A phase I pharmacokinetic (PK) and pharmacodynamic (PD) study of the selective aurora kinase inhibitor GSK1070916A.

Abstract

2525 Background: GSK1070916A is a potent and selective inhibitor of Aurora B and C. This phase I study in collaboration with GlaxoSmithKline was part of the Cancer Research UK Clinical Development Programme. Methods: Patients (pts) with advanced/metastatic solid cancers for whom there was no standard therapy, with adequate performance status and organ function were eligible for GSK1070916A (1 hour i.v. infusion days 1 – 5, every 21 days). The primary objectives were to determine the safety profile, dose limiting toxicity (DLT) and maximum tolerated dose (MTD) of GSK1070916A. The starting dose was 5mg/m2/day, with initial single pt cohorts, followed by “3 + 3” cohorts and expansion at the MTD. DLTs included prolonged (> 5 days) or complicated grade 4 neutropenia; the MTD was the highest dose at which < 1 of 3 - 6 pts experienced DLT. Cycle 1 blood and healthy skin biopsies were obtained for PK and PD assays. The expanded cohort included 6 pts having pre- and post-treatment functional imaging studies (FDG PET-CT and MRI), and a further 6 having paired tumour biopsies for PD studies. Results: Nine single pt cohorts received up to 73mg/m2/day of GSK1070916A with no grade 3 or 4 related adverse events. At 102.2mg/m2/day, 1 pt had a DLT (febrile neutropenia) and 2 pts non-DLT grade 4 neutropenia; this dose was considered unacceptably toxic and 23 pts received a lower dose of 85mg/m2/day; 7/23 pts had prolonged/complicated grade 4 neutropenia, 5 of whom continued GSK1070916A with dose reduction +/- delay. There were no treatment related deaths. A pt with ovarian cancer (102.2mg/m2/day) had a RECIST PR; 19 pts had stable disease for < 223 days. GSK1070916A PK were linear with a strong correlation between exposure (AUC) and reduction in neutrophils (r2 0.91). At the 85 mg/m2 dose, mean day 1 t1/2 was 8.98 hours and Cl 9.2 l/h; AUCinf was 10% higher on day 5 than day 1. PD results in healthy skin (phosphoHistone-H3, Ki 67 and cleaved caspase-3) were inconsistent. Conclusions: The MTD of GSK1070916A as a 1 hour i.v. infusion on days 1 – 5, every 21 days is 85mg/m2/day, with predictable and manageable neutropenia as the DLT and evidence of clinical activity. Serum levels of cytokeratin-18, tumour PD and functional imaging data will be presented. Clinical trial information: NCT01118611.