Response to Pembrolizumab in Metastatic Melanoma: Computed Tomography Texture Analysis as a Predictive Biomarker

Inclusion Criteria: * Histologically confirmed melanoma that is recurrent/metastatic and not amenable to potentially curative surgery. * Presence of clinically and/or radiologically documented disease based on RECIST 1.1. At least one site of disease must be unidimensionally measurable by contrast-enhanced CT scan as follows: CT scan (with slice thickness of ≤ 5 mm) ≥ 10 mm --\> longest diameter Lymph nodes by CT scan ≥ 15 mm --\> measured in short axis * Age ≥ 18 years. * ECOG Performance Status of 0 to 1. * Previous Therapy Surgery: Previous surgery is permitted provided that it has been at least 21 days prior to patient registration and that wound healing has occurred. Systemic Therapy: Patients may not have received any prior systemic therapy for metastatic melanoma. Radiation: Palliative radiation is permitted provided \> 7 days has elapsed between last dose and enrollment on the trial. * Laboratory Requirements Absolute neutrophils ≥ 1.5 x 10\^9/L Platelets ≥ 100 x 10\^9/L Hemoglobin ≥ 90 g/L or ≥ 5.6 mmol/L (without transfusion or EPO dependency) Serum creatinine or measured or calculated creatinine: ≤1.5 x ULN or ≥ 60 mL/min for subject with creatinine clearance levels \> 1.5 x ULN Serum Total Bilirubin ≤ 1.5 x ULN or Direct bilirubin ≤ ULN for subjects with total bilirubin levels \> 1.5 x ULN AST and ALT ≤ 2.5 x ULN (≤ 5 x ULN for subjects with liver mets) Albumin ≥ 25 g/L * Women/men of childbearing potential must have agreed to use a highly effective cont…