This is a ulticenter, single arm, open-label, Phase II clinical trial to evaluate the safety, tolerability, pharmacokinetics, and efficacy of CB-103 in combination with a non-steroidal aromatase inhibitor (NSAI), anastrozole or letrozole, in Hormone Receptor-positive and Human Epidermal Growth Factor Receptor 2 (HER2)-negative advanced breast cancer patients who have achieved clinical benefit during prior NSAI-based treatment.~Eligible patients include pre- and post-menopausal women age ≥ 18 years with HR-positive and HER2-negative unresectable advanced breast cancer (ABC, including metastatic), having achieved at least clinical benefit upon treatment with prior NSAI. Evidence of measurable or evaluable disease, as per RECIST (Response Evaluation Criteria In Solid Tumors) v.1.1, with a tumor lesion amenable to biopsy. Pre-menopausal women must be under treatment with luteinizing hormone-releasing hormone (LHRH) analogues. Patients are not eligible if they are candidates for a local treatment with a curative intention~The primary objective is to assess the efficacy, defined as progression-free survival (PFS), of CB-103 in combination with NSAI therapy (anastrozole or letrozole) in women with HR-positive, HER2-negative, unresectable ABC with evidence of Notch signaling pathway activation and with progressive disease after clinical benefit while on prior NSAI-containing regimen.~Approx 80 patients are expected to be recruited
Multicenter, single-arm, open label, phase II clinical trial with safety run-in to evaluate the safety, tolerability, pharmacokinetics and efficacy of CB-103 in combination with a non-steroidal aromatase inhibitor (NSAI), anastrozole or letrozole, in Hormone Receptor-positive and Human Epidermal Growth Factor Receptor 2 (HER2)-negative advanced breast cancer patients who have achieved clinical benefit during prior NSAI-based treatment.