Monitoring of cytomegalovirus viral loads by two molecular assays in whole-blood and plasma samples from hematopoietic stem cell transplant recipients

Prospective comparison of cytomegalovirus quantification in whole blood and plasma samples among hematopoietic stem cell transplant and kidney transplant recipients

BACKGROUND

Cytomegalovirus (CMV) induces multi-organ pathogenesis in hematopoietic stem cell transplant (HSCT) and kidney transplant (KT) recipients. Effective management involves systematic monitoring for CMV reactivation by quantitative real-time PCR, allowing timely preemptive intervention. However, the optimal blood compartment for CMV surveillance remains undetermined.

OBJECTIVE

The aim of the study was to compare the quantification of CMV DNA in paired plasma and whole blood samples.

STUDY DESIGN

From June and October 2022, we conducted a prospective study with 390 sets of paired plasma and whole blood specimens collected from 60 HSCT and 24 KT recipients. CMV DNA levels were compared between the cobas® CMV assay on the automated cobas® 6800 system for plasma and the reference assay, Abbott RealTime CMV assay on the m2000 RealTime platform for whole blood.

RESULTS

The sensitivity and specificity of CMV quantification in plasma using the cobas® CMV assay were 90.0 % (95 %CI: 81.5 to 95.9) and 94.8 % (95 %CI: 91.8 to 96.8), respectively, compared to whole blood quantification with the Abbott assay. The overall agreement between these two strategies was 0.89 (95 %CI: 0.86-0.91). In samples with quantifiable results, a correlation was observed between the two methods (R2 = 0.62, 95 %CI: 0.65-0.87, p < 0.0001). CMV loads were significantly higher in whole blood, with a mean bias of 0.42 log10 IU/mL (95 %CI: -0.32-1.15).

CONCLUSION

The cobas® CMV assay in plasma showed significant concordance with the Abbott RealTime CMV assay in whole blood, confirming the relevance of plasma samples for CMV monitoring in HSCT and KT recipients.

Impact of Primary Letermovir Prophylaxis Versus Preemptive Antiviral Therapy for Cytomegalovirus on Economic and Clinical Outcomes after Hematopoietic Cell Transplantation

Preemptive therapy (PET) historically has been the primary strategy to reduce early-onset cytomegalovirus (CMV) reactivation after allogeneic hematopoietic cell transplantation (HCT) but is associated with antiviral-associated toxicities and increases in healthcare resource utilization and cost. Despite its high cost, letermovir (LTV) prophylaxis has largely supplanted PET due to its effectiveness and tolerability. Direct comparisons between LTV and PET approaches on economic and clinical outcomes after allogeneic HCT remain limited. Objective: To compare total cost of care (inpatient and outpatient) between LTV prophylaxis and PET through day+180 after allogeneic HCT. Adult allogeneic CMV seropositive (R+) HCT recipients who initiated LTV <30 days after HCT between 01/01/18 and 12/31/18 were matched 1:1 to allogeneic CMV R+ HCT recipients between 01/01/15 and 12/31/17 (PET cohort). Patients were grouped into high-risk (HR) or standard-risk (SR) for CMV to compare the LTV and PET cohorts. Direct costs for each patient's index HCT admission and all subsequent inpatient and outpatient care through day+180 after HCT were determined and converted into 2021 US dollars and then to Medicare proportional dollars (MPD). A secondary analysis using 2019 average wholesale price was conducted to specifically evaluate anti-CMV medication costs. There were a total of 176 patients with 54 HR CMV pairs and 34 SR CMV pairs. No differences in survival between LTV and PET for both HR and SR CMV groups were observed. The rate of clinically significant CMV infection decreased for both HR CMV (11/54, 20.4% versus 38/54, 70.4%, P < .001) and SR CMV (1/34, 2.9% versus 12/34, 35.3%, P < .001) patients who were given LTV prophylaxis with corresponding reductions in val(ganciclovir) and foscarnet (HR CMV only) use. Among HR CMV patients, LTV prophylaxis was associated with reductions in CMV-related readmissions (3/54, 5.6% versus 18/54, 33.3%, P < .001) and outpatient visits within the first 100 days after HCT (20 versus 25, P = .002), and a decreased median total cost of care ($36,018 versus $75,525, P < .001) in MPD was observed. For SR CMV patients on LTV, a significant reduction in the median inpatient cost ($15,668 versus $27,818, P < .001) was found, but this finding was offset by a higher median outpatient cost ($26,145 versus $20,307, P = .030) that was not CMV-driven. LTV prophylaxis is highly effective in reducing clinically significant CMV reactivations for both HR and SR HCT recipients. In this study, LTV prophylaxis was associated with a decreased total cost of care for HR CMV patients through day+180. Specifically, reductions in CMV-related readmissions, exposure to CMV-directed antiviral agents, and outpatient visits in the first 100 days after HCT were observed. SR CMV patients receiving LTV prophylaxis benefited by having a reduced inpatient cost of care due to lowered room and pharmacy costs.

