Larazotide

Think of it as a promising academy footballer who scored in the reserves (Phase 2) and earned a big-money move to the first team (Phase 3), only to be quietly released mid-season because, against top opposition, the goals dried up. The talent was real and the data exist, but it never proved it could do the actual job, and it is now on nobody's team sheet.

Acts locally in the gut lumen as a tight-junction regulator, antagonising the zonulin pathway. Zonulin signalling normally opens the tight junctions between intestinal epithelial cells; in coeliac disease gliadin drives this opening, increasing paracellular ("leaky") permeability and letting immunogenic gluten peptides cross the gut barrier. Larazotide promotes reassembly of tight junctions and stabilises the epithelial actin cytoskeleton, reducing that leak. It is minimally systemically absorbed, so its effect is intended to be confined to the gut.

Research contexts. Not proven uses, and not recommendations.

Substantial for a peptide, but ultimately negative where it mattered. Multiple randomised, placebo-controlled human studies were run. An exploratory gluten-challenge RCT (Kelly et al., 2013, n=184) suggested reductions in gluten-induced symptoms but did not meet its primary intestinal-permeability endpoint. A Phase 2b RCT in 342 adults with coeliac disease who still had symptoms despite a gluten-free diet (Leffler et al., 2015) met its primary symptom endpoint, but only at the lowest dose tested, with higher doses showing no benefit - a non-monotonic pattern that should temper confidence. That signal nonetheless drove CeDLara, a large Phase 3 trial (NCT03569007, target ~525 patients) - reportedly the first Phase 3 trial of any coeliac disease drug. In June 2022 it was stopped early after a pre-specified interim analysis indicated the trial was unlikely to demonstrate a meaningful effect over placebo (futility). So while real human efficacy signals existed at Phase 2, the definitive trial did not confirm benefit, and larazotide is approved nowhere.

• !Failed its pivotal Phase 3 trial (CeDLara) - discontinued for futility in June 2022; the Phase 2 benefit did not replicate at scale.
• !The Phase 2b signal was confined to a single dose with a flat/inverse dose-response, and the earlier gluten-challenge study missed its primary permeability endpoint - the human evidence base is weaker than a headline 'positive trial' suggests.
• !Not an approved or licensed medicine in the UK, EU or US for any condition.
• !Coeliac disease has an effective management strategy (a strict gluten-free diet); any unproven peptide is no substitute and could give a false sense of security around gluten exposure.
• !Grey-market 'larazotide' sold as a 'research chemical' or 'gut peptide' is unregulated: identity, purity, sterility and actual content are unverified, and it is sold 'not for human consumption'.
• !Marketing it for 'leaky gut' in healthy people extrapolates well beyond the evidence - the human data are in coeliac disease, and even there the drug did not succeed.
• !Long-term safety in non-coeliac or self-dosing populations is essentially uncharacterised.

Not a licensed medicine in the UK. Larazotide has no MHRA marketing authorisation and is not approved by the EMA or FDA for any indication. It is an investigational drug whose lead development programme (coeliac disease) was discontinued in 2022. Any product sold to UK consumers as "larazotide" is an unlicensed research chemical, typically labelled "not for human consumption"; supplying or selling it for human use would fall foul of the Human Medicines Regulations 2012. It is not available on NHS or private prescription.

• NCT03569007· Phase 3· Discontinued (terminated June 2022 after a pre-specified interim futility analysis)

  CeDLara: Phase 3 study of larazotide acetate in coeliac disease patients with persistent symptoms on a gluten-free diet

  Sponsor 9 Meters Biopharma; target ~525 patients; primary endpoint CeD-PRO abdominal domain over a 12-week double-blind period. Reportedly the first Phase 3 trial of any coeliac disease drug.

• · Phase 2b· Completed - met primary endpoint at the lowest dose only

  Phase 2b randomised controlled trial of larazotide acetate for persistent coeliac symptoms (Leffler 2015)

  n=342; the trial that drove the move into Phase 3, though the benefit was dose-discordant.

1. 01
   Larazotide acetate for persistent symptoms of celiac disease despite a gluten-free diet: a randomized controlled trial — Leffler DA, Kelly CP, Green PHR, et al., Gastroenterology (2015)

   Phase 2b RCT (n=342). Met its primary symptom endpoint at the lowest dose only; the signal that justified Phase 3.

2. 02
   Larazotide acetate in patients with coeliac disease undergoing a gluten challenge: a randomised placebo-controlled study — Kelly CP, Green PHR, Murray JA, et al., Alimentary Pharmacology & Therapeutics (2013)

   Earlier exploratory human gluten-challenge RCT (n=184); reduced symptoms but missed its primary intestinal-permeability endpoint.

3. 03
   9 Meters Biopharma Announces Interim Analysis of Phase 3 Study of Larazotide for Celiac Disease Does Not Support Trial Continuation — 9 Meters Biopharma (company announcement), BioSpace / company press release (2022)

   Documents the June 2022 discontinuation of the CeDLara Phase 3 trial for futility.

4. 04
   Larazotide acetate, zonulin and tight-junction regulation in coeliac disease (PubMed search), PubMed (2021)

   Search link for the broader literature on the zonulin pathway and tight-junction regulation.