A Case Report of Successful Use of Twice-Daily Letermovir in the Treatment of Resistant Cytomegalovirus in a Small Bowel Transplant Recipient

•First case on the successful use of letermovir in treating cytomegalovirus disease in a small bowel transplant with ganciclovir resistance due to UL97 mutation.•The use of maintenance letermovir prevented the recurrence of the tissue invasive disease and led to clearance or stabilization of the viral load.•Twice-daily dosing of letermovir with lower doses 480 mg orally was used for the first time with fewer gastrointestinal side effects and a similar outcome to 960 mg once daily dosing that was reported in the literature. Cytomegalovirus (CMV) is considered one of the most notable pathogens that affect patients after solid organ transplantation (SOT), especially small bowel transplant patients with a risk of high mortality rate. Its management relies historically on the use of CMV DNA polymerase inhibitors (namely, ganciclovir and valganciclovir). Second-line options include foscarnet and cidofovir, which are highly nephrotoxic and thus less preferred and only used in ganciclovir intolerance or resistance cases. Letermovir is a novel antiviral agent approved for CMV prophylaxis in hematopoietic stem cell transplant, but not for SOT (neither for prophylaxis nor for treatment). We report the first case on the successful use of letermovir in treating CMV disease in a small bowel transplant patient who failed to achieve viral clearance due to ganciclovir resistance and severe intolerance to foscarnet.