FDA approves Optilume drug-coated balloon catheter for urethral strictures

The FDA has approved the Optilume drug-coated balloon catheter system for the treatment of men with urethral strictures.1 The approval was based on data from the ROBUST I and ROBUST 3 clinical trials.

The ROBUST I pilot study (NCT03014726) enrolled and treated 53 patients with recurrent bulbar strictures ≤2 cm who had received 1 to 4 previous endoscopic treatments. The average stricture length was 0.9 cm and the mean number of prior dilations was 1.7. Overall, 43% of men had undergone ≥2 previous dilations.

There were 43 patients in ROBUST I who were evaluable for efficacy at 3 years. Of these patients, 77% (n = 33) remained free of repeat intervention (dilation, urethroplasty, or clean intermittent catheterization).2 Further, 67% (n = 29) of these patients achieved a ≥50% improvement in International Prostate Symptom Score (IPSS).

Additional findings from ROBUST I showed that the mean IPSS improved from 25.2 at baseline to 5.5 at 3 years (P <.001) and the mean IPSS QOL improved from 4.9 to 0.7 during that time. Also between baseline and 3 years, Qmax improved from 5.0 mL/sec to 15.1 mL/sec and the International Index of Erectile Function (IIEF) overall satisfaction score improved from 6.5 to 8.2.

Interim 1-year results from the ROBUST III trial demonstrated that Optilume improved outcomes versus standard endoscopic management in patients with recurrent anterior urethral strictures.

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.3 The study defined anatomical success as the “ability to pass a 16F flexible cystoscope through the treated area without prior repeat intervention.”

The time to treatment failure (P <.0001) and the rate of freedom from repeat intervention through 1 year (P <.0001) were also significantly higher in the Optilume arm.

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 included data from 127 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 = 48). 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.

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. There were no cases of these primary safety end points in either study arm.

"As the ROBUST 1 and ROBUST 3 clinical trials demonstrated, Optilume significantly reduces the incidence of stricture recurrence," Sean Elliott, MD, MS, FACS, principal investigator for the ROBUST trials and professor, vice chair of urology, and director of reconstructive urology at the University of Minnesota, stated in a news release. "At three years, durability continued with a 77% freedom from reintervention rate, a 176% increase in Qmax, and a 65% decrease in IPSS. Optilume may serve as an important alternative for men with recurrent strictures that want to avoid or delay urethroplasty."


1. FDA Approves Optilume® Urethral Drug Coated Balloon, a breakthrough treatment for urethral strictures. Published online December 13, 2021. Accessed December 13, 2021. https://bit.ly/3s3elQQ.

2. Chee J, Elliott S, Virasoro R, et al. The Optilume urethral drug coated balloon for recurrent anterior urethral strictures: 3-year results from the ROBUST I Study. Paper presented at: 2021 International Continence Society Annual Meeting; October 14-October 17; Melbourne, Australia. Abstract 1.

3. 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.