Pitfalls in Valganciclovir Prophylaxis Dose Adjustment Based on Renal Function in Kidney Transplant Recipients

Valganciclovir (VGC) is administered as prophylaxis to kidney transplant recipients (KTR) CMV donor (D)+/recipient (R)- and CMV R+ after thymoglobulin-induction (R+/TG). Although VGC dose adjustments based on renal function are recommended, there is paucity of real-life data on VGC dosing and associations with clinical outcomes. This is a retrospective Swiss Transplant Cohort Study-embedded observational study, including all adult D+/R- and R+/TG KTR between 2010 and 2020, who received prophylaxis with VGC. The primary objective was to describe the proportion of inappropriately (under- or over-) dosed VGC week-entries. Secondary objectives included breakthrough clinically significant CMV infection (csCMVi) and potential associations between breakthrough-csCMVi and cytopenias with VGC dosing. Among 178 KTR, 131 (73.6%) patients had ≥2 week-entries for the longitudinal data of interest and were included in the outcome analysis, with 1,032 VGC dose week-entries. Overall, 460/1,032 (44.6%) were appropriately dosed, while 234/1,032 (22.7%) and 338/1,032 (32.8%) were under- and over-dosed, respectively. Nineteen (14.5%) patients had a breakthrough-csCMVi, without any associations identified with VCG dosing (p = 0.44). Unlike other cytopenias, a significant association between VGC overdosing and lymphopenia (OR 5.27, 95% CI 1.71-16.22, p = 0.004) was shown. VGC prophylaxis in KTR is frequently inappropriately dosed, albeit without meaningful clinical associations, neither in terms of efficacy nor safety.

Patterns of CMV infection after letermovir withdrawal in recipients of posttransplant cyclophosphamide-based transplant

Reactivation of latent cytomegalovirus (CMV) is increased in recipients of allogeneic hematopoietic cell transplantation (allo-HCT) with seropositive CMV using posttransplant cyclophosphamide (PT-Cy)-based graft-versus-host disease (GVHD) prophylaxis. Letermovir, a novel DNA terminase complex inhibitor, reduces the incidence of clinically significant CMV infection (csCMVi) in this population; however, parameters that predict csCMVi after letermovir withdrawal are not well described. Here, we examined clinical and immunological parameters in 294 recipients of PT-Cy-based allo-HCT, including 157 patients with CMV, of whom 80 completed letermovir prophylaxis without csCMVi and subsequently stopped letermovir. In this population, the median duration of letermovir exposure was 203 days (interquartile range [IQR], 160-250 days). After letermovir withdrawal, the 90-day cumulative incidence of csCMVi was 23.0% (95% confidence interval, 14.3-32.8). There were no episodes of CMV end-organ disease. Hypogammaglobulinemia before letermovir discontinuation was predictive of csCMVi (hazard ratio, 0.33; 95% confidence interval, 0.12-0.93; P = .03), whereas T-cell and B-cell reconstitution before letermovir withdrawal were not predictive of csCMVi. Higher numbers of natural killer cells were found before letermovir withdrawal in patients who experienced csCMVi (median, 202 vs 160; P = .03). In recipients with seropositive CMV, CD3+CD4-CD8+ T-cell reconstitution was faster in patients with CMV regardless of letermovir exposure. Taken together, these data suggest that csCMVi after letermovir withdrawal was frequent in patients treated with PT-Cy, despite prolonged exposure. Strategies to boost CMV-specific adaptive immunity in patients with persistent hypogammaglobulinemia is a logical pathway to reduce csCMVi after letermovir withdrawal.

