Incidence of Immune Related Adverse Events in Patients Treated with Immune Checkpoint Inhibitors, Case Series from Two Tertiary Care Centeers in Dubai, UAE

Introduction: Immune checkpoint inhibitors (ICI) represent a major component of systemic therapy in advanced malignancy. Studies have reported unique spectrum of toxicity profile of ICI as compared to systemic chemotherapy. Aim of this study is to evaluate toxicities of ICI in our population and to compare this with published data. Material and Methods: We retrospectively reviewed medical records of patients treated with ICI at Dubai hospital and American hospital Dubai from November 2015 to April 2019. After patient identification from hospitals cancer registry, data regarding patients’ demographics, cancer type, type of ICI, adverse events, and duration of treatment were collected. Results: Forty-Five patients were identified with median age of 60 (27-80) years. 27 (60%) patients were male and 18 (40%) were female. Underlying diagnosis was lung cancer (n=25), renal cell cancer (n=6), melanoma (n=5), bladder cancer (n=3), Hodgkins lymphoma (n=3) and other malignancies (n=3). Majority of patients received Nivolumab (n=20, 44%) followed by Pembrolizumab (n=19, 42%), Atezolizumab (n=4, 9%) and Durvalumab (n=2, 5%) respectively. Thyroid dysfunction was the most common side effect observed in 17 (38%) patients including hypothyroidism (n=12, 27%) and hyperthyroidism (n=5, 11%). 53 % patients treated with Nivolumab developed thyroid dysfunction as compared to Pembrolizumab (22%). 7 patients (16%) had elevated liver enzymes. Grade II and III hepatotoxicity was noted in 1 patient (2.2 %) each. One patient (2.2 %) developed grade II skin toxicity. One patient (2.2 %) developed grade III colitis. Grade II, III and IV pneumonitis was observed in 2 (4.4 %), 1 (2.2%) and 1 (2.2%) patient respectively. Immune mediated adverse events were managed according to standard guidelines and 2 patients (4.4 %) had treatment discontinuation due to grade IV Pneumonitis and grade III Colitis. Conclusion: Our study reports relatively higher incidence of thyroid adverse events in patients treated with ICI. The incidence of grade III-IV immune related toxicity remains low. Overall treatment with ICI was tolerated reasonably well and toxicity was manageable.