Immuno-related cardiac toxicity in patients with cancer: A prospective study applying multiparametric cardiac MRI.

e24014 Background: Since Immune checkpoint inhibitor (ICI) immunotherapy has emerged as a cornerstone of modern oncology, oncologists are facing a new spectrum of ‘immune-related adverse events’ (irAEs), potentially affecting every tissue and organ. ICI-induced symptomatic myocarditis occurs only in around 1% of ICI-treated patients (pts), but is fatal in 50% of cases. Methods: Pts undergoing ICI therapy at the Humanitas Cancer Center from May 2021 to December 2023 were prospectively recruited and assigned to three study groups: 1) ICI given as monotherapy (Mono) 2) ICI given in combination (Combo) 3) history of cardiac disease or two cardiological risk factors other than smoke (Cardio). Exclusion criteria were: previous exposure to any immunotherapy, combination with other cardiotoxic therapies, and acute (in the last 3 months) cardiac events. All pts underwent a complete cardiological assessment with clinical visit, 12-lead ECG, and multiparametric cardiac MRI (cMRI) at two time-points: prior initiation of the ICI therapy, and around 8 weeks later. Peripheral blood samples for immunophenotyping analyses were collected at the same time-points. cMRI scans were performed using a 1.5 Tesla scanner. Chi-square, Fisher exact and paired t-test were used to compare groups; all analyses were performed using SAS v9.4. Objectives of the study were: detection of subclinical cardiac damage and identification of groups of patients at major risk, who may benefit from cardiological pre- or/and on-treatment assessment. Results: We present data on the first 47 pts enrolled, diagnosed with a wide range of solid tumors, including 16 renal carcinoma, 11 melanoma and 3 NSCLC; 15 (32%), 16 (34%) and 16 (34%) pts were assigned to the Mono, Combo and Cardio group, respectively. Most pts (42, 89%) were treated with ICI for locally advanced/metastatic disease (26 as first-line therapy, 16 from second-line on), while 5 (11%) as adjuvant therapy. All pts received an anti-PD-(L)1, either as single agent (25, 53%) or in combination, with ICI plus a TKI being the most frequent combinatorial strategy (16; 34%). Overall, the cMRI analysis showed a statistically significant left ventricle ejection fraction (LVEF) reduction pre- versus post-ICI treatment (p < 0.001), with 18 (38%) pts experiencing a loss of > 3 points of LVEF. No statistically significant differences in LVEF reduction were observed considering the three different groups (p = 0.6), tumor types (p = 0.2), or occurrence of any grade non-cardiological irAEs (p = 0.6). Conclusions: Our study was able to show a statistically significant reduction in LVEF, with more than 3% LVEF loss in a clinically significant proportion of ICI-treated patients (18; 38%), not selected for suspected cardiac symptoms, warranting prospective evaluation to eventually identify pts at higher risk. The trial is continuing prospective enrollment and immunophenotyping analyses are ongoing.