EAU 2018: The WATER study clinical results – a phase III blinded randomized trial of Aquablation vs. TURP with blinded outcome assessment for moderate-to-severe LUTS in men with BPH
Aquablation, a new technique utilizing robotic, high-velocity waterjets for prostate resection, has been introduced as a more minimally invasive alternative for treatment of LUTS in BPH patients. Early reports at the 2017 National American Urological Association meeting have shown aquablation to be similarly efficacious as the TURP.
Dr. Roehrborn of UT Southwestern Medical Center in Dallas, TX United States presents an update on the WATER study, a phase III blinded, multi-institutional, randomized trial of aquablation versus TURP in men with moderate-to-severe LUTS. Similar to their previous presentations, this FDA-approval trial had two co-primary endpoints reporting safety and efficacy and was designed to show non-inferiority between the two methods of resection.
Patients were randomized 2 to 1 in aquablation versus TURP, with a total of 117 in the former group and 67 in the latter. There were no statistically significant differences in covariates such as prostate volume, middle lobe BPH presentation, voided volume, peak voiding rate, q max, and IIEF-5 score. Similarly, the mean baseline IPSS score was similar in both arms, with a mean of 22.9 in the aquablation group and a mean of 22.2 in the TURP group. While the authors assert that operative time was equivalent between the two groups, it is also important to note that the mean resection time was significantly lower in the aquablation group (27 vs. 4 minutes, p<0.001).
The primary safety endpoint was the occurrence of Clavien-Dindo Grade 1 or Grade 2 complications at 3 months follow-up, which occurred in 29 aquablation patients (25%) versus 26 TURP patients (40%). While non-inferiority was tested, this difference was statistically significant and established superiority of aquablation over TURP.
The primary efficacy endpoint was the reduction of IPSS score at 6 months. In the aquablation group, mean IPSS scores decreased from 22.9 to 5.9; comparatively, the TURP patients experienced a decrease from 22.2 to 6.8. Because the IPSS score change at 6 months was 1.8 points larger in the aquablation group, non-inferiority to the TURP was established.
Overall, aquablation met both the primary safety and efficacy endpoints compared to TURP. Aquablation provided TURP-like results despite the newness of the procedure, as the combination of robotics and image-guided procedure enables predictable and reproducible procedure regardless of prostate size. Even further, Dr. Roehrborn asserts that aquablation may contribute to lower rates of sexual dysfunctions – a minimization of side effects which has left both the urologic and patient communities eager for FDA approval.
Authors: Roehrborn C. 1 , Gilling P. 2
Written by: Linda M. Huynh, B.S., University of California-Irvine, at the 2018 European Association of Urology Meeting EAU18, 16-20 March, 2018 Copenhagen, Denmark