Aquablation Study Receives IDE Approval in Low-Grade Prostate Cancer

The FDA has granted investigational device exemption (IDE) approval for a randomized study in the WATER IV prostate cancer program, the WATER IV AS study, evaluating aquablation therapy vs active surveillance among patients with low- to high-risk localized prostate cancer, according to a news release from the developer, PROCEPT BioRobotics.¹ Additionally, another prospective, randomized study within the program, the WATER IV RP trial (NCT06651632), which is evaluating aquablation vs radical prostatectomy in this patient population, has completed enrollment.

In the WATER IV RP trial, a total of 280 patients were enrolled and randomly assigned to receive aquablation or radical prostatectomy. According to the developers, the primary end point results are expected to be ready for presentation by the 2027 American Urological Association (AUA) Annual Meeting.

Moreover, the WATER IV AS trial is expected to enroll up to 333 patients with grade 1 or 2 prostate cancer. The study is designed to evaluate whether aquablation may provide an earlier treatment option for patients who would traditionally undergo active surveillance prior to disease progression. The investigators will follow patients for up to 10 years, with biopsy assessments occurring at 1 year and whole-gland evaluation per MRI occurring at 3 years.

“We are excited to complete enrollment in the first randomized WATER IV protocol, reflecting strong interest from physician investigators as well as patients in evaluating aquablation as a new approach to prostate cancer treatment,” Larry Wood, president and chief executive officer of PROCEPT BioRobotics, stated in the release.¹ “The IDE approval for the additional randomized WATER IV protocol enables us to evaluate whether earlier intervention with aquablation may offer [patients] on active surveillance a quality-of-life–preserving treatment option rather than waiting for the disease to progress.”

Investigators noted that aquablation is an ultrasound-guided, transurethral robotic waterjet using a saline solution to resect the prostate, resulting in more than 95% of the gland being resected and leaving the outer prostatic capsule intact. This procedure is intended to remove cancerous, at-risk tissue as well as any obstructive tissue.

Patients enrolled on the WATER IV RP study were 45 years and older with biopsy-positive grade 1 to 3 prostate cancer and candidates for radical prostatectomy.² For patients with grade 1 disease, patients would have already selected radical therapy as treatment. Additionally, those who underwent random assignment had clinical stage T2c disease or lower, a prostate-specific antigen level of 20 ng/mL or less, and a prostate volume of at least 25 mL.

Radical prostatectomy was performed using an incision in the lower abdomen or perineum, or through a laparoscopic or robotic system for whole-gland removal.

The coprimary end points of the study are rate of pad use for urinary incontinence and rate of erectile dysfunction. Secondary end points include disease control and quality-of-life outcomes, including those impacting urinary, sexual, and overall function.

Patients who previously received or were undergoing systemic treatment for their disease; those who received previous surgery or minimally invasive treatment of benign prostatic hyperplasia within 3 months of study treatment; and those with evidence of lymph node or bone metastases, extracapsular extension, or seminal vesicle invasion were ineligible to enroll on the WATER IV RP protocol. Additional exclusion criteria included an unwillingness to receive a blood transfusion or a history of illness or surgery that could pose an additional risk to the receipt of aquablation or radical prostatectomy.

References

1. PROCEPT BioRobotics® advances prostate cancer program with WATER IV study enrollment completion and expanded IDE approval. News release. PROCEPT BioRobotics. May 28, 2026. Accessed May 28, 2026. https://tinyurl.com/3txx9fac
2. WATER IV prostate cancer (WATER IV PCa). ClinicalTrials.gov. Updated May 4, 2026. Accessed May 28, 2026. https://tinyurl.com/4kuz9s3k