Final results of Australasian Gastrointestinal Trials Group ARCTIC study: an audit of raltitrexed for patients with cardiac toxicity induced by fluoropyrimidines

Background: Cardiac toxicity an uncommon but serious side-effect of some fluoropyrimides. Cardiac toxicity from raltitrexed is rarely reported. With this background, we initiated this study to investigate the incidence of cardiac events in patients who had switched to raltitrexed following cardiac toxicity from fluoropyrimidines (5-fluorouracil or capecitabine). Patients and methods: Pharmacy records were used to identify patients receiving raltitrexed from January 2004 till March 2012. Medical records were then reviewed to confirm the use of raltitrexed after cardiac toxicity from 5-fluorouracil or capecitabine. The primary end point was the rate of further cardiac events after commencing raltitrexed. Results: Forty-two patients were identified and the majority had colorectal cancer. Prior regimens included 5-fluorouracil ± leucovorin, capecitabine alone, FOLFOX, FOLFIRI, epirubicin/cisplatin/5-fluorouracil, and capecitabine/ oxaliplatin. Seven patients (17%) had bolus 5-fluorouracil regimens, 26 patients (62%) had infusion 5-fluorouracil regimens, and 9 patients (21%) had capecitabine alone or in combination. Angina was the most common cardiac toxicity from 5-fluorouracil or capecitabine and usually occurred in the first or the second cycle. Four patients after their first cardiac event continued with the same 5-fluorouracil or capecitabine regimen with the addition of nitrates and calcium antagonists but still had further cardiac events. After changing to raltitrexed, either as a single agent or a continuing combination regimen, no patients experienced further cardiac toxicity. Conclusion: Raltitrexed is associated with no significant cardiac toxicity in patients who have experienced prior cardiac toxicity from 5-fluorouracil or capecitabine. Raltitrexed, alone or in combination with oxaliplatin or irinotecan, provides a safe option in terms of cardiac toxicity for such patients.