Evaluation of Performance Characteristics of the Aptima CMV Quant Assay for the Detection and Quantitation of CMV DNA in Plasma Samples

Quantification of Cytomegalovirus (CMV) DNA has become the standard of care in the diagnosis and management of CMV infection in transplant recipients. The objective of the study was to evaluate performance characteristics of the Aptima CMV Quant assay in comparison to Abbott RealTime CMV assay, Qiagen Artus CMV RGQ MDx assay, and Roche cobas CMV test using plasma samples. The performance of the Aptima assay was evaluated by comparing the Exact Diagnostics CMV verification panel and positive controls, Hologic CMV internal reproducibility panel, and SeraCare CMV DNA qualification panel to the RealTime assay. Clinical agreement was evaluated using 389 clinical plasma samples comparing the Aptima assay to three comparator assays. The Aptima assay demonstrated good linearity and strong linear correlation between the assays (R² = 0.99); the intra- and interassay reproducibility was excellent overall (SD = 0.09 to 0.14 and SD = 0.04 to 0.14, respectively); 95% limit of detection (LOD) is 32 IU/mL and LOQ is 45 IU/mL. The SeraCare qualification panel yielded a strong linear correlation (R² = 0.99). A total of 262 positive samples were analyzed to compare Aptima and Realtime assays using Deming regression and Bland-Altman analysis and demonstrated a mean bias of 0.092 Log₁₀ IU/mL. Artus (85) and cobas (159) positive samples were compared to the Aptima assay using Deming regression and Bland-Altman analyses and showed mean bias of 0.184 and -0.208 Log₁₀ IU/mL, respectively. The findings demonstrate that the Aptima assay is sensitive and accurate in quantifying CMV in plasma specimens on the fully automated Panther system and that the results were comparable to the other FDA-approved CMV assays.

Correlation of cytomegalovirus viral load between whole blood and plasma of congenital cytomegalovirus infection under valganciclovir treatment

BACKGROUND

Congenital cytomegalovirus (CMV) infection (cCMV) can cause sensorineural hearing loss and neurodevelopmental disabilities in children. Oral valganciclovir (VGCV) therapy has been reported to improve long-term audiological and neurodevelopmental outcomes in patients with cCMV. The levels of CMV DNA in whole blood have been monitored in previous studies. However, quantitative methods using whole blood have not been standardized. Recently, the plasma viral load has been standardized and widely used in CMV-associated diseases.

METHODS

CMV viral loads in whole blood and plasma were serially measured in 24 patients with a confirmatory diagnosis of cCMV during oral VGCV therapy using an in-house real-time PCR assay. Plasma samples were assayed using the Cobas 6800 system (Roche Diagnostics) in addition to an in-house assay.

RESULTS

Plasma CMV viral loads were remarkably decreased at the end of therapy compared to before therapy. A significant correlation of CMV levels between whole blood and plasma was observed (Spearman's ρ = 0.566). The levels of CMV DNA before therapy were significantly correlated with the period of decreasing the viral loads to below the detection limit, not only in whole blood (Spearman's ρ = 0.901) but also in plasma (Spearman, ρ = 0.804). Finally, CMV viral loads between the in-house assay and commercially available standardized assay in 75 plasma samples with positive PCR results for CMV were compared; a significant correlation was observed between the results of both assays.

CONCLUSIONS

There was a significant correlation between the two assays (Spearman, ρ = 0.882), suggesting that CMV plasma viral loads measured by the standardized assay are widely used to monitor the levels of CMV DNA in patients with cCMV during oral VGCV therapy.

Performance Evaluation of the Fully Automated NeuMoDx RT-PCR Platform for the Quantification of CMV and EBV DNA in EDTA Plasma: Implications for Clinical Management and Establishment of a Conversion Formula

