The purpose of this study is to find out whether giving the study drug pembrolizumab in combination with the chemotherapy drugs melphalan and dactinomycin, delivered directly to the affected arm or leg using a technique called isolated limb infusion (ILI), is a safe treatment that can delay the time before your disease gets worse (progresses).
Age >/= 12 years at the time of informed consent
Willing and able to provide written informed consent/assent for the trial
Willing to comply with treatment protocol
Have a histologically confirmed metastatic and/or locally advanced sarcoma
Have any other malignancy that requires active treatment
Ineligible for ILI because of underlying physical conditions (e.g. coronary artery disease with inability to tolerate anesthesia) as determined by treating physician
Has previously experienced hypersensitivity to pembrolizumab or any of its excipients
Has uncontrolled intercurrent illness including active infection requiring systemic therapy or symptomatic congestive heart failure within the past 6 months