Vibegron (RVT-901/MK-4618/KRP-114V) Administered Once Daily as Monotherapy or Concomitantly with Tolterodine in Patients with an Overactive Bladder - Beyond the Abstract

Vibegron, is an oral, once-daily, highly selective beta-3 agonist in development for the treatment of overactive bladder. Antimuscarinics are commonly used to treat overactive bladder but are associated with unwanted side effects. In this large Phase 2 dose-ranging study in 1395 patients with overactive bladder, vibegron demonstrated clinically and statistically significant improvements in OAB symptoms (urgency, urge urinary incontinence and frequency) over placebo. Vibegron was well tolerated and there were no clinically meaningful differences in overall incidence or severity of adverse events observed between vibegron and placebo. The incidence of dry mouth, a typical antimuscarinic side effect, was higher among patients treated with tolterodine compared to vibegron.

Based on the clinical data from Phase 2 and PK/PD modeling, a single convenient once daily dose of vibegron 75 mg was selected to confirm the safety and efficacy of vibegron in Phase 3. EMPOWUR, a large (n=1518) international Phase 3 study in patients with overactive bladder, has recently been completed. Vibegron met both co-primary endpoints demonstrating highly significant reductions in daily urge urinary incontinence (UUI) episodes and micturitions, compared to placebo (p<0.0001 and p<0.001, respectively). Additionally, vibegron also met all seven key secondary endpoints, including a clinically meaningful reduction in daily urgency episodes versus placebo (p=0.002); see Table 1 below. 

Table 1. Phase 3 (EMPOWUR) Efficacy Profile of Vibegron – Reductions in Key OAB Symptoms*

OAB patients want to observe fast relief of OAB symptoms and vibegron delivered rapid onset of efficacy at two weeks in both co-primary endpoints and daily urgency episodes (p<0.001 for these endpoints) and statistically significant efficacy was maintained at all time points measured through the end of the study. While antimuscarinics are often associated with higher rates of unwanted side effects, vibegron was well tolerated and the most common adverse events reported versus placebo (>2% in vibegron and greater than placebo) were headache (4.0% vs 2.4%), nasopharyngitis (2.8% vs 1.7%), diarrhea (2.2% vs 1.1%), and nausea (2.2% vs 1.1%). An important concern for the beta-3 class is the risk of hypertension. However, the incidence of the reported adverse event of hypertension for vibegron was equal to placebo (1.7% in vibegron, 1.7% in placebo, and 2.6% in tolterodine) in the Phase 3 study. This Phase 3 study demonstrated the favorable safety, tolerability and efficacy profile of 75mg vibegron for patients suffering from the bothersome symptoms of overactive bladder.

Written by: Paul Mudd, Urovant Sciences, Inc., Irvine, California, United States

Read the Abstract

Rutman, M. AUA 2019: Once-Daily Vibegron, a Novel Oral β3 Agonist Does Not Inhibit CYP2D6, a Common Pathway For Drug Metabolism in Patients on OAB Medications. UroToday. May 2019