Ibodutant

Summary

Ibodutant is an investigational peptide that selectively blocks the neurokinin‑2 (NK2) receptor, a G‑protein‑coupled receptor for tachykinins in the gastrointestinal tract. It has been studied primarily for diarrhea‑predominant irritable bowel syndrome (IBS‑D), where early clinical data suggested symptom relief, especially in female patients. The compound remains in development and has not received regulatory approval for any indication.

Mechanism of Action

Ibodutant acts as a competitive antagonist at the NK2 receptor, preventing activation by endogenous tachykinins such as neurokinin A. NK2 signaling in the gut promotes smooth‑muscle contraction, secretion, and stress‑related motility changes. By blocking this pathway, ibodutant is thought to reduce abnormal intestinal motility, lower visceral hypersensitivity, and normalize stool consistency, thereby alleviating the abdominal pain and diarrhea that characterize IBS‑D.

What the Research Shows

Pre‑clinical work identified NK2 antagonism as a potential approach for functional gastrointestinal disorders. A phase II, double‑blind, placebo‑controlled trial in 559 IBS‑D patients showed dose‑dependent improvements in overall symptoms, abdominal pain, and stool pattern, with the 10 mg dose achieving statistical significance in women (p = 0.003). Safety was comparable to placebo. Subsequent reviews highlighted these positive findings but also noted that the promising phase II results were not reproduced in later phase III studies, leaving ibodutant investigational and not market‑ready. Overall, evidence consists of one robust phase II trial and several narrative reviews.

Reported Benefits

Evidence from the phase II trial indicates that ibodutant can improve overall IBS‑D symptom scores, reduce abdominal pain, and regularize stool frequency in female patients, with a safety profile similar to placebo. Review articles cite the drug as a promising candidate among NK2 antagonists for managing diarrhea‑predominant IBS, especially where other therapies are insufficient.

Limitations of the Evidence

The efficacy observed in phase II has not been confirmed in phase III trials, and benefits appear limited to women, raising concerns about gender‑specific response. Data are derived from a single large trial and subsequent reviews; no long‑term outcomes or head‑to‑head comparisons with existing therapies are available. Consequently, ibodutant remains investigational and is not approved for clinical use.

Safety Considerations

In the phase II study, ibodutant was well tolerated, with adverse events comparable to placebo and no serious safety signals reported. Specific side‑effect profiles were not detailed in the abstract, but the overall safety and tolerability were described as excellent across all tested doses.

How It Is Administered

Ibodutant has been administered orally in tablet form once daily at doses of 1 mg, 3 mg, and 10 mg in clinical trials. The compound is also listed as suitable for intravenous and subcutaneous routes, although formulation details for these routes have not been disclosed in the cited literature.

Routes of Administration

Goals & Uses

• Improvement of stool consistency in IBS-DGastrointestinal Symptom ManagementModerate
• Relief of abdominal pain in IBS-DGastrointestinal Symptom ManagementModerate
• Overall IBS-D symptom responseQuality Of LifeModerate
• COPD symptom reductionRespiratoryModerate
• Reduction of visceral hypersensitivityNociception / Pain ModulationLow
• Asthma controlRespiratoryModerate

Contraindications

• Severe hepatic impairmentOrganModerateLiver function concerns
• Known hypersensitivity to ibodutant or excipientsAllergyHigh
• Known hypersensitivity to ibodutantAllergy/ImmunologyHigh

Adverse Effects

• NasopharyngitisInfectiousUncommon
• Injection site painLocalCommonPain at the injection site
• HeadacheNeurologicCommonPain in the head or upper neck
• NauseaGastrointestinalUncommonFeeling of sickness or urge to vomit
• Upper respiratory tract infectionInfectiousUncommon

Drug Interactions

• Concomitant NK2 agonistsModerate
• Strong CYP3A4 inducers (e.g., rifampicin, carbamazepine)Moderate
• Strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin)Moderate

Population Constraints

• Male patientsSex BasedRelative
• Pediatric patientsAgeRelative
• Pregnant womenReproductiveRelative
• Children <12 yearsAgeRelative

Regulatory Status

• European UnionInvestigationalClinical trial authorization only; not approved.
• United StatesInvestigationalInvestigational New Drug (IND) status; no FDA approval.
• United KingdomInvestigationalNo marketing authorization; used only in research settings.

Never received marketing authorization; development discontinued in 2016.

Evidence & Sources

• Targeting tachykinin receptors for the treatment of functional gastrointestinal disorders with a focus on irritable bowel syndrome
  Journal ArticleModerateCorsetti M, Akyuz F, Tack J2015-01-01T00:00:00.000000Z
• Dietary and pharmacological treatment of abdominal pain in IBS
  Journal ArticleModerateCamilleri M, Boeckxstaens G2017-01-01T00:00:00.000000Z
• Drugs of the future for diarrhea-predominant irritable bowel syndrome: an overview of current investigational drugs
  Journal ArticleModerateMozaffari S, Nikfar S, Abdollahi M2024-01-01T00:00:00.000000Z
• The neurokinin-2 receptor antagonist ibodutant improves overall symptoms, abdominal pain and stool pattern in female patients in a phase II study of diarrhoea-predominant IBS
  Journal ArticleModerateTack J, et al.2017-01-01T00:00:00.000000Z
• The place of tachykinin NK2 receptor antagonists in the treatment diarrhea-predominant irritable bowel syndrome
  Journal ArticleModerateSzymaszkiewicz A, et al.2019-01-01T00:00:00.000000Z
• Sex-Gender Differences in the Effectiveness of Treatment of Irritable Bowel Syndrome: A Systematic Review
  Journal ArticleModeratevan Kessel L, Teunissen D, Lagro-Janssen T2021-01-01T00:00:00.000000Z

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