The NeuMoDx96 platform is a fully automated real-time PCR (RT-PCR) system. To provide continued testing quality with the introduction of new assays, the primary aim of this study was to evaluate the analytical and clinical performance of the NeuMoDx platform for the detection and quantification of CMV and EBV DNA in EDTA plasma. As no conversion from log₁₀ international units per milliliter to copies per milliliter was provided, the secondary aim was to calculate and establish a conversion factor for the output of results in copies per milliliter for CMV and EBV. Archived ETDA plasma samples (cytomegalovirus [CMV], n = 290; Ebstein-Barr virus [EBV], n = 254) were used to evaluate the analytical performance of the NeuMoDx96 platform against the routine real-time quantitative PCR (qPCR) assays. Additionally, the first WHO international standards (WHO-IS) for CMV (n = 70) and EBV (n = 72) were used for the calculation of the intra- and interassay variation. WHO-IS qualitative agreement between the assays was 100%. Intra-assay variability was low for both CMV assays (coefficient of variation [CV], phosphate-buffered saline [PBS], 3 log₁₀ IU/mL NeuMoDx, 3.67%; Abbott RealTime, CMV, 3.35%) and NeuMoDx EBV assay (CV, PBS, 3 log₁₀ IU/mL, 3.05%) but high for the Altona EBV assay (CV, PBS, 3 log₁₀ IU/mL, 26.13%). The overall qualitative concordance in clinical samples was 96.8% (270/279) for CMV and 96.7% (237/245) for EBV. The mean difference between the assays was -0.2 log₁₀ IU/mL (CMV) and -0.18 log₁₀ IU/mL (EBV). High qualitative concordance and a significant correlation of quantitative values for both assays make NeuMoDx CMV and EBV assays suitable for routine diagnostic testing. The new RT-PCR system and conversion formulas to report results in copies per milliliter are now applied in clinical routine testing. IMPORTANCE Clinical management of solid organ transplant (SOT) patients requires the careful monitoring of immunosuppression and viral infection or reactivation. qPCR is the gold standard for the detection and quantification of very small amounts of viral DNA and allows for an early assessment of viral load kinetics. The tested NeuMoDx 96 platform provides faster results than the previously used RT-PCR workflows for CMV (Abbott m2000 and RealTime CMV assay) and EBV (LightCycler 480 II, Roche high pure extraction, and Altona RealStar EBV assay) DNA detection. The implemented conversion formulas allow the continued reporting in clinically established copies per milliliter, important for long-term care of SOT patients.

Whole Blood versus Plasma Samples-How Does the Type of Specimen Collected for Testing Affect the Monitoring of Cytomegalovirus Viremia?

Viral infections, or their reactivations, are one of the most important groups of transplantation complications that can occur among recipients of both hematopoietic cells and solid organ transplants. They are the most commonly caused by cytomegalovirus (CMV). Currently, the use of whole blood or plasma samples is recommended for CMV viral load monitoring. The aim of the study was to assess and compare the level of CMV DNA, depending on the type of clinical material—whole blood or plasma fraction derived from the same patient. The studies were carried out on 156 whole blood samples in which the presence of CMV genetic material was confirmed and the corresponding plasma samples from the same rounds of sampling. CMV DNA was not present in 59 (37.8%) of plasma samples compared to whole blood-positive counterparts. Of the samples positive in both types of clinical specimen, 77 (79.4%) had higher viral DNA levels in the whole blood samples. There were statistically significant differences in the detected CMV DNA load in the whole blood compared to plasma fraction counterparts (p < 0.001). The detected CMV DNA value is usually higher in whole blood compared to plasma samples of the same patient. Due to the variability in CMV viral load depending on the clinical material used for a particular patient, one type of specimen should be always used consequently for CMV viremia monitoring.

CMV viral load kinetics predict CMV end-organ disease and mortality after hematopoietic cell transplant (HCT)

BACKGROUND

We investigated the association between time-averaged area under the curve (AAUC) of CMV viral load (VL) by D100 and overall survival (OS) at one-year post-hematopoietic cell transplantation (HCT).

METHODS

A retrospective cohort study, including patients receiving HCT between 2010.6 and 2017.12 from Memorial Sloan Kettering Cancer Center. AAUC was calculated for patients with detected VL. Patients were categorized into "non-controllers" (Q4) and "controllers" (Q1-3) using the highest AAUC quartile as cutoff. Kaplan-Meier analyses and Cox models were used to estimate the association between AAUC and OS. Patients with non-detected CMV VL were categorized into "elite-controllers" (R+ or R-/D+) and "R-/D-".

RESULTS

The study (N=952) included 282 controllers, 93 non-controllers, 275 elite-controllers, and 302 R-/D-. OS was 80.1% and 58.1% for controllers and non-controllers, respectively. In multivariable models, non-controllers had worse OS versus controllers (adjusted hazard ratio [HR] 2.65, 95% CI 1.71-4.12). In landmark analyses, CMV controllers had similar OS as elite-controllers (HR 1.26, 95% CI 0.83-1.91) or R-/D- (HR 0.98, 95% CI 0.64-1.5).

CONCLUSION

CMV non-controllers had worse OS at one-year post-HCT. CMV controllers had similar OS as elite-controllers or R-/D-. Future studies are needed to validate our AAUC cutoff across different cohorts and CMV management strategies.

