Final results from the pivotal PRESERVE trial (NCT04972097) have been published in European Urology, suggesting that irreversible electroporation (IRE) with the NanoKnife System is a safe and effective method for prostate tissue ablation in patients with intermediate-risk prostate cancer.1
The PRESERVE trial enrolled 121 patients with intermediate-risk prostate cancer.
The NanoKnife System was granted FDA 510(k) clearance in December 2024 based on findings from the PRESERVE trial.2
Overall, the trial met its primary end point by demonstrating a negative in-field biopsy rate of 71% (95% CI, 62 to 79) at 12 months. When excluding patients without 12-month biopsy data, 80% (95% CI, 72 to 87) had a negative in-field biopsy at 12 months. The negative in-field biopsy rate per Delphi consensus criterion was 84% (95% CI, 76 to 90).
Further, the negative out-of-field biopsy rate was 64% (95% CI, 54 to 73) at 12 months.
At baseline, the median prostate-specific antigen (PSA) level was 5.8 ng/mL. At 12 months following the procedure, the median decrease in PSA level was 3.4 ng/mL. The median PSA nadir was 1.3 ng/mL (IQR, 0.8 to 2.6), and the median time to PSA nadir was 3.5 months (IQR, 2.7 to 6.6).
Ninety-five percent of patients experienced a PSA reduction by 12-month follow-up.
Patients in the study also had a median prostate volume of 41.0 cm3 at baseline. The percent decreases in prostate volume were 16.3% (IQR, 0 to 29) and 16% (IQR, 0 to 31) at 3- and 12-months following the procedure, respectively.
From baseline to 12 months, the mean change in urinary function was 3 per the University of California Los Angeles Expanded Prostate Cancer Index Composite (UCLA-EPIC) urinary domain total score and –2 per the International Prostate Symptom Score (IPSS) total symptom score.
According to the authors, “The mean UCLA-EPIC urinary domain total score improved significantly by 6 months after the procedure, and the total IPSS improved significantly by 3 months.” Improvements in urinary function were maintained through 12 months.
Further, 96% of patients who were pad free at study entry remained pad free at 12 months following the procedure.
Data also showed that erectile function declined overall but approached baseline by 12 months.
The authors reported, “At 12 [months], 84% of patients with good baseline sexual function maintained erections sufficient for penetration.”
Regarding safety, 86% of patients experienced an adverse event (AE), with most being grade 1 to 2. The most common AEs included hematuria (44%), erectile dysfunction (18%), dysuria (16%), urinary retention (15%), micturition urgency (14%), pollakiuria (12%), and hematospermia (12%).
AEs of grade 3 or higher were reported in 12% of patients (n = 14). Procedure-related grade 3 AEs occurred in 3 patients.
In total, the prospective, single-arm PRESERVE trial enrolled 121 adult patients with intermediate-risk prostate cancer across 17 clinical trial sites in the US.3
To be eligible for enrollment, patients needed to be at least 50 years of age with histologically confirmed organ-confined prostate cancer staged ≤T2c and at least a 10-year life expectancy. Patients also had to have a Gleason score of 3+4 or 4+3 and a PSA level of 15 ng/mL or lower or a PSA density lower than 0.2 ng/mL2 if the PSA is greater 15 ng/mL. Additionally, patients could not have evidence of extraprostatic extension or seminal vesicle invasion by mpMRI.
For the study, all patients received IRE of the prostate with high voltage (2-3 kV) pulses lasting up to 100 microseconds through 2 to 6 monopolar probes.
The primary efficacy end point was the rate of negative in-field biopsy at 12 months, and the primary safety end point was the incidence of AEs through 12 months. Secondary outcome measures included PSA kinetics, changes in prostate volume, retreatment, and urinary/sexual function.
Overall, the authors concluded, “The promising short-term oncological outcomes of the study provide supporting evidence for IRE as a viable treatment for select cases of localized [prostate cancer].”
REFERENCES
1. George AK, Miocinovic R, Patel AR, et al. Irreversible Electroporation for Prostate Tissue Ablation in Patients with Intermediate-risk Prostate Cancer: Results from the PRESERVE Trial. Eur Urol. 2025:S0302-2838(25)00346-X. doi:10.1016/j.eururo.2025.06.003
2. AngioDynamics receives FDA clearance for the NanoKnife System for prostate tissue ablation. News release. AngioDynamics, Inc. December 9, 2024. Accessed July 22, 2025. https://www.businesswire.com/news/home/20241209958174/en/AngioDynamics-Receives-FDA-Clearance-for-The-NanoKnife%C2%AE-System-for-Prostate-Tissue-Ablation
3. Pivotal study of the NanoKnife System for the ablation of prostate tissue (PRESERVE). ClinicalTrials.gov. Last updated February 12, 2025. Accessed July 22, 2025. https://clinicaltrials.gov/study/NCT04972097