Instylla's Embrace® Hydrogel Embolic System Receives FDA Approval for Peripheral Arterial Bleeds

First and Only Liquid Embolic Approved for Both Peripheral Arterial Bleeds and Hypervascular Tumors Supported by Two Prospective, Multicenter Pivotal Clinical Trials

BURLINGTON, Mass., Oct. 29, 2026 /PRNewswire/ -- Instylla, Inc., a privately held company advancing resorbable embolics for peripheral vascular embolization, announced today that the U.S. Food and Drug Administration (FDA) has approved the expanded indication for the Embrace® Hydrogel Embolic System (HES) to include embolization of peripheral arterial bleeds in vessels ≤ 6 mm. The approval follows the company's initial premarket approval (PMA) in August 2025 for hypervascular tumor embolization. Embrace HES is commercially available in the U.S.

"Patients facing complex vascular conditions need more options. Embrace HES was built to deliver that versatility," said Sean Boyle, CEO, Instylla, Inc. "With approvals now in both interventional oncology and peripheral hemostasis, we're redefining what's possible in interventional care and building a transformative platform for the many vascular conditions still ahead."

The approval was based on the HALT study, a prospective, multicenter, single-arm trial that enrolled 130 patients with peripheral arterial bleeds at 22 U.S. sites. Embrace HES met both prespecified primary endpoints, with 100% freedom from major adverse events and 90.0% clinical success (no rebleeding from the target lesion) through 30 days.¹

"When treating an arterial bleed, you need an embolic solution that can reach the source of bleeding while providing precise control. Embrace HES allows you to tailor your approach to the anatomy, achieving either distal or proximal embolization with a single embolic agent. Its novel design also allows you to maintain microcatheter access after embolization, unlike many currently available liquid embolics. This combination of control, versatility, and preserved access makes it a valuable new option for interventional radiologists," said Suvranu Ganguli, MD, FSIR, Chief of Interventional Radiology, Boston Medical Center and Professor of Radiology and Surgery, Boston University School of Medicine, and Principal Investigator of the HALT study.

Hemorrhage is the leading cause of potentially preventable death after trauma,² and arterial bleeding also arises from non-traumatic sources such as non-variceal upper gastrointestinal (GI) bleeding, solid-organ bleeds, and tumors. Transcatheter arterial embolization (TAE) has become a mainstay of treatment, with reported success rates of 81%–100% in unstable pelvic fractures³ and a role in upper GI bleeds not controlled by endoscopy.⁴ Conventional embolics have limits, however. For instance, coils depend on the patient's own clotting and can be less effective in coagulopathy.⁵ 

"What sets Embrace HES apart is its safety profile and controlled delivery. In the HALT Study, I saw firsthand how its design features help minimize non-target embolization and allow you to adjust the embolic placement. I'm looking forward to what this expanded indication could mean for patients," said Susie Park MD, Harbor-UCLA Medical Center.

About Embrace Hydrogel Embolic System:

Embrace HES is indicated for embolization of hypervascular tumors in peripheral arteries ≤ 5mm and peripheral arterial bleeds in vessels ≤ 6mm. Embrace HES is a water-based polyethylene glycol hydrogel that forms in the vessel. The non-adhesive hydrogel eliminates the possibility of catheter entrapment, is coagulation independent, and contains no DMSO or components that obscure CT or MRI. Upon delivery, the hydrogel casts out the vasculature to create a rapid and sustained occlusion. The hydrogel liquifies via hydrolysis over approximately 11 months.

About Instylla:

Instylla, Inc. is a privately held company based in Burlington, MA, focused on advancing resorbable embolic agents with products approved for use in interventional oncology and peripheral hemostasis. Instylla was founded in 2017 by Incept LLC and is funded by several leading venture capital groups.

To learn more, please visit https://www.instylla.com/

1 Data on file
2 Holcomb JB. Methods for improved hemorrhage control. Crit Care. 2004;8(Suppl 2):S57–S60. (DOI: 10.1186/cc2407)
3 Papakostidis C, Kanakaris N, Dimitriou R ...The role of arterial embolization in controlling pelvic fracture haemorrhage: A systematic review of the literature. European Journal of Radiology, 81, 897-904
4 Wilkins T, Wheeler B, Carpenter M. Upper gastrointestinal bleeding in adults: evaluation and management. Am Fam Physician. 2020;101(5):294–300.
5 Kord A, Kuwahara JT, Rabiee B, Ray CE Jr. Basic Principles of Trauma Embolization. Semin Intervent Radiol. 2021 Mar;38(1):144-152. doi: 10.1055/s-0041-1726004. Epub 2021 Apr 15. PMID: 33883812; PMCID: PMC8049756.

SOURCE Instylla, Inc.