[Impact of initial cytomegalovirus viral load on efficacy of preemptive therapy with ganciclovir in allogeneic stem cell transplant recipients].

OBJECTIVE

To study the impact of initial cytomegalovirus (CMV) viral load on virological response to ganciclovir preemptive therapy in allogeneic stem cell transplant (SCT) recipients after 4 weeks of treatment.

METHODS

Eighty-one consecutive allogeneic SCT recipients were included. Preemptive therapy was initiated when CMV load was positive for 2 consecutive weeks or when a viral load >5000copies/mL was detected in 1 sample. If viral load was >400copies/mL after 2 weeks of treatment, maintenance treatment with ganciclovir was continued for 2 additional weeks. Virological failure was defined as a CMV load >400copies/mL after 4 weeks of treatment.

RESULTS

Ganciclovir preemptive therapy was initiated in 32 patients (39.5%) who had 39 episodes of CMV replication. Virological failure occurred in 16 patients (50%) after 18 episodes of replication (46%). Clinical failure additionally occurred in 2 episodes (5%). The only risk factor for virological failure was a peak viral load >20,000copies/mL at the beginning of treatment (OR 5.88; 95% CI: 1.49-25, P=.03). The main risk factor for CMV replication >20,000copies/mL at the start of treatment was the presence of grade II-IV acute graft-versus-host-disease (OR 16; 95% CI: 8.5-45).

CONCLUSION

CMV viral load >20,000copies/mL is the main risk factor for virological failure after 4 weeks of ganciclovir preemptive therapy following SCT.