Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients

Background: Postoperative ileus is a significant clinical challenge lacking effective management strategies. Ghrelin-receptor stimulation has promotility effects in the upper and lower gastrointestinal tract. Objective: This proof-of-concept, phase 2, randomized study evaluated the safety and efficacy of the ghrelin-receptor agonist ipamorelin in the treatment of postoperative ileus following abdominal surgery (ClinicalTrials.gov NCT00672074). Design: The design was a multicenter, double-blind, placebo-controlled, clinical trial. Settings: The settings include hospital inpatients. Patients: The patients were adults undergoing small and large bowel resection by open or laparoscopic surgery. Intervention: The intervention was intravenous infusions of 0.03-mg/kg ipamorelin vs placebo twice daily, on postoperative day 1 to 7 or hospital discharge. Main outcome measures: Safety was assessed by monitoring adverse events and laboratory tests. The key efficacy endpoint was time from first dose of study drug to tolerance of a standardized solid meal. Results: One hundred seventeen patients were enrolled, of whom 114 patients composed the safety and modified intent-to-treat populations. Demographic and disease characteristics were balanced between groups. Overall incidence of any treatment-emergent adverse events was 87.5 % in the ipamorelin group and 94.8 % in placebo group. Median time to first tolerated meal was 25.3 and 32.6 h in the ipamorelin and placebo groups, respectively (p = 0.15). Limitations: This proof of concept study was small and enrolled patients with a broad range of underlying conditions. Conclusions: Ipamorelin 0.03-mg/kg twice daily for up to 7 days was well tolerated. There were no significant differences between ipamorelin and placebo in the key and secondary efficacy analyses.