# Refractory CMV Enteritis in Small Bowel Transplantation: A Case Highlighting the Challenges of Balancing Immunosuppression and Novel Antiviral Therapies

## TL;DR

This case study shows the difficulty of treating CMV enteritis in small bowel transplant patients due to the need for heavy immunosuppression and limited effectiveness of antiviral treatments.

## Contribution

The paper highlights the use of novel antiviral agents in managing refractory CMV disease in small bowel transplant recipients.

## Key findings

- Refractory CMV disease occurred despite absence of genotypic resistance and use of first-line therapy.
- Combination antiviral strategies, including maribavir, showed clinical improvement in the patient.
- Outcomes remain poor despite aggressive therapies due to severe immunologic compromise.

## Abstract

Background: Cytomegalovirus (CMV) remains a formidable complication in small bowel transplantation (SBT) due to the graft’s high immunogenicity and profound immunosuppression required, with refractory disease representing a particularly devastating challenge. Case: We report an 18-year-old male who underwent SBT, complicated by recurrent acute rejection episodes requiring intensive immunosuppression. He developed refractory CMV disease, marked by non-response to first line therapy with ganciclovir—despite the absence of genotypic resistance—necessitating sequential use of foscarnet, dual antivirals, CMV immunoglobulin, and novel agents (maribavir and letermovir). Discussion: This case illustrates the multifactorial drivers of refractory CMV disease in SBT recipients, including donor–recipient serostatus mismatch, profound immunosuppression through T-cell-depleting induction, corticosteroid exposure, and biologic therapy. It highlights the distinction between refractory and resistant CMV, and the role of combination antiviral strategies including novel agents to achieve disease control. Outcomes remain dismal despite aggressive and innovative therapies, underscoring the limited efficacy of interventions in the context of severe immunologic compromise. Conclusions: Refractory CMV enteritis in SBT exemplifies the extreme difficulty of balancing viral control with rejection management. Despite exhausting antiviral strategies, survival remains poor. Highlights: Refractory CMV enteritis is a significant challenge in small bowel transplant recipients due to intense immunosuppression. Persistent CMV disease may occur despite antiviral prophylaxis and the absence of resistant gene mutations. Combination antiviral strategies, including maribavir, demonstrated significant clinical improvement. Profound immunosuppression required to manage acute graft rejection episodes complicates antiviral management and disease clearance. Despite best efforts in CMV management in this population, outcomes may still be compromised by unrelated or compounding factors.