Risk factors for CMV resistance in HCT recipients
| Host factors |
| Prolonged antiviral CMV drug exposure (>3 mo) |
| Previous antiviral CMV drug exposure |
| Recurrent CMV infection |
| Inadequate antiviral CMV drug absorption and bioavailability |
| Inadequate antiviral CMV oral prodrug conversion |
| Variation in antiviral CMV drug clearance |
| Subtherapeutic antiviral CMV drug level |
| Poor compliance |
| T-cell depletion |
| Haploidentical, allogeneic, and cord blood HCT |
| Delayed immune reconstitution |
| CMV-seropositive recipient |
| Treatment with antithymocyte antibodies |
| Active GVHD |
| Young age |
| Congenital immunodeficiency syndromes |
| Viral factors |
| CMV viral load rise while receiving treatment (after >2 wk with adequate dosing) |
| Failure of CMV viral load to fall despite appropriate treatment |
| Rise in CMV viral load after decline while receiving appropriate therapy |
| Intermittent low-level CMV viremia |
| High CMV viral loads |
| Host factors |
| Prolonged antiviral CMV drug exposure (>3 mo) |
| Previous antiviral CMV drug exposure |
| Recurrent CMV infection |
| Inadequate antiviral CMV drug absorption and bioavailability |
| Inadequate antiviral CMV oral prodrug conversion |
| Variation in antiviral CMV drug clearance |
| Subtherapeutic antiviral CMV drug level |
| Poor compliance |
| T-cell depletion |
| Haploidentical, allogeneic, and cord blood HCT |
| Delayed immune reconstitution |
| CMV-seropositive recipient |
| Treatment with antithymocyte antibodies |
| Active GVHD |
| Young age |
| Congenital immunodeficiency syndromes |
| Viral factors |
| CMV viral load rise while receiving treatment (after >2 wk with adequate dosing) |
| Failure of CMV viral load to fall despite appropriate treatment |
| Rise in CMV viral load after decline while receiving appropriate therapy |
| Intermittent low-level CMV viremia |
| High CMV viral loads |