This study will be evaluating the safety and tolerability of CFI-402257 in subjects with advanced solid tumors and in advanced breast cancer. The study is designed to build on encouraging data from another study and to obtain further safety, efficacy, pharmacokinetics (PK) and pharmacodynamics (PD) data of CFI-402257.
The purpose of this study is to test the safety of an investigational drug called CFI-402257 alone in advanced solid tumors and in combination with Fulvestrant in advanced breast cancer patients.