Post‐Pyloric Enteral Immunoglobulin for Treatment of Chronic Norovirus Diarrhea in Solid Organ Transplant Recipients: A Single Center Retrospective Study

BACKGROUND: Norovirus can cause devastating, chronic diarrhea in immunocompromised individuals. There is no approved therapy for this infection. Case series have described oral immunoglobulin (Ig) as a treatment option, but destruction by gastric enzymes may affect efficacy. This study reviews clinical outcomes and safety of enteral Ig given via post-pyloric nasoduodenal tube in solid organ transplant recipients (SOTRs) with chronic norovirus-related diarrhea. METHODS: All cases of chronic norovirus-related diarrhea in SOTRs managed with enteral Ig at our center were retrospectively reviewed. Enteral Ig was prepared from the intravenous Ig (IVIg) product and dosed at 50 mg/kg/dose every 6 h for 48 h. The primary outcome was resolution of diarrhea at 100 days; the secondary outcome was recurrence of norovirus-related diarrhea within 1 year. RESULTS: Seven SOTRs (five kidney, one kidney/pancreas, and one double lung recipient) with chronic norovirus-related diarrhea who received enteral Ig were identified. All patients had previously failed treatment with nitazoxanide, 28% had failed prior IVIg, and 80% had mycophenolate held without improvement. Diarrhea resolved in all patients following enteral Ig without documented recurrence, with median time to resolution of 21 days (IQR: 10-50). Adverse events included nausea and vomiting in one patient. CONCLUSION: Our small size and single-center study suggests that enteral Ig given via a nasoduodenal tube may be further evaluated as a potential approach for chronic norovirus infection in SOTRs. Large randomized controlled trials with symptom diaries to assess time to resolution more accurately, and serial stool nucleic acid testing, will be needed for confirmation.