Peptide Schedule
Larazotide (AT-1001)8 residuesGGVLVQPGEach bubble = one amino acid. Size = residue mass. Color = chemical class.Larazotide (AT-1001)
Benefits
About Larazotide (AT-1001)
Larazotide acetate (AT-1001) is a synthetic eight-amino-acid peptide (sequence: GGVLVQPG) derived from Vibrio cholerae's zonula occludens toxin. It's the first-in-class tight junction regulator designed to treat celiac disease by reducing intestinal permeability — commonly called "leaky gut." Unlike most peptides, larazotide is taken orally as a capsule and works entirely within the gut lumen without entering the bloodstream. This local action gives it a clean safety profile with minimal systemic side effects. In Phase 2b trials involving 342 celiac patients on a gluten-free diet, the 0.5 mg three-times-daily dose significantly reduced GI symptoms compared to placebo, with a 26% decrease in symptomatic days and a 31% increase in improved symptom days. It's designed to complement — not replace — a gluten-free diet, targeting the roughly 40% of celiac patients who continue experiencing symptoms despite strict dietary adherence. The peptide blocks zonulin receptors on intestinal epithelial cells, preventing tight junction disassembly triggered by gluten-derived gliadin peptides. This keeps the paracellular space sealed, reducing the inflammatory cascade that drives celiac symptoms. Early trials also showed it could prevent the spike in intestinal permeability during controlled gluten challenges. However, the Phase 3 CedLara trial (525 patients) was discontinued in 2022 when interim analysis revealed the treatment effect was insufficient to reach significance with a practical sample size. 9 Meters Biopharma, the developer, subsequently analyzed subgroup data for potential responder populations. The drug's story highlights both the promise of oral peptide therapeutics and the difficulty of translating Phase 2 results into Phase 3 success.
Who Should Consider Larazotide (AT-1001)
- Celiac disease patients with persistent GI symptoms despite strict gluten-free diet adherence
- Individuals with confirmed increased intestinal permeability (elevated lactulose/mannitol ratio)
- Celiac patients seeking an adjunct therapy to complement their gluten-free diet
- Adults with non-celiac gluten sensitivity and documented barrier dysfunction
- Researchers studying tight junction regulation and zonulin pathway interventions
How Larazotide (AT-1001) Works
Larazotide acts as a zonulin receptor antagonist at the intestinal epithelial surface. When gluten-derived gliadin peptides reach the intestinal lumen, they trigger zonulin release from enterocytes. Zonulin then binds to epidermal growth factor receptor (EGFR) and protease-activated receptor 2 (PAR2) on the basolateral side of epithelial cells, transactivating EGFR in a PAR2-dependent manner. This activates phospholipase C, which generates inositol 1,4,5-triphosphate and diacylglycerol, leading to PKC-alpha activation. PKC-alpha phosphorylates tight junction proteins — including ZO-1 and myosin 1C — and promotes actin polymerization, physically pulling apart the tight junction complex and increasing paracellular permeability. Larazotide blocks this entire cascade by occupying zonulin binding sites, preventing receptor activation. It also inhibits myosin light chain kinase (MLCK), which reduces cytoskeletal tension on actin filaments and promotes tight junction closure. The net effect is stabilization and redistribution of tight junction proteins back to the cell membrane, restoring the intestinal barrier. Because larazotide works in the luminal space and isn't absorbed, it targets the disease mechanism at its origin without systemic immune suppression.
What to Expect
Begin taking 0.5 mg capsules three times daily before meals. No immediate symptom changes expected. Larazotide works locally in the gut and requires consistent dosing to stabilize tight junctions.
Some patients began noticing reduced bloating and abdominal discomfort during this period in clinical trials. Intestinal permeability markers may start to shift.
Measurable symptom improvement becomes more apparent. In Phase 2b, the 0.5 mg group showed a 26% decrease in symptomatic days by this point. Abdominal pain scores typically show the clearest response.
Peak clinical benefit observed in trials. Patients achieving response typically show a 50% or greater reduction in weekly average abdominal pain scores. Symptom improvement plateaus.
Long-term maintenance data is limited since trials capped at 12 weeks. Continued use alongside a gluten-free diet is the intended model. No tolerance development was seen during trial durations.
