Retrospective Analysis Of Immune-Related Adverse Events (Irae) In Metastatic Renal Cell Carcinoma (Mrcc) Patients Treated With First-Line Ipilimumab And Nivolumab (I Plus N).

e17094 Background: Incidence of irAEs has grown with increasing use of immunotherapies and can affect multiple organ systems: I+N followed by N maintenance is approved as front-line therapy for intermediate & poor-risk mRCC. Most common associated irAEs are gastrointestinal, dermatologic & hepatic. The purpose of this retrospective, single-institution analysis is to describe irAE incidence and identify risk factors in mRCC pts treated with I+N. Methods: Patients with mRCC started on first-line I+N at the Cleveland Clinic between March 2018 and April 2019 were retrospectively reviewed. Patient demographics, tumor characteristics, radiologic response and irAE history were collected. IRAE incidence was estimated with cumulative incidence. Risk factors for IRAE were assessed with Fine and Gray competing risk regression. Results: Of forty-six (N = 46) pts with mRCC treated with 1L I+N, median age 60 (range: 34-81): 95% clear cell histology; IMDC risk 20%/56%/24% favorable/intermediate/poor respectively. 67% (N = 31) experienced ≥ 1 irAE with total of N = 44 irAEs. Most common systems affected included Gastrointestinal (27%), Musculoskeletal (23%), Dermatologic (14%) & Renal (9%). Most common irAEs were colitis (23%), arthralgia (16%), transaminitis (9%). 82% of irAEs were treated with front-line glucocorticoids and 14% required additional immunosuppressants. 82% of irAEs were attributed to the I+N induction phase and 32% required discontinuation of I+N. 1 pt died as result of irAEs. Incidence of irAEs at 1, 3 and 6 months was 20%, 52%, 59% respectively. Among 31 pts who developed irAEs, median onset from start of I+N was 1.6 months (range 0-11.7). None of the variables examined (i.e. age at I+N initiation, gender, race, IMDC risk, ECOG status, stage at diagnosis, prior nephrectomy, prior radiation therapy) were identified as statistically-significant risk factors for irAEs. Development of irAEs was not associated with progression-free survival (PFS). Conclusions: IRAEs from I+N in mRCC tend to occur early in treatment course and are associated with high rates of treatment discontinuation and need for corticosteroids and other immunosuppressants. The lack of association between baseline factors and development of irAEs should increase physician alertness to potential irAEs with any change in clinical status.