Abstract B216: Mass balance, routes of excretion and pharmacokinetics of investigational oral [14C]alisertib (MLN8237) in patients with advanced solid tumors or lymphoma

Background: Alisertib (MLN8237) is an investigational, orally administered, selective oral Aurora A kinase inhibitor under clinical development for treatment of solid tumors and hematologic malignancies. We herein report the mass balance, routes of excretion and pharmacokinetics (PK) of alisertib following oral administration of radiolabeled [14C]alisertib in cancer patients. Material and methods: This was a two-part, open-label, single oral dose (Part A) followed by multiple-dose (Part B) study in patients with advanced malignancies. Eligible patients were aged ≥ 18 years with histologic or cytologic diagnosis of advanced solid tumors or lymphoma, ECOG PS 0-1. In Part A, patients received a single 35 mg dose of 14C-labeled alisertib (approximately 80 μCi) administered as oral solution. Serial blood samples were collected over a 10-day period for analysis of plasma and whole blood PK of alisertib and total radioactivity (drug-related material). Complete urinary and fecal outputs were collected until at least 80% of the administered radioactivity was recovered or excretion of radioactivity fell below 1% per day for assessment of drug-related material recovery in excreta and products of alisertib biotransformation. In Part B, patients received 50 mg of nonradiolabeled alisertib twice daily administered as enteric-coated tablets for 7 days in 21-day cycles until disease progression or unacceptable toxicity. Results: Three patients with ovarian cancer, bladder cancer and mesothelioma, respectively, completed Part A of the study. Demographic features of patients enrolled in the study were: 2 males and 1 female, median age 66 years, mean body weight 79 kg. Following single dose of [14C]alisertib oral solution, the median time to first reach maximal plasma concentration of alisertib and drug-related material was 1 hr. The mean terminal half-life for alisertib and drug-related material were 22 and 39 hrs, respectively. The mean plasma exposure (AUC0-inf) ratio of alisertib versus total drug-related material was 0.46, indicating the presence of alisertib metabolites in circulation. The apparent oral clearance of alisertib was 3.9 L/hr and renal clearance of the parent drug was negligible. Following a single oral dose of [14C]alisertib, 87% and 2.7% of administered radioactivity were recovered in feces and urine, respectively, by 2 weeks post-dose. Grade 1 fatigue was the most frequent adverse event (2/3) during the study. One patient experienced grade 3 neutropenia. Conclusions: The predominant route of elimination for drug-related material was fecal, consistent with hepatic metabolism and biliary excretion of alisertib. Renal clearance of unchanged alisertib was negligible. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B216. Citation Format: Xiaofei Zhou, Sandeepraj Pusalkar, Swapan Chowdhury, Shawn Searle, Yuexian Li, Jaime Mertz, Bin Zhang, Yong Ben, Karthik Venkatakrishnan. Mass balance, routes of excretion and pharmacokinetics of investigational oral [14C]alisertib (MLN8237) in patients with advanced solid tumors or lymphoma. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B216.