Sunobinop shows promising efficacy in interstitial cystitis/bladder pain syndrome

Sunobinop (V117957) demonstrated encouraging preliminary symptom improvement in patients with interstitial cystitis/bladder pain syndrome (IC/BPS), according to initial findings from a phase 1b trial (NCT06285214) of the agent, shared by Purdue Pharma.¹

Specifically, the study found that 41% of patients who received sunobinop achieved a marked or moderate improvement in IC/BPS symptoms, compared with 9% of patients who received placebo. Symptom improvement included reduced bladder pain, less need to urinate urgently, less need to urinary frequently, and larger volumes per void.

Sunobinop is an investigational oral compound that is “designed to bind to and activate the nociceptin/orphanin-FQ peptide receptor (NOP), a protein that is widely expressed in the central and peripheral nervous system and involved in a range of biological functions,” according to the company.

“We are very pleased with the study results on this novel treatment approach”, said Julie Ducharme, BPharm, MSc, PhD, vice president and chief scientific officer of Purdue Pharma, in the news release.¹ “Sunobinop has pharmacokinetic attributes that target the bladder and is the only orally administered NOP agonist being studied for this disorder.”

In total, the study enrolled 47 female patients with IC/BPS through clinical trial sites across the US.² Patients in the study received sunobinop or placebo once daily at bedtime. The study included a single blind run-in phase (a 2-week placebo exposure) followed by a double-blind treatment phase (2 weeks of placebo followed by 6 weeks of sunobinop), and a safety follow-up phase (2 weeks).

The primary end point was the change from baseline in eDiary bladder pain/discomfort scores after 2 weeks and 6 weeks of treatment. Scores were assessed as worst pain overnight and worst pain over the day via an 11-point numerical rating scale (NRS). 

Overall, data showed a statistically significant reduction in NRS score at both 2 weeks and 6 weeks. Specifically, at the end of the 2-week treatment period, the reduction from baseline was -0.7 (overnight) and -0.8 (over the days). From baseline to 6 weeks, these reductions were -1.6 (overnight) and -1.7 (during the day).

Data also showed an average total score in the Interstitial Cystitis Symptom Index of 12.2 (SD, 3.14) with placebo and 9.8 (SD, 3.98) with sunibinop. In the burning/pain in bladder subscore, the average scores were 3.4 (SD, 1.00) with placebo vs 2.7 (SD, 1.26) with sunobinop.

According to Purdue Pharma, these findings “further support a positive effect on symptoms during the sunobinop treatment period and were consistent with the study’s primary end point.”

Regarding safety, no deaths, serious adverse events (AEs), nor discontinuations of sunobinop due to AEs were reported. The most common AEs were urinary tract infection and somnolence.

Further evaluation of study results is ongoing.

In addition to IC/BPS, sunobinop is also being evaluated for the treatment of patients with overactive bladder (OAB) in a phase 1b trial (NCT06024642).

“Patients with interstitial cystitis experience disruptive symptoms that can severely affect daily activities, work productivity, and overall quality of life. The findings from this study help us understand sunobinop’s potential as a possible new treatment option,” said Craig Landau, MD, president and CEO of Purdue, in the news release.¹ “We are encouraged by the findings from the study of sunobinop in these patients, which add to data we have collected in other bladder disorders.”

REFERENCE

1. Results from sunobinop phase 1B study in patients with interstitial cystitis/bladder pain syndrome announced. News release. Purdue Pharma. September 9, 2025. Accessed September 10, 2025. https://www.purduepharma.com/news/2025/09/09/results-from-sunobinop-phase-1b-study-in-patients-with-interstitial-cystitis-bladder-pain-syndrome-announced/

2. Study of V117957 in interstitial systitis/​bladder pain syndrome. ClinicalTrials.gov. Last updated February 5, 2025. Accessed September 10, 2025. https://clinicaltrials.gov/study/NCT06285214