A Study of PF-06873600 in People With Cancer

This is a Phase 1/2a, open-label, multi-center, non-randomized, multiple dose, safety, tolerability, pharmacokinetic, and pharmacodynamic study of PF-06873600 administered as a single agent in sequential dose levels and then in combination with endocrine therapy. In Part 1A and Part 1C, successive cohorts of patients will receive escalating doses of PF-06873600 and then in dose finding (Part 1B) with PF-06873600 in combination with endocrine therapy (ET). This study contains 2 parts, dose escalation with single agent (Part 1A and 1C) and then dose finding with PF-06873600 in combination with endocrine therapy (Part 1B) followed by dose expansion arms of PF-06873600 in combination with endocrine therapy (Part 2).