Sunobinop Shows Promising Results in Phase 1b Trial for Interstitial Cystitis/Bladder Pain Syndrome
Key Insights
Sunobinop demonstrated statistically significant pain reduction in a phase 1b trial, with 41% of patients achieving marked or moderate symptom improvement compared to 9% on placebo.
The investigational oral NOP (search) receptor agonist showed reductions in bladder pain scores of -1.6 (overnight) and -1.7 (daytime) after 6 weeks of treatment.
The study enrolled 47 female patients with IC/BPS (search) and reported no serious adverse events, with urinary tract infection and somnolence as the most common side effects.
Purdue Pharma (search) announced positive preliminary results from a phase 1b clinical trial evaluating sunobinop (V117957), an investigational oral compound for treating interstitial cystitis/bladder pain syndrome (search) (IC/BPS (search)). The study demonstrated encouraging efficacy signals for this potential first-in-class treatment targeting a debilitating urologic condition that severely impacts patients' quality of life.
Primary Efficacy Results
The trial met its primary endpoint, showing statistically significant reductions in bladder pain scores on an 11-point numerical rating scale (NRS). At the 2-week treatment period, patients experienced reductions from baseline of -0.7 (overnight) and -0.8 (daytime). These improvements increased substantially by 6 weeks, with reductions of -1.6 (overnight) and -1.7 (daytime) from baseline.
Notably, 41% of patients receiving sunobinop achieved marked or moderate improvement in overall IC/BPS (search) symptoms, compared with only 9% of patients on placebo. Symptom improvements included reduced bladder pain, decreased urinary urgency and frequency, and increased voiding volumes.
Secondary Outcome Measures
Additional patient-reported outcomes supported the primary findings. The Interstitial Cystitis Symptom Index showed average total scores of 9.8 (SD 3.98) with sunobinop versus 12.2 (SD 3.14) with placebo. For the burning/pain in bladder subscore specifically, patients on sunobinop averaged 2.7 (SD 1.26) compared to 3.4 (SD 1.00) on placebo.
"These findings further support a positive effect on symptoms during the sunobinop treatment period and were consistent with the study's primary end point," according to Purdue Pharma (search).
Novel Mechanism of Action
Sunobinop is designed to bind to and activate the nociceptin/orphanin-FQ peptide receptor (search) (NOP (search)), a protein widely expressed in the central and peripheral nervous system involved in various biological functions. The compound has pharmacokinetic attributes that target the bladder and represents the only orally administered NOP agonist being studied for IC/BPS (search).
"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 (search). "Sunobinop has pharmacokinetic attributes that target the bladder and is the only orally administered NOP (search) agonist being studied for this disorder."
Study Design and Safety Profile
The multicenter, two-period, single-sequence, crossover study enrolled 47 female patients diagnosed with IC/BPS (search) across clinical trial sites in the United States. The study design included a single-blind run-in phase (2-week placebo exposure), followed by a double-blind treatment phase (2 weeks placebo followed by 6 weeks sunobinop), and a 2-week safety follow-up phase.
Patients received sunobinop or placebo once daily at bedtime. The safety profile was favorable, with no deaths, serious adverse events, or discontinuations due to adverse events reported. The most common adverse events were urinary tract infection and somnolence.
Clinical Context and Future Development
IC/BPS (search) is a chronic, painful, and debilitating urologic disorder that negatively affects patients' quality of life and can lead to radical lifestyle and behavioral modifications. "Patients with interstitial cystitis experience disruptive symptoms that can severely affect daily activities, work productivity, and overall quality of life," said Craig Landau, MD, president and CEO of Purdue.
Beyond IC/BPS (search), sunobinop is being evaluated in a separate phase 1b trial for overactive bladder (search) syndrome (NCT06024642) and for alcohol use disorder (search). Purdue Pharma (search) indicated that further evaluation of the IC/BPS study results is ongoing, and all indications for sunobinop are open to partnering opportunities.