441 Background: The modified Glasgow prognostic score (mGPS) is a pre-treatment prognostic system based on inflammatory biomarkers that is comparable in accuracy to the Memorial Sloan-Kettering Cancer Center (MSKCC) score for patients with metastatic renal cell carcinoma (mRCC) treated with cytokines. However, data are limited regarding the current utility of prognostic models developed in the cytokine era. In this study we examined the correlation between pre-treatment and post-treatment mGPS values and clinical benefit response (CBR) in patients treated with targeted agents for mRCC. Methods: After obtaining approval from the Emory Institutional Review Board, mGPS values were determined retrospectively using published methods and measurements of serum C-reactive protein (CRP) and serum albumin from patients who received targeted therapy for mRCC of any histology at the Emory Winship Cancer Institute between January 1, 2005 and June 30, 2011. CBR was defined as complete response (CR), partial response (PR) and stable disease (SD). Inclusion criteria included availability of at least 3 CRP values per patient. Results: Of the 635 patients who were screened, 56 were found to meet inclusion criteria. Of these, 43 received one evaluable line(s) of therapy (ELOT), 9 received two, 3 received three and 1 received four. The 74 ELOT included temsirolimus (16), sunitinib (20), sorafenib (14), pazopanib (20), everolimus (3) and bevacizumab/interferon (1). The correlation of post-treatment mGPS values to CBR was greater than pre-treatment mGPS values with sensitivity (81%), specificity (87%), positive predictive value (85%) and negative predictive value (83%). The p values were <0.001 for each parameter. Conclusions: Although these data require prospective validation, they provide evidence for the prognostic utility of mGPS assessments before and after therapy with targeted agents. Of note, the likelihood of having a CBR was much greater in patients who achieved or maintained an mGPS value of 0 after therapy. If confirmed, serial assessments of the mGPS to determine inflammatory response rates may prove to be a valuable and cost effective tool for patient care and drug development in mRCC.