Medical devices & diagnostics · Urology
Zenflow
A small nitinol coil that props open the prostatic urethra, delivered through a flexible scope and removable at any time. FDA approved in December 2025 after eleven years of development, and sold to its first commercial patients in the summer of 2026.
The first one sold
On July 29, 2026, in an office in Winter Garden, Florida, a urologist named Sijo Parekattil ran a flexible scope up a man’s urethra and released a small spring of nickel titanium into the prostatic channel. The patient went home the same day, with no catheter.
It was the first commercial Zenflow Spring procedure in the United States, twelve years after two Stanford fellows decided the device ought to exist.
Six weeks later the company named three more physicians who had finished their first cases, in New York, California and Idaho. Four centers. That is where Zenflow stands in September 2026: approved, launched, and counting in single digits.
The problem, and the crowded middle
An enlarged prostate squeezes the urethra it surrounds. The result is straining, urgency, a weak stream, and getting up at night. It is close to universal with age: company materials citing a 2005 review put it at more than half of men by fifty, seventy percent by seventy, ninety percent by eighty.
For decades the choice was a drug or a knife. Pills work modestly and carry side effects that patients quit over. Transurethral resection works well and carries a real risk of sexual dysfunction and a catheter afterward. So men wait.
The middle ground filled in while Zenflow was building. NeoTract’s UroLift reached the market in 2013 and sold to Teleflex four years later in a deal worth up to $1.1 billion. Rezum followed with water vapor. Both go in through a rigid scope, and neither can be undone.
Zenflow’s pitch is those two gaps: a fully flexible scope, and an implant a doctor can take back out. The company calls the category first-line interventional therapy, a label it coined for itself.
Two fellows and a clinic rotation
Nick Damiano and Shreya Mehta were Biodesign Innovation Fellows at Stanford in 2013 and 2014, assigned to urology and nephrology. What they saw in clinic decided the company.
They incorporated in 2014 under a name recorded in a later SEC filing as Torix Medical, Inc. Y Combinator took them into the Winter 2015 batch, and MedCity News later reported that Zenflow was the first medical device startup in the accelerator’s ten year history. A National Science Foundation grant of $179,999 started that July, followed by four National Institutes of Health awards worth $2.54 million with Damiano as principal investigator.
Damiano ran the company through the first two rounds. Mehta, a biomedical engineer who had been a lead reviewer of cardiovascular devices at the FDA, started as chief technology officer and moved into the top job in 2024. Damiano’s name appears on the Form D filed in May 2021 and on none after it.
Ten years of trials
The first in human study opened in April 2016 in Bulgaria and New Zealand. Three more pilots ran from 2018 to 2021 in Mexico, Australia, New Zealand and Canada; their pooled results, 72 men, were published in June 2026 in Prostate Cancer and Prostatic Diseases.
The pivotal trial, BREEZE, treated its first patient in October 2021 with a recruitment goal of 279 and an estimated primary completion of June 2022. It finished with 205 men randomized two to one against a sham procedure, and reached a plenary session at the American Urological Association meeting in May 2026.
The scope went through the regulatory door first, cleared as a 510(k) on September 23, 2025. The implant took the harder route, a premarket approval, granted December 11, 2025.
