Investigation of cardiotoxicity with concomitant use of anthracyclines and checkpoint inhibitors.

e24022 Background: Immune checkpoint inhibitors (ICI) have revolutionized cancer treatment and currently are the standard of care for early stage triple negative breast cancer in combination with anthracyclines (AC). It is known that both ICI and AC carry risk of cardiotoxicity. Studies have also shown that there is increased risk of cardiotoxicity with dual ICI. However no studies have evaluated the risk with concomitant use of ICI and AC. Here we investigated if there is increased cardiotoxicity risk with this combination regimen in a retrospective study. Methods: We did a retrospective analysis of patients with stage II and stage III triple negative breast cancer treated with combined AC and ICI at University of South Alabama Mitchell Cancer Institute Mobile, AL from January 2020 until June 2023. Data included demographics, cardiovascular (CV) risk factors and treatment. CV risk factors were detailed from 2022 ASCO guidelines. Echocardiograms were used to evaluate left ventricular ejection (LVEF). Therapy related cardiovascular toxicity was defined by ESC guidelines 2022 as any new decrease in LVEF to 55%. Two patients (0.04%) developed cardiotoxicity. One patient had LVEF that decreased to EF 45-50% while on surveillance. Another patient developed myocarditis during treatment with EF 25-30% and died from cardiogenic shock. Both patients had 2 CV risk factors and were African American. Only 24% (n = 12) had surveillance echocardiograms completed one year post treatment. Conclusions: Our study results showed that cardiotoxicity risk was lower compared to that in the Keynote-522 trial. The outcomes are limited as a majority (76%) of the patients did not have surveillance echos completed. While the risk of cardiotoxicity with ICI and AC have been studied independently, there have been mouse models that showed that AC therapy may make heart vulnerable to toxicity from ICI therapy. To our knowledge, this is the first study to evaluate cardiotoxicity in patients who received concomitant AC and ICI treatment. Our study highlights the importance of prospective studies and long term follow up to monitor cardiotoxicity in these patients as early detection is key to prevent future morbidity. Table: see text