Ipamorelin Phase 2 Postoperative-Ileus Trial: NCT00672074

NCT00672074 was a small randomized, blinded, placebo-controlled phase 2 study of ipamorelin in adults hospitalized after small- or large-bowel resection. The reported median time to tolerate a standardized solid meal was numerically shorter with ipamorelin, but the difference was not statistically significant. The authors reported no significant differences in the key or secondary efficacy analyses. The study did not demonstrate improvement on those reported gastrointestinal-recovery outcomes.[1][2][3]

This is a source-limited summary of the public paper abstract and publisher disclosures, the registry, and FDA's later review. The complete journal methods, a standalone study protocol, and a statistical analysis plan were not available for this review. Their details have not been independently verified; the limits are explained below.

Study at a glance

The regimen identifies the experiment; it is not practical-use guidance. These results do not establish transferability to another route, form, formulation, or material.[1][2][3]

What was measured

The paper abstract identifies the key efficacy endpoint as time from the first study dose to tolerance of a standardized solid meal. FDA's review describes meal-tolerance criteria involving meal consumption, vomiting, and nausea.[1][4] Without the full protocol and analysis plan, this summary cannot independently verify when those detailed criteria or analyses were specified.

Secondary measures described by FDA included time to first bowel movement, a composite of upper- and lower-gastrointestinal recovery, readiness for discharge, time to the discharge order, length of stay, appetite and nausea measures, vomiting episodes, nasogastric-tube insertion, passage of flatus, and bowel sounds.[4]

The registry is less specific: its only listed primary outcome is “Recovery of GI function” through hospital discharge.[3] That registry-to-paper difference should remain visible. A broad registered outcome label does not disclose the complete endpoint definition or analysis.

Primary efficacy result

The median time to the first tolerated meal was 25.3 hours with ipamorelin and 32.6 hours with placebo, a numerical difference of 7.3 hours. FDA's review reports a hazard ratio of 1.34, with a 95% confidence interval from 0.90 to 1.98 and p=0.15. Its table identifies a Cox proportional-hazards model for this comparison.[1][4]

The reported key comparison was not statistically significant and did not demonstrate superiority. That is not proof of an exactly zero effect or of equivalence between the groups. The PubMed abstract gives the medians and p-value but not the confidence interval; the hazard ratio and interval above come from FDA's review, not a new calculation or independent reanalysis.[1][4] The negative and null results guide explains these distinctions.

Secondary outcomes

The authors reported no statistically significant differences between ipamorelin and placebo in the key or secondary efficacy analyses.[1] FDA's table also reports non-significant comparisons for composite gastrointestinal recovery and length of stay.[4]

FDA describes a shorter recovery pattern in a surgery-type subgroup.[4] An exploratory subgroup pattern cannot replace the overall null finding. Without the full analysis plan, this summary does not assert that the subgroup analysis was prespecified or multiplicity-controlled.

Adverse events and safety uncertainty

Any treatment-emergent adverse event was reported in 87.5% of the ipamorelin group and 94.8% of the placebo group. Although the abstract's authors described the short treatment course as well tolerated, that is not proof of safety beyond this small inpatient study.[1]

FDA's 2024 review reported serious adverse events in 10 of 56 ipamorelin-treated participants (17.9%) and 9 of 58 placebo-treated participants (15.5%). Hypokalemia, insomnia, and discharge hyperglycemia were numerically more frequent with ipamorelin. Two ipamorelin-treated participants died following postoperative complications; FDA states that whether those deaths were related to ipamorelin was unclear.[4] This summary does not independently classify them as drug-caused or drug-unrelated.

Surgery and underlying illness complicate interpretation, and this sample cannot characterize uncommon or delayed harms. The adverse-event and tolerability guide explains why event occurrence, seriousness, and causality are different questions.

FDA currently lists ipamorelin acetate in Category 2 under its section 503B interim compounding policy. The page identifies potential immunogenicity and peptide-characterization concerns and insufficient safety information for certain other injectable routes.[5] This is form- and policy-specific safety-risk information, not an approval determination for the trial material. The 2024 advisory-committee briefing is a scientific review, not itself FDA's final regulatory determination.[4]

Attrition and missing information

The paper reports 117 enrolled participants and 114 in the safety and modified intention-to-treat populations: 56 ipamorelin and 58 placebo.[1][4] FDA describes consent withdrawal and failure of postoperative entry criteria as reasons for exclusions, but the reviewed account does not give a reliable numerical split between those reasons. The timing relative to randomization is also unresolved. This summary therefore does not call all 117 participants randomized or describe three confirmed post-randomization exclusions.

