• Age 18 years

• Histologically confirmed diagnosis of HMB-45+ clear cell sarcoma which is unresectable and/or metastatic

• HLA-A\*02:01 positive

• ECOG Performance Status of £ 2 at screening

• At least one site of measurable disease on CT/MRI scan as defined by RECIST v 1.1 criteria. Baseline imaging must be performed within 28 days of Cycle 1 Day 1 of study.

• Adequate organ function within 28 days of Day 1 of study defined as:

• Absolute Neutrophil Count (ANC) ≥ 1.5

• Platelets ≥ 75

• ALT and AST ≤ 2.5 x institutional upper limit of normal (ULN) or ≤ 5.0 x institutional ULN if considered due to tumor

• Alkaline phosphatase ≤ 2.5 x institutional ULN unless considered due to tumor

• Serum bilirubin ≤ 1.5 x institutional ULN. NOTE: Patients with elevated bilirubin secondary to Gilbert's disease are eligible to participate in the study

• Serum creatinine ≤ 1.5 x institutional ULN or 24-hour creatinine clearance ≥ 50 ml/min (calculated creatinine clearance using Cockroft formula is acceptable)

• Written, voluntary informed consent

• Patients must demonstrate progression of disease by RECIST 1.1 within 6 months of study enrollment. Newly diagnosed patients with unresectable or metastatic disease and only one baseline scan are eligible to screen and enroll.

• All other relevant medical conditions must be well-managed and stable, in the opinion of the investigator, for at least 28 days prior to first administration of study drug