Zenflow spring system for benign prostatic hyperplasia - 24 month outcomes of the ZEST pilot studies

Benign Prostatic Hyperplasia (BPH) affects more than half of men over age 50, yet current treatment options are limited to medications that cause bothersome side effects or surgical procedures, including minimally invasive surgical therapies (MIST) that involve piercing, cutting, or burning tissue, often leading to discomfort and recovery concerns. The Zenflow Spring System® provides a tissue-preserving alternative that offers symptom relief with quicker recovery and less procedural discomfort.

Three single-arm, multicenter, prospective pilot studies with similar trial designs were conducted from 2018-2021 across four countries and data were combined to evaluate the feasibility, safety, and effectiveness of the Spring System in relieving symptoms of obstructive BPH. Men ≥ 45 years with moderate-to-severe symptoms (International Prostate Symptom Score (IPSS ) >13), peak urinary flow rate (QMax) between 5 and 15 mL/s, prostate volume between 25 and 80 cc, prostatic urethral length between 25 and 45 mm, and voided volume of at least ≥ 125 mL were enrolled. The primary endpoint was symptom improvement 3 months post-procedure, measured by change in IPSS. Secondary endpoints included IPSS-QoL, and functional improvement measured by Qmax. Follow-up visits occurred through 24 months.

Successful implantation of the Spring Implant was achieved in all 72 study participants, with no perioperative serious adverse events. At 3 months, mean change from baseline was -10.71 (95% CI: -12.90, -8.51, p < 0.001) for IPSS, -2.1 (95% CI: -2.61, -1.58, p < 0.001) for IPSS-QoL, and 2.86 (95% CI: 1.68, 4.04, p < 0.001) for Qmax, corresponding to 49%, 47%, and 27% improvements, respectively. These improvements were sustained through 24 months, with 48%, 55%, and 32% improvement relative to baseline in IPSS, IPSS-QoL, and Qmax, respectively.

At 24-months, treatment with the Spring System resulted in immediate, significant, and durable improvements compared with baseline, supporting its role as a minimally invasive, tissue-preserving treatment option for men with lower urinary tract symptoms secondary to BPH.

NCT03595735, NCT03577236, NCT04309695.