Instylla Logo

Instylla Announces Enrollment of Initial Patient in the Prospective Multicenter “HALT” Study

Pivotal study to evaluate Embrace™ Hydrogel Embolic System for the embolization of arterial bleeds in the peripheral vasculature

BEDFORD, Mass., – January 10, 2023 – Instylla, Inc., a privately held company developing next-generation liquid embolics for peripheral vascular embolotherapy, today announced the enrollment of the first patient in the HALT Study¹ for the treatment of peripheral arterial bleeds. The HALT study is a Prospective, Multicenter Single-Arm Study to Evaluate the Safety and Effectiveness of the Embrace Hydrogel Embolic System (HES) for the Embolization of Arterial Bleeding in Solid Organs and Peripheral Arteries.

According to the American Association for the Surgery of Trauma (AAST), injury is a major public health problem accounting for over 150,000 deaths and over 3 million non-fatal injuries annually². Traumatic injuries, specifically pelvic and hepatic injuries, are the leading causes of hemorrhage in trauma patients³. Transcatheter arterial embolization (TAE) has played an increasingly significant role in controlling hemorrhage, with an efficacy rate of 81%-100% in unstable pelvic fractures for example.

Acute gastrointestinal bleeding has a mortality rate ranging from 4% to 10%. TAE facilitates highly selective embolization of bleeding vessels, with clinical success rates of 74.7%⁵ in treating acute upper gastrointestinal bleeding.

“We are excited to have enrolled the first patient nationally in the prospective HALT study, evaluating an innovative in-situ forming liquid embolic for hemorrhage control in patients,” commented Dr. David Tahour, Chief of Vascular and Interventional Radiology, MemorialCare Long Beach Medical Center. “Embrace HES has demonstrated rapid and durable hemostasis in preclinical studies⁶ while reducing the risk of non-target embolization. I look forward to being involved with this innovative technology which will change the standard of care for future embolizations.”

The HALT study is led by Dr. Suvranu Ganguli, Section Chief, Interventional Radiology, Boston Medical Center. The study is estimated to enroll 118 patients in up to 25 U.S. sites. Patients with upper GI bleeds, kidney, liver, or spleen end organ bleeds, spontaneous hematomas, or other peripheral arterial bleeds such as pelvic hemorrhage may be considered suitable for this study.

“I would like to thank Dr. Tahour and his team for their effort in achieving this significant clinical milestone,” said Amar Sawhney, Instylla CEO. “We are excited to study the performance of the Embrace HES in this additional indication, which reflects the versatility of this novel liquid embolic.”

About Embrace Hydrogel Embolic System:

Embrace HES is an investigational device intended to be used to embolize peripheral arterial bleeds in vessels ≤ 6 mm. Embrace HES consists of two injectable liquid precursors that solidify when simultaneously delivered into blood vessels, forming a soft hydrogel that fills the vessel lumens during the embolization procedure. The Embrace HES embolization uses no solvents, does not need sizing to the vessel diameter, and eliminates the possibility of catheter entrapment. Its main components are water and polyethylene glycol (PEG).

About Instylla:

Instylla, Inc. is a privately held company based in Bedford, MA, focused on developing next-generation liquid embolics for interventional radiology, with initial clinical applications in interventional oncology and peripheral hemostasis. The company’s first product, Embrace HES, is designed for controlled, complete, and persistent embolization in these clinical conditions. Instylla was founded in 2017 by Incept LLC and is funded by several leading venture capital groups.

To learn more, please visit




³ 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.

  The role of arterial embolization in controlling pelvic fracture haemorrhage: A systematic review of the literature
Papakostidis, Costas et al. European Journal of Radiology, Volume 81, Issue 5, 897 – 904

⁵ Empiric Transcatheter Embolization for Acute Arterial Upper Gastrointestinal Bleeding: A Meta-Analysis
Qian Yu, Brian Funaki, Rakesh Navuluri, Steven Zangan, Amanda Zhang, David Cao, Jeffrey Leef, and Osman Ahmed
American Journal of Roentgenology 2021 216:4, 1-14.

⁶ Eric John Gandras, Timothy Jarrett, Raymond Lareau, Evaluation of a Hydrogel Liquid Embolic Agent in a Porcine Mesenteric Hemorrhage Model, Journal of Vascular and Interventional Radiology, Volume 33, Issue 6, 2022, Pages 653-659, ISSN 1051-0443,

Caution: Investigational Device. Limited by Federal (or US) law to investigational use only. Not available for sale.