The efficacy and safety of cardio-protective therapy in patients with 5-FU (Fluorouracil)-associated coronary vasospasm.

Background: Coronary vasospasm is a known side effect of 5-FU (fluorouracil) therapy. Beyond switching to non-5FU-based chemotherapy, there are no established treatments for 5-FU associated coronary vasospam. Our objective was to assess the safety and efficacy of re-challenge with 5-FU after pre-treatment with calcium channel blockers (CCBs) and long-acting nitrates among patients 5-FU associated coronary vasospasm.
Methods: We conducted a retrospective study of patients with 5-FU coronary vasospasm at a single academic center. By protocol, those referred to cardio-oncology received pre-treatment with either combination [nitrates and CCBs] or single-agent therapy [nitrates or CCBs]) prior to re-challenge with 5-FU. Our primary outcome was overall survival. Other important outcomes included progression-free survival and safety.
Results: Among 6,606 patients who received 5-FU from January 2001 to Dec 2020, 115 (1.74%) developed coronary vasospasm. Of these 115 patients, 81 patients continued 5-FU therapy, while 34 stopped. Of the 81 who continued, 78 were referred to cardio-oncology and prescribed CCBs and/or nitrates prior to subsequent 5-FU, while the remaining 3 continued 5-FU without cardiac pre-treatment. Of the 78, 56.4% (44/78) received both nitrates and CCBs, 19.2% (15/78) received CCBs alone, and 24.4% (19/78) received nitrates alone. When compared to patients who stopped 5-FU, those who continued 5-FU after pre-treatment (single or combination therapy) had a decreased risk of death (HR 0.42, P = 0.005 [95% CI 0.23-0.77]) and a trend towards decreased cancer progression (HR 0.60, P = 0.08 [95% CI 0.34-1.06]). No patient in the pre-treatment group had a myocardial infarct after re-challenge; however, chest pain (without myocardial infarction) recurred in 19.2% (15/78) among those who received cardiac pre-treatment vs. 66.7% (2/3) among those who did not (P = 0.048). There was no difference in efficacy or the recurrence of vasospasm among patients who received pre-treatment with a single agent (nitrates or CCBs) or combination therapy (14.7% (5/34) vs. 25.0% (11/44), P = 0.26).
Conclusion: Re-challenge after pre-treatment with CCBs and nitrates guided by a cardio-oncology service was safe and allowed continued 5-FU therapy.
Competing Interests: TGN is supported, in part, through a kind gift from Curtis Greer and Pamela Kohlberg. TGN also reports acting as a consultant for Parexel, H3 Biomedicine, Bristol Myers-Squibb, Abbvie and Intrinsic Imaging, unrelated to the current research. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose. There are no patents, products in development or marketed products associated with this research to declare. This does not alter our adherence to PLOS ONE policies on sharing data and materials.