Study progresses of sunobinop for interstitial cystitis/bladder pain syndrome

The final patient visit has been conducted in a phase 1b study (NCT06285214) evaluating the investigational oral agent sunobinop (V117957) in patients with interstitial cystitis/bladder pain syndrome (IC/BPS), announced Imbrium Therapeutics, a subsidiary of Purdue Pharma, in a news release.¹

Sunobinop is also being evaluated in the treatment of patients with overactive bladder.

"Patients with interstitial cystitis experience very disruptive symptoms that can severely affect daily activities, work productivity, and overall quality of life. The findings from this study will help us understand sunobinop’s potential as a possible new treatment option for this chronic disorder,” said Craig Landau, MD, president and CEO of Purdue Pharma, in the news release.¹ “We look forward to reviewing and analyzing the results later this year, as we continue our commitment to innovation through research and development.”

In total, the phase 1b study enrolled 47 female patients with IC/BPS across clinical trial sites in the US.² Those enrolled in the study were randomly assigned to receive 1 mg sunobinop taken orally at bedtimeor to a matched placebo tablet. Crossover was permitted in the trial.

To be eligible for enrollment, patients needed to be aged 18 or older and capable of voiding. Participants also needed to have IC/BPS per American Urological Association criteria, a Bladder Pain/Interstitial Cystitis Symptom Score (BPIC-SS) of 19 or higher, a worst bladder pain/discomfort sub-score of 4 to 9, and an evaluation ruling out other conditions that cause bladder pain.

The primary outcome measure was the change from baseline in bladder pain/discomfort scores over the last 12 hours, assessed at weeks 2, 4, 6, 8, and 9. Secondary outcome measures included change from baseline in mean number of microuritions per 12 hours, the change from baseline in BPIC-SS, and the change from baseline in Subject Global Response Assessment, among other measures.

About Sunobinop

According to the company, “Sunobinop is an investigational, novel and potential first-in-class oral compound designed to bind to and activate the nociceptin/orphanin-FQ peptide receptor, a protein that is widely expressed in the central and peripheral nervous system and involved in a range of physiologic processes, including bladder voiding function as well as sensory perception of bladder pain.”

In addition to IC/BPS, the investigational drug is also being evaluated for the treatment of patients with overactive bladder (OAB). Results from a phase 1b trial (NCT06024642) of sunobinop in OAB were shared by Imbrium Therapeutics earlier this year, showing initial efficacy and safety of the drug in these patients.³ 

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.

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 0.1 to 0.2 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.

REFERENCES

1. Imbrium Therapeutics achieves last patient last visit in clinical trial of potential treatment for interstitial cystitis/bladder pain syndrome. News release. Ibrium Therapeutics. Published online and accessed March 11, 2025. https://www.imbriumthera.com/news/imbrium-therapeutics-achieves-last-patient-last-visit-in-clinical-trial-of-potential-treatment-for-interstitial-cystitis-bladder-syndrome/

2. Study of V117957 in interstitial cystitis/​bladder pain syndrome. ClinicalTrials.gov. Last updated February 5, 2025. Accessed March 11, 2025. https://clinicaltrials.gov/study/NCT06285214

3. Imbrium Therapeutics announces results of a sunobinop phase 1b study in patients with overactive bladder syndrome. News release. Imbrium Therapeutics. January 7, 2025. Accessed March 11, 2025. https://www.imbriumthera.com/news/imbrium-therapeutics-announces-results-of-a-sunobinop-phase-1b-study-in-patients-with-overactive-bladder-syndrome/