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 * Serum creatinine ≤ 1.5 x ULN or creatinine clearance (CrCl) ≥ 40 mL/min (using the Cockcroft-Gault formula) * Women of childbearing potential (WOCBP): Agreement to use contraceptive methods with a failure rate of \< 1 % per year during the treatment period and for at least 120 days after the treatment. Safe contraceptive methods for women are birth control pills, intrauterine device, contraceptive injection, contraceptive implant,contraceptive patch or contraceptive vaginal ring. * Men who are sexually active with WOCBP must use any contraceptive method with a failure rate of less than 1% per year during the treatment period and for at least 120 days after the treatment. * Women who are not of childbearing potential (ie, who are postmenopausal or surgically sterile) as well as azoospermic men do not require contraception Exclusion Criteria: * Have an anticipated life expectancy of \<3 months. * Moderate to severe degree of bronchial asthma or chronic obstructive pulmonary disease. * Acute or non-stable congestive heart failure * Any other condition listed as contraindication for treatment with propranolol according to SPC * Have received any previous systemic therapy targeting the PD-1/PDL-1 signaling pathway or other immune checkpoint inhibitors. * Have received propranolol within 4 weeks prior to treatment. * Prior to study day one received radiation therapy, chemotherapy or targeted small molecule therapy within 2 weeks and/or monoclonal antibody treatment within 4 weeks. * Not recovered from the effects of previously administered agents * Clinically active or unstable CNS metastases as assessed by the treating physician * Any serious or uncontrolled medical disorder that, in the opinion of the investigator, may increase the risk associated with study participation or study drug administration, impair the ability of the subject to receive protocol therapy, or interfere with the interpretation of study results * Participants with active, known or suspected autoimmune disease. Participants with vitiligo, type I diabetes mellitus, residual hypothyroidism 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 * Serum creatinine ≤ 1.5 x ULN or creatinine clearance (CrCl) ≥ 40 mL/min (using the Cockcroft-Gault formula) * Women of childbearing potential (WOCBP): Agreement to use contraceptive methods with a failure rate of \< 1 % per year during the treatment period and for at least 120 days after the treatment. Safe contraceptive methods for women are birth control pills, intrauterine device, contraceptive injection, contraceptive implant,contraceptive patch or contraceptive vaginal ring. * Men who are sexually active with WOCBP must use any contraceptive method with a failure rate of less than 1% per year during the treatment period and for at least 120 days after the treatment. * Women who are not of childbearing potential (ie, who are postmenopausal or surgically sterile) as well as azoospermic men do not require contraception Exclusion criteria * Have an anticipated life expectancy of \<3 months.