The analysis total of 114 is not a treatment-completion count. FDA reports study-drug discontinuation because of adverse events in three participants in each group.[4] ClinicalTrials.gov has no posted participant-flow or summary-result tables, and no full protocol or statistical analysis plan is attached to the record.[3]

The available sources do not resolve allocation concealment, the complete analysis-set rules, time-to-event censoring, missing-data handling, or multiplicity control. Identifying the Cox model does not verify its assumptions or how incomplete recovery observations were handled. These are reporting limits of this review, not invented findings about the original methods.

Statistical significance, effect size, and clinical importance

• Statistical significance: the reported p=0.15 did not demonstrate superiority on the key efficacy outcome.
• Effect size: the medians differed by 7.3 hours, but subtracting medians is not a complete time-to-event treatment estimate.
• Uncertainty: FDA's reported hazard-ratio interval, 0.90 to 1.98, crosses 1 and permits effects in either direction. It does not account for every possible bias or unverified analysis assumption.[4]
• Clinical importance: faster recovery could matter to patients and hospitals, but this study did not establish that its numerical difference represented a reliable clinical benefit.

Sponsor and disclosures

The registry names Helsinn Therapeutics (U.S.), Inc. as sponsor. The publisher's public disclosures state that Helsinn supported the study and provided grants to the authors' institutions. Helsinn also supported manuscript development; The Curry Rockefeller Group, LLC provided copyediting, editorial, and production assistance. The authors declared no financial or proprietary conflicts of interest.[2][3]

These disclosures should be reported together. Industry support is relevant context, but it does not by itself validate or invalidate a result.

Important limitations

• This was a small proof-of-concept study with 114 participants in the reported analysis populations.
• Participants had a broad range of underlying conditions and underwent different types of bowel-resection surgery.
• Enrollment, analysis inclusion, and treatment completion are distinct counts; the exact exclusion split and randomization timing remain unresolved.
• The published endpoint description is more specific than the registered outcome label.
• The full journal methods, standalone protocol, and analysis plan were not available for this review. Prespecification, censoring, missing-data rules, and multiplicity handling have not been independently established.
• The hazard ratio and interval are reported through FDA's later scientific review; the abstract omits them and the registry has no summary results.
• The trial tested a short intravenous inpatient protocol, not other routes, formulations, populations, or claimed uses.
• The study and manuscript-support disclosures belong alongside the findings and limitations.

What this study does not prove

The numerical 7.3-hour median difference does not establish efficacy when the reported key comparison was not statistically significant. Nor does this study prove no biological activity, an exactly zero clinical effect, or equivalence to placebo.

It does not support claims about body composition, athletic recovery, sleep, longevity, growth-hormone deficiency, or other untested outcomes. It also does not authenticate separately sourced ipamorelin or establish equivalence across free-base and acetate forms, routes, formulations, manufacturing processes, or lots.

Registration, publication, and product-specific regulatory status are separate questions. See the registry and FDA status-check guide for how to keep them distinct.

Frequently asked questions

What did NCT00672074 test?

It tested protocol-defined intravenous ipamorelin against placebo for postoperative gastrointestinal recovery in adults after bowel-resection surgery.

Did ipamorelin meet the key efficacy endpoint?

It did not demonstrate superiority on the reported key comparison. Median time to the first tolerated meal was 25.3 versus 32.6 hours, with p=0.15.[1]

Were secondary outcomes positive?

The authors reported no significant differences in the key or secondary efficacy analyses. A subgroup pattern does not overturn that overall result.[1][4]

Does p=0.15 prove there was no effect?

No. A non-significant result is not proof of zero effect or equivalence. FDA reports a hazard ratio of 1.34 with a 95% confidence interval from 0.90 to 1.98; the estimate, uncertainty, and unverified methods all matter.[4]

Were deaths reported in the study?

FDA's review reports two deaths among ipamorelin-treated participants after postoperative complications and says their relationship to ipamorelin was unclear.[4]

Are results or a full protocol posted on ClinicalTrials.gov?

As checked September 2, 2026, the record was completed but had no summary results, participant-flow tables, or attached full protocol or statistical analysis plan.[3] That does not establish that those documents never existed.

Does the trial support other marketed uses of ipamorelin?

No. It studied one inpatient postoperative question and does not establish outcomes for untested uses or another material.

Primary and official sources

1. Primary paper record: Ipamorelin postoperative-ileus trial, PMID 25331030
2. Publisher's public abstract and disclosures; primary paper DOI: 10.1007/s00384-014-2030-8
3. ClinicalTrials.gov: NCT00672074
4. FDA 2024 scientific briefing on ipamorelin-related bulk drug substances
5. FDA: Certain bulk drug substances that may present significant safety risks

Review and corrections

Sources checked September 2, 2026. Serum Research is responsible for this source-limited editorial summary. No independent clinical, statistical, scientific, analytical, or regulatory review is claimed. The complete paper methods, standalone protocol, and statistical analysis plan were not available for this review; this page does not claim a full-methods audit. It is not medical advice, dosing or administration guidance, or a finding that any separate material is authentic, equivalent, safe, or effective.

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