This is a first-in-human, open-label, phase I/II, multi-center study consisting of an ECI830 single agent treatment arm in patients with advanced HR+/HER2- breast cancer or other advanced solid tumors harboring CCNE1 amplification or extensive-stage small cell lung cancer (ES-SCLC), and a combination treatment arm of ECI830 with ribociclib and fulvestrant in patients with advanced breast cancer. Single agent escalation may be followed by an expansion part stratified by disease indication. The escalation of the combination arm may continue into a randomized, open label, Phase II with optional dose optimization in advanced breast cancer patients.
