Trial of vibegron yields favorable results for patients with OAB

The urgency associated with overactive bladder (OAB) can often be debilitating for patients, as it has associated symptoms of frequency, nocturia, and urge urinary incontinence (UUI). Clinicians are constantly developing new non-invasive treatments for this condition to improve patients’ quality of life.

David Staskin, MD

In a recent study presented at the 2021 American Urological Association Annual Meeting,¹ David Staskin, MD, assessed the efficacy of the drug vibegron (Gemtesa) in minimizing the daily number of urgency and frequency episodes encountered in patients with OAB. Staskin is a director of the Center for Male and Female Pelvic Health and associate professor of urology at Tufts University, Boston, Massachusetts.

Could you discuss the background for this study?

The original phase 3 Gemtesa trial involved 1515 patients, and it was a 5:5:4 ratio of placebo to vibegron to an active control. It was done in the standard fashion and at 12 weeks 43% of the total population had at least a 50% reduction in urge symptoms. Our abstract today is a sub analysis to show that people with OAB wet, who were 77% of the group, and OAB dry, who were 23% of the group, had the same response versus placebo to frequency and urgency symptoms. That’s a big concern for physicians. The drug performed very nicely in the Phase III study; 60% reduction in incontinence episodes compared to 40%. But if I'm in my office, and I'm dealing with a patient who doesn't have OAB wet, but has OAB dry, I'd like to know that the drug works for urgency and frequency just as well as it did in the study for the wet patients. In other words, cull that OAB dry group out of the total group.

What were some of the notable findings? Were any of them surprising to you and your co-authors?

I don't think there's anything that we didn't expect. We believed that the drug would work as well in OAB wet as it did in OAB dry, so we're pleased to see that it was statistically significantly better than placebo at the 12-week point for looking at response to both metrics in both groups.

What is the take-home message for the practicing urologist?

I think it's reassuring to see this data point. It's a very interesting compound. It's a single dose of 75 mg. It has no hypertension warning in the label. It has no 2D6 or other CYP interaction that's clinically significant. And in addition to looking at urgency in this particular study, this is the first OAB drug to actually have urge data in the label. So, if you're going to sit down, look at a patient and make a decision about what prescription you want to write, you want to be sure that even though you've seen the overall study response to frequency and urgency in the OAB wet and OAB dry populations combined, you're going to see this statistically significant response in the subset of OAB dry.

Please discuss the significance of these findings for patients with dry overactive bladder.

Patients want to see an improvement. They want a drug that obviously is efficacious and safe, where the side effects are low. But what they really want to know is, are they going to get a robust response—even if they're a patient that doesn't have accidents—to the symptoms that bother them the most? Urgency is the core symptom of OAB. Urgency drives frequency. Urgency drives nocturia—getting up at night. Urgency happens before an urge incontinence episode. Patients want to be confident that this is the right medication for them.

Is there anything else you feel our audience should know about the findings?

With the beta 3 subclass, you want to make sure that there's very little beta 1 response in the drug. This was tested in vitro, so 104%, with isoproterenol as being the 100% control at beta 3, and essentially 0% compared to isoproterenol at beta 1. So, you know you've got a good compound, you know it's going to be convenient for them to take, and you know that the data supports your choice.

Reference

1. Staskin D, Frankel J, Varanno S, et al. Vibegron for the treatment of patients with dry overactive bladder: A subgroup analysis from the EMPOWUR trial. Paper presented at: 2021 American Urological Association Annual Meeting; September 10-13, 2021; virtual. Abstract MP63-15