The primary and secondary endpoints of this study are to determine the kinetics of Circulating tumor DNA (ctDNA) as defined by a set of patient-specific tumor mutations. The analysis will be undertaken using the Signatera Assay from Natera. Circulating tumor DNA in plasma samples obtained over the course of pembrolizumab treatment will be assessed by high-intensity, next-generation genetic sequencing to identify genomic alterations in genes. The assay will target 16 defined patient specific mutations. Data acquired will be analyzed to characterize the association between these genetic elements, clinical response, and durability of responses. There will be prospective and retrospective groups for the study. Samples will be collected from patients in the prospective cohort who have been treated with pembrolizumab monotherapy at Columbia University Irving Medical Center under standard of care treatment. Subjects in the retrospective cohort will provide genetic data.
