Phase I Study to Assess the Safety and Tolerability of AZD1152 In Combination with Low Dose Cytosine Arabinoside In Patients with Acute Myeloid Leukemia (AML)

Aurora B kinase is a key mitosis regulator that is overexpressed in a range of malignancies, including AML. AZD1152 is a potent selective inhibitor of Aurora B kinase. This ascending dose cohort study was designed to assess the safety and tolerability of AZD1152 in combination with low dose cytosine arabinoside (LDAC), the only agent that has currently demonstrated a survival advantage over palliative care in older patients with AML.

Patients aged ≥60 years with newly diagnosed AML unfit for intensive induction chemotherapy were included. Cohorts of 6 patients received escalating doses of a 7-day continuous iv infusion of AZD1152, at doses of 800 mg up to the monotherapy maximum tolerated dose (MTD) of 1200 mg, in combination with LDAC 20 mg sc injection twice daily for 10 days. AZD1152 and LDAC were administered in 28-day cycles. If 1 or fewer dose-limiting toxicities (DLTs) were observed in a cohort, AZD1152 dose was escalated. A DLT was an adverse event (AE) or laboratory abnormality considered related to AZD1152, which was a Common Terminology Criteria for Adverse Events (CTCAE) grade ≥3 non-hematological toxicity (despite adequate supportive care). If 2 or more of 6 patients had a DLT, the dose was reduced or enrollment was stopped into that cohort. The MTD was defined as the dose at which 0 or 1 of 6 patients experienced a DLT. Following determination, the MTD cohort was expanded to 12 patients.

Objective response was evaluated by the investigators using AML International Working Group clinical response criteria. AEs and serious AEs (SAEs) were evaluated according to CTCAE version 3. Blood samples were taken pre-dose and at selected times post dose for 3 cycles to determine levels of AZD1152, its active metabolite AZD1152 hQPA and LDAC.

At the data cut-off on 02/08/10 (data validation ongoing), 22 patients had been treated with the combination of LDAC plus AZD1152 (n=6 800 mg; n=13 1000 mg; n=3 1200 mg). Mean age (range) across the 3 cohorts was 71.1 (61–82) years, 14 (64%) were male, 21 were Caucasian and 1 was African American. The mean age of the 800 mg cohort was older (75.2 years) compared with the 1000 mg and 1200 mg cohorts (70.3 and 67.3 years, respectively). At baseline, 8 (36%) patients had de novo AML, and 7 (32%), 2 (9%) and 1 (5%) had AML secondary to myelodysplastic syndrome, myeloproliferative disorder and chemotherapy, respectively. All 22 patients had newly diagnosed AML. All patients received at least 1 cycle of treatment, 10 received ≥2 cycles and 1 received 5 cycles. One patient received an AZD1152 dose reduction (1000 mg to 800 mg) for their second cycle due to a high creatinine level, which was present at pre-dosing. Two patients in the 1200 mg group had DLT episodes of CTCAE grade 3 mucositis. The MTD of AZD1152 in combination with LDAC was defined as 1000 mg. All patients had at least 1 AE, the most common were myelosuppression (febrile neutropenia, anemia and thrombocytopenia in 50%, 36% and 27% of patients, respectively), stomatitis/mucosal inflammation, nausea, diarrhea and infection (each in 45% of patients). The most common grade 3/4 CTCAEs were febrile neutropenia, infection, thrombocytopenia and anemia. There were 3 (13.6%) deaths, 1 in each cohort; 2 were due to SAEs of febrile neutropenia (multiple-organ failure) and hypoxia (fungal pulmonary infection) and 1 was due to an unknown cause. Nine of 21 patients (43%) were reported by the investigators to have had a clinical response (CR + CRi) (Table).

The MTD of AZD1152 in combination with LDAC in older patients with newly diagnosed AML was 1000 mg. AZD1152 at a dose of 1000 mg combined with LDAC had an acceptable tolerability profile. Two patients had DLTs of mucositis at the monotherapy MTD of 1200 mg. AEs of febrile neutropenia, thrombocytopenia and anemia were slightly higher than those in patients treated with either agent alone, although many patients experienced these AEs at study entry. The investigator-reported clinical response rate (CR + CRi) was 43%. The development of AZD1152 is continuing with a Phase II study in older patients with AML considered unfit for intensive chemotherapy.

Kantarjian:AstraZeneca: Research Funding. Off Label Use: Low-dose cytosine arabinoside is an approved agent for the treatment of patients with AML; this study evaluated low-dose cytosine arabinoside in combination with AZD1152, an investigational agent that inhibits Aurora Kinase B . Sekeres:Celgene Corp: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees. Ribrag:Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; LFB Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Servier: Research Funding; Celgene: Research Funding; LFB: Research Funding. Owen: AstraZeneca: Employment, Equity Ownership. Stockman:AstraZeneca: Employment, Equity Ownership. Oliver:AstraZeneca: Employment, Equity Ownership.