OBJECTIVES: This study sought to assess the efficacy of the drug-coated balloon (DCB) ESSENTIAL for the treatment of in-stent restenosis (ISR). BACKGROUND: DCBs have proven a valid therapeutic option for the management of ISR in several clinical trials, yet no class effect can be claimed. Accordingly, every new DCB model has to be individually evaluated through clinical studies. METHODS: This is a prospective, multicenter study including consecutive patients undergoing percutaneous coronary intervention for ISR with the ESSENTIAL DCB. A 6-month quantitative coronary angiography (QCA)/optical coherence tomography (OCT) follow-up was scheduled. The primary endpoint was OCT-derived in-segment maximal area stenosis. Secondary endpoints included QCA-derived in-segment late lumen loss (LLL) and target lesion failure (TLF) rates at 6, 12, and 24 months. TLF was defined as the composite of cardiac death, target vessel myocardial infarction, and target lesion revascularization. RESULTS: A total of 31 patients were successfully treated with DCB, with 67% of ISR corresponding to drug-eluting stents (DES). At 6 months, 26 patients underwent the scheduled angiographic follow-up. The mean value for in-segment maximal area stenosis was 51.4 ±â€¯13% and the median value was 53% (IQR 46.4-59.5). In the DES-ISR subgroup, these parameters were 52.6 ±â€¯10% and 55.2% (IQR 49.3-58.5), respectively. In-segment LLL was 0.25 ±â€¯0.43 mm with only 2 (7.7%) patients showing binary restenosis (>50%). The incidence of TLF was 10% at 6 months, 13.3% at 12 months, and 13.3% at 24 months. CONCLUSIONS: In this study, the ESSENTIAL DCB showed sustained efficacy in the prevention of recurrent restenosis after treatment of ISR. SUMMARY: We sought to assess the efficacy of the drug-coated balloon ESSENTIAL for the treatment of in-stent restenosis through a prospective, multicenter study including QCA and OCT assessment at 6-month follow-up. The primary endpoint was in-segment maximal area stenosis. Among the 31 patients successfully treated with the ESSENTIAL DCB, an angiographic follow-up was conducted in 26. Mean in-segment maximal area stenosis was 51.4 ±â€¯13% and the median value was 53% (IQR 46.4-59.5). In the DES-ISR subgroup, corresponding values were 52.6 ±â€¯10% and 55.2% (IQR 49.3-58.5), respectively. The observed in-segment LLL was 0.25 ±â€¯0.43 mm and binary restenosis rate was 7.7%. TLF was 10% at 6 months and 13.3% at 12 and 24 months.