SYD985 in Patients With HER2-expressing Recurrent, Advanced or Metastatic Endometrial Carcinoma

Main Inclusion Criteria: * Females with histologically confirmed recurrent, advanced or metastatic endometrial carcinoma * Eligible patients should have progressed on or after first line platinum-based chemotherapy for advanced/metastatic endometrial cancer. Patients who have had two or more lines of chemotherapy for advanced/metastatic disease are not eligible, taking into account the following: * Patients may have received up to one additional line of chemotherapy if given in the neoadjuvant or adjuvant setting. If such treatment was completed less than 6 months prior to the current tumor recurrence or progression it is to be considered first-line treatment; * No more than one line of non-cytotoxic systemic cancer therapy (such as immunotherapy, trastuzumab or protein kinase inhibitors) is allowed. * HER2 tumor expression defined as a 1+, 2+ or 3+ score on IHC or positive by ISH * At least one measurable cancer lesion as defined by the Response Evaluation Criteria for Solid Tumours (RECIST version 1.1); * Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2; Exclusion Criteria: * Current or previous use of a prohibited medication as listed in the protocol; * History of infusion-related reactions and/or hypersensitivity to trastuzumab; * History of keratitis; * Severe, uncontrolled systemic disease at screening; * Left Ventricular Ejection Fraction (LVEF) \< 50%, or a history of clinically significant decrease in LVEF during previous treatment with trastuzumab; * History of clinically significant cardiovascular disease; * Symptomatic brain metastases, brain metastases requiring steroids to manage symptoms, or treatment for brain metastases within 8 weeks prior to randomization; * History or presence of idiopathic pulmonary fibrosis, organizing pneumonia (e.g. bronchiolitis obliterans), drug-induced pneumonitis, idiopathic pneumonitis, or evidence of active pneumonitis on screening chest computed tomography (CT) scan.