An Open, Phase I Study of Cediranib in Patients with Acute Myeloid Leukemia (AML).

Abstract

Prognosis is poor for the majority of AML patients, particularly the elderly and those with relapsed or refractory AML, and more effective treatment options are needed. Vascular endothelial growth factor-A (VEGF) and its receptors (VEGFRs) may contribute to the pathophysiology of AML and are considered as potential therapeutic targets. Cediranib (RECENTIN™; AZD2171) is an oral, highly potent and selective VEGF signaling inhibitor with activity versus VEGFR-1, -2 and -3, and additional activity against c-Kit. This two-part study evaluated the safety and tolerability of multiple once-daily oral doses of cediranib in patients with relapsed or refractory AML and elderly patients with de novo or secondary AML, with secondary assessments of pharmacokinetics (PK), pharmacodynamics (PD) and efficacy. Part A was a dose-escalation phase to determine the maximum tolerated dose (MTD); Part B was an expansion phase to explore the MTD and a lower, biologically active dose. A total of 35 patients (mean age, 68 years [range 50–81]; 15 male, 20 female) entered the study and received treatment with cediranib (Part A, n=23; Part B, n=12). Part A comprised 10mg (n=4), 20mg (n=6) and 30mg (n=13) dose cohorts, and intra-patient dose escalation was permitted. In Part B, patients received cediranib 20mg (n=3) or 30mg (n=9). Cediranib ≤30mg was generally well tolerated; diarrhea (n=19), hypertension (n=14) and fatigue (n=13) were the most common adverse events (AEs). Cediranib 30mg was the highest dose studied, and was declared the MTD based on dose-limiting toxicities of hypertension and diarrhea experienced by 3 patients receiving 30mg in Part A. Maximal plasma concentrations at steady-state were attained 0.83–4.1 h post-dosing. Steady-state plasma concentrations were attained after approximately 7 days of repeated once-daily dosing. Following multiple oral doses of cediranib 30mg in Parts A and B, the unbound geometric mean Css,min was 5x the IC50 value required to inhibit proliferation of human umbilical vein endothelial cells in preclinical assays, supporting the once-daily oral dosing regimen. The relationship between PK and two PD parameters (VEGF levels and blood pressure) were investigated and there appeared to be a positive correlation between exposure (Css,max and AUCss) and plasma VEGF levels, but not blood pressure. Time-dependent changes in soluble VEGFR-2 levels were observed. A best investigator assessment of AML objective response according to predefined criteria (Cheson et al, J Clin Oncol2003;21:4642–9) was observed for 6 patients (1 morphological complete remission with incomplete blood recovery [Cri], 4 partial responses and 1 minor response). However, none of the responses resulted in improvement in normal hemopoiesis. No responses were observed in 6 patients with Flt-3 ITD mutations. One patient remained on treatment for 455 days. Once-daily oral cediranib ≤30mg was generally well tolerated in patients with AML, with encouraging preliminary evidence of activity as a monotherapy. The AE and PK profiles of cediranib in AML are consistent with those seen in solid tumors.