191 Association of immune related adverse events with the efficacy of immune checkpoint inhibitors in metastatic renal cell carcinoma

Background Immune checkpoint inhibitors (ICI) are first-line therapy for tumors including metastatic renal cell carcinoma (mRCC). Use of ICI is complicated by diverse immune-related adverse events (irAEs), which can add significant morbidity but are also associated with improved efficacy of therapy.1 2 Risk factors for development of irAE are still poorly understood. We hypothesized that patients with mRCC treated with ICI as first-line therapy have higher rates of developing irAE’s than patients previously treated with other therapies. Methods We conducted a single-institution, retrospective medical record review of patients with mRCC treated with immune-checkpoint inhibitors from March 2011 through April 15, 2020. We identified therapy duration, and presence, severity, and treatment of adverse events. We defined overall survival as time elapsed from date of diagnosis until death or until completion of study. We classified severity of adverse events according to CTCAE guidelines. Statistical methods included univariate Cox proportional hazards and logistic regression models, and Kaplan-Meier curves were plotted for subgroups. Results A total of 64 unique charts were reviewed. 18 patients (28%) of patients were treated with ICI as first-line therapy. 28 patients (44%) experienced immune-related adverse events with a total of 40 irAE’s identified. Most irAE were grade I-II (78%), with 7 (17%) grade III and 1 (2.4%) grade IV irAE’s. Most common sites were skin (29%), thyroid (20%) and gastrointestinal (15%). Patients with irAE had increased survival compared to those who did not have irAE (median survival not reached, vs 139 weeks, p=0.0004) (figure 1). This finding remained after excluding patients who had only experienced dermatologic irAE (median survival not reached in non-derm irAE subgroup, vs 144 weeks for dermatologic or no irAE, p=0.01) (figure 2). Patients treated with ICI as first line therapy had greater rates of developing irAE (72%) than those who had prior therapies (32%) (OR 5.4; p = 0.006). There was no association between histology type and rate of irAE. Conclusions The development of irAE’s in patients with mRCC treated with ICI is associated with longer survival. This study joins the growing body of evidence showing that presence of irAE’s is associated with increased treatment efficacy. Use of ICI as first-line therapy is associated with higher risk of irAE. Given growing use of ICI as first-line therapy, further study to predict onset and severity of irAE’s is required. Acknowledgements Hong Wang, PhD, for statistical support. Ethics Approval This study was approved by the University of Pittsburgh Institutional Review Board. Approval number STUDY19100386. References Elias R, Yan N, Singla N, Levonyack N, Formella J, Christie A, et al. Immune-related adverse events are associated with improved outcomes in ICI-treated renal cell carcinoma patients. J Clin Oncol 2019;37(7):S645. Verzoni E, Carteni G, Cortesi E, et al. Real-world efficacy and safety of nivolumab in previously-treated metastatic renal cell carcinoma, and association between immune-related adverse events and survival: the Italian expanded access program. J Immunother Cancer 2019;7(1):99.