CMV is a common herpesvirus that can infect people of all ages, remaining latent within the body but reactivating and shedding when the immune system is compromised. Although most people infected with CMV typically exhibit few or no symptoms, severe and life-threatening infections — characterized by fever, pancytopaenia and inflammatory changes in multiple organs — often occur in immune-incompetent or immunodeficient individuals, such as transplant recipients, HIV/AIDS patients and newborn babies.
A small number of antiviral drugs (all of which inhibit the viral DNA polymerase) are available for the treatment of CMV but their use is restricted by dose-limiting toxicity and drug resistance. “The key treatment options for CMV are intravenous ganciclovir and oral valganciclovir. Both work reasonably well, although bone marrow toxicity can be limiting and resistance can occur, especially if the drug is under-dosed. In stem cell transplant patients, this is particularly problematic since their bone marrow is tenuous at best. There are two other alternatives, intravenous foscarnet and cidofovir, but both have significant nephrotoxicity,” explains David Snydman, Tufts University School of Medicine, Boston, Massachusetts, USA.
