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Zenflow Pivotal Clinical Trial


Pivotal trial launches of novel Spring System for BPH-related LUTS

October 5, 2021
Jason M. Broderick

The first patient in the pivotal BREEZE trial has been treated with the novel Spring System, a minimally invasive device used to relieve lower urinary tract symptoms (LUTS) related to benign prostatic hyperplasia (BPH).1

The successful initial procedure was performed by Michael D. Trotter, MD, lead investigator at Midtown Urology Associates in Austin, Texas.

“The efficiency of the procedure and clear visual opening of the prostatic urethral channel makes the Zenflow device an exciting new tool in the treatment for BPH,” Trotter stated in a news release.

Also in the release, Zenflow, the developer of the Spring System, explained that the implanted device uses “a small spring-like coil to gently prop open the urethra, relieving symptoms while preserving the natural anatomy.”

The prospective, multicenter, single-blinded BREEZE trial (NCT04987138) is enrolling male patients aged ≥45 years with BPH-related LUTS, a baseline IPSS score ≥13, and a score of ≥1 in the IPSS voiding to storage sub-score ratio (IPSS-V/S).2 Patients must also have prostate volume of 25 to 80 cc as measured by transrectal ultrasound ≤120 of study consent; a prostatic urethral length between 25 and 45 mm measured by cystoscopic pull-back; and failed, been intolerant to, or rejected medication for LUTS.

Patients enrolled in the study will be randomized in a 2:1 ratio to the Spring System or a sham procedure. Patients and personnel conducting follow-up assessments will be blinded to the randomization. Unblinding will occur following the 3-month follow-up visit. At that point, patients who received the sham procedure have the option to cross over and receive treatment with the Spring System. Patient follow-up will continue for a total of 5 years.

The primary end point of the trial is the efficacy of the Spring System at reducing LUTS as measured by the IPSS symptom questionnaire. The recruitment goal of the study is 279 patients and the estimated primary completion date is June 1, 2022.

“The symptoms associated with enlarged prostate have a substantial impact on patients’ quality of life. I am encouraged by the potential for the Spring treatment to improve the patient experience and am proud to be part of this rigorous clinical trial program,” Claus Roehrborn, MD, professor and chair, Department of Urology, UT Southwestern Medical Center in Dallas, and principal investigator for the BREEZE study, stated in the news release.

According to Zenflow, the BREEZE trial is designed to support FDA clearance of the Spring System.


1. Zenflow Launches Pivotal Clinical Trial of Minimally Invasive Spring® Treatment for Enlarged Prostate Symptoms. Posted online October 4, 2021. Accessed October 5, 2021.

2. NIH US National Library of Medicine Safety and Effectiveness Study of the Zenflow Spring System (BREEZE). Last updated September 16, 2021. Accessed October 5, 2021.