FDA Grants Humanitarian Device Exemption Approval to Cerebral Venous Stent

Serenity Medical has earned U.S. Food and Drug Administration (FDA) Humanitarian Device Exemption (HDE) approval for its River stent, a product specifically developed to treat severe idiopathic intracranial hypertension (IIH) in adult patients who have failed medical therapy.

The approval is a landmark clinical milestone, according to the company. For the first time, clinicians have a purpose-built, FDA-approved tool to help address a condition that has long challenged the neurovascular community and suffering patients.

IIH is a serious neurological condition caused by elevated intracranial pressure, leading to debilitating chronic headaches, vision loss, and cognitive impairment. The condition disproportionately affects obese women aged 20–50, a growing demographic. Certain patients with severe IIH symptoms have long struggled to find appropriate surgical therapies that are FDA-approved and indicated to safely relieve their symptoms.

“Delivering the first venous stent approved for severe, refractory IIH is incredibly meaningful to our dedicated team and to people living with IIH who have had limited options for relief until now,” Serenity Medical Founder Y. Pierre Gobin, M.D., an internationally recognized neurointerventional expert practicing at Weill-Cornell Medicine in New York, N.Y. “Our company was founded with the goal of addressing a problem that has long perplexed the medical community and caused debilitating symptoms in the women suffering with it. Reaching this moment reflects years of persistence, partnership with investigators, and a shared commitment to bring new possibilities to this underserved patient community.”

The FDA reviewed and approved the River stent based on the findings of “The River Study: the first multicenter trial of a novel venous stent for the treatment of Idiopathic Intracranial Hypertension (IIH),” published in the Journal of Neurointerventional Surgery (JNIS) last winter. The study was a prospective, open-label, multi-center, single-arm trial that enrolled 39 subjects at five U.S. centers and aimed to demonstrate the safety and probable benefit of the River stent in patients who are refractory or intolerant to medications. The River Study’s one-year results met the primary safety endpoint with a 5.4% observed major adverse event rate.ⁱ Improvements were observed in opening CSF pressure, headaches, papilledema, pulsatile tinnitus, visual symptoms, and Quality of Life scores.

“The River Study was groundbreaking as the first-of-its-kind study to evaluate a stent specifically designed for intracranial venous sinuses,” said Adnan Siddiqui, M.D., Ph.D., vice chairman and professor of neurosurgery, Jacobs School of Medicine & Biomedical Sciences, and senior author on the paper. “There is no other stent that is optimized or approved for this indication. The FDA’s review and acceptance of these data will now enable access to this important tool to the broader medical community to treat these patients.”

Serenity Medical has formed a strategic partnership with Radical Catheter Technologies to commercialize the River stent.

“Radical has built a commercialization team with a proven track record of launching neurovascular technologies through strategic physician engagement, rigorous clinical education, and hands-on procedural support,” commented Serenity Medical Chairman/NTI Managing Director Martin Dieck, who also serves as Radical Catheter Technologies chair. “The team is now expanding its collaborative reach across the NTI portfolio and beyond to serve as a commercialization partner—uniting its neurovascular access and delivery catheters with other neuro solutions to accelerate market adoption and broaden patient access to transformative care.”

The FDA approved the humanitarian use of the River stent for adult IIH patients with significant stenosis who are resistant or intolerant to medications. It is reserved for patients with severe headaches who have not responded to six months of medical therapy, including attempts at weight loss, or for patients who have had visual symptoms or visual signs that are vision-threatening despite medical therapy.

Serenity Medical is a neurovascular device company development venous sinus stenosis treatments. A NeuroTechnology Investors (NTI) portfolio company, Serenity Medical’s flagship River stent is a purpose-engineered venous stent designed for the anatomy of the stenotic sinuses, featuring variable radial force and diameter, flexible construction, and reduced metal surface area designed to minimize venous thrombotic risk. Serenity Medical is expanding its technological portfolio to optimize venous sinus stenosis procedures.

Radical Technologies fields a specialized neurovascular team with expertise in bringing medical technologies to market. Through hospital and KOL engagement, physician education, and ongoing clinical support, Radical ensures safe and efficacious large-scale adoption. By integrating its neurovascular access and delivery catheters with NeuroTechnology Investors’ portfolio of neurovascular and neurosurgical solutions, Radical Technologies is building a unified commercial infrastructure to address significant unmet clinical needs and expand patient access to transformative care.

NeuroTechnology Investors (NTI) is an investment group advancing breakthrough neurological technologies in the medical device sector, with a diverse portfolio that includes Synchron, Radical Technologies, Borvo Medical, and Serenity Medical. Established in 2016 and headquartered in Mountain View, Calif., NTI investors bring extensive clinical expertise to accelerate portfolio company development and improve patient access to transformative clinical solutions.

References
ⁱ Patsalides A, Fargen KM, Davies JM, et al. The River study: the first prospective multicenter trial of a novel venous sinus stent for the treatment of idiopathic intracranial hypertension. J Neurointerv Surg. 2025;18(1):11-19. Published 2025 Dec 17. doi:10.1136/jnis-2024-022540