Imbrium Therapeutics Reveals Sunobinop Phase 1b Study Results for Overactive Bladder

STAMFORD, Conn.--Imbrium Therapeutics L.P., a branch of Purdue Pharma L.P., has unveiled findings from a Phase 1b clinical study examining the safety and potential effectiveness of sunobinop, a new investigational therapy for overactive bladder syndrome (OAB). OAB is a condition that prompts sudden, uncontrollable urges to urinate and affects approximately 14% of both men and women in the United States.

The study revealed that patients using sunobinop experienced a noticeable reduction in the urgency to urinate, the frequency of urination, and episodes of incontinence compared to the period when they were given a placebo. Patients' diaries showed the most significant improvement in the reduction of incontinence episodes over a 24-hour period. During the placebo phase, the average number of incontinence incidents ranged from 1.0 to 1.3, showing a reduction of 0.10 to 0.20 from baseline. In contrast, during the sunobinop treatment period, these incidents ranged from 0.6 to 0.8, reflecting a reduction of 0.3 to 0.5 from baseline and an additional decrease of 0.18 to 0.37 over the placebo. The improvements were more pronounced in patients with severe OAB. Moreover, patient feedback, including responses regarding nocturia, reinforced the overall positive impact during the sunobinop treatment phase.

Sunobinop is an innovative oral compound that targets the nociceptin/orphanin-FQ peptide receptor (NOP), which plays a role in various biological functions and is found throughout the central and peripheral nervous systems. Craig Landau, MD, President and CEO of Purdue, stressed the need for new treatment options for OAB sufferers, stating, "We are optimistic that sunobinop has shown potential in this patient group and anticipate further validation in upcoming clinical trials."

The study involved 51 female participants diagnosed with OAB in a multicenter, randomized, double-blind, placebo-controlled crossover trial. This study aimed to evaluate the effects of sunobinop, taken at bedtime, on key OAB symptoms such as urinary urgency, frequency, incontinence, and nocturia, in comparison to a placebo. Initially, patients underwent two weeks of a single-blind placebo phase, followed by two weeks of a double-blind placebo phase. Subsequently, patients were switched in a blinded manner to receive 1 mg of sunobinop nightly for six weeks, followed by a final week on placebo. This duration marks the longest exposure to sunobinop recorded in a clinical trial so far. No severe adverse events were reported, and no patients discontinued treatment due to adverse effects. The most common side effect observed was a urinary tract infection.

Roger R. Dmochowski, MD, MS, MMHC, FACS, a distinguished urologist and researcher who contributed to the study design and assessment of the results, remarked, "These are promising findings for a novel treatment strategy that also considers nighttime symptoms such as nocturia." He highlighted sunobinop's unique mechanism of action as the first oral medication that blocks sensory impulses triggering bladder symptoms.

Beyond OAB, Imbrium is evaluating sunobinop for potential use in treating interstitial cystitis/bladder pain syndrome (IC/BPS) and alcohol use disorder. Opportunities for partnership are available for all sunobinop indications.