Comparison of biolimus eluted from an erodible stent coating with bare metal stents in acute ST-elevation myocardial infarction (COMFORTABLE AMI trial): rationale and design

Aims: Compared with bare metal stents (BMS), early generation drug-eluting stents (DES) reduce the risk of revascularisation in patients with ST-elevation myocardial infarction (STEMI) at the expense of an increased risk of very late stent thrombosis (ST). Durable polymer coatings for controlled drug release have been identified as a potential trigger for these late adverse events and this has led to the development of newer generation DES with durable and biodegradable polymer surface coatings with improved biocompatibility. In a recent all-comers trial, biolimus-eluting stents with a biodegradable polymer surface coating were found to reduce the risk of very late ST by 80% compared with sirolimus-eluting stents with durable polymer, which also translated into a lower risk of cardiac death and myocardial infarction (MI) beyond one year. Methods and results: The multicentre COMFORTABLE AMI trial (NCT00962416) randomly assigned 1,161 patients to treatment with biolimus-eluting stents with biodegrable polymer and bare metal sterns of otherwise identical design at 11 international sites. The primary endpoint is a composite of cardiac death, target-vessel MI and target lesion revascularisation at one year. Assuming a relative risk reduction of 40% in event rates of the primary endpoint in favour of biolimus-eluting stents with biodegradable polymer, 1,064 patients will provide 80% power to demonstrate superiority. Clinical follow-up will be continued through five years. Conclusions: The COMFORTABLE AMI trial will determine whether biolimus-eluting stents with biodegradable polymer are superior to bare metal stents of otherwise identical design. This is the first randomised controlled trial (RCT) investigating DES with a biodegradable polymer surface coating for drug release in the treatment of patients with STEMI.