Letermovir for Prevention of Cytomegalovirus Reactivation in Haploidentical and Mismatched Adult Donor Allogeneic Hematopoietic Cell Transplantation with Post-Transplantation Cyclophosphamide for Graft-versus-Host Disease Prophylaxis

Cytomegalovirus (CMV) is serious viral infection in allogeneic hematopoietic cell transplantation (allo-HCT) recipients. November 2017, the novel CMV DNA terminase complex inhibitor letermovir was approved for prophylaxis of CMV infection in CMV-seropositive allo-HCT recipients. Here we sought to determine the effectiveness of letermovir in preventing CMV infection in CMV-seropositive patients undergoing haploidentical or mismatched adult unrelated donor allo-HCT using post-transplantation cyclophosphamide-based graft-versus host-disease prophylaxis. Sixty-four patients underwent transplantation between 2014 and 2019, of whom 32 received letermovir and 32 did not receive letermovir. The day 180 cumulative incidence of CMV infection requiring therapy was 45.3% (95% confidence interval [CI], 32.7% to 57.1%) in the entire cohort, 68.8% (95% CI, 48.9% to 82.2%) in the patients who did not receive letermovir, and 21.9% (95% CI, 9.5% to 37.6%; P < .001) in patients who received letermovir. Adjusting for regimen intensity, disease histology, and age, the hazard ratio for CMV infection was .19 (95% CI, .08 to .47; P < .001) in patients who received primary prophylaxis with letermovir. The 1-year cumulative incidence of treatment- related mortality was similar between patients with and without letermovir treatment (16.9% versus 18.9%), as was overall survival (64.0% versus 49.0%). Persistent CMV infection requiring >28 days of therapy was more common in patients who did not receive letermovir (31.2% versus 6.2%; P = .02). In summary, letermovir was effective in preventing CMV infection in this high-risk population of HLA-mismatched allo-HCT recipients.

Impact of Preemptive Therapy for Cytomegalovirus on Hospitalizations and Cost after Hematopoietic Stem Cell Transplantation

Cytomegalovirus (CMV) viremia occurs in 40% to 80% of CMV-seropositive (R+) recipients of allogeneic hematopoietic cell transplantation (HCT). The preemptive therapy (PET) strategy has reduced the risk of CMV end-organ disease (EOD) and associated mortality but may lead to substantial healthcare resource utilization (HCRU) and costs. Real-world data on the economic impact of PET is relevant for the evaluation of alternative strategies for CMV management. We examined the impact of clinically significant CMV treated with PET on inpatient length of stay (LOS), number of readmissions, and associated costs from day 0 through day 180 post-HCT. This was a retrospective study of R+ adults who underwent peripheral blood or marrow allogeneic HCT at Memorial Sloan Kettering Cancer Center between March 2013 and December 2017. Patients were routinely screened for CMV by qPCR and received PET according to institutional standards of care. Data were extracted from electronic medical records and hospital databases. Itemized cost data per patient were obtained from the Vizient database, adjusted to 2017 dollars using inflation indices. Study outcomes included HCRU evaluated by inpatient LOS and inpatient cost in patients who received PET for clinically significant CMV (PET group) compared with those who did not receive PET (no PET group) and the frequency and cost of CMV-related readmissions compared with non CMV-related readmissions. We used generalized linear models to examine the incremental HCRU and costs associated with PET controlling for other potential factors. Of 357 patients, PET was initiated in 208 (58.3%), at a median of 35 days after HCT. By day 180, 23 patients (6.4%) had developed CMV EOD and 3 (.8%) had died of CMV. Compared with the no PET group, the PET group had a longer LOS for HCT admission (P = .0276), longer total LOS by day 180 (P = .0001), a higher number of readmissions (P = .0001), a higher mean inpatient cost for HCT admission ($189,389 versus $151,646; P = .0133), and a higher total inpatient cost ($297,563 versus $205,815; P < .0001). Among PET recipients, CMV-related readmissions were associated with higher mean cost per episode compared with non CMV-related readmissions ($165,455 versus $89,419; P = .005). CMV-related readmissions comprised 40.6% of total all-cause readmissions and incurred 55.9% of total all-cause readmission costs in PET recipients. Our data show that patients treated with currently available PET had greater inpatient HCRU and cost, by day 180 compared with patients who did not receive PET. The cost of CMV-related readmissions accounted for 56% of total readmission cost among PET recipients. Future studies are needed to examine the cost-effectiveness of alternative strategies for CMV management.

