Ph 2 Elacestrant in ER Positive Uterine Sarcomas

Inclusion Criteria: Participant must have histologically confirmed uterine sarcoma of one of the following subtypes: uterine leiomyosarcoma (uLMS), endometrial stromal sarcoma (ESS), uterine adenosarcoma, or uterine PEComa. Tumor must have moderate to strong immunohistochemical expression in ≥75% of tumor cells of estrogen receptor (ER) as assessed by institutional pathology review. Participants must have locally advanced or metastatic disease that is not amenable to surgery. Participants must have measurable disease, defined as at least one lesion that can be accurately measured in at least one dimension (longest diameter to be recorded for non-nodal lesions and short axis for nodal lesions) as ≥20 mm (≥2 cm) by chest x-ray or as ≥10 mm (≥1 cm) with CT scan, MRI, or calipers by clinical exam. See Section 12 (Measurement of Effect) for the evaluation of measurable disease. Age ≥18 years at the time of consent ECOG performance status ≤2 (Karnofsky ≥60%, see Appendix A). Participants must have adequate organ and marrow function as defined below: Hemoglobin ≥ 8.0 g/dL absolute neutrophil count ≥1,000/mcL platelets ≥100,000/mcL total bilirubin ≤1.5 × institutional upper limit of normal (ULN) AST(SGOT)/ALT(SGPT) ≤3.0 × institutional ULN (unless liver metastases are present in which case it must be ≤ 5 × ULN) glomerular filtration rate (GFR) ≥60 mL/min/1.73 m2 Human immunodeficiency virus (HIV)-infected participants on effective non-CYP3A4 interacting (see Section 3.2…