larazotide

first-in-class zonulin antagonist for celiac disease, an oral gut-barrier peptide. positive phase 2b, then the pivotal phase 3 failed a feasibility interim in 2022 and 9 meters shelved it.

tier D · healing · octapeptide celiac P3 · failed 2022

verdict

an oral tight-junction peptide that tried to make celiac disease livable, and got further than any drug in its class before the pivotal phase 3 failed. discontinued, not approved.

if you're asking whether larazotide works for celiac — on the pivotal evidence, no. larazotide reached a phase 3 trial (CeDLara) for persistent celiac symptoms on a gluten-free diet, and in June 2022 a pre-planned interim analysis concluded the trial could not feasibly reach statistical significance. 9 meters biopharma halted it and shelved the program. that verdict came despite a positive phase 2b (Leffler 2015, 0.5mg three times daily), which is what makes the failure notable: the mechanism looked real, the pivotal did not confirm it.

if you came for the tight-junction / 'leaky gut' angle — larazotide is the most legitimate tight-junction drug ever built. it is a synthetic octapeptide derived from a cholera-toxin fragment that antagonizes zonulin, the signal that loosens the junctions between gut-lining cells. taken orally, it stays in the gut lumen and is barely absorbed, so it acts locally to keep the barrier tight. that is a real, well-characterized mechanism, and larazotide took it furthest in the clinic. the biology is not why it sits at D. the failed pivotal is.

if you're asking about sourcing larazotide as a gut peptide — it is not approved, not on any pharmacy shelf, and the developer discontinued it. any research-peptide vial sold under this name is trading on a mechanism whose one pivotal trial failed. if you are after gut-barrier support, the more-studied peptides in that lane sit higher on the board. larazotide's arc is a cautionary one: a clean mechanism is not the same as a drug that works.

based on published trials. larazotide is investigational, discontinued, and not available. not medical advice.

why D-tier

larazotide grades D, and the mechanism is not the reason. this is the most legitimate tight-junction drug ever built: a real zonulin target, an oral gut-local octapeptide, and a positive phase 2b. but D is the board's slot for failed pivotals, and larazotide's is textbook. its phase 3 (CeDLara) was terminated in June 2022 after a pre-planned interim concluded it could not feasibly reach significance, and 9 Meters discontinued the program. a clean mechanism that failed its one decisive trial and has no path to market sits at D, with the honest note that the failure was efficacy magnitude, not safety.

the core tension

larazotide is the cleanest mechanism on this tier and still landed here. a real target (zonulin), a real oral gut-local peptide, a positive phase 2b, and the most credible shot the entire tight-junction field ever got. then the pivotal phase 3 failed a feasibility interim in 2022 and the program was shelved. the tension is that good biology and a discontinued drug can be the same molecule.

what it is

A first-in-class synthetic octapeptide (8 amino acids, Gly-Gly-Val-Leu-Val-Gln-Pro-Gly), derived from a fragment of the Vibrio cholerae zonula occludens toxin. It antagonizes zonulin, the human protein that signals the tight junctions between intestinal cells to loosen. Taken orally, larazotide is designed to act locally in the gut lumen with minimal systemic absorption. Development code AT-1001. CAS 258818-34-7.

what it does

In celiac disease, gluten triggers zonulin release, the junctions loosen, and gluten fragments cross the barrier to drive the immune response. Larazotide's premise is to keep those junctions shut, blunting the leak even when a gluten-free diet is imperfect. It was studied as an adjunct to the diet, for patients who still have symptoms despite avoiding gluten, not as a replacement for the diet.

origin

The zonulin pathway was mapped by Alessio Fasano's group, and larazotide (AT-1001) came out of Alba Therapeutics, later moving to Innovate Biopharmaceuticals and then 9 Meters Biopharma. A phase 2b trial (Leffler et al., Gastroenterology 2015) found the 0.5mg three-times-daily dose reduced symptoms in celiac patients on a gluten-free diet. That result launched the pivotal phase 3, CeDLara.

why researchers are interested

For years larazotide was the great hope of the tight-junction world, the one 'leaky gut' compound with a real target (zonulin), a real mechanism, and a real trial program behind it. It gave the entire intestinal-permeability field its most credible clinical shot. That is why the failure landed so hard: this was not a supplement with a story, it was the best case the mechanism ever got.

does it work

Not on the pivotal evidence. The phase 2b signal was genuine, but in June 2022 a pre-planned interim analysis of the phase 3 concluded the trial could not feasibly reach statistical significance, and 9 Meters discontinued it. As of 2026 no further development has been announced. The mechanism stays scientifically interesting; the drug did not clear the bar that decides it.

claims vs the data

key facts

frequently asked questions

What is larazotide?

Larazotide (larazotide acetate, AT-1001) is a first-in-class synthetic octapeptide that antagonizes zonulin, the signal that loosens the tight junctions between gut-lining cells. Taken orally, it acts locally in the gut to keep the intestinal barrier tight. It was developed for celiac disease as an adjunct to a gluten-free diet and reached phase 3 before being discontinued in 2022.

Does larazotide work for celiac disease?

Not on the pivotal evidence. A phase 2b trial (Leffler et al., 2015) found the 0.5mg dose reduced symptoms, but the phase 3 CeDLara trial was terminated in June 2022 after a pre-planned interim analysis concluded it could not feasibly reach statistical significance. The program was discontinued. It is not approved for celiac disease or anything else.

How does larazotide work?

In celiac disease, gluten triggers release of zonulin, which loosens the tight junctions between intestinal cells and lets gluten fragments cross the barrier to provoke the immune response. Larazotide antagonizes zonulin to keep those junctions shut, reducing the leak. It is designed to stay in the gut lumen with minimal systemic absorption, so it acts locally on the barrier.

Can you buy larazotide?

It is not approved and not on any pharmacy shelf, and the developer (9 Meters Biopharma) discontinued it after the phase 3 failure. Any research-peptide vial sold under the name is trading on a mechanism whose one pivotal trial did not confirm efficacy.

Is larazotide FDA approved?

No. Larazotide is investigational and was never approved. Its pivotal phase 3 was terminated in 2022 and no further development has been announced as of 2026.

Why did larazotide fail?

The phase 2b signal at 0.5mg did not hold up at scale. In June 2022, an independent interim analysis of the phase 3 determined that the number of additional patients needed to reach statistical significance would be too large to feasibly continue. This was unexpected given the phase 2b, and it is a textbook example of a promising mid-stage signal not confirming in a pivotal trial.

related peptides

reptides grades the research record and cites the literature behind every call. research reference only; not medical advice.