What is proven, and what is still claimed
| Evidence | What the record shows | Source type |
|---|---|---|
| FDA approval | PMA P250007 for the implant and delivery system, Dec 11, 2025, the pathway that requires clinical evidence. 510(k) K251140 for the single-use Spring Scope, Sep 23, 2025. | Public record |
| BREEZE, as presented | 205 randomized, 137 implant and 68 sham. Intent to treat: 3 month responder rates 51.8 against 39.7 percent, reported as comparable at P=.102, and a 12 month IPSS change of 32.1 percent at P=.231. Intended use analysis, 109 and 57 patients: both co-primary endpoints met, 59.6 against 33.3 percent at 3 months and 37.2 percent mean IPSS improvement at 12 months. | Independent |
| BREEZE, as marketed | Company releases give the responder rate as 60 percent against 33 percent for sham “at one year.” Two independent reports of that presentation place the same pair of numbers at 3 months. The company physician page gives 62 percent at one year. No company material found mentions the intent to treat result. | Differs from reporting |
| Peer-reviewed publication | One paper: pooled 24 month pilot results in 72 men, Jun 9, 2026. Implantation succeeded in all 72 with no perioperative serious adverse events; IPSS improved 49 percent at 3 months and 48 percent at 24 months. No BREEZE paper found. | Public record |
| Explants | The lead pilot investigator reports 12 of 72 patients, 17 percent, removed within 24 months, and no removal caused an adverse event. In BREEZE, about 98 percent remained implanted at 12 months. | Independent |
| Sexual function | No deterioration in erectile or ejaculatory scores through 24 months in the pilots and 12 months in BREEZE. Independent reporting of the pivotal data records a 100 percent preservation rate. | Independent |
| Trial registry upkeep | Five completed Zenflow studies, BREEZE included, still carry an unknown status on ClinicalTrials.gov with no results posted. A 300 patient post-market registry began recruiting Jul 29, 2026, primary completion estimated Jul 2028. | Not posted |
| Commercial traction | Four named centers had completed procedures by Sep 8, 2026. No revenue, unit volume, price or payer coverage disclosed. | Company-stated |
Read plainly: the approval is real, the safety record is unusually clean, and the durability data run three years. The efficacy story is narrower than the marketing. BREEZE succeeded in a defined subgroup covering about four fifths of the randomized patients and did not separate from sham across everyone enrolled. That is a legitimate, pre-specified way to run a device trial. It is also a fact the company has never put in a press release. Sham response in prostate symptom trials runs high, which is exactly why the comparison matters.
What to watch
- A peer-reviewed BREEZE paper, and whether it reports the intent to treat analysis beside the intended use one.
- Results posted to ClinicalTrials.gov. Five Zenflow studies sit there with an unknown status.
- A procedure code and payer coverage. Nothing has been published on what the Spring costs or who pays.
- The post-market registry, the first look at the device outside trial selection criteria.
- Cook Medical, a strategic investor since 2024 that sells into the same urology channel.
In their words
“It was patient perspectives that led us down the path to our current device.”
Nick Damiano, co-founder, Stanford Biodesign interview · Interview
“Before founding this company, we interviewed a lot of BPH patients in the urology clinic and were astounded by the impact that the disease had on their quality of life.”
Nick Damiano, co-founder and CEO, Series A release, 2018 · Company release
“This created a problem because we only had three investigational sites.”
Nick Damiano on the first trial, Stanford Biodesign interview · Interview
“When men have BPH issues, it’s the first time that something’s happening below the belt that isn’t pleasure.”
Shreya Mehta, co-founder and CEO, Medsider interview, 2026 · Interview
“My daughter was born on Sunday night, and I literally had her in one hand and DocuSign in the other on Monday morning.”
Shreya Mehta on closing the Series C, Medsider interview, 2026 · Interview
“In this study, 12 of 72 subjects (17%) had their device explanted during the 24-month follow-up period.”
Dean Elterman, MD, lead pilot investigator, UroToday, 2026 · Investigator
“It is very exciting that we can now offer patients a truly innovative treatment solution that will bring meaningful symptom relief and improve their quality of life.”
Sijo Parekattil, MD, on the first commercial case, September 2026 · Company release
Related companies
Sources
- Public recordFDA PMA P250007 and 510(k) K251140
- Public recordClinicalTrials.gov NCT04987138, BREEZE
- Public recordClinicalTrials.gov NCT02786290, NCT03577236, NCT03595735, NCT04309695
- Public recordClinicalTrials.gov NCT07538622 and NCT07797348, post-market studies
- Public recordZenflow spring system for benign prostatic hyperplasia, 24 month outcomes of the ZEST pilot studies
- Public recordNSF award 1520412; NIH RePORTER R44DK112587 and R44DK124094
- Public recordForm D filings, Zenflow, Inc., CIK 0001718715
- IndependentBREEZE trial meets efficacy and safety endpoints, supporting Zenflow Spring for BPH
- IndependentFirst commercial procedures performed with Zenflow Spring for BPH
- IndependentFDA approves first-line Zenflow system for the treatment of BPH
- IndependentStanford spin-out Zenflow raises $31M to join the megamarket for enlarged prostate
- IndependentPivotal trial launches of novel Spring System for BPH-related LUTS
- InvestigatorZEST pilot studies, Beyond the Abstract
- InterviewInterview with Shreya Mehta, CEO of Zenflow
- InterviewAn interview with Nick Damiano of Zenflow
- CompanyFDA approves the Zenflow Spring Implant and Delivery System
- CompanyZenflow announces U.S. commercialization progress with four centers
- CompanyZenflow website, home and physician pages
Profile researched and written by Healthcare Discovery. Last updated September 29, 2026.
