Adoptive Immunotherapy for Prophylaxis and Treatment of Cytomegalovirus Infection

Cytomegalovirus (CMV), a member of the Herpesviridae family, is frequent among hematopoietic cell transplant (HCT) and solid organ transplant (SOT) recipients in absence of antiviral prophylaxis, and is a major cause of morbidity and mortality in these vulnerable populations. Antivirals such ganciclovir, valganciclovir, and foscarnet are the backbone therapies, however drug toxicity and antiviral resistance may render these agents suboptimal in treatment. Newer therapies such as letermovir and maribavir have offered additional approaches for antiviral prophylaxis as well as treatment of drug resistant CMV infection, though may be limited by cost, drug intolerance, or toxicity. Adoptive immunotherapy, the transfer of viral specific T-cells (VSTs), offers a new approach in treatment of drug-resistant or refractory viral infections, with early clinical trials showing promise with respect to efficacy and safety. In this review, we will discuss some of the encouraging results and challenges of widespread adoption of VSTs in care of immunocompromised patients, with an emphasis on the clinical outcomes for treatment and prophylaxis of CMV infection among high-risk patient populations.