Abstract 15424: The Toxic Tango: Tyrosine Kinase Inhibitors (TKI) and Immune Checkpoint Inhibitors (ICI) Toxicities

Abstract

Introduction: ICI and TKI have several cardiotoxicity side effects. We present a case of TKI-ICI toxicity resulting in multiorgan inflammatory syndrome with myocarditis and thrombotic STEMI that was treated with high-dose steroids and PCI. Case Presentation: 72-year-old man presented with acute SOB and inferior STEMI. He complains of severe DOE for the past 3 months, chronic diarrhea, and altered mental status. PMH of renal cell carcinoma (RCC) limited to kidney s/p nephrectomy. Follow-up CT scan with 4cm inferior left adrenal gland mass avid for FDG-PET and IR-biopsy positive for RCC. He was started on Pembrolizumab 200mg IV q3 weeks and axitinib 5mg PO q12h for the past 5 months. Investigation: LHC showed a thrombotic lesion in RCA with normal rest of coronaries without evidence of atherosclerosis or bystander plaque with successful PCI-DES. TTE with inferior wall hypokinesis and moderate pericardial effusion with organized material. Elevated CRP/ESR. Despite PCI, he is unable to walk 200ft due to DOE and needs supplemental O2. VQ scan low % for PE, PFT mild obstructive disease with severe reduction DLCO, and HRCT moderate emphysema, bronchial/ septal thickening, and normal hemodynamics in RHC. CMR demonstrated moderate pericardial effusion with internal debris, LVEF 38%, myocardial edema, and delayed gadolinium enhancement from base to apical inferior wall. Treatment: Empirical trial of IV-methylprednisolone 500mg IV q12 was started with drastic improvement of shortness of breath, resolution of AMS, ESR/CRP, and discontinuation of oxygen. Follow-up TTE with normal LVEF and resolution of pericardial effusion. Conclusions: ICI-Myocarditis is a severe irAE. The diagnosis requires clinical suspicion and exclusion of other cardiac conditions due to the high fatality rate. Early recognition and prompt treatment are needed to improve mortality. TKI-related arterial-thromboembolic events is not common but if present different therapy options should be offered.