Letermovir is an antiviral medication that the Food and Drug Administration (FDA) approved on November 8, 2017. It is used to treat cytomegalovirus (CMV) infection in adult patients who have received an allogeneic hematopoietic stem cell transplant. Letermovir works by inhibiting the replication of CMV, thereby helping to prevent CMV infection in these high-risk patients.

Letermovir is used for the prophylaxis of cytomegalovirus (CMV) infection and disease in adult CMV-seropositive recipients of an allogeneic hematopoietic stem cell transplant (HSCT). It is also used for the prophylaxis of CMV disease in adult kidney transplant recipients who are at high risk (Donor CMV seropositive/Recipient CMV seronegative [D+/R-]).

Letermovir is used for CMV prophylaxis in HSCT and kidney transplant recipients, with administration either orally or via IV infusion. If administered intravenously, it will be given by a healthcare professional in a hospital setting through a sterile 0.2 or 0.22 micron filter. If co-administered with cyclosporine, dosage adjustments may be needed. For specific dosing instructions, consult your healthcare provider.

Side effects are unwanted symptoms caused by medicines. Although all drugs can cause side effects, not everyone experiences them.

Common side effects of Letermovir:

• Nausea
• Cough
• Diarrhea
• Headache
• Vomiting
• Tiredness
• Swelling in arms and legs
• Stomach (abdominal) pain

Serious side effects of Letermovir:

• Severe allergic reactions (e.g., rash, itching, difficulty breathing)
• Liver problems (e.g., yellowing of the skin/eyes, dark urine)
• Severe gastrointestinal issues

• Risk of Drug Interactions: Concomitant use with certain drugs can cause significant interactions, leading to adverse reactions or reduced effectiveness of either Letermovir or the other drugs.
• Consider Drug Interactions: Review and monitor concomitant medications during Letermovir therapy. Consider potential drug interactions before and during treatment.
• Impact on Transporters and Enzymes: Letermovir is a substrate of OATP1B1/3, P-glycoprotein (P-gp), and UGT1A1/3 enzymes. Using it with inhibitors of these transporters can increase its plasma concentrations.
• Cyclosporine Interactions: The drug interaction effects may differ when co-administered with cyclosporine. Refer to the prescribing information for cyclosporine for further details.

Monitor for potential drug interactions during treatment with Letermovir, especially when co-administered with inhibitors or inducers of transporters and enzymes. Adjust the dose if used with cyclosporine or other interacting medications. Carefully review all concomitant medications to prevent adverse reactions and ensure optimal efficacy. Always consult your healthcare provider before starting Letermovir therapy.

Always follow your healthcare provider’s instructions regarding dosage and administration, especially when using Letermovir alongside other medications. Inform your doctor about all the medicines you are taking to avoid potential drug interactions. Regular monitoring may be required to ensure the treatment is working effectively and to detect any side effects early. If you experience any unusual symptoms or side effects, contact your healthcare provider promptly.

1. https://www.accessdata.fda.gov/drugsatfda_docs/label/2023/209939s011,209940s010lbl.pdf

2. Daniels K, Clemmons A. Letermovir for Cytomegalovirus Prevention in Patients Undergoing Hematopoietic Cell Transplantation. https://pmc.ncbi.nlm.nih.gov/articles/PMC7517777/

3. Lin A, Flynn J, DeRespiris L, Figgins B, Griffin M, Lau C, Proli A, Devlin SM, Cho C, Tamari R, Jakubowski AA, Papadopoulos EB, Giralt SA, Perales MA, Seo SK, Shaffer B. Letermovir for Prevention of Cytomegalovirus Reactivation in Haploidentical and Mismatched Adult Donor Allogeneic Hematopoietic Cell Transplantation with Post-Transplantation Cyclophosphamide for Graft-versus-Host Disease Prophylaxis. https://pmc.ncbi.nlm.nih.gov/articles/PMC8441845/

The drug information on this page is not a substitute for medical advice, it is meant for educational purposes only. For further details consult your doctor about your medical condition to know if you are eligible to receive this treatment.