Clinical Study to Evaluate Debio0123 + Sacituzumab Govitecan Combination in TNBC or HR+/HER2- Advanced Breast Cancer

This is an international, multicenter, open-label, single arm, phase Ib/II clinical trial to evaluate Debio 0123's RP2D when administered in combination with Sacituzumab govitecan, safety and efficacy of this combination therapy in advanced/metastatic breast cancer patients. Patients aged ≥ 18 years with TNBC or HR+/HER2- advanced/metastatic breast cancer relapsing after one or two lines of treatment are eligible to participate in the study. In the phase Ib of the study the investigators will recruit 12-24 patients with TNBC or HR+/HER2- advanced/metastatic breast cancer and the dose escalation will follow pre-defined dose levels, starting at DL1. In the phase II, 26 patients with advanced/metastatic TNBC and 26 patients with HR+/HER2- advanced/metastatic breast cancer will be treated with Debio 0123's RP2D plus 10 mg/kg of Sacituzumab govitecan. Patients will be treated until disease progression, discontinuation for any reason or study termination.