The Optilume Drug Coated Balloon has been studied in three clinical investigations (ROBUST I, II and III). ROBUST I is the first in man trial conducted and is a single arm, prospective multicenter study conducted in 4 sites in Latin America, recruiting a total of 53 subjects. This was followed by ROBUST II, an early feasibility study performed at 5 sites in the United States with a total of 15 subjects. Finally ROBUST III, the randomized controlled pivotal trial, was performed in the United States and Canada with 79 patients receiving the Optilume® Drug Coated Balloon (DCB) and 48 patients undergoing Standard of Care (SOC) Direct Vision Internal Urethrotomy (DVIU) or dilation. Data combined from all three studies is presented here.

A total of 148 subjects were treated with the Optilume® DCB in ROBUST I, II and III in Latin America, Canada, and the United States. Men with strictures ≤ 3cm and 1-4 prior endoscopic interventions were included in the studies. Patients were excluded who had prior urethroplasty, hypospadias, lichen sclerosus, or other confounding pathology. Follow-up was completed post-procedure at foley removal (2-5 days), 30 days, 3 months, 6 months and annually thereafter. All studies were designed to follow subjects through 5 years with ROBUST I currently at 4-year follow-up, ROBUST II at 3-year follow-up and ROBUST III at 2-year follow-up.

The safety endpoint assessed serious treatment-related adverse events. The effectiveness endpoint was the proportion of subjects with ≥50% improvement in International Prostate Symptom Score (IPSS). Secondary outcomes included quality of life, freedom from repeat intervention, erectile function, flow rate, and post-void residual volume. Subjects receiving any secondary treatment, including clean intermittent catheterization, were considered failures and were censored at that time point. Significance was set at 0.05.

Patient demographics and stricture characteristics were similar in the three studies, with ROBUST III including some patients with penile strictures (10.1%) and prior pelvic radiation (11.4%). Outcomes across all three studies were consistent. IPSS improved in all patients treated with the Optilume® DCB: from 22.5 at baseline to 7.8 at 4 years. Peak urinary flow rate (Qmax) had a sharp improvement in the DCB group and is sustained through current follow-up (7.1 to 14). Freedom from repeat intervention is approximately 73% at four-year follow-up.

Subjects with recurrent bulbar strictures treated with Optilume® paclitaxel-coated balloon exhibited significant improvement in symptomatic and functional outcomes through 4 years post treatment with demonstrably improved recurrence rates. Results at longest follow up in all three studies were similar, indicating that there was little selection bias in the earlier, non-randomized trials. There was no impact on erectile function and there were no serious treatment related adverse events across all studies.

The Optilume® DCB is a safe and effective treatment option for appropriately selected men with recurrent anterior urethral strictures. Follow up will be continued through 5 years in all studies.