Propranolol and Pembrolizumab in Advanced Soft Tissue Sarcoma Patients

Inclusion Criteria: * Subjects must have signed and dated an IRB/IEC approved written informed consent form in accordance with regulatory and institutional guidelines. This must be obtained before the performance of any protocol related procedures that are not part of normal subject care * Subjects must be willing and able to comply with scheduled visits, treatment schedule, laboratory testing, and other requirements of the study * Histologically confirmed diagnosis of unresectable locally advanced or metastatic Angiosarcoma or Undifferentiated Pleomorphic Sarcoma, who has progressed/failed to provide clinical benefit on first line standard chemotherapy. * Age ≥18 years * Eastern Cooperative Oncology Group Performance Status (ECOG PS) score of ≤2 at the time of enrollment. * Evaluable disease as defined by Response Evaluation Criteria in Solid Tumors (RECIST version 1.1). * Available material from archived formalin-fixed paraffin-embedded tumor tissue obtained within 3 months of study enrollment for biomarker related studies. If not sufficient or available, a newly obtained core or excisional biopsy of a tumor lesion may be performed. * Patients must have normal organ and marrow function as defined below: * Absolute neutrophil count (ANC) ≥ 1 x 10⁹/L * Platelet count ≥ 75 x 10⁹/L * Serum bilirubin ≤ 1.5 x upper limit of normal (ULN) (patients with Gilbert's Syndrome must have a total bilirubin ≤ 50 mmol/L) * Aspartate transaminase (AST)/Alanine transaminase (ALT) ≤ 5 x ULN *…