Add-on vibegron effective for OAB in men receiving standard BPH treatments

Adding vibegron (Gemtesa) to treat overactive bladder (OAB) symptoms in men receiving standard first-line treatment for benign prostatic hyperplasia (BPH) is safe and effective, according to a study published in Urology.¹

The study specifically assessed add-on vibegron in 42 patients who had persistent storage symptoms after being treated for ≥12 weeks with α-1 blockers (n = 22) or PDE5 inhibitor (n = 20) as frontline BPH therapy. The study met its primary end point with a significant decrease in Overactive Bladder Symptom Score (OABSS) between baseline and the completion of vibegron treatment at 12 weeks: 6.21 versus 4.38 respectively (P <.001; higher results on OABSS indicate worse symptom severity).

Patients enrolled on the trial had an OABSS score of 3 or higher and at least 1 characteristic persistent storage symptom, such as urgency, urgency incontinence, daytime frequency, and/or nighttime frequency. The mean patient age at baseline was 72 years and the mean prostate volume was 40.6 mL. The α-1 blockers received for BPH/BPH-related lower urinary tract symptoms (LUTS) included silodosin (8 patients), naftopidil (10 patients) and tamsulosin (4 patients). The remaining 20 patients received tadalafil for BPH/BPH-related LUTS. The dose of vibegron administered was 50 mg once daily for 12 weeks.

Among their findings, the researchers noted that, “Although each score of several questionnaires, especially for storage symptoms, improved significantly, no significant improvement was found in stress incontinence, straining, bladder pain and urethral pain in the Core Lower Urinary Tract Symptom score. Maximum flow rate and residual urine volume did not change.”

The investigators also used statistical modeling to determine independent factors affecting the efficacy of vibegron. These factors were found to be prostate volume (P = .028), monotherapy with α-1 blocker (P = .007), and Core Lower Urinary Tract Symptom score (P = .014).

Regarding safety, there were no patient discontinuations during the 12-week treatment period that were caused by treatment-emergent adverse events. The researchers did note in their paper that 4 patients, due to unknown reasons, did not attend their 12-week follow-up visit with their urologist.

The FDA approved vibegron in December 2020 for the treatment of adult patients with OAB with symptoms of urge urinary incontinence (UUI), urgency, and urinary frequency.²

The approval was based on the phase 3 EMPOWUR trial. In the primary study analysis, at 12 weeks, vibegron showed a mean change from baseline in the average daily number of micturitions of -1.8 compared with -1.3 for placebo and -1.6 for tolterodine (P <.001).³ The mean change from baseline in UUI episodes was -2.0, -1.4, and -1.8, respectively.

Reference

1. Ishikawa K, Tsujimura A, Miyoshi M, et al. Efficacy and safety of vibegron add-on therapy in men with persistent storage symptoms after receiving alpha 1-blocker or phosphodiesterase 5 inhibitor: a preliminary study [published online ahead of print on January 20, 2021]. Urology. doi: 10.1016/j.urology.2021.01.021

2. Urovant Sciences Announces U.S. FDA Approval of GEMTESA® (vibegron) 75 mg Tablets for the Treatment of Patients with Overactive Bladder (OAB). Published online December 23, 2020. https://bit.ly/37I8SVc. Accessed February 10, 2021.

3. Staskin D, Frankel J, Varano S, et al. International phase III, randomized, double-blind, placebo and active controlled study to evaluate the safety and efficacy of vibegron in patients with symptoms of overactive bladder: EMPOWUR. J Urol. 2020;204(2):316-324. doi: 10.1097/JU.0000000000000807