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.

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 2009-2021 were routinely initiated on pre-emptive CMV treatment for a PCR viral threshold above 4,000 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 4,000 IU/mL is reached appears appropriate and decreases unnecessary treatment toxicity and resistance.

Efficacy of delayed pegfilgrastim administration following consolidation therapy with high-dose cytarabine (HiDAC) in acute myeloid leukemia (AML) patients.

PURPOSE: To study the effects of delaying pegfilgrastim administration following high-dose cytarabine (HiDAC) consolidation in AML patients on time to neutrophil count recovery, infectious complications, and survival. METHODS: Single-center retrospective chart review of 55 patients receiving pegfilgrastim as early administration (within 72 h) or delayed administration (after 72 h) of HiDAC. RESULTS: The difference in neutrophil recovery time was similar between the early and delayed groups (18 days versus 19 days, p < 0.28). Infections were seen in four patients in the early administration group following chemotherapy compared to none in the delayed group (p = 0.04). Febrile neutropenia rates were also decreased in the delayed administration group (23.1% versus 10.3%, p = 0.28) as well as a trend towards longer median survival (16 months versus 19 months, p = 0.69) and overall survival (21 months versus 31 months, p = 0.47). CONCLUSION: A difference in time to neutrophil recovery was not observed between the early and delayed administration groups yet decreased infectious complications may support the delayed administration of pegfilgrastim in these patients.

Evaluation of prolonged magnesium infusion after allogeneic hematopoietic cell transplant.

PURPOSE: Calcineurin inhibitor use after allogeneic hematopoietic cell transplantation (allo-HCT) is associated with significant magnesium wasting. Utilization of a prolonged magnesium infusion is thought to lead to a lower serum peak concentration and therefore, decreased renal wasting of magnesium. In November 2017, our institution implemented a modification to our inpatient electrolyte replacement protocol for allo-HCT recipients that extended the magnesium infusion rate from 4 g/2 h to 4 g/4 h based on this theoretical advantage. The primary objective of this study was to compare the median magnesium requirements per day of admission between patients who received magnesium 4 g/2 h to patients who received magnesium 4 g/4 h. Secondary objectives included a comparison of the per-patient median serum magnesium concentration during admission, as well as the median incremental difference in serum magnesium concentration after intravenous replacement per patient per admission. METHODS: Allo-HCT recipients who received prolonged infusion magnesium infusions were compared to a historical cohort of allo-HCT patients who received shorter IV magnesium infusions. Admissions were included if the patient had received an allo-HCT within 100 days prior, was admitted to the Transplant and Cellular Therapy Unit at WVU Medicine J.W. Ruby Memorial Hospital, and received at least one magnesium infusion and one dose of cyclosporine or tacrolimus. Admissions were excluded if the patient received oral magnesium, total parenteral nutrition, aminoglycosides, amphotericin, carboplatin, cisplatin, or foscarnet. RESULTS: The pre-implementation group consisted of 81 admissions (n = 64 patients), while the post-implementation group consisted of 90 admissions (n = 60 patients). Median magnesium requirements per day of admission were not different between groups at 1.4 g of magnesium in the pre-implementation group and 1.9 g of magnesium in the post-implementation group (P = 0.25). Median serum magnesium concentrations and median incremental difference in serum magnesium concentration after intravenous replacement were also not different between groups: 1.65 mg/dL vs 1.60 mg/dL (P = 0.65) and 0.30 mg/dL vs 0.28 mg/dL (P = 0.67), respectively. CONCLUSIONS: Prolonged infusion of magnesium in allo-HCT recipients receiving CNI therapy does not result in improvement in magnesium retention.

Evaluation of the Pharmacokinetic Interaction Between Letermovir and Tacrolimus in Allogeneic Hematopoietic Cell Transplantation Recipients.

Data describing the magnitude of the pharmacokinetic interaction between letermovir and tacrolimus in allogeneic hematopoietic cell transplantation (allo-HCT) recipients are limited, and varying outcomes have been reported. The need for empiric dose adjustment of tacrolimus on initiation of letermovir has not been established; instead, guidelines suggest closely monitoring the tacrolimus trough concentration and adjusting the dose as needed. A better understanding of this interaction is imperative to accurately manage the narrow therapeutic window of tacrolimus post-transplantation. The primary objective of this study was to determine the percent change in tacrolimus concentration-to-dose ratio over the 14-day period after initiation of letermovir. Secondary objectives were to describe the frequency of tacrolimus dose adjustments after initiation of letermovir, the percent change in daily tacrolimus dose over the 14-day period after initiation of letermovir, and the incidence of both subtherapeutic and supratherapeutic tacrolimus trough concentrations. This retrospective chart review included adult allo-HCT recipients at our institution who received tacrolimus in combination with oral letermovir and had been taking tacrolimus for at least 5 days before letermovir initiation. Patients receiving strong CYP3A4 inhibitors or i.v. tacrolimus were excluded. Thirty-five patients were included in the analysis. The median percent increase in tacrolimus concentration-to-dose ratio over the 14-day period after initiation of letermovir was 22% on days 2 to 4, 47% on days 5 to 7, 66% on days 8 to 11, and 81% on days 12 to 14. The mean frequency of tacrolimus dose adjustments was 0.66 on days 2 to 4, 0.69 on days 5 to 7, 1.06 on days 8 to 11, and 0.57 on days 12 to 14. The results of this study show that the pharmacokinetic interaction between tacrolimus and letermovir is substantial and continues to affect tacrolimus concentration over the 14-day period after letermovir initiation. Close monitoring of tacrolimus trough concentration on initiation of letermovir should be considered.