(P062) THERAPEUTIC RECHALLENGE WITH ANTI-ANGINAL AGENTS IN PATIENTS EXPERIENCING FLUOROPYRIMIDINE-INDUCED CARDIOTOXICITY (TRAFIC): A RETROSPECTIVE CHART REVIEW

Background: Fluoropyrimidines (FP) are standard of care for the treatment of many solid organ tumours. Fluoropyrimidine-induced cardiotoxicity (FIC) is a concerning adverse effect and may occur in up to 30% of patients, with varying severity. FIC may present as chest pain or in more severe cases, myocardial ischemia which can be life-threatening. However, interrupting or discontinuing FP therapy may result in the use of less effective second line therapies, leading to poor cancer outcomes and reduced survival. FP rechallenge using cardioprotective medications has been trialed in small numbers of patients; particularly in clinical situations in which there are no suitable alternatives for cancer treatment. Current guidelines vary in terms of recommendations for rechallenging patients who have experienced FIC. Provincial cancer agency protocols recommend against rechallenge, whereas the Canadian Cardiovascular Guidelines suggest a rechallenge may be considered in a controlled environment using cardioprotective medications such vasodilators in cases where limited treatment options are available.

METHODS AND RESULTS: This retrospective, single-arm cohort study included adults with suspected FIC who attended the VGH Cardio-Oncology clinic and were planned for FP rechallenge using cardioprotective medications (January 2013- August 2023). The primary outcome was successful rechallenge with at least one dose of FP, while secondary outcomes were to describe the FP regimens associated with FIC presentation, the vasodilator regimens used to prevent recurrence of FIC and to characterize baseline cardiovascular risk of patients presenting with FIC. We included 20 patients (median age 57.5 years, 85% gastrointestinal cancer). In total, 17 (85%) patients were successfully rechallenged with FP. 9 (45%) patients had recurrent symptoms that were tolerable, with 33% of these patients requiring anti-anginal dose escalation. The most commonly used anti-anginal therapy used was amlodipine and as needed nitroglycerin spray, followed by diltiazem, bisoprolol, nifedipine and nitroglycerin patches.

Conclusion: Our observed data demonstrates success in the use of anti-anginal medications for FP rechallenge with good tolerability and patient safety.