Letermovir is a novel anti cytomegalovirus (CMV) drug that inhibits the virus terminating enzyme complex through a unique mechanism. It is mainly used for the prevention of CMV infection in allogeneic hematopoietic stem cell transplantation (HSCT) recipients and has the characteristics of high efficiency and low toxicity, significantly reducing the risk of clinical associated CMV infection.

1. Indications

(1) Prevention of CMV infection: Suitable for adult recipients of allogeneic hematopoietic stem cell transplantation with CMV serum positivity, to prevent cytomegalovirus infection and disease.

(2) Target audience: Preventive medication specifically designed for high-risk periods after transplantation (usually within 100 days after transplantation).

2. Therapeutic effect

(1) Preventive effect: Clinical trials have shown that it can reduce the risk of CMV infection by more than 50%, significantly better than the placebo group.

(2) Safety advantage: Compared with traditional anti CMV drugs, the incidence of bone marrow suppression and nephrotoxicity is significantly reduced.

3. Mechanism of action

(1) Unique target: interferes with CMVDNA processing and packaging by inhibiting the virus terminating enzyme complex (pUL56-pUL89), unlike traditional DNA polymerase inhibitors.

(2) High selectivity: has no inhibitory effect on human DNA polymerase, therefore has low toxicity.

4. Medication plan

(1) Standard dose: 480mg orally or intravenously once daily, starting medication immediately after transplantation.

(2) Course of treatment: Continue to use until 100 days after transplantation, or extend according to risk.

5. Special populations

(1) Liver dysfunction: Mild injury does not require dose adjustment, moderate to severe cases require halving of dosage.

(2) Drug interactions: Attention should be paid to dosage adjustment when combined with cyclosporine.