Evaluation of low dose famciclovir as herpes simplex virus and varicella zoster virus prophylaxis in cytomegalovirus low-risk solid organ transplant recipients.

Objective: Famciclovir is a recommended option for herpes simplex virus (HSV) and varicella-zoster virus (VZV) prophylaxis in cytomegalovirus (CMV) low-risk solid organ transplant (SOT) recipients in current guidelines; however there is currently no data evaluating its use in SOT recipients. We conducted a multicenter provider survey on antiviral prophylaxis in CMV low-risk SOT recipients and evaluated the efficacy and safety of once daily famciclovir antiviral prophylaxis.

Methods: Two-part analysis consisting of a national provider survey and a retrospective chart review of 78 kidney transplant recipients at a single institution.

Results: Providers from 45 transplant centers within the United States responded to the survey. Across all organs, acyclovir 400 mg twice daily was utilized by the majority of respondents (70.4%), with most using prophylaxis for a duration of 3 months (68.8%). No respondents reported use of famciclovir at their institution. In the retrospective review there were no documented cases of HSV/VZV/CMV infection during the 3 months of famciclovir prophylaxis, and only one patient (1.3%) later developed VZV infection at 12 months post-transplant. One patient (1.3%) required premature discontinuation of famciclovir due to concern for acute interstitial nephritis.

Conclusion: Nationwide, the most common antiviral prophylaxis used in CMV low-risk SOT recipients is acyclovir 400 mg twice daily. Among patients receiving once daily famciclovir for CMV low-risk antiviral prophylaxis, there was no HSV/VZV/CMV infection while on prophylaxis. Once daily famciclovir may provide an effective and convenient once daily dosing regimen for antiviral prophylaxis in CMV low-risk SOT recipients.