Letermovir

How it works

It inhibits the CMV DNA terminase complex, preventing the cleavage and packaging of viral DNA into mature virions, a target distinct from that of other anti-CMV agents.

Prescribing in practice

• It is active only against CMV and provides no cover against other herpesviruses, so it does not replace prophylaxis directed at those pathogens.
• Letermovir inhibits CYP3A and OATP1B transporters, notably increasing exposure to drugs such as ciclosporin and certain statins, requiring co-medication review and dose adjustment.
• The dose is reduced when given with ciclosporin, and the oral and intravenous routes can be used interchangeably without dose change as set out in the SPC.

Monitoring

Monitor for CMV reactivation despite prophylaxis and review levels of interacting immunosuppressants such as ciclosporin and tacrolimus.

Counselling the patient

• Continue prophylaxis for the full prescribed duration even if you feel well.
• Report symptoms of infection promptly to your transplant team.
• Do not start new medicines without checking, as several interact with this drug.

Evidence & guidelines

Efficacy in transplant CMV prophylaxis was established in a pivotal randomised placebo-controlled trial and is reflected in the SPC.