Impact of Preemptive Therapy for Cytomegalovirus on Toxicities after Allogeneic Hematopoietic Cell Transplantation in Clinical Practice: A Retrospective Single-Center Cohort Study

(Val)ganciclovir (vGCV) or foscarnet (FCN) as preemptive therapy (PET) for cytomegalovirus (CMV) after allogeneic hematopoietic cell transplantation (HCT) is associated with myelosuppression and nephrotoxicity, respectively. We analyzed a cohort of CMV-seropositive (R⁺) HCT recipients managed preemptively at a single center. The objectives of our study were to (1) quantify the frequencies of neutropenia and acute kidney injury (AKI) through day +100 (D100) post-HCT and at PET discontinuation and (2) assess the impact of PET on neutropenia and AKI in multivariate models. This was a retrospective cohort study of adult CMV R⁺ recipients who underwent allo-HCT at Memorial Sloan Kettering Cancer Center from March 18, 2013, through December 31, 2017, and were managed with PET. Patients were grouped by receipt of PET (PET and no PET). Neutropenia and AKI were defined by Common Terminology Criteria for Adverse Events version 4. Frequencies of toxicities by D100 were compared between relevant groups. The impact of PET on toxicities was examined in univariate and multivariate Poisson/negative binomial regression models. Of 368 CMV R⁺ HCT recipients, 208 (56.5%) received PET. Neutropenia by D100 occurred in 41.8% and 28.6% patients in PET and no PET, respectively (P = .0009). PET increased the risk of neutropenia (adjusted relative risk = 1.81; 95% confidence interval [CI], 1.48 to 2.21; P < .0001) in multivariate analyses. AKI by D100 occurred in 12.0% and 7.8% patients in PET and no PET, respectively (P = .19). PET increased the risk of AKI by 2.75-fold (95% CI, 1.71 to 4.42; P < .0001). When PET recipients were grouped by first antiviral, neutropenia by D100 occurred in 34.8% and 48.9% of vGCV and FCN recipients, respectively, (P = .08), and AKI occurred in 13.0% and 34.0% of vGCV and FCN recipients, respectively (P = .001). At discontinuation of vGCV or FCN, neutropenia was present in 11.2% versus 2.1% patients, respectively (P = .08), and AKI was present in 1.9% of versus 12.8% patients respectively (P = .005). Preemptive therapy for CMV increased the risk of neutropenia and AKI in the first 100 days post-HCT by 1.8-fold and 2.8-fold, respectively. Our results underscore the need for safer antivirals for CMV management in HCT recipients.

Guidelines for the management of cytomegalovirus infection in patients with haematological malignancies and after stem cell transplantation from the 2017 European Conference on Infections in Leukaemia (ECIL 7)

Cytomegalovirus is one of the most important infections to occur after allogeneic haematopoietic stem cell transplantation (HSCT), and an increasing number of reports indicate that cytomegalovirus is also a potentially important pathogen in patients treated with recently introduced drugs for hematological malignancies. Expert recommendations have been produced by the 2017 European Conference on Infections in Leukaemia (ECIL 7) after a review of the literature on the diagnosis and management of cytomegalovirus in patients after HSCT and in patients receiving other types of therapy for haematological malignancies. These recommendations cover diagnosis, preventive strategies such as prophylaxis and pre-emptive therapy, and management of cytomegalovirus disease. Antiviral drugs including maribavir and letermovir are in development and prospective clinical trials have recently been completed. However, management of patients with resistant or refractory cytomegalovirus infection or cytomegalovirus disease is a challenge. In this Review we summarise the reviewed literature and the recommendations of the ECIL 7 for management of cytomegalovirus in patients with haematological malignancies.

Relationship of Ganciclovir Therapeutic Drug Monitoring with Clinical Efficacy and Patient Safety

