A Phase II Trial Testing Oral Administration of Lucitanib in Patients With Fibroblast Growth Factor Receptor (FGFR)1-amplified or Non-amplified Estrogen Receptor Positive Metastatic Breast Cancer

Inclusion Criteria: * Histologically confirmed breast adenocarcinoma. * Presence of an accessible metastatic lesion for biopsy or at least one archived metastatic tumour sample. * Prior first-line systemic therapy in the metastatic setting. * Demonstrated progression of disease by radiological or clinical assessment. * Female patient, aged ≥18 years old. * Estimated life expectancy \>3 months. * Normal Left ventricular function * Adequate haematological, hepatic and renal functions. * For women with childbearing potential, a negative pregnancy test prior to initiation of the study drug and willingness to use an effective contraception. * Ability to swallow oral capsules or tablets. Exclusion Criteria: * More than two lines of chemotherapy with or without targeted therapy in the metastatic setting. * Previous treatment with bevacizumab within 3 months of first dose of Investigational Medicinal Product. * Active central nervous system metastases, cerebral oedema, and/or progressive growth. * Patients with impaired cardiac function. * Uncontrolled arterial hypertension * Patients with history of thrombotic disorders or hereditary risk factors of thromboembolic events * Serum potassium level below Lower Limit of Normal * Uncontrolled hypothyroidism. * Pregnant or breastfeeding women.