Aims: Treatriwitain-stent restenosis of coronary stents is challenging. The use of drug-coated balloons (DCB) is a promising technique to treat in-stent restenosis without adding another metal layer. The aim of the AGENT ISR randomised trial is to evaluate angiographic and clinical outcomes in patients with ISR of a previously treated lesion who were treated with either a DCB with a new coating formulation (Agent) or a standard DCB (SeQuent Please).

Methods and results: AGENT ISR is a multicentre, randomised, open-label, non-inferiority study comparing the Agent and SeQuent Please DCB. A total of 125 patients (mean age similar to 68 years, 18% female) with in-stent restenosis of a previously treated lesion <28 mm in length were randomised at 11 sites in Europe to Agent (n=65) or SeQuent Please (n=60). The primary endpoint, six-month in-stent late lumen loss, in the Agent group (0.3971-0.43 mm [n=51]) was non-inferior to that of the SeQuent Please group (0.3931-0.536 mm [n=49]), as the two-sided upper 95% confidence boundary for the difference between groups was less than the pm-specified non-inferiority margin of 0.20 (difference 0.004, 95% CI [-0.189, 0.196]; p(non- inferiority)=0.046). At one year, mortality was 3.1% in Agent and 1.7% in SeQuent Please patients (p>0.99), target lesion revascularisation 7.7% versus 10.0% (p=0.89), and stent thrombosis 0% versus 3.3% (p=0.44). Similar improvements in quality of life were seen in the two groups.

Conclusions: In this head-to-head comparison of two DCB, Agent proved to be non-inferior to SeQuent Please for in-stent late lumen loss at six months.