Zenflow says Spring Device delivered sustained benefits and safety in long-term BPH study

How is Zenflow’s Spring System Transforming the BPH Treatment Landscape?

Zenflow, Inc., a South San Francisco-based medical device innovator, has announced compelling three-year data from its investigational Zenflow Spring System. Presented at the 2025 Annual Meeting of the American Urological Association (AUA) in Las Vegas, the findings confirmed that the Zenflow Spring continues to deliver durable, significant clinical benefits for men suffering from benign prostatic hyperplasia (BPH), commonly known as an enlarged prostate.

The Zenflow Spring System, designed under the company’s newly coined treatment category of First-Line Interventional Therapy (FIT), aims to offer minimally invasive solutions that bridge the gap between pharmaceutical interventions and traditional surgery. By emphasizing reversibility, the device mirrors the safety advantages typically associated with medications while providing mechanical relief from urinary obstruction without the permanent alterations often linked to surgical procedures.

What Are the Key Highlights of the Three-Year Clinical Data?

The latest results from the ZEST pilot studies, which tracked 72 patients who underwent treatment with the Zenflow Spring, revealed durable symptom relief and improved urinary function. Statistically significant reductions in International Prostate Symptom Score (IPSS) were observed at every measured interval, culminating in a 46% improvement at 36 months compared to baseline figures.

Importantly, the quality of life impact scores (IPSS-QOL) were halved, showcasing a notable decline in the day-to-day burden caused by BPH symptoms. Urinary flow rates (Qmax) improved from a baseline of 10.6 mL/s to 13.9 mL/s at the 36-month checkpoint. Perhaps most notably, sexual function, an area of concern with many prostate interventions, remained stable with no deterioration in erectile or ejaculatory function as measured through standard indices like the Sexual Health Inventory for Men (SHIM) and Male Sexual Health Questionnaire–Ejaculatory Domain (MSHQ-EjD).

The responder rate, defined as the percentage of patients achieving at least a 30% improvement in IPSS, stood at 74% at three years, reflecting sustained clinical efficacy. Notably, the responder rates remained stable across earlier intervals: 75% at 12 months and 70% at 24 months.

Why Does the FIT Category Matter in the Evolution of BPH Therapies?

Zenflow’s leadership in the FIT category positions it uniquely within the competitive urology market. FIT technologies, including Zenflow’s Spring System, aim to deliver an intervention that offers efficacy akin to surgical procedures but with the safety, reversibility, and lower complication rates traditionally reserved for medical therapies.

Dean Elterman, M.D., Associate Professor at the University of Toronto and investigator in the ZEST studies, emphasized during the AUA meeting that Zenflow is pioneering a fresh approach to BPH management. He stated that Zenflow is the first to deliver consistent, durable results with the added benefit of a device tailored to the patient’s anatomy through a range of available lengths and diameters. He further noted that the absence of device-related complications like encrustation or migration highlighted the Spring System’s robust design.

How Is Zenflow Preparing for FDA Approval and Commercialization?

Shreya Mehta, CEO of Zenflow, indicated that the three-year data reinforced the company’s confidence in the device’s long-term efficacy and safety. She added that the results built upon the strong two-year data previously observed, and the company remains focused on securing U.S. Food and Drug Administration (FDA) approval, followed by commercial launch.

The next phase of validation for the Zenflow Spring System is the BREEZE study, a large, multi-center, randomized clinical trial spanning the United States and Canada. The study is currently underway and aims to provide pivotal evidence necessary for regulatory clearance.

What Differentiates the Zenflow Spring from Other BPH Treatments?

Zenflow’s Spring technology represents a distinctive innovation in the field of urology. Unlike traditional therapies such as transurethral resection of the prostate (TURP) or laser ablation, the Spring System is designed to be reversible, anatomical-preserving, and minimally traumatic. Its unique design—a small, spring-like coil—gently props open the urethra, allowing urine to flow more freely without altering the natural tissue structures.

In contrast to pharmacologic therapies, which often offer modest symptom relief and bring systemic side effects, the Spring System provides mechanical relief directly at the site of obstruction. Furthermore, unlike some permanent implants, the Zenflow Spring can be removed if necessary, providing a critical safety net for patients hesitant about permanent alterations.

What Is the Market Outlook and Sentiment Surrounding Zenflow’s Innovation?

The emerging success of Zenflow’s Spring System coincides with a growing global demand for non-surgical solutions to BPH, a condition that affects nearly half of men over the age of 50. According to urology market analysts, the FIT segment is expected to expand significantly over the next decade as aging populations seek safer, more convenient therapies.

While Zenflow, Inc. is a privately held company and not yet publicly traded, institutional sentiment surrounding novel urological therapies is robust. Investors are showing heightened interest in companies developing less invasive alternatives within the multibillion-dollar global BPH market. Should Zenflow secure FDA approval, it could be well-positioned to capitalize on this momentum and potentially explore public listing opportunities or strategic partnerships with larger medical device firms.

Why Should the Urology Community Pay Close Attention to Zenflow?

The three-year durability results place Zenflow’s Spring System among the most promising developments in BPH care in recent years. Given the high unmet need for treatments that are effective yet minimally invasive, the Zenflow Spring System could redefine the therapeutic algorithm for men suffering from moderate-to-severe BPH.

Experts believe that if BREEZE study results mirror the durability shown in the ZEST studies, Zenflow could rapidly establish itself as a frontrunner in the FIT category, with strong adoption potential among urologists eager to offer their patients better options between chronic medication and invasive surgery.

The broader urology landscape is increasingly focused on innovations that preserve sexual health, provide immediate symptom relief, and minimize the risk of complications—a trifecta that Zenflow appears to address comprehensively.

Final Thoughts: A Springboard for the Future of BPH Treatment?

The Zenflow Spring System is emerging as a pivotal development in the treatment of BPH. Offering a unique balance between efficacy, safety, and patient-centric design, the system provides a compelling case for the broader adoption of First-Line Interventional Therapies. As Zenflow moves toward FDA approval and subsequent commercialization, the Spring System’s three-year data underscore its potential to transform how urologists and patients approach the management of an enlarged prostate.

The medical community, investors, and patients alike will be closely watching Zenflow’s next steps. If momentum continues, the Zenflow Spring may not just be an investigational device for long but a transformative standard in modern urology.