Larazotide Acetate 881851-50-9

Larazotide More Info

Larazotide is an investigational, first-in-class octapeptide drug candidate designed to regulate intestinal tight junctions. Chemically known as larazotide acetate, this synthetic compound consists of eight amino acids (Gly-Gly-Val-Leu-Val-Gln-Pro-Gly) and has a molecular weight of approximately 725.8 g/mol . Its structure is derived from a protein (zonula occludens toxin) secreted by the bacterium Vibrio cholerae, and it shares a conserved motif with the human protein zonulin, which is involved in modulating intestinal permeability . As a non-systemic, gut-restricted agent, larazotide is designed to act locally within the gastrointestinal tract, thereby minimizing potential systemic side effects .

The primary mechanism of action for larazotide is its function as a zonulin receptor antagonist . In conditions like celiac disease, exposure to gluten peptides (gliadin) triggers the release of zonulin from intestinal epithelial cells. Zonulin then initiates a signaling cascade that leads to the disassembly of tight junction protein complexes, increasing paracellular permeability . Larazotide inhibits this process by blocking the putative zonulin receptors on the luminal surface of the small intestine, thereby preventing the breakdown of tight junctions and limiting the trafficking of immunogenic gluten fragments into the lamina propria . More recent research suggests it may also inhibit myosin light chain kinase, which further contributes to stabilizing the tight junction structure .

While initially developed and most extensively studied for celiac disease, recent clinical investigations have revealed potential applications for larazotide beyond this primary indication. A phase 2a trial published in 2025 examined its use in children with multisystem inflammatory syndrome in children (MIS-C), a rare but serious post-COVID-19 inflammatory condition . The study found that larazotide was safe and well-tolerated, and was associated with faster clearance of SARS-CoV-2 spike antigen from circulation, quicker resolution of gastrointestinal symptoms, and an accelerated return to normal activities compared to standard care alone . This therapeutic benefit is hypothesized to result from strengthening intestinal barriers, which limits the translocation of persistent viral particles from the gut into the bloodstream .

The development pathway for larazotide has included multiple clinical trials across phases 1 through 3. Early phase 1 studies focused on establishing safety, tolerance, and pharmacokinetic profiles in both healthy volunteers and patients with controlled celiac disease . Phase 2 trials demonstrated that larazotide could reduce gastrointestinal symptoms and blunt the increase in anti-tissue transglutaminase antibodies following gluten challenge . Subsequently, phase 3 trials were initiated to evaluate its efficacy and safety for relieving persistent symptoms in adult celiac disease patients maintaining a gluten-free diet . According to clinical trial registries, a phase 3 study with 307 participants was conducted, though it was ultimately terminated .

The safety profile of larazotide observed across clinical trials has been generally favorable. In the MIS-C pediatric study, no larazotide-related adverse events were reported, and the drug was well tolerated at the dosing regimen of 10 mcg/kg (maximum 500 mcg/dose) four times daily for three weeks . Its gut-restricted nature as a non-systemic, intestine-targeted peptide is considered a valuable characteristic, as therapeutic activity is concentrated within the gastrointestinal tract while the risk for systemic exposure and whole-body toxicities is diminished . This safety profile supports ongoing research into larazotide for additional conditions where barrier dysfunction plays a pathogenic role, including potential applications in type 1 diabetes and long COVID .