Phase I study of orally administered 14Carbon-isotope labelled-vistusertib (AZD2014), a dual TORC1/2 kinase inhibitor, to assess the absorption, metabolism, excretion, and pharmacokinetics in patients with advanced solid malignancies

Vistusertib is an orally bioavailable dual target of rapamycin complex (TORC) 1/2 kinase inhibitor currently under clinical investigation in various solid tumour and haematological malignancy settings. The pharmacokinetic, metabolic and excretion profiles of 14Carbon-isotope (14C)-labelled vistusertib were characterised in this open-label phase I patient study. Four patients with advanced solid malignancies received a single oral solution dose of 14C-labelled vistusertib. Blood, urine, faeces, and saliva samples were collected at various time points during the 8-day in-patient period of the study. Safety and preliminary efficacy were also assessed. 14C-labelled vistusertib was rapidly absorbed following administration (time to maximum concentration (Tmax) 90% of radioactivity was recovered with the majority recovered as metabolites in faeces (on average 80% vs. 12% recovered in urine). The majority of circulating radioactivity (~ 78%) is unchanged vistusertib. Various morpholine-ring oxidation metabolites and an N-methylamide circulate at low concentrations [each