A multicenter, randomized, double-blind, placebo controlled study of onabotulinumtoxinA 200 U to treat lower urinary tract symptoms in men with benign prostatic hyperplasia

Abstract

Purpose: We assessed the efficacy and tolerability of onabotulinumtoxinA 200 U vs placebo to treat lower urinary tract symptoms/benign prostatic hyperplasia in men previously treated with oral benign prostatic hyperplasia medication in a 24-week phase 2, multicenter, double-blind, randomized, placebo controlled, parallel group trial.

Materials and methods: Patients with I-PSS (International Prostate Symptom Score) 14 or greater, peak urinary flow rate 4 to 15 ml per second and total prostate volume 30 to 80 ml were randomized 1:1 to a single intraprostatic treatment of onabotulinumtoxinA 200 U or placebo. A single-blind sham procedure followed by a 4-week run-in was included to attempt to minimize any potential placebo effect. Patients who still met eligibility criteria after the run-in entered the double-blind active treatment period. The primary end point was the change from baseline in total I-PSS at week 12. Other end points assessed at weeks 6, 12 and 24 included the change from baseline in total I-PSS, peak urinary flow rate, total prostate volume and post-void residual urine volume.

Results: Of 427 patients enrolled 315 were randomized and treated. Decreases from baseline in I-PSS were observed in the onabotulinumtoxinA and placebo groups (-6.3 vs -5.6 points, p <0.001) with no difference between the groups overall or in subgroups. Improvement was observed in the peak urinary flow rate, which was significant only at week 6 compared to placebo. Improvement was significant at all time points in a patient subgroup on stable concurrent α-blockers or 5α-reductase inhibitors during the study. Adverse events were similar in the 2 treatment groups.

Conclusions: OnabotulinumtoxinA 200 U and placebo improved I-PSS and were well tolerated but no between group difference in efficacy was observed.

Keywords: benign prostatic hyperplasia; lower urinary tract symptoms; onabotulinumtoxinA; prostate; prostatic hyperplasia.