BURLINGTON, Massachusetts, October 29, 2026
Instylla, Inc. has announced that the U.S. Food and Drug Administration (FDA) has approved an expanded indication for its Embrace® Hydrogel Embolic System (HES) to include the embolization of peripheral arterial bleeds in blood vessels measuring 6 mm or smaller. The regulatory approval marks an important milestone for the medical technology company, expanding the clinical applications of its resorbable embolic technology beyond its previously approved use in hypervascular tumour embolization. The original Premarket Approval (PMA) was granted in August 2025, and the latest regulatory decision introduces an additional indication for controlling peripheral arterial haemorrhage. According to Instylla, Embrace HES is the first and only liquid embolic approved for both peripheral arterial bleeding and hypervascular tumour embolization, supported by two prospective, multicentre pivotal clinical trials. The system is commercially available in the United States, providing interventional radiologists with an additional technology for managing complex vascular bleeding conditions.
FDA Approval Supported by Positive HALT Clinical Trial Results
The expanded FDA indication is supported by findings from the HALT clinical study, a prospective, multicentre, single-arm clinical trial designed to evaluate the safety and effectiveness of Embrace HES in patients with peripheral arterial bleeding. The study enrolled 130 patients across 22 clinical sites in the United States. According to the company, the investigational device met both prespecified primary endpoints, demonstrating encouraging clinical outcomes through 30 days following treatment. The trial reported 100% freedom from major adverse events and a 90.0% clinical success rate, defined as the absence of rebleeding from the targeted lesion. These findings provide clinical evidence supporting the expanded indication and the use of the hydrogel embolic system for peripheral arterial haemorrhage. The HALT study evaluated the device in patients requiring targeted vascular embolization, an interventional procedure used to control bleeding by blocking blood flow through selected blood vessels. The results are particularly relevant for interventional radiology, where precise embolic delivery and effective bleeding control are essential considerations when treating patients with complex vascular conditions.
Hydrogel Technology Enables Controlled Vascular Embolization
The Embrace Hydrogel Embolic System is a water-based, polyethylene glycol (PEG) hydrogel technology designed to provide controlled and targeted vascular occlusion. The system uses two liquid precursor solutions that are delivered through a microcatheter and combine within the blood vessel to form a hydrogel. Once formed, the material creates a mechanical barrier that blocks blood flow to the targeted vascular area, helping control haemorrhage. One of the distinguishing characteristics of Embrace HES is its non-adhesive hydrogel composition, which is designed to reduce the risk of catheter entrapment during embolization procedures. The system also allows physicians to maintain microcatheter access following embolic delivery, providing additional procedural flexibility. Unlike conventional embolic materials that may depend on the patient’s natural clotting ability, Embrace HES is designed to achieve vascular occlusion independently of the coagulation process. This feature may be particularly relevant when treating patients with impaired blood clotting. Additionally, the hydrogel contains no dimethyl sulfoxide (DMSO) and does not include components that obscure computed tomography (CT) or magnetic resonance imaging (MRI). Following delivery, the material gradually breaks down through hydrolysis over approximately 11 months.
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Expanding Treatment Options for Peripheral Arterial Bleeding
Peripheral arterial bleeding can occur following traumatic injuries and medical complications, as well as from non-traumatic conditions such as gastrointestinal haemorrhage, solid-organ injuries and bleeding associated with tumours. Severe haemorrhage remains a major clinical concern because uncontrolled blood loss can lead to haemodynamic instability and potentially life-threatening complications. Transcatheter arterial embolization (TAE) has become an important minimally invasive approach for managing selected cases of arterial bleeding, particularly when conventional interventions are unsuccessful or unsuitable. During the procedure, an interventional radiologist guides a catheter through the vascular system to reach the bleeding vessel and delivers an embolic agent to block blood flow. Conventional embolization technologies, including metallic coils and other liquid embolic materials, have different procedural characteristics and limitations. For example, coil-based embolization can depend partly on the patient’s ability to form blood clots, potentially limiting effectiveness in certain patients with coagulopathy. Instylla’s Embrace HES is designed to provide another option through its controlled delivery characteristics and coagulation-independent mechanism of action. The expanded indication covers peripheral arterial bleeds in vessels measuring 6 mm or smaller, while the original tumour embolization indication covers peripheral arteries measuring 5 mm or smaller.
The latest FDA approval represents a significant advancement in Instylla’s medical device development programme and expands the potential clinical applications of its hydrogel embolization platform. With approved indications covering both interventional oncology and peripheral haemostasis, the company aims to strengthen its presence in the vascular intervention market. The clinical evidence generated through the HALT study provides an important foundation for the expanded indication, while continued clinical experience will help establish the technology’s role in interventional procedures. Embrace HES is now commercially available in the United States for its approved indications, offering healthcare professionals another option for managing selected vascular conditions. The development highlights the growing role of advanced biomaterials and catheter-based technologies in minimally invasive cardiovascular and interventional radiology procedures.
Source: Instylla Inc press release
