The Rezūm System is intended to relieve symptoms, obstructions, and reduce prostate tissue associated with benign prostatic hyperplasia(BPH). It is indicated for men ≥ 50 years of age with a prostate volume 30 cm³ ≤ 150 cm³. The Rezūm System is also indicated for treatment of prostate with hyperplasia of the central zone and/or a median lobe.

Device Description

The Rezūm System is designed to treat patients with bothersome urinary symptoms associated with benign prostatic hyperplasia (BPH). The Rezūm System utilizes radiofrequency current to generate "wet" thermal energy in the form of water vapor, which is then injected into the transition zone and/or median lobe of the prostate tissue in controlled 9-second doses. The vapor that is injected into the prostate tissue rapidly disperses through the interstitial space between the tissue cells. As the vapor cools, it condenses immediately on contact with tissue and the stored thermal energy is released, denaturing the cell membranes and causing cell death.

The denatured cells are absorbed by the body, which reduces the volume of prostate tissue adjacent to the urethra. The vapor condensation process also causes a rapid collapse of vasculature in the treatment zone, resulting in a bloodless procedure.

Following thermal therapy for BPH, small pieces of coagulated tissue may slough off and be expelled via urination. This sloughing process may continue for a few months post-procedure depending on the rate of healing.

The Rezūm System consists of the following:
• Rezūm Generator – reusable, non-sterile capital equipment, provided with one power cord
• Rezūm Delivery Device Kit – sterile, single-use kit containing the following disposable components:

One sterile Delivery Device with cable and tubing
One sterile syringe
One sterile spike adaptor
One sterile water vial

AI/ML Overview

The provided FDA 510(k) clearance letter and summary for the Rezūm System (K250584) focuses on an expanded indication for use, specifically for larger prostate volumes, rather than establishing acceptance criteria for a new device's performance. The information provided describes studies demonstrating the comparable safety and effectiveness of the device for this expanded range, rather than defining specific performance metrics against pre-defined acceptance criteria for a novel device.

Since the document is for an expanded indication and not a de novo clearance, the acceptance criteria are implicitly that the device performs similarly in safety and effectiveness in the expanded patient population as it did in the previously cleared population. The study's goal was to demonstrate this similarity.

Here's an analysis based on the provided text, outlining what can and cannot be extracted regarding acceptance criteria and performance data:

Acceptance Criteria and Device Performance

The concept of "acceptance criteria" in this context is less about a numerical threshold for a novel device's performance (e.g., sensitivity > X%, accuracy > Y%) and more about demonstrating that the device's safety and efficacy profile remains acceptable and comparable within the expanded patient population.

Implicit Acceptance Criteria:

Safety: No new or unexpected adverse events in patients with prostate volumes >80 cm³ and ≤150 cm³. The rates of adverse events, including serious complications, should be generally similar to those observed in patients with prostate volumes ≤80 cm³.
Effectiveness: Significant and similar improvements in functional and quality of life outcomes in patients with prostate volumes >80 cm³ and ≤150 cm³ compared to patients with prostate volumes ≤80 cm³. No negative impact on sexual function.

Reported Device Performance (as demonstrated by the supporting studies):

Safety: "Patients with prostate volumes >80 cm³ had generally similar rates of adverse events, including serious complications. No unexpected adverse events were reported, and all adverse events were consistent with those reported in the Rezūm System pivotal clinical study."
Effectiveness: "Significant and similar improvements in functional and quality of life outcomes were demonstrated in both patient populations, with no negative impact to sexual function."

Table of (Implicit) Acceptance Criteria and Reported Device Performance:

Acceptance Criteria Category	Implicit Acceptance Criterion	Reported Device Performance (from supporting studies)
Safety Efficacy	No new or unexpected adverse events in patients with prostate volumes >80 cm³ and ≤150 cm³. Rates of adverse events, including serious complications, generally similar to patients with prostate volumes ≤80 cm³.	Patients with prostate volumes >80 cm³ had generally similar rates of adverse events, including serious complications. No unexpected adverse events were reported, and all adverse events were consistent with those reported in the Rezūm System pivotal clinical study.
Functional & QoL Outcomes	Significant and similar improvements in functional and quality of life outcomes in the expanded population compared to the previously cleared population.	Significant and similar improvements in functional and quality of life outcomes were demonstrated in both patient populations (prostate volumes >80cm³ and ≤80 cm³).
Sexual Function	No negative impact on sexual function in the expanded population.	No negative impact to sexual function was observed in the expanded population.

Study Details:

The document describes two types of clinical evidence used to support the expanded indication:

Systematic review and meta-analysis of clinical studies: This reviewed existing data on the Rezūm System for patients with prostate volumes >80 cm³ and compared outcomes to patients with prostate volumes ≤80 cm³.
Manufacturer-sponsored prospective, non-randomized, single-arm study: This study specifically evaluated the safety and effectiveness of the Rezūm System in patients with prostate volumes >80 cm³ and ≤150 cm³. The results were compared to data from the Rezūm System's original "pivotal clinical study."

Based on the provided text, here's what can be answered for each point:

Sample size used for the test set and the data provenance:
- Systematic Review/Meta-analysis: The text does not specify the exact sample size. It states it was a "systematic review and meta-analysis of clinical studies," implying a pooling of data from multiple studies. The data provenance (country of origin, retrospective/prospective) is not specified for the individual studies included in the meta-analysis, but they are existing clinical studies.
- Manufacturer-sponsored study: The text does not specify the exact sample size. It describes the study as "prospective, non-randomized, single-arm." It evaluates patients with prostate volumes >80 cm³ and ≤150 cm³. Data provenance is primarily domestic, as it's a manufacturer-sponsored study submitted to the FDA. It is prospective.
Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
The Rezūm System is a therapeutic device (for relieving symptoms and reducing prostate tissue), not a diagnostic algorithm. Therefore, "ground truth" in the typical sense of expert label annotations for images or diagnostic classifications is not directly applicable here. The outcomes (symptom relief, prostate tissue reduction, adverse events, quality of life, sexual function) are assessed directly from patient reports, objective measurements (e.g., prostate volume changes), and clinical evaluations by treating physicians. The text does not mention a specific "ground truth" panel of experts, nor would it typically be required for a therapeutic device study focused on clinical outcomes.
Adjudication method (e.g., 2+1, 3+1, none) for the test set:
Not applicable (N/A). As a therapeutic device focusing on direct clinical outcomes, adjudication methods like those used for diagnostic algorithms (e.g., for image interpretation) are not described or typically relevant in this context. Clinical events and outcomes are recorded based on predefined criteria, and adverse events are typically reported and classified by investigators and reviewed by safety committees.
If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:
Not applicable (N/A). This is a therapeutic device, not an AI-powered diagnostic tool. Therefore, a multi-reader multi-case study comparing human readers with and without AI assistance is not relevant to this submission.
If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
Not applicable (N/A). This is a therapeutic medical device, not an algorithm. The Rezūm System is a physical device used in a procedure performed by a human clinician.
The type of ground truth used (expert concensus, pathology, outcomes data, etc):
As explained in point 3, the concept of "ground truth" for a therapeutic device is different. For this submission, the "ground truth" and evidence of effectiveness and safety comes from:
- Clinical Outcomes Data: Patient-reported symptoms, quality of life scores, measures of sexual function, and potentially objective measures like post-treatment prostate volume.
- Adverse Event Reporting: Documentation and classification of adverse events.
- Comparison to a Pivotal Clinical Study: The study for the expanded indication compared its outcomes to those established in the device's original pivotal clinical study.
The sample size for the training set:
Not applicable (N/A). This is a therapeutic medical device; there is no "training set" in the context of machine learning or AI algorithms. The development of the device itself would have involved engineering, preclinical, and early human studies, but these are not referred to as a "training set."
How the ground truth for the training set was established:
Not applicable (N/A), as there is no "training set" in the AI/ML context for this device.

Summary

FDA 510(k) Clearance Letter - Rezūm System

Page 1

U.S. Food & Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993
www.fda.gov

Doc ID # 04017.07.05

June 11, 2025

Boston Scientific Corporation
Joseph Tabor
Regulatory Affairs Specialist
100 Boston Scientific Way
Marlborough, Massachusetts 01752

Re: K250584
Trade/Device Name: Rezūm System
Regulation Number: 21 CFR 876.4300
Regulation Name: Endoscopic Electrosurgical Unit and accessories
Regulatory Class: II
Product Code: KNS
Dated: February 27, 2025
Received: May 6, 2025

Dear Joseph Tabor:

We have reviewed your section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (the Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database available at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.

Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device" (https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).

Page 2

K250584 - Joseph Tabor
Page 2

Your device is also subject to, among other requirements, the Quality System (QS) regulation (21 CFR Part 820), which includes, but is not limited to, 21 CFR 820.30, Design controls; 21 CFR 820.90, Nonconforming product; and 21 CFR 820.100, Corrective and preventive action. Please note that regardless of whether a change requires premarket review, the QS regulation requires device manufacturers to review and approve changes to device design and production (21 CFR 820.30 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting (reporting of medical device-related adverse events) (21 CFR Part 803) for devices or postmarketing safety reporting (21 CFR Part 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reporting-combination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.

All medical devices, including Class I and unclassified devices and combination product device constituent parts are required to be in compliance with the final Unique Device Identification System rule ("UDI Rule"). The UDI Rule requires, among other things, that a device bear a unique device identifier (UDI) on its label and package (21 CFR 801.20(a)) unless an exception or alternative applies (21 CFR 801.20(b)) and that the dates on the device label be formatted in accordance with 21 CFR 801.18. The UDI Rule (21 CFR 830.300(a) and 830.320(b)) also requires that certain information be submitted to the Global Unique Device Identification Database (GUDID) (21 CFR Part 830 Subpart E). For additional information on these requirements, please see the UDI System webpage at https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance/unique-device-identification-system-udi-system.

Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-devices/medical-device-safety/medical-device-reporting-mdr-how-report-medical-device-problems.

For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See

Page 3

K250584 - Joseph Tabor
Page 3

the DICE website (https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).

Sincerely,

Mark J. Antonino -S

Mark J. Antonino, M.S.
Assistant Director
DHT3B: Division of Reproductive,
Gynecology, and Urology Devices
OHT3: Office of Gastrorenal, ObGyn,
General Hospital, and Urology Devices
Office of Product Evaluation and Quality
Center for Devices and Radiological Health

Enclosure

Page 4

DEPARTMENT OF HEALTH AND HUMAN SERVICES
Food and Drug Administration

Indications for Use

Form Approved: OMB No. 0910-0120
Expiration Date: 07/31/2026
See PRA Statement below.

Submission Number (if known)
K250584

Device Name
Rezūm System

Indications for Use (Describe)
The Rezūm System is intended to relieve symptoms, obstructions, and reduce prostate tissue associated with benign prostatic hyperplasia(BPH). It is indicated for men ≥ 50 years of age with a prostate volume 30 cm³ ≤ 150 cm³. The Rezūm System is also indicated for treatment of prostate with hyperplasia of the central zone and/or a median lobe.

Type of Use (Select one or both, as applicable)
☒ Prescription Use (Part 21 CFR 801 Subpart D) ☐ Over-The-Counter Use (21 CFR 801 Subpart C)

CONTINUE ON A SEPARATE PAGE IF NEEDED.

This section applies only to requirements of the Paperwork Reduction Act of 1995.
DO NOT SEND YOUR COMPLETED FORM TO THE PRA STAFF EMAIL ADDRESS BELOW.

The burden time for this collection of information is estimated to average 79 hours per response, including the time to review instructions, search existing data sources, gather and maintain the data needed and complete and review the collection of information. Send comments regarding this burden estimate or any other aspect of this information collection, including suggestions for reducing this burden, to:

Department of Health and Human Services
Food and Drug Administration
Office of Chief Information Officer
Paperwork Reduction Act (PRA) Staff
PRAStaff@fda.hhs.gov

"An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a currently valid OMB number."

Page 5

510(k) Summary

K250584
Page 1 of 3

A. Date Prepared

This 510(k) summary was prepared February 27, 2025

B. Submitter

Boston Scientific Corporation
Urology Division
100 Boston Scientific Way
Marlborough, MA 01752

C. Contacts

Joseph Tabor
Regulatory Affairs Specialist II
Joseph.Tabor@bsci.com
(508) 382-0313

Alternate:
Cody Johnson
Regulatory Affairs Manager
Cody.Johnson@bsci.com
(952) 930-5736

D. Subject Device

Trade Name	Rezūm System
Common Name	Vapor Ablation Device
Regulation Name	Endoscopic electrosurgical unit and accessories
Regulation Number	21 CFR 876.4300
Classification	Class II
Product Code	KNS

E. Predicate Device

Trade Name	Rezūm System
Common Name	Vapor Ablation Device
Regulation Name	Endoscopic electrosurgical unit and accessories
Regulation Number	21 CFR 876.4300
Classification	Class II
Product Code	KNS
510(k) Submitter/Holder	Boston Scientific Corporation
510(k) #/Clearance Date	K191505/cleared August 2, 2019

Page 6

K250584
Page 2 of 3

510(k) Summary

F. Device Description

One sterile Delivery Device with cable and tubing
One sterile syringe
One sterile spike adaptor
One sterile water vial

G. Intended Use/Indications for Use

The Rezūm System is intended to relieve symptoms, obstructions, and reduce prostate tissue associated with benign prostatic hyperplasia (BPH). It is indicated for men ≥ 50 years of age with a prostate volume 30 cm³ ≤ 150 cm³. The Rezūm System is also indicated for treatment of prostate with hyperplasia of the central zone and/or a median lobe.

H. Technological Characteristics Compared to the Predicate Device

The technological characteristics of the proposed (subject) Rezūm System are identical to those of the predicate device. There are no changes to any device features. The only change is a modification to the Indications for Use to expand the prostate volume upper limit from ≤ 80 cm³ to ≤ 150 cm³. The change in Indications for Use does not create a new intended use. The predicate and the proposed Rezūm System are both intended to relieve symptoms, obstructions, and reduce prostate tissue associated with BPH. The modification to the Indications for Use is supported by manufacturer-sponsored and independent clinical studies and the clinical evidence demonstrates that there are no new safety or effectiveness concerns regarding use of the Rezūm System in patients with prostates >80 cm³ and ≤150 cm³.

I. Substantial Equivalence

The proposed Rezūm System is substantially equivalent to the predicate Rezūm System (K191505). The proposed and predicate Rezūm System are both intended to relieve symptoms, obstructions, and reduce prostate tissue associated with BPH, and the modification to the

Page 7

K250584
Page 3 of 3

510(k) Summary

Indications for Use does not introduce any new safety or effectiveness concerns. The Rezūm System intended use, principle of operation and technological characteristics remain the same.

J. Performance Data

The Indications for Use modification to the proposed Rezūm System has been evaluated in comparison to the predicate device. The expanded indication is supported by a systematic review and meta-analysis of clinical studies that examined safety and effectiveness of the Rezūm System in symptomatic BPH patients with prostate volumes >80 cm³ and compared outcomes to patients with prostate volumes ≤80 cm³. In addition, data from a manufacturer-sponsored prospective, non-randomized, single-arm study that evaluated safety and effectiveness of the Rezūm System in patients with prostate volumes >80 cm³ and ≤150 cm³ was compared to data from the Rezūm System pivotal clinical study. The clinical evidence showed overall comparable results between patients with prostate volumes >80cm³ and ≤80 cm³. Significant and similar improvements in functional and quality of life outcomes were demonstrated in both patient populations, with no negative impact to sexual function. Patients with prostate volumes >80 cm³ had generally similar rates of adverse events, including serious complications. No unexpected adverse events were reported, and all adverse events were consistent with those reported in the Rezūm System pivotal clinical study. Use of the proposed device in the expanded patient population does not result in any new concerns of safety or effectiveness.

K. Conclusion

Based on the intended use, technological characteristics, and the clinical evidence presented in this submission to support use of the device in the expanded patient population, the Rezūm System is substantially equivalent to the predicate device.

Regulation Number and Section

§ 876.4300 Endoscopic electrosurgical unit and accessories.

(a)
Identification. An endoscopic electrosurgical unit and accessories is a device used to perform electrosurgical procedures through an endoscope. This generic type of device includes the electrosurgical generator, patient plate, electric biopsy forceps, electrode, flexible snare, electrosurgical alarm system, electrosurgical power supply unit, electrical clamp, self-opening rigid snare, flexible suction coagulator electrode, patient return wristlet, contact jelly, adaptor to the cord for transurethral surgical instruments, the electric cord for transurethral surgical instruments, and the transurethral desiccator.(b)
Classification. Class II (performance standards).