Larazotide

What it is

Larazotide is an eight amino acid peptide that acts on the tight junctions between intestinal epithelial cells. In coeliac disease, gluten exposure triggers zonulin release, tight junctions loosen, and gliadin fragments cross the epithelium to meet the immune system underneath. Larazotide is designed to keep those junctions closed.

It is taken orally and is not meaningfully absorbed. That is intentional: the target is the gut lumen, not the bloodstream.

Why it is rated higher than most gut peptides

Because somebody ran the trials.

Phase 2b, published in 2015, tested larazotide in coeliac patients who still had symptoms despite a gluten-free diet. The 0.5 mg dose significantly reduced symptoms against placebo. That is a real randomised result in the actual target population, and it is more than almost anything else in this category has.

The phase 3, CedLara, enrolled 525 patients across 0.25 mg, 0.5 mg and placebo arms. An interim analysis after the twelve week double-blind efficacy portion found the effect too small to justify continuing: the sample size that would have been required to demonstrate significance was larger than the trial could support. It was discontinued in 2022.

What a futility stop actually means

It is not the same as a safety failure, and it is not quite the same as a clean negative either.

The trial was stopped because the observed effect size made success improbable, not because the drug harmed anyone. The phase 2 result did not replicate at scale, which is the single most common fate of promising phase 2 findings across all of medicine.

This entry sits at the trials tier because randomised human data exists, and the honest reading of that data is that the compound did not work well enough. That is a more informative position than the compounds on this site with no trials at all, and it is not a recommendation.

Practical notes

• It was never proposed as a way to eat gluten. Every trial enrolled people already on a gluten-free diet, targeting residual symptoms from incidental exposure. Any framing of this as a gluten-blocking pill misrepresents what was studied.
• The dosing schedule was demanding. Three times daily before meals, because the peptide has to be in the lumen when the gluten is. Adherence to that in real life is a separate problem from efficacy.
• The interim data has not been fully published. As with AOD-9604, the negative pivotal result is harder to find than the positive earlier one.

Side effects and warning signs

Commonly reported

• Headache
• Nausea
• Abdominal pain
• Generally well tolerated in trials, with adverse events close to placebo

Stop and get medical help

• This is not a substitute for a gluten-free diet and was never tested as one. It was studied only as an adjunct in people already avoiding gluten
• Persistent coeliac symptoms should be investigated rather than medicated, since refractory coeliac disease and other diagnoses look similar

Sources

1. Larazotide acetate for persistent symptoms of coeliac disease despite a gluten-free diet, randomised controlled trialtrial
2. 9 Meters discontinues phase 3 trial of larazotide, Celiac Disease Foundation 2022news

From the community

Discussion for this compound concentrates in r/Celiac and r/Peptides.

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