Prospective Post Market Clinical Trial for the Zenflow Spring System - A Minimally Invasive Treatment for LUTS Associated With BPH.

August 27, 2026 updated by: Zenflow, Inc.

Prospective Post Market Clinical Trial for the Zenflow Spring System - A Minimally Invasive Treatment for LUTS Associated With BPH

This is a prospective, randomized, open-label, parallel-group post-market clinical trial (PMCT). The overall objective of this PMCT is to compare the effectiveness, durability, and patient-centered outcomes of the Zenflow Spring System versus Tamsulosin in men who are not on active therapy with moderate to severe LUTS/BPH. Patients randomized to the Tamsulosin therapy arm will be allowed to crossover to receive treatment with the Zenflow Spring System after 1) their 3-month follow-up assessments are completed, 2) the patient's symptoms are confirmed to continue to warrant treatment; and 3) the patient continues to meet the study enrollment criteria.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The purpose of this post-market clinical trial (PMCT) is to compare the Zenflow Spring System with Tamsulosin in men with moderate to severe BPH symptoms who are not currently receiving treatment.

The study will look at how well each treatment works, how long the results last, how quickly patients return to normal activities, how satisfied they are with their treatment, and any side effects. Patients will be followed at 1, 3, 6, and 12 months. The study will also track any implant removals or additional procedures, as well as any changes to or stopping of Tamsulosin.

Patients who qualify for the study will be randomly assigned, with an equal chance, to receive either the Zenflow Spring System or Tamsulosin.

Patients randomized to the Tamsulosin therapy arm will be allowed to crossover to receive treatment with the Zenflow Spring System after 1) their 3-month follow-up assessments are completed, 2) the patient's symptoms are confirmed to continue to warrant treatment; and 3) the patient continues to meet the study enrollment criteria. No crossover will be permitted beyond 30 days after completion of the 12-month follow-up. Patients who elect crossover and have a successful placement of the Spring Implant will be followed for 1 additional month and then will exit the study.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
110

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 4

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

The Spring® Implant and Delivery System is indicated for the treatment of obstructive lower urinary tract symptoms secondary to benign prostatic hyperplasia (BPH) in men with prostatic urethral lengths between 25mm and 45mm and prostate sizes between 25cc and 80cc.

In addition to the above labeling requirements, patients must also meet all the following criteria to be eligible for enrollment in this study:

  1. Moderate to severe LUTS, defined as an International Prostate Symptom Score (IPSS ≥ 8)

  2. Not actively taking any medication indicated for BPH, defined as current use of:

    1. Alpha-adrenergic antagonists (Alpha Blockers) within 2 weeks of baseline IPSS assessment
    2. 5-alpha reductase inhibitors (5ARI) within 6 months of baseline IPSS assessment
    3. PDE5 daily use (on demand use is permitted)
  3. Ability to provide informed consent and comply with study procedures and follow-up schedule

Exclusion Criteria:

  1. Known, previous adverse reaction to use of alpha-adrenergic antagonists (e.g., Tamsulosin)

  2. Neurologic conditions affecting bladder function, including but not limited to:

    1. Multiple sclerosis
    2. Parkinson's disease
    3. Neurogenic bladder or other conditions causing non-obstructive voiding dysfunction

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Zenflow Arm: Zenflow Spring System Treatment
Zenflow Arm: Patients randomized to the Zenflow Spring System arm will undergo the procedure according to manufacturer specifications and standardized procedural protocols.
Device: Zenflow Arm: Zenflow Spring System implant procedure
The Zenflow Spring Implant is designed to be a permanent implant but can be repositioned or removed by the physician.
Active Comparator: Tamsulosin Treatment
Medical Therapy Arm: Patients randomized to the medical therapy arm will receive Tamsulosin 0.4 mg once daily. Subjects will be encouraged to remain on this medical therapy through at least 3 months of treatment, unless significant adverse health reaction occurs.
Drug: Medical Therapy Tamsulosin
Tamsulosin is a prescription medicine that relaxes the muscles around the prostate and bladder to help men with an enlarged prostate (BPH) urinate more easily

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
International Prostate Symptom Score (IPSS) Total Score
Time Frame: Baseline (Day 1) to 3 months
Mean change in IPSS Total Score from baseline at 3 months. This is a 7-question patient questionnaire used to measure the severity of lower urinary tract symptoms associated with BPH. Each of the 7 symptom questions is scored from 0 to 5, giving a total possible score of 0-35. Lower scores are better.
Baseline (Day 1) to 3 months
Observed rate of device-related or Tamsulosin-related serious adverse events (SAEs).
Time Frame: Baseline through study completion, an average of 1 year (Duration of study)
Observed rate of device-related or Tamsulosin-related serious adverse events (SAEs).
Baseline through study completion, an average of 1 year (Duration of study)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Mean change in International Prostate Symptom Score (IPSS) Total Score from baseline at 1, 6, and 12 months
Time Frame: Baseline at 1, 6, and 12 months
Mean change in International Prostate Symptom Score (IPSS) Total Score from baseline at 1, 6, and 12 months. This is a 7-question questionnaire used to measure the severity of lower urinary tract symptoms associated with BPH. Each of the 7 symptom questions is scored from 0 to 5, giving a total possible score of 0-35. Lower scores are better
Baseline at 1, 6, and 12 months
Mean change in International Prostate Symptom Score (IPSS) Quality of Life (QoL) from baseline 1, 3, 6 and 12 months
Time Frame: Baseline 1, 3, 6 and 12 months
Mean change in International Prostate Symptom Score (IPSS) Quality of Life (QoL) from baseline 1, 3, 6 and 12 months. This separate Quality of Life (QoL) question, scored 0-6, is asking how the patient would feel if they had to live with their current urinary condition for the rest of their life. The QoL score is reported separately and is not included in the 0-35 IPSS total
Baseline 1, 3, 6 and 12 months
Adherence to assigned treatment (Spring Implant arm or Medical Therapy Arm) and reasons for any discontinuations
Time Frame: Baseline through study completion, an average of 1 year (Study duration)
In the Spring Implant arm, the patient will be asked if they remain implanted with the Spring Implant and if since last visit, if patient initiated any concomitant BPH medication use (for > 2 weeks). In the Medical Therapy Arm the patient will be asked since last visit, to confirm if they have been consistently taking Tamsulosin at the required dose.
Baseline through study completion, an average of 1 year (Study duration)
The observed rates of device related AEs or Tamsulosin-related adverse events
Time Frame: Baseline through study completion, an average of 1 year (Duration of study)
The observed rates of device related AEs or Tamsulosin-related adverse events
Baseline through study completion, an average of 1 year (Duration of study)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Zenflow, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 1, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 1, 2029

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 19, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 27, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 1, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
September 1, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 27, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • CLIN-0298

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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