Larazotide acetate (AT-1001, INN-202)
Tight-junction-modulating peptide investigated as an adjunct therapy for celiac disease.
At a glance
What it is: Tight-junction-modulating peptide investigated as an adjunct therapy for celiac disease..
Primary research applications:
- Celiac disease (adjunct to gluten-free diet, investigational)
- Tight junction / intestinal permeability research
Editorial summary: Larazotide is the most clinically advanced "leaky gut" therapy ever taken to large trials. It is designed to tighten intestinal junctions in the presence of gluten exposure. Phase 3 results were mixed, and the program's regulatory pathway has been challenging — but it remains the reference compound for the tight-junction-modulator class.
- Class / structure
- Synthetic 8-amino-acid peptide (Gly-Gly-Val-Leu-Val-Gln-Pro-Gly)
- Half-life
- Designed to act locally in the gut
- First described
- Early 2000s
- Regulatory status
- Investigational (Phase 3 completed)
What is Larazotide?
Larazotide acetate is a synthetic eight-amino-acid peptide that modulates intestinal tight junctions, reducing the permeability increase triggered by gluten exposure in celiac patients.
Discovery and development
Larazotide (originally AT-1001) emerged from work on the protein zonulin and its modulation of intestinal tight junctions, led by Alessio Fasano's group. It was developed by Alba Therapeutics and later 9 Meters Biopharma as the first oral peptide therapeutic explicitly targeting paracellular permeability in celiac disease.
Mechanism of action
In celiac disease, gluten exposure triggers release of zonulin and downstream loosening of intestinal tight junctions, allowing immunogenic gluten peptides to cross the epithelial barrier and activate the lamina propria immune response. Larazotide is hypothesized to oppose this loosening — keeping tight junctions intact even in the presence of gluten exposure — thereby reducing the symptomatic and inflammatory consequences.[1]
Pharmacokinetics
Larazotide is administered orally and is designed to act locally in the small intestinal lumen. Systemic absorption is minimal — its therapeutic action is at the apical surface of intestinal epithelial cells.
What the research shows
The peer-reviewed literature on Larazotide is summarized below across two tiers: human research (the highest standard), and preclinical / emerging research (animal models and early-stage human work).
Claims and the evidence behind them
This table summarizes commonly discussed claims and how the published evidence weighs in. The aim is clarity — supported claims, claims that look promising but need more data, and claims that outrun the science.
| Claim | What the evidence shows | Verdict |
|---|---|---|
| Reduces celiac symptoms in some Phase 2 trials | CeD-PRO | Supported |
| Reached Phase 3 efficacy | CeDLara missed primary endpoint | Unsupported |
| Provides protection from accidental gluten exposure | Mechanistically plausible; clinical efficacy is mixed | Mixed |
Reported user experiences
How the research describes administration
Larazotide is given orally before meals in trial protocols, typically three times daily.
Editorial note
Administration details above describe how the peptide is given in published studies. We summarize this for educational completeness — these descriptions are not protocols, dosing recommendations, or instructions for personal use. Decisions about treatment require an appropriately licensed clinician.
Safety considerations and open questions
The takeaway
Larazotide remains the most rigorously tested tight-junction-modulating peptide and the closest thing the field has had to a clinically validated probe of paracellular permeability biology. Its Phase 3 setback was significant but does not invalidate the underlying mechanism — and the broader tight-junction therapeutic concept continues to attract investigational interest.
Frequently asked questions
Is larazotide approved for celiac disease?
No. Despite reaching Phase 3, it has not been approved by the FDA. Strict gluten-free diet remains the standard of care.
Does larazotide treat "leaky gut"?
The trial evidence is in celiac disease specifically. Broader "leaky gut" claims outside celiac are not supported by the larazotide data.
References
- Fasano A. Zonulin and its regulation of intestinal barrier function. Physiol Rev. 2011;91(1):151-175. https://pubmed.ncbi.nlm.nih.gov/21248165/
- Leffler DA, et al. Larazotide acetate for persistent symptoms of celiac disease despite a gluten-free diet. Gastroenterology. 2015;148(7):1311-1319. https://pubmed.ncbi.nlm.nih.gov/25683116/