Sunobinop shows promise in phase 1b trial for overactive bladder

Sunobinop (V117957) demonstrated initial efficacy and safety in the treatment of patients with overactive bladder (OAB), according to preliminary findings from a phase 1b trial (NCT06024642) of the oral agent.¹

No serious adverse events were reported.

“These are exciting results with a novel treatment approach that includes consideration of nighttime symptoms such as nocturia”, said Roger R. Dmochowski, MD, MS, MMHC, FACS, professor of urology, gynecology, and surgery at Vanderbilt University Medical Center, Nashville, Tennessee, in a news release on the findings.¹ “With it’s unique mechanism of action, sunobinop is the first oral agent that blocks the sensory impulses that trigger patients’ bladder symptoms.”

Imbrium Therapeutics, a subsidiary of Purdue Pharma and developer of the compound, shared the interim results from the trial in a news release.

Overall, treatment with sunobinop resulted in a reduction in urinary urgency, urinary frequency, and incontinence episodes over the treatment period compared with placebo. Results also showed an improvement in nocturia compared with placebo.

The greatest improvements in patient-reported microurition were seen in the reduction of incontinence episodes over 24 hours when comparing the sunobinop treatment period following the 2-week placebo period. Patients experienced a 0.18 to 0.37 additional reduction in mean incontinence episodes during the sunobinop period vs placebo.

Specifically, during the placebo period, the mean number of incontinence episodes ranged from 1.0 to 1.3, translating to a reduction of 0.10 to 0.20 from baseline. During the sunobinop period the mean number of incontinence episodes ranged from 0.6 to 0.8, translating to a 0.3 to 0.5 reduction in the average number of incontinence episodes from baseline.

Reductions were also shown to be greater among patients with more severe disease.

Regarding safety, no serious adverse events (AEs) were reported, and no patients discontinued treatment due to AEs. Urinary tract infection was the most common AE reported.

In total, the phase 1b, multicenter, double-blind, placebo-controlled crossover trial enrolled 51 female patients with OAB across 12 clinical trial sites in the US.²

Those enrolled in the study first received 2 weeks of single blind placebo followed by 2 weeks of double-blind placebo. Patients were then randomly assigned in a blinded fashion to receive a 1 mg tablet of sunobinop taken orally at bedtime or a continuation of placebo for 6 weeks. All patients received a final week on placebo.

The primary end points for the study are the change from baseline in the number of micturition episodes and the number of incontinence episodes in 24 hours as well as the change from baseline in the volume voided per 24 hours, as assessed at baseline and weeks 2, 4, 6, 8, and 9. Secondary outcome measures include the change from baseline in scores on the Patient Perception of Bladder Condition questionnaire, Overactive Bladder Questionnaire: Long-Form, 1-week Recall, Subject Global Response Assessment, Patient Perception of Intensity of Urgency Scale, and the Symptom Impact Sleep Questionnaire.

Participants were eligible for enrollment in the trial if they were female, aged 18 to 70 years, capable of voiding independently, able to comply with acceptable methods of contraception, had symptoms of OAB––including urinary urgency and urinary frequency with incontinence for 3 or more months––and were willing to modify their current treatment regimen for OAB.

Craig Landau, MD, president and CEO of Purdue Pharma, added in the news release, “Millions of people in the United States struggle with OAB, which can have a negative effect on patients’ daily activities. New treatment options are needed for OAB patients. We are encouraged that sunobinop produced a signal in this population and look forward to confirming these positive findings in additional clinical studies.”

In addition to the study in patients with OAB, sunobinop is also being evaluated in a phase 1 study (NCT06285214) for patients with interstitial cystitis/bladder pain syndrome (IC/BPS). The first patient visit in the trial was reported in December 2022.³

References

1. Imbrium Therapeutics announces results of a sunobinop phase 1b study in patients with overactive bladder syndrome. News release. Imbrium Therapeutics. Published online and accessed January 7, 2025. https://www.imbriumthera.com/news/imbrium-therapeutics-announces-results-of-a-sunobinop-phase-1b-study-in-patients-with-overactive-bladder-syndrome/

2. Study of V117957 in overactive bladder syndrome. ClinicalTrials.gov. Last updated June 21, 2024. Accessed January 7, 2025. https://clinicaltrials.gov/study/NCT06024642

3. Imbrium therapeutics completes first patient visit in phase 1 study of potential treatment for interstitial cystitis/bladder pain syndrome. News release. Inbrium Therapeutics. December 20, 2022. Accessed January 7, 2025. https://www.imbriumthera.com/news/imbrium-therapeutics-completes-first-patient-visit-in-phase-1-study-of-potential-treatment-for-interstitial-cystitis-bladder-pain-syndrome/