maribavir
Meaning of maribavir: An antiviral taken by mouth that leaves the marrow and the kidney alone, kept for infections the older drugs no longer hold down.
Definition of maribavir
Maribavir is an antiviral drug taken by mouth, used against cytomegalovirus infection after a transplant and particularly where the virus no longer responds to standard treatment. It blocks a viral enzyme known as UL97 protein kinase, which the virus needs in order to package new copies of itself and move them out of the cell nucleus.
What problem does it address?
Cytomegalovirus sits dormant in most adults and causes nothing. After a stem cell or organ transplant, with the immune system deliberately suppressed, it reactivates and can inflame the gut, the lungs, the liver or the retina. The established drugs for it are effective but limited by what else they do: one class flattens the bone marrow at a point when blood counts are already fragile, and two others are hard on the kidney. Virus that stops responding to them narrows the options further. This drug was developed for that gap, and its role is treatment of resistant or refractory infection rather than routine prevention, where trials did not show the hoped-for benefit.
How does it work?
It jams a viral enzyme rather than the viral copying machinery. The older antiviral drugs all attack the enzyme that copies viral DNA, so a single mutation in that enzyme can blunt several of them at once. Maribavir attacks a different protein altogether, one the virus uses to cut finished DNA to length, wrap it and shift it out of the nucleus. Because the target is unrelated, virus carrying resistance to the older group usually remains susceptible. The drug is absorbed well by mouth, and the side effect reported most often is a persistent altered or metallic taste.
How does it compare with the older options?
| Drug group | Target | Main limitation |
|---|---|---|
| Maribavir | UL97 protein kinase | Taste disturbance; resistance can emerge |
| Ganciclovir and valganciclovir | Viral DNA copying | Suppression of the bone marrow |
| Foscarnet | Viral DNA copying | Kidney injury and salt disturbance |
| Cidofovir | Viral DNA copying | Kidney injury |
One interaction follows directly from the table. Ganciclovir has to be switched on by the very enzyme maribavir shuts down, so combining them undermines both. Preventing cytomegalovirus disease after a donor transplant continues to rely on the older agents and on monitoring for early signs of the virus.
Also known as
Used in a sentence
Maribavir was started after cytomegalovirus levels persisted despite valganciclovir.
Good to know
Ganciclovir depends for its activation on the same viral enzyme that maribavir inhibits, so the two oppose each other, and maribavir is established as treatment for resistant infection rather than as routine prevention.