Michael J. Boeckh

Pre-emptive therapy (PET) and letermovir prophylaxis are effective in preventing CMV disease within the first 100 days after allogeneic hematopoietic cell transplantation (HCT) but are associated with late-onset CMV disease. We retrospectively examined the clinical manifestations, risk factors, prevention algorithm, and outcome of late CMV disease in CMV seropositive day 100 survivors transplanted between 2001-2017 (PET cohort) and 2018-2021 (letermovir cohort). There were 187 episodes of late CMV disease among 2469 day 100 survivors and the estimated cumulative incidence of first late CMV disease was 6.7% (95% CI 5.6-%-7.6%) with no difference between the PET 6.7% (95% CI 5.7%-7.8%) and the letermovir group 5.4% (95% CI 3.2%-8.3%). 32 (1.3%) patients had a second episode of late CMV disease. In multivariable Cox regression models, post-transplant cyclophosphamide was associated with an increased risk of gastrointestinal CMV disease. CMV viremia detected before day 100, corticosteroid treatment after day 100 at dose ≥1mg/kg, acute and chronic GvHD, lymphopenia, HLA mismatched related donors status and recipient age were also associated with late CMV disease. HLA mismatched donor status and late use of corticosteroids (≥1 mg/kg) were risk factors for late CMV disease recurrence. Late CMV disease occurred most frequently in a setting of prolonged low-level untreated viremia and was independently associated with death by year two after HCT. In summary, late CMV disease continues to occur in the current era. Improved prevention strategies for late CMV disease are needed.