Dosing Protocol
| Level | Dose / Injection | Frequency |
|---|---|---|
| Beginner | 0.5mg | 3x Daily |
| Moderate | 0.5mg | 3x Daily |
| Aggressive | 1mg | 3x Daily |
Note: Larazotide is an oral peptide — one of the few peptides that doesn't require injection. It acts locally in the intestinal lumen and isn't absorbed into the bloodstream. Clinical trials used oral capsules dosed three times daily before meals. The 0.5 mg TID dose showed the strongest results in Phase 2b; higher doses (1 mg, 2 mg) didn't outperform placebo, suggesting an inverted dose-response. The Phase 3 CedLara trial was discontinued in June 2022 after interim analysis showed the effect size was too small to reach statistical significance with a feasible sample size. Despite this setback, larazotide remains the most clinically advanced tight junction regulator ever tested.
How to Inject Larazotide (AT-1001)
Larazotide is taken orally as a capsule three times daily, 15 minutes before meals (breakfast, lunch, dinner). The clinically supported dose is 0.5 mg per capsule, three times daily (1.5 mg total daily). Higher doses (1 mg, 2 mg TID) were tested but didn't show benefits over placebo in Phase 2b. Capsules should be swallowed whole with water on an empty stomach. No reconstitution, injection, or refrigeration is required.
Cycling Protocol
Clinical trials used 12-week continuous dosing periods. Larazotide is intended for ongoing daily use alongside a gluten-free diet, not as a short-term cycle. No evidence of tachyphylaxis or tolerance was observed during 12-week treatment periods. Long-term use patterns haven't been established in controlled trials.
Pharmacokinetics
Source: Estimated luminal activity duration of 1-4 hours based on porcine model showing peak duodenal concentrations at ~1 hour post-dose; larazotide is not systemically absorbed so plasma half-life is not applicable
Loading the interactive decay curve.
Side Effects
Safety was comparable to placebo across all clinical trials. The most commonly reported adverse events were headache (~5-7%) and urinary tract infections (~5%), both occurring at similar rates in the placebo group. Mild GI symptoms (nausea, flatulence) were occasionally noted but didn't differ from placebo. No serious drug-related adverse events were reported in any trial. No clinically significant changes in liver enzymes, kidney function, bone markers, hemodynamic measures, or ECG parameters were observed. The favorable safety profile is expected given that larazotide isn't systemically absorbed.
Contraindications
- Pregnancy or breastfeeding (insufficient safety data in these populations)
- Known hypersensitivity to larazotide acetate or any capsule excipients
- Children under 18 years (clinical trials enrolled adults only)
- Active gastrointestinal infections or acute inflammatory bowel disease flares
- Patients who haven't been evaluated for celiac disease — larazotide is not a diagnostic tool
Drug Interactions
- Immunosuppressants (azathioprine, methotrexate) — overlapping effects on intestinal immune responses; combined use not studied
- Oral medications with narrow therapeutic windows — changes in intestinal permeability could theoretically alter absorption of co-administered drugs
- Proton pump inhibitors and H2 blockers — altered gastric pH could affect capsule dissolution timing
- NSAIDs — these increase intestinal permeability independently and may counteract larazotide's barrier-protective effects
Storage & Stability
Molecular Profile
Related Peptides
References
- Larazotide acetate for persistent symptoms of celiac disease despite a gluten-free diet (Kelly et al., Gastroenterology 2015)PubMed 25683116
- A randomized, double-blind study of larazotide acetate to prevent the activation of celiac disease during gluten challenge (Leffler et al., Am J Gastroenterol 2012)PubMed 22825365
- Larazotide acetate: a pharmacological peptide approach to tight junction regulation (Slifer et al., Am J Physiol 2021)PubMed 33881350
- The potential utility of tight junction regulation in celiac disease: focus on larazotide acetate (Khaleghi et al., Ther Adv Gastroenterol 2016)PubMed 26770266
- Larazotide acetate for treatment of celiac disease: a systematic review and meta-analysis (Troisi et al., Clin Res Hepatol Gastroenterol 2022)PubMed 34339872