OBJECTIVES: Conducting comparative effectiveness research among multiple classes of treatments may inform optimal treatment based on real-world effectiveness. We conducted a retrospective analysis comparing selected resource utilization (emergency room visits and hospitalizations) among six leading treatment options in renal cell carcinoma stratified by drug class and line of therapy. METHODS: Using claims data (MORE Registry), patients with renal cell carcinoma (ICD9 189.0) who completed a first line treatment (switched to second line regimen or had at least 90 days of no treatment claims)  during the study period (July 2014 to June 2015). Line of therapy (LOT) was assigned based on patient’s available treatment history. Analysis was stratified by drug class (mammalian target of rapamycin [MTOR] vs. tyrosine kinase inhibitors [TKI]) and by LOT. Independent samples t-test was performed to compare first line mean treatment duration. Chi-square analysis was performed to compare the frequency of emergency room visit and hospitalization during the first line of therapy. RESULTS: