WATER IV PCa (AS Sub-study)

WATER IV Prostate Cancer: Aquablation Versus Active Surveillance for the Treatment of Localized Prostate Cancer

The WATER IV study is a multicenter, prospective, randomized clinical trial that aims to evaluate the safety and efficacy of Aquablation therapy in men with localized prostate cancer.

Study Overview

• Status: Not yet recruiting
• Conditions: Localized Prostate Cancer
• Intervention / Treatment: Device: Aquablation Therapy; Other: Active Surveillance

Detailed Description

The WATER IV AS sub-study is a multicenter, prospective, randomized clinical trial that aims to evaluate the safety and efficacy of Aquablation therapy in men with low to intermediate risk localized prostate cancer who are candidates for active surveillance. Participants will be randomized to either Aquablation Therapy or active surveillance and followed up to 10 years.

• Study Type: Interventional
• Enrollment (Estimated): 333
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Angela Lee; Phone Number: 650-232-7215; Email: a.lee@procept-biorobotics.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Biological male with age ≥ 45 years at the time of consent
2. Biopsy positive Grade Group 2 prostate cancer or biopsy positive Grade Group 1 MRI visible lesion (PI-RADS/Likert ≥ 3)
3. First prostate cancer diagnoses within 18 months (545 days) of consent
4. Are candidates for active surveillance
5. Clinical Stage ≤ T2c
6. PSA < 15 ng/ml
7. Prostate volume ≥25 ml

Exclusion Criteria:

1. Any prior or current local or systemic treatment for prostate cancer, including but not limited to surgery, radiation therapy (external or brachytherapy), tissue ablation, hormone therapy or chemotherapy.
2. Patients with previous surgical or minimally invasive treatment of benign prostatic hyperplasia within the prior 3 months of study treatment.
3. Evidence of lymph node, bone metastasis, extracapsular extension or seminal vesicle invasion.
4. Patient is unwilling to accept a blood transfusion if required.
5. Any condition or history of illness or surgery that may pose an additional risk to patients undergoing the Aquablation or radical prostatectomy procedure such as:

5a. Medical conditions that preclude the use of anesthesia; 5b. Any condition or history of active rectal inflammatory bowel disease or other factors which might increase the risk of rectal injury (i.e. fistula formation); 5c. Patient is unable to stop anticoagulants or antiplatelet agents prior to study treatment per standard of care; 5d. Any other condition or history of infection, illness or surgery that in the opinion of the investigator might affect the outcome of the study procedure, study conduct, and study results; or pose additional risks to the patient (e.g., other cancer, active urethral stricture disease).

6. Patients who are unable to provide informed consent due to cognitive impairment, legal status (such as incarceration), or other factors limiting autonomy or unwilling or unable to follow study instructions including randomization and complete all required study visits through 10 years. This includes individuals with severe cognitive disabilities, those under legal guardianship, or those currently incarcerated.

7. Patient currently participating in other studies unless approved by Sponsor in writing.

8. More than one complete biopsy beyond the diagnostic biopsy comprising both a systematic biopsy and biopsy of any MRI visible lesion (PI-RADS/Likert ≥ 3).

9. GG2 disease with PSA ≥ 10 OR stage ≥ T2b OR ≥ 50% of biopsy cores positive (multiple cores taken from any MRI visible lesion are counted as one continuous core).

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Aquablation Therapy; The Aquablation Therapy arm will receive Aquablation with either the AQUABEAM Robotic System or HYDROS Robotic System	Device: Aquablation Therapy; The AquaBeam Robotic System and the HYDROS Robotic System utilize high-velocity sterile saline waterjet to resect prostate tissue, guided by real-time visualization through cystoscopy and transrectal ultrasound imaging. This minimally invasive surgical procedure is called the Aquablation therapy.
Active Comparator: Active Surveillance; The active surveillance arm will receive standard-of-care for prostate cancer management.	Other: Active Surveillance; Active surveillance is a management strategy for men with low- and favorable intermediate-risk localized prostate cancer that involves close monitoring with curative intent, reserving treatment for evidence of disease progression. Monitoring typically includes serial PSA testing, periodic prostate MRI, and repeat biopsies at scheduled intervals, with intervention triggered by evidence of disease progression.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Freedom from GG ≥ 2	12 Months

Secondary Outcome Measures

Outcome Measure	Time Frame
Freedom from persistent or increased MRI suspicion AND additional prostate cancer treatment	3 Years

Collaborators and Investigators

• Sponsor: PROCEPT BioRobotics

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): December 1, 2028
• Study Completion (Estimated): December 1, 2038

Study Registration Dates

• First Submitted: June 10, 2026
• First Submitted That Met QC Criteria: June 10, 2026
• First Posted (Actual): June 16, 2026

Study Record Updates

• Last Update Posted (Actual): June 16, 2026
• Last Update Submitted That Met QC Criteria: June 10, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: Prostate Cancer; Active Surveillance; Aquablation; HYDROS; AquaBeam; Aquablation Therapy
• Additional Relevant MeSH Terms: Urogenital Diseases; Genital Diseases; Genital Neoplasms, Male; Urogenital Neoplasms; Neoplasms by Site; Neoplasms; Genital Diseases, Male; Prostatic Diseases; Male Urogenital Diseases; Prostatic Neoplasms; Health Services Administration; Quality of Health Care; Outcome Assessment, Health Care; Outcome and Process Assessment, Health Care; Watchful Waiting
• Other Study ID Numbers: CSP0005 - AS Sub-study

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes