WEDNESDAY, Aug. 6, 2025 (HealthDay News) -- Treatment of multisystem inflammatory syndrome in children (MISC), a postacute sequela of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), with larazotide speeds resolution of gastrointestinal symptoms and clearance of spike antigen, according to a study published online July 30 in Science Translational Medicine.According to Lael M. Yonker, M.D., from Massachusetts General Hospital in Boston, and colleagues, a potential role for viral spike protein translocated via zonulin-mediated trafficking from gastrointestinal reservoirs of SARS-CoV-2 into the circulation has been suggested for treatment of postacute sequelae of COVID-19 (PASC). Yonker and colleagues reported the results of a phase 2a randomized trial testing the zonulin antagonist larazotide in 12 children with MISC (median age, 5.7 years). Children were enrolled during acute MISC hospitalization and were treated four times daily with adjuvant larazotide therapy for three weeks. Twenty-four weeks of follow-up was conducted for safety monitoring.The researchers found no reports of larazotide-related adverse events. They found a correlation of concentration of SARS-Cov-2 spike protein antigen in blood samples with inflammatory markers, including interferon-γ and interleukin-6, and with gastrointestinal symptoms. Faster resolution of gastrointestinal symptoms, faster clearance of spike antigen, and a faster return to usual activities were seen for children treated with larazotide."Whereas the study here targeted MISC, evidence suggests a continuum of pathogenesis across other forms of postacute sequelae of COVID-19, and, therefore, larazotide should be considered as an adjuvant therapy targeting gastrointestinal symptoms in other forms of PASC," the authors write.Several authors disclosed ties to the biopharmaceutical industry; several authors are coinventors on a patent relating to zonulin antagonists for treatment of MISC.Abstract/Full Text (subscription or payment may be required).Sign up for our weekly HealthDay newsletter