Analysis of spontaneous cytomegalovirus clearance after low level reactivation using a pre-emptive treatment threshold of 4,000 IU/mL in allogeneic hematopoietic cell transplant recipients.

ABSTRACT

BACKGROUND: Cytomegalovirus (CMV) can be a serious complication after allogeneic hematopoietic cell transplant (HCT). CMV viral load is routinely monitored, and pre-emptive therapy is initiated to prevent CMV viremia from developing into CMV organ disease based on institutional thresholds. There is no established universal threshold for pre-emptive therapy and many centers utilize different strategies. METHODS: Allogeneic HCT recipients at WVU Medicine from 2009 to 2021 were routinely initiated on pre-emptive CMV treatment for a PCR viral threshold above 4000 IU/mL. Adult patients with quantifiable values below this threshold, were analyzed to evaluate the rate of spontaneous clearance without initiation of CMV-directed therapy, during their first episode of CMV reactivation. This study excluded any patients that received letermovir prophylaxis. RESULTS: Sixty patients were included in the analysis. The spontaneous clearance rate was 60 %. The risk factors that were associated with a lower spontaneous clearance rate were reactivation within thirty days after transplant (p = 0.031), presence of graft-versus-host-disease (p = 0.031), and CMV PCR values of 2500-4000 IU/mL (p = 0.02). Although these patients had lower rates of spontaneous clearance, they still spontaneously cleared in 42 %, 42 %, and 43 % of the cases, respectively. CONCLUSION: Delaying pre-emptive treatment until a CMV PCR value of 4000 IU/mL is reached appears appropriate and decreases unnecessary treatment toxicity and resistance.