defined below, may be switched to treatment with the combination of fosciclopirox and cytarabine. Patients who respond to the combination treatment may continue to receive treatment cycles of fosciclopirox in combination with cytarabine until evidence of disease progression. Patients who do not respond to the combination of fosciclopirox and cytarabine will be discontinued from the study. Patients enrolled in Cohort 2a (if initiated) will initially be treated with fosciclopirox in combination with cytarabine. The first patient to receive this combination will be observed during Cycle 1 (21 days) and for a further 7 days (if they do not continue to Cycle 2) before any further patients are accrued to the combination arm. As above, patients who respond to the combination treatment may continue to receive treatment cycles until evidence of disease progression, and patients who do not respond will be discontinued from the study. Fosciclopirox will be administered as 900 mg/m2 once daily as a 20-minute intravenous infusion on Days 1 to 5 (D1-D5) of each 21-day treatment cycle (rest days D6-D21). When added to fosciclopirox therapy, cytarabine will be administered as 1 gm/m2 once daily on D1 D5 of each 21-day treatment cycle (rest days D6-D21).