First report of the safety, tolerability, and pharmacokinetics of the Src kinase inhibitor saracatinib (AZD0530) in Japanese patients with advanced solid tumours.

backgroundSaracatinib (AZD0530) is a selective, oral Src inhibitor that has demonstrated antitumour activity in preclinical studies.

methodsThis open-label, dose-escalation, phase I study evaluated the safety and tolerability of saracatinib in Japanese patients with advanced solid tumours (clinicaltrials.gov NCT00704366). Patients received continuous once-daily oral dosing with saracatinib starting 7 days after a single dose in ascending dose cohorts until dose-limiting toxicity (DLT) or disease progression. Pharmacokinetics and efficacy were also evaluated.

resultsA total of 12 patients received saracatinib at doses of 50 (n = 3), 125 (n = 6), and 175 mg (n = 3). Median durations of exposure were 65, 44, and 16 days in the 50, 125, and 175 mg cohorts, respectively. The most common adverse events were diarrhoea (67 %), nausea (67 %), decreased appetite (58 %), lymphopenia (50 %) and pyrexia (50 %). The most common grade ≥3 adverse events were leukopenia, lymphopenia, neutropenia, and haemoglobin decreased (all 17 %). DLTs occurred in two patients, both in the 175 mg cohort: grade 3 aspartate aminotransferase increased with grade 3 gamma-glutamyltransferase increased (n = 1); and grade 3 hypoxia (n = 1). Following a single dose, saracatinib median t(max) across the doses was 2-4 h, and thereafter plasma concentrations declined in a biphasic manner, with mean terminal half-life of approximately 45 h. Geometric mean saracatinib exposures were 0.8-2.1 times greater than those reported in Caucasian patients. The best response was stable disease (50 mg, n = 2; 125 mg, n = 1).

conclusionsSaracatinib was tolerated in Japanese patients with advanced solid tumours at doses up to 125 mg.