The clinical utility of ganciclovir therapeutic drug monitoring (TDM) is unknown. We retrospectively analyzed adult patients treated for cytomegalovirus (CMV) infection with ganciclovir with TDM between 2005 and 2015. The primary outcome was an association between ganciclovir TDM and clinical efficacy endpoints within 30 days, defined by viral load and symptomatology. Secondary outcomes included safety endpoints, evaluated within 7 days of the last administered dose of ganciclovir. Of 175 patients evaluated, 82 patients with CMV infection were included in our analysis with a median (interquartile range) baseline CMV viral load of 5,500 (3,000 to 15,200) copies/ml. The majority achieved undetectable or reduced CMV viral load below the lower limit of quantification (74.4%) with improvement in symptomatology (70.7%) at 30 days. Among patients with detectable CMV viremia at 30 days, the viral load had declined to a median of 1,000 (1,000 to 3,090) copies/ml. We did not observe significant associations between the efficacy outcomes and ganciclovir trough (P = 0.20 and P = 0.20, respectively) or peak concentrations (P = 0.14 and P = 0.14, respectively). Similarly, there was no significant association between ganciclovir trough or peak concentrations and safety endpoints, including leukopenia (P = 0.48 and P = 0.69), neutropenia (P = 0.59 and P = 0.69), thrombocytopenia (P = 0.29 and P = 0.37), anemia (P = 0.51 and P = 0.35), nephrotoxicity (P = 0.41 and P = 0.57), and neurotoxicity (P = 0.22 and P = 0.48). We did not observe any associations between ganciclovir TDM and clinical efficacy or safety endpoints. Routine ganciclovir TDM may be of limited value. Future studies may be warranted to identify specific populations with unpredictable pharmacokinetic and pharmacodynamics profiles in whom ganciclovir TDM may be of benefit.

Treatment and Prevention of CMV Disease in Transplant Recipients: Current Knowledge and Future Perspectives

This review summarizes the significant impact of cytomegalovirus (CMV) infection on solid organ and hematopoietic stem cell transplant recipients. A discussion of the various CMV prevention and treatment strategies is provided, including a detailed description of each of the available CMV antiviral drugs.

Cytomegalovirus Infection in Allogeneic Hematopoietic Cell Transplantation Managed by the Preemptive Approach: Estimating the Impact on Healthcare Resource Utilization and Outcomes

We quantified cytomegalovirus (CMV) antiviral use and hospital length of stay (LOS) associated with CMV infection in a contemporary cohort of conventional (CONV) and CD34-selected (T cell-depleted) hematopoietic cell transplantation (HCT) recipients managed by preemptive therapy (PET) in a single US center. Adults who received first allogeneic HCT at Memorial Sloan Kettering Cancer Center from June 2010 through December 2014 were analyzed. Days on PET, number of readmissions, and readmission LOS by day 180 post-HCT were summarized. Estimated unit value (EUV) was defined as the expected number of PET days for a cohort of 100 HCT with characteristics as the analyzed cohort. Standardized incidence ratio was calculated as the ratio of observed outcomes of patients with CMV viremia over the outcomes of patients without CMV viremia. Of 318 patients, 88 received CONV and 230 CD34-selected HCT. Rates of CMV viremia were 26.3% for CONV and 41.9% for CD34-selected (P = .003). Among patients with viremia 68.2% CONV and 97.9% CD34-selected received PET. EUV for PET was 852 days and 2821 days for CONV and CD34-selected, respectively. The standardized incidence ratios for number of readmission and readmission LOS were 1.7 (95% confidence interval [CI], 1.4 to 2.1) and 1.2 (95% CI, 1.1 to 1.3), respectively, for CONV HCT and 1.7 (95% CI, 1.3 to 2.1) and 1.6 (95% CI, 1.5 to 1.7), respectively, for CD34-selected HCT. Overall survival was similar between patients with and without CMV viremia by HCT type. CMV end-organ disease was associated with lower overall survival only in CD34-selected HCT (P = .0007). CMV infection managed by PET requires substantial antiviral use and is associated with longer readmission LOS more, particularly among CD34-selected HCT.

Cytomegalovirus resistance in CD34+ -selected hematopoietic cell transplant recipients

BACKGROUND

Cytomegalovirus (CMV) viremia after CD34+ -selected hematopoietic stem cell transplant (HCT) often requires prolonged antiviral therapy. We report rates and outcomes of resistant CMV in a contemporary cohort of CD34+ -selected HCT recipients managed preemptively.

METHODS

We retrospectively reviewed 220 consecutive, CMV-seropositive recipients (R+), who received CD34+ -selected HCT at Memorial Sloan Kettering Cancer Center between June 2010 and December 2014. Patients were monitored by quantitative CMV PCR and were treated preemptively. CMV resistance was tested by a genotypic assay.

RESULTS

One hundred and sixty-one (73%) patients developed CMV viremia and 47 (29% of viremic and 21% of total patients) had CMV resistance testing by one-year from HCT. CMV resistance was confirmed in 19 (12% of viremic and 9% of total) patients and was identified >3 months from HCT in 90% of patients. Twelve patients had mutations in UL97 only; the remaining 7 patients had mutations in UL54 only or UL54 and UL97. By 1 year from HCT, 11 of 19 (58%) patients with mutations had CMV end-organ disease. CMV-related mortality in patients with resistance was 42%.

