Positive Extension Study Results for OAB Drug Gemtesa

Overactive bladder, which results in a sudden urge to urinate and a need to urinate often, is an increasingly common condition. According to a meta-analysis published in February 2025 in the International Urogynecology Journal, the global prevalence has increased from 18% to 20% over the past 20 years, and women tend to be more affected by the condition than men. Age and being overweight or obese are risk factors. There is a wide array of treatments, ranging from exercise to strengthen the pelvic floor to stimulation of nerves that supply the bladder to Botox. The pharmaceutical armamentarium is also quite large and includes Toviaz (fesoterodine), Myrbetriq (mirabegron), Vesicare (solifenacin) and Detrol (tolterodine).

Researchers have recently reported positive results for Gemtesa (vibegron). Approved by the FDA in 2020, it is a beta-3 adrenergic agonist, like Myrbetriq. Last year, researchers reported the results of the phase 3 COURAGE trial of Gemtesa as a treatment for men with overactive bladder and benign prostatic hyperplasia (BPH) who were taking an alpha blocker with and without a 5-alpha reductase inhibitor. The alpha blockers used to treat BPH include Uroxatral (alfuzosin), Cardura (doxazosin), Flomax (tamsulosin) and Hytrin (terazosin). The 5-alpha reductase inhibitors include Proscar (finasteride) and Avodart (dutasteride).

David R. Staskin, M.D.

The researchers conducting the trial, which was sponsored by Sumitomo Pharma America, the maker of Gemtesa, enrolled just over 1,100 men, ages 45 and older, to participate in the trial and randomly assigned them evenly into two groups, one that took a 75-milligram dose of Gemtesa daily and the other, a placebo. David R. Staskin, M.D., an associate professor at the Tufts University School of Medicine, and his colleagues reported results in the Journal of Urology that at week 12, Gemtesa was associated with significant reductions in daily micturitions and urgency episodes and improvement in nocturia and urge urinary incontinence episodes. They reported that the adverse event rates were similar in the two groups.

In April, Staskin and his colleagues reported the results of a 28-week open-label extension of the 24-week COURAGE study at the 2025 American Urological Association (AUA) meeting in Las Vegas. They enrolled 276 participants from the COURAGE trial into the extension study, 142 who had been randomly assigned to take Gemtesa and 134 to take a placebo. The primary outcome of the extension trial was safety. They reported that the incidences of adverse events with treatment with Gemtesa were approximately the same during the initial double-blinded portion of the study and the open-label extension (35.9% vs. 29.6%). The most commonly reported adverse events during the open-label extension were hypertension (6.3%), COVID-19 (5.6%) and liver enzyme increases (2.1%). They said they recorded no clinically relevant changes in clinical laboratory parameters or vital signs, and none of the study participants had sustained postvoid residual volume of 200 milliliters or more for two or more consecutive assessments. The study participants who took Gemtesa for a total of 52 weeks — for 24 weeks in the original study and then for an additional 28 weeks during the open-label extension — had decreases in their International Prostate Symptom Score, which is based on answers to a standard questionnaire and is commonly used in research studies of BPH symptoms. Staskin and his colleague also reported that there were positive changes in secondary efficacy outcomes in the men who took Gemtesa for 52 weeks, including daily micturition, daily urgency episodes and nightly nocturia episodes.

Findings from the phase 4 real-world study of Gemtesa were also reported at the AUA meeting, according to a news release from Sumitomo. That study showed that a majority of patients were satisfied with Gemtesa as a treatment for overactive bladder and remained on the drug after 12 months. The most common adverse events were urinary tract infections (4%), headache (2.7%), dizziness (2.2%) and diarrhea (2.0%), according to the news release.

“Guided by our dedication to the urology community, we remain committed to providing differentiated, convenient treatment options for women and men suffering from urological conditions, including OAB,” Tsutomu Nakagawa, Ph.D., president and CEO of Sumitomo Pharma America, said in the news release.