Vibegron Proves Effective as Oral Therapy for Patients With Overactive Bladder

Nearly 30% of adult men and 40% of adult women¹ live with symptoms of overactive bladder (OAB). Because OAB is not a singular disease and rather a group of urinary symptoms including a sudden, uncontrolled need/urge to urinate, with or without incontinence,² providers must weigh several treatment options to achieve the best potential benefits for an individual case. 

While OAB is not associated with high mortality rates, its effects on quality of life and overall burden can be stressful to patients and diagnosis/treatment is often delayed due to patients’ lack of understanding of available treatments.

Per the American Urological Association’s updated guidelines, “Clinicians should offer behavioral therapies [eg, bladder training, bladder control strategies, pelvic floor muscle training, fluid management] as first-line therapy to all patients with OAB.”²

When behavioral therapies and lifestyle changes do not improve OAB, there are several medicinal treatments like antimuscarinics and beta-3 agonists to reduce symptoms.¹ More severe cases may result in surgical intervention. 

Highlighting Newest Treatment Option

Recently, Gemtesa (vibegron), the first beta-3 adrenergic receptor (β3) agonist available as a once-daily pill that does not require titration was approved by the FDA.³ Its efficacy was demonstrated in the double-blind, placebo-controlled, phase 3 EMPOWUR clinical trial in which it showed statistically significant reductions in micturitions, urgency episodes and urge incontinence, and increased the volume per micturition.⁴

In the EMPOWUR trial, researchers assessed the efficacy, safety, and tolerability of vibegron with a 1- to 5-week screening period, 28-day washout; 2-week single-blind (patient) placebo run-in; 12-week, double-blind (patients, investigators, and sponsor), randomized treatment period; and a 4-week follow-up safety evaluation. Patients in the final cohort met the following criteria: aged 18 years or older, a history of OAB, and an OAB diagnoses ≥3 months prior to screening. Up to 15% of patients could be male, and 25% or less could have dry OAB. Patients were not enrolled in the study if they had a urine volume output of greater than 3000 ml.

Adult OAB patients with eight or more reported micturitions per day were randomized 5:5:4 to receive 75 mg of vibegron, placebo, or 4 mg extended-release tolterodine. Up to 25% of patients with dry OAB or fewer than one urge incontinence episode per day were included. Patients reported episodes and voiding via 7-day diaries at baseline, and weeks 2, 4, 8, and 12.

Approximately 90% of the final 1518 patients completed the full trial. In the group receiving vibegron, patients saw a decreased adjusted mean of 1.8 episodes per day vs 1.3 episodes and 1.6 episodes in the placebo and tolterodine groups, respectively. For patients with incontinence, vibegron decreased episodes by an adjusted mean of 2 episodes per day, vs 1.4 (placebo) and 1.8 (tolterodine).⁴

 “Moreover, vibegron was statistically significantly superior to placebo for key secondary measures of number of urgency episodes, volume per micturition, and proportion of incontinent patients with a 75% or greater reduction in urge incontinence episodes,” said researchers.⁴ 

The researchers reported that 1.7% of patients treated with vibegron discontinued treatment compared with 1.1% (placebo) and 3.3% (tolterodine) due to adverse effects.⁴

“[Vibegron] is the first beta 3-agonist available as a once-daily pill which does not require dose titration,” said David Staskin, MD, clinical trial investigator and a leading urologist with St. Elizabeth’s Medical Center in Boston, MA, in a press release.³ “Notably, [Vibegron] did not have any increase in the adverse event of hypertension compared to placebo in the key EMPOWUR study and has no interactions with medications metabolized by CYP2D6, which is important since many common medications are metabolized by CYP2D6.”

Recommended dosage of vibegron is one 75-mg tablet taken orally once-daily with water or crushed in food like applesauce.

“The FDA’s approval of [vibegron] is an important milestone for the tens of millions of patients living with overactive bladder,” said Jim Robinson, president and chief executive officer of Urovant Sciences, in a statement.³ “We look forward to launching vibegron in the coming months and believe that it will provide a compelling alternative for the many patients suffering from the burden of an overactive bladder. We also remain committed to bringing more new therapies to market that address unmet medical needs of patients suffering from urologic diseases.” 

“Over 30 million people in the US suffer from OAB symptoms and many patients are unable to find relief,” said Dr Staskin in a press release.⁵ “The results of this clinical trial have demonstrated that vibegron…could provide an important new oral treatment for patients suffering with OAB.” 

References: 

1. Urology Care Foundation. What is overactive bladder (OAB)? Accessed March 31, 2021.https://www.urologyhealth.org/urology-a-z/o/overactive-bladder-(oab)
2. Lightner DJ, Gomelsky A, Souter L, et al. Diagnosis and treatment of overactive bladder (non-neurogenic) in adults: AUA/SUFU Guideline amendment 2019. Accessed March 31, 2021. https://www.auanet.org/guidelines/overactive-bladder-(oab)-guideline#x2906
3. Urovant sciences announces US FDA approval of Gemtesa (vibegron) 75 mg tablets for the treatment of patients with overactive bladder (OAB). Urovant Sciences. December 23, 2020. Accessed March 26, 2021. https://ir.urovant.com/news-releases/news-release-details/urovant-sciences-announces-us-fda-approval-gemtesar-vibegron-75
4. Staskin D, Frankel J, Varano S, Shortino D, Jankowich R, Mudd PN Jr. 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. Urovant Sciences announces publication of phase 3 EMPOWUR trial results In the Journal of Urology. Urovant Sciences. March 2, 2020. Accessed March 26, 2021. https://www.businesswire.com/news/home/20200302005268/en/Urovant-Sciences-Announces-Publication-of-Phase-3-EMPOWUR-Trial-Results-in-the-Journal-of-Urology