Feasibility, safety, and efficacy of the amber peripheral liquid embolic system: results from stage I of the first-in-human OPAL study

Abstract Purpose To evaluate the early safety and technical feasibility of Amber 20 for peripheral vascular embolization in a prospective, multicenter, first-in-human stage I study. Materials and methods This was a prospective, single-arm, multicenter, open-label first-in-human stage I trial conducted across 11 centers in Spain. Fifteen patients requiring peripheral embolization for various indications (including hemorrhage, aneurysm/pseudoaneurysm, endoleak, portal vein embolization, and hypervascular tumors) were enrolled. The primary endpoint was the rate of device-related serious adverse events (SAEs) within 24 h. Secondary endpoints included overall adverse events (AEs) and technical success, defined as complete vascular occlusion or devascularization on final angiography. Results Fifteen patients (60% female; median age 56 years) underwent embolization using Amber 20. Technical success was achieved in 100% of cases (15/15). No device-related SAEs or AEs were reported within 24 h. Five patient (33%) experienced a mild adverse event (postembolization syndrome) related to the procedure. All adverse events resolved without sequelae. No device deficiencies were observed. Conclusion In this first-in-human, multicenter study, Amber 20 demonstrated a favorable safety profile and high technical success rate for peripheral vascular embolization. These preliminary findings support its potential as an effective liquid embolic agent, warranting further evaluation in larger studies with longer follow-up (stage II).