A Phase I, First Time in Human, Open-Label, Dose Escalation Study to Investigate the Safety, Pharmacokinetics, and Pharmacodynamics of Anti-Her3 Monoclonal Antibody GSK2849330 in Subjects With Advanced Her3-Positive Solid Tumors

Human Epidermal Growth Factor Receptor 3 (HER3) expression is seen across a wide variety of
solid malignancies and is associated with poor prognosis. Up-regulation of HER3 expression
and activity is also associated with resistance to multiple pathway inhibitors. GSK2849330, a
monoclonal antibody targeting HER3, is a new agent for subjects whose tumors express HER3.
This study is a phase I, first time in human, open-label, dose escalation study. The purpose
of this study is to investigate the safety, pharmacokinetics (PK), and pharmacodynamics (PD)
of GSK2849330 in subjects with advanced HER3-positive solid tumors. The study will be
conducted in two parts. Part 1 (Dose-Escalation Phase) will include dose escalation and PK/PD
cohorts to evaluate safety, PK, and PD to guide selection of dose regimen(s) for Part 2. In
Part 2 (Expansion Cohorts), up to 3 cohorts will be enrolled at the dose regimen(s) selected
based on Part 1 data, to evaluate safety in a larger cohort of subjects at the recommended
dose regimen and also to evaluate preliminary evidence of clinical benefit.