Efficacy and safety of ribavirin therapy for chronic hepatitis E after kidney transplantation

Recent advances in hepatitis E virus research and the Japanese clinical practice guidelines for hepatitis E virus infection

Acute hepatitis E was considered rare until reports emerged affirming the existence of hepatitis E virus (HEV) genotypes 3 and 4 infections in Japan in the early 2000s. Extensive studies by Japanese researchers have highlighted the pivotal role of pigs and wild animals, such as wild boars and deer, as reservoirs for HEV, linking them to zoonotic infections in Japan. Currently, when hepatitis occurs subsequent to the consumption of undercooked or grilled pork, wild boar meat, or offal (including pig liver and intestines), HEV infection should be considered. Following the approval of anti-HEV immunoglobulin A antibody as a diagnostic tool for hepatitis E by Japan's Health Insurance System in 2011, the annual number of diagnosed cases of HEV infection has surged. Notably, the occurrence of post-transfusion hepatitis E promoted nationwide screening of blood products for HEV using nucleic acid amplification tests since 2020. Furthermore, chronic hepatitis E has been observed in immunosuppressed individuals. Considering the significance of hepatitis E, heightened preventive measures are essential. The Japan Agency for Medical Research and Development Hepatitis A and E viruses (HAV and HEV) Study Group, which includes special virologists and hepatologists, held a virtual meeting on February 17, 2024. Discussions encompassed pathogenesis, transmission routes, diagnosis, complications, severity factors, and ongoing and prospective vaccination or treatments for hepatitis E. Rigorous assessment of referenced studies culminated in the formulation of recommendations, which are detailed within this review. This comprehensive review presents recent advancements in HEV research and Japanese clinical practice guidelines for HEV infection.

Hepatitis E virus infections

Hepatitis E virus (HEV) infection is now endemic worldwide. Most patients with acute infection recover uneventfully. Outbreaks and sporadic cases, particularly in high-risk individuals are emerging increasingly. The patients with risk factors like pregnancy and pre-existing chronic liver disease, present with or progress rapidly to severe disease. Immuno-suppression in post-transplant patients is an additional risk factor. Standardized FDA-approved diagnostic tests are the need of the hour. Further studies are needed to establish guideline-based treatment regimen and outbreak preparedness for HEV to decrease global morbidity, mortality, and healthcare burden. Policies for screening donors and transplant cases are required.

Monitoring of hepatitis E virus RNA during treatment for chronic hepatitis E virus infection after renal transplantation

Background

Recently, chronic hepatitis E virus (HEV) infections gained increasing attention as a possible cause for elevated liver enzymes of unknown origin and liver cirrhosis in solid organ transplant recipients. Reduction of immunosuppressive therapy and/or use of antiviral drug ribavirin have been established as possible treatment strategies.

Methods

The efficacy of dose reduction of mycophenolic acid (MPA) and ribavirin therapy was retrospectively analyzed in eight renal transplant patients of our outpatient clinic who were diagnosed with HEV infection by detection of specific antibodies (immunoglobulin M and immunoglobulin G) and/or positive RNA in blood and stool. In four patients serial HEV viral loads in blood were measured.

Results

Only one patient reached HEV clearance after reduction of immunosuppressive therapy (predominantly reduction of MPA daily dose) alone, whereas six patients were treated with ribavirin after reduction of immunosuppressive therapy due to persistent virus replication. Four of six patients reached HEV clearance after 3 months of ribavirin therapy. HEV clearance was observed after 34–42 days. Two patients, both treated with rituximab within the last 12 months before diagnosis of HEV infection, needed prolonged ribavirin therapy due to persistent viral replication.

Conclusion

Reduction of daily dose of MPA therapy alone in transplant patients with chronic HEV infection may not be sufficient to control viral replication. HEV clearance under ribavirin therapy shows interindividual variability. Therefore, serial viral monitoring may be useful to personalize treatment duration. Rituximab therapy is a risk factor for complicated‐to‐treat chronic HEV infection.

Ribavirin as a First Treatment Approach for Hepatitis E Virus Infection in Transplant Recipient Patients

The hepatitis E virus (HEV) is the major cause of acute hepatitis of viral origin worldwide. Despite its usual course as an asymptomatic self-limited hepatitis, there are highly susceptible populations, such as those with underlying immunosuppression, which could develop chronic hepatitis. In this situation, implementation of therapy is mandatory in the sense to facilitate viral clearance. Currently, there are no specific drugs approved for HEV infection, but ribavirin (RBV), the drug of choice, is used for off-label treatment. Here, we present two cases of chronic HEV infection in transplant patients, reviewing and discussing the therapeutic approach available in the literature. The use of RBV for the treatment of an HEV infection in organ transplant patients seems to be effective. The recommendation of 12 weeks of therapy is adequate in terms of efficacy. Nevertheless, there are important issues that urgently need to be assessed, such as optimal duration of therapy and drug dosage.