CONCLUSIONS

Nine percent of CMV R+, CD34+ -selected HCT recipients had resistant CMV by 1 year from HCT. Of 19 patients with resistant CMV, 58% had CMV end-organ disease and 42% died of CMV. Effective strategies for CMV prevention and restoration of CMV immunity are needed for CD34+ -selected HCT.

Results of cytomegalovirus DNA viral loads expressed in copies per millilitre and international units per millilitre are equivalent

Quantification of Cytomegalovirus (CMV) DNA is required for the initiation and monitoring of anti-viral treatment and the detection of viral resistance. However, due to the lack of standardisation of CMV DNA nucleic acid tests, it is difficult to set universal thresholds. In 2010, the 1st WHO International Standard for Human Cytomegalovirus for Nucleic Acid Amplification Techniques was released. Since then CMV DNA viral load assays have been calibrated using this standard. Three external quality assessment (EQA) providers sent the same five samples to their participants and analysed the results to determine the equivalence of reporting CMV DNA results in international units per millilitre (IU/mL), and compared the difference in results reported in IU/mL with those reported in copies per millilitre (c/mL), and to determine the rate of adoption of IU/mL. About 78% of participants continue to report results in c/mL even though six of the 12 commercial assays are calibrated against the standard. The range of the results reported in IU/mL was less than those reported in c/mL indicating that the adoption of the WHO standard successfully improved the reporting of the CMV viral load. The variation in individual sample results reported by different assays, irrespective of whether in IU/mL or c/mL, is still great and therefore more standardisation of the assays is needed to allow the setting of treatment and monitoring thresholds. This study can act as a bench mark to determine rate of future adoption if reporting CMV DNA viral load results in IU/mL.

Comparison of Standardized Cytomegalovirus (CMV) Viral Load Thresholds in Whole Blood and Plasma of Solid Organ and Hematopoietic Stem Cell Transplant Recipients with CMV Infection and Disease

Background

Quantification of cytomegalovirus (CMV) deoxyribonucleic acid (DNA) has important diagnostic, prognostic, and therapeutic implications in the management of transplant recipients. We aimed to assess a viral load in plasma and whole blood that distinguishes CMV disease from asymptomatic infection in a cohort of solid organ and hematopoietic stem cell transplantation.

Methods

We prospectively measured and compared CMV viral load in paired plasma and whole blood samples collected from transplant recipients with CMV infection and disease. Cytomegalovirus viral loads were determined by a commercially available US Food and Drug Administration-approved quantitative assay (COBAS AmpliPrep/COBAS TaqMan CMV Test [CAP/CTM CMV]) calibrated to the first World Health Organization International Standard for CMV DNA quantification.

Results

Moderate agreement of CMV viral load was observed between plasma and whole blood, with 31% of samples having discordant findings, particularly among samples with low DNA levels. Among the subset of samples where both paired samples had quantifiable levels, we observed a systematic bias that reflected higher viral load in whole blood compared with plasma. Based on receiver operating curve analysis, an initial plasma CMV viral load threshold of 1700 IU/mL in solid organ transplant recipients (sensitivity 80%, specificity 74%) and 1350 IU/mL in allogeneic hematopoietic stem cell transplant recipients (sensitivity 87%, specificity 87%) distinguished CMV disease and asymptomatic infection.

Conclusions

This study identifies standardized viral load thresholds that distinguish CMV disease from asymptomatic infection using CAP/CTM CMV assay. We propose these thresholds as potential triggers to be evaluated in prospective studies of preemptive therapy. Plasma was better than whole blood for measuring viral load using the CAP/CTM CMV assay.

Co-Infections by Double-Stranded DNA Viruses after Ex Vivo T Cell-Depleted, CD34+ Selected Hematopoietic Cell Transplantation

Recipients of ex vivo T cell-depleted (TCD) hematopoietic cell transplantation (HCT) are at risk of infection by double-stranded (ds) DNA viruses. We report rates of dsDNA viremia, end-organ disease (EOD), infection-related mortality, and overall survival (OS) in a contemporary cohort of adult TCD HCT recipients routinely monitored for cytomegalovirus (CMV), adenovirus (ADV), human herpesvirus 6 (HHV6), and Epstein-Barr virus (EBV). Healthcare utilization in the first 6 months post-HCT was compared between patients with dsDNA viremia versus no viremia. This was an observational study of adult patients with acute leukemia and myