{"denoms":[{"counts":[{"groupId":"OG000","value":"0"}],"units":"Participants"}],"description":"PD-L1 expression by mass spectrometry and correlation with PD-L1 expression by IHC as well as tumor response, and the T-cell inflamed phenotype will be performed. Multivariate logistic regression will be performed to determine whether these biomarkers or combinations of biomarkers are predictive of response. Exact logistic regression models will be fit given the small number of responders expected (4 from part A and 7-8 from part B).","groups":[{"description":"Patients receive pembrolizumab IV over 30 minutes on day 1. Treatment repeats every 21 days for up to 24 months in the absence of disease progression or unacceptable toxicity. Patients may be eligible for up to 1 year of additional pembrolizumab therapy if they progress after stopping pembrolizumab.\n\nPembrolizumab: Given IV\n\nLaboratory Biomarker Analysis: Correlative studies\n\nPharmacogenomic Study: Correlative studies","id":"OG000","title":"Treatment (Pembrolizumab)"}],"populationDescription":"Exploratory outcome. Data not collected.","reportingStatus":"POSTED","timeFrame":"Baseline","title":"PD-L1 Expression by Mass Spectrometry","type":"OTHER_PRE_SPECIFIED"}