Interim 1-year results from the pivotal ROBUST III trial showed that the novel Optilume urethral drug-coated balloon improved outcomes versus standard endoscopic management in patients with recurrent anterior urethral strictures.1
Findings presented during the 2021 International Continence Society Annual Meeting showed the primary end point of anatomical success at 6 months was reached by 74.6% of patients in the Optilume arm versus 26.8% of patients in the standard of care arm.
According to presenting author Justin Chee, MBBS, FRACS, a reconstructive urologist at MURAC health in Melbourne, Australia, the study defined anatomical success as the “Ability to pass a 16F flexible cystoscope through the treated area without prior repeat intervention.”
Chee also reported that the time to treatment failure (P <.0001) and the rate of freedom from repeat intervention (dilation, urethroplasty, or clean intermittent catheterization) through 1 year (P <.0001) were also significantly higher in the Optilume arm.
Also, although immediate symptomatic improvement and immediate improvement in functional improvement of maximum flow rate were observed in both arms, these improvements were only sustained in the Optilume arm, while levels in the control arm returned to near baseline at 1 year.
“Optilume exhibited a significant improvement in [the primary] objective outcome at 6 months and subjective outcomes at 1-year post treatment compared to standard of care,” said Chee. “The novel drug-coated balloon may represent a breakthrough in the endoscopic management of recurrent anterior urethral stricture disease.”
The prospective, single-blind, multicenter ROBUST III trial was open to all patients with urethral strictures, although over 90% of patients had strictures located in the bulbar. Patients had to have strictures ≤3 cm, an IPSS >10, max voiding flow rates of <15 mls/s, and at least 2 prior dilations.
Baseline characteristics were similar in both arms with an average of 3.6 prior endoscopic treatments and an average stricture length of 1.7 cm.
The analysis Chee presented included data from 123 patients enrolled across 23 clinical sites in the United States and Canada.
Patients were randomized in a 2:1 ratio to Optilume (n = 79) or standard endoscopic management (n = 49). Stratification was done by prior radiation and number of dilations (less than 5 or greater than 5).
The standard endoscopic treatment assigned in the control arm was either a rod, uncoated balloon, or direct vision internal urethrotomy, depending on which approach was considered to be the best standard of care for the patient.2
The trial was single blind, with subjects blinded to the 6-month primary end point. At the unblinding, patients in the control arm who met predetermined eligibility criteria were allowed to cross over to receive Optilume.
The investigators observed that outcomes consistently favored Optilume among subgroups with either ≥5 or <5 dilations, as well as subgroups with either a ≥2 cm or <2 cm stricture length.
The primary safety endpoint was freedom from these 3 severe adverse events at 3 months: the formation of a urethral fistula, de novo SUI not resolved by 3 months, and urethral rupture or burst.
Chee reported that there were no cases of these primary safety end points in either study arm.
He added that, “Adverse event rates were similar between arms with the exception of a trend toward more mild post-procedure dysuria and hematuria in the Optilume arm, which generally resolved within 30 days of treatment.”
In his concluding remarks, Chee said that going forward, “Follow-up through 5 years is planned to further define the durability of the treatment.”
1. Chee J, Elliott S, Virasoro R, et al. A randomized controlled trial evaluating the Optilume urethral drug coated balloon vs endoscopic management for treatment of recurrent anterior urethral strictures. Paper presented at: 2021 International Continence Society Annual Meeting; October 14-October 17; Melbourne, Australia. Abstract 2.
2. ROBUST III- Re-Establishing Flow Via Drug Coated Balloon For The Treatment Of Urethral Stricture Disease (ROBUST-III). NIH US National Library of Medicine: ClinicalTrials.gov. Posted April 17, 2018. https://clinicaltrials.gov/ct2/show/NCT03499964. Accessed September 23, 2020.