A three-part, phase I, dose-escalation study of GSK1120212, a potent MEK inhibitor, administered orally to subjects with solid tumors or lymphoma

Abstract

e14584 Background: GSK1120212 is a potent and highly selective inhibitor of MEK1, a component of the MAP kinase pathway. GSK1120212 demonstrates efficient inhibition of p-ERK which correlates with inhibition of cell proliferation and induction of apoptosis. PO administration of GSK1120212 achieved tumor regression in multiple mouse xenograft models. The objectives of this study are to define the maximum tolerated dose (MTD) and to evaluate the pharmacokinetics (PK) and pharmacodynamic (PD) effects of GSK1120212. Methods: In Part 1, patients (pts) with solid tumors or lymphoma are enrolled in successive cohorts and receive a single PO dose of GSK1120212 followed by QD doses on days 1 - 21 of each 28-day cycle. Tumor response is assessed Q 8 weeks. PK blood samples are collected from all pts. Ophthalmic exams are administered at baseline and as clinically warranted. Dose escalation occurs via an accelerated titration followed by a standard 3+3 escalation. In Part 2, pts with pancreatic or K-Ras mutant CRC will be enrolled at the MTD. In Part 3, pts with biopsiable tumors will enroll at MTD and sub-MTD doses. Tumor biopsies will be taken pre- and post-dose to measure pERK and other markers of cell proliferation. Results: Six pts with advanced malignancies (neuroendocrine, thyroid, colorectal (n=2), melanoma (n=2) have been treated with tablets at four dose levels: 0.125 (n=2), 0.25 (n=1), 0.5 (n=2), and 1.0 mg (n=1). No DLTs or grade 2 toxicities have been reported. One patient was on study for over 17 weeks. Based on mean AUC and Cmax, GSK1120212 exposures following 15 days of repeat-dose administration were approximately dose proportional across the dose range (0.125–0.5 mg) with a median Tmax of approximately 1.5 hours. Conclusions: GSK1120212 has been well tolerated to date. Dose escalation is ongoing. [Table: see text]