Vibegron equally effective in OAB wet and dry patients

Vibegron (Gemtesa) is effective in both overactive bladder (OAB) patients with urge urinary incontinence (OAB wet) and those without urge urinary incontinence (OAB dry), according to a post-hoc analysis of the phase 3 EMPOWUR study published online in the International Journal of Clinical Practice.^1,2

Compared with placebo, vibegron showed a mean change in average daily urgency episodes of -1.0 in the dry group and -0.6 in the wet population. The mean change versus placebo from baseline to week 12 in average daily number of micturitions was -0.8 and -0.5 respectively.

The EMPOWUR trial also included a third study arm in which patients were randomized to tolterodine. The investigators for the post-hoc analysis reported that, “There were no significant differences in either outcome between tolterodine and placebo for either the dry or wet populations in this study.”

Vibegron is an investigational, highly selective oral β3‐adrenoreceptor agonist that does not inhibit the CYP2D6 enzyme pathway. The overall EMPOWUR trial assigned patients with OAB in a 5:5:4 ratio to vibegron (75 mg once daily), placebo, or tolterodine. The post-hoc analysis included 1463 patients, comprising 336 (23%) patients with OAB dry (vibegron, n = 123; placebo, n = 115; and tolterodine, n = 98), and 1127 (77%) patients with OAB wet (vibegron, n = 403; placebo, n = 405; and tolterodine, n = 319).

“In this subgroup analysis of data from the EMPOWUR trial, vibegron was associated with significant reductions in urgency episodes and micturitions compared with placebo in both the OAB dry and wet populations,” said lead author Jeffrey Frankel, MD, medical director, Seattle Urology Research Center, stated in a news release. “This indicates that vibegron may be similarly efficacious in improving these endpoints in patients with and without urge urinary incontinence.”

FDA approval of vibegron

Based on the EMPOWUR trial, the FDA approved vibegron on December 23, 2020, for the treatment of adult patients with OAB and symptoms of urge urinary incontinence (UUI), urgency, and urinary frequency. 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).^3,4 The mean change from baseline in UUI episodes was -2.0, -1.4, and -1.8, respectively.

Treatment with vibegron also led to a statistically significant improvement in the key secondary outcome measures of number of urgency episodes, volume per micturition, and proportion of incontinent patients with a ≥75% reduction in urge incontinence episodes (P <.01 for all).

Vibegron continued to demonstrate improved clinical outcomes versus tolterodine in results of an extension study of the phase 3 EMPOWUR trial presented during the 2020 International Continence Society online meeting.⁵

The extension results showed that at week 52, 61% of patients receiving vibegron had a 75% or higher reduction in UUI episodes compared with 54.5% of patients who received tolterodine. Additionally, 40.8% versus 34.2% of patients, respectively, had a 100% reduction in UUI episodes and experienced no incontinence episodes over a 7-day diary

Patients who completed their 12-week treatment course from the primary EMPOWUR analysis were eligible for a 40-week, double-blind extension phase. In the extension, patients continued to receive their active medication from the previous 12 weeks, or if they were initially randomized to placebo, they were randomized in a 1:1 ratio to vibegron or tolterodine.

Of the 587 patients who completed their initial EMPOWUR regimen, 506 chose to participate in the extension study. The mean age of these patients was 61 years, 78% were women, and 78% had OAB wet.

Overall, 183 of the 506 patients had been assigned to placebo, and were thus randomized in the extension to either 40 weeks of vibegron (92 patients) or 40 weeks of tolterodine (91 patients). Of these patients, 85.9% and 79.1%, respectively, completed their 40-week extension regimen.

Among 182 patients who completed their initial vibegron regimen, 85.7% also completed their additional 40 weeks of vibegron. In the group continuing on tolterodine, 87.2% completed their 40-week extension regimen.

At 52 weeks, vibegron showed a mean change from baseline in the average daily number of micturitions of -2.4 compared with -2.0 with tolterodine. Also at week 52, the mean change from baseline in the average number of UUI episodes was -2.2 versus -1.7, respectively.

In the extension, AEs across all grades were experienced by 62.6% of patients receiving vibegron and 54.3% of patients receiving tolterodine. AE-related treatment discontinuations occurred in 1.5% (4 patients) versus 3.4% (8 patients) of the 2 groups respectively.

Adverse events of blood pressure elevation were more common in the tolterodine group (1.7%) than in the vibegron group (0.7%). There was 1 patient death in the vibegron group, which was due to arteriosclerotic heart disease and not deemed to be related to study treatment.

References

1. Urovant Sciences Announces Publication of EMPOWUR Trial Subgroup Analysis Showing Similar Efficacy for GEMTESA® in Dry and Wet Overactive Bladder Populations. Published online April 19, 2022. Accessed April 19, 2022. https://bwnews.pr/3OEcU49

2. Staskin D, Frankel J,Varano S, et al. Vibegron for the Treatment of Patients with Dry and Wet Overactive Bladder: A Subgroup Analysis from the EMPOWUR Trial [published online April 13, 2022]. International Journal of Clinical Practice. doi: 10.1155/2022/6475014

3. 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 December 23, 2020.

4. 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

5. Staskin D, Frankel J, Varano S, et al. Once-daily vibegron 75 mg for overactive bladder: double-blind 52-week results from an extension study of the international phase 3 trial (EMPOWUR). Presented during: 2020 the International Continence Society online meeting. November 19-22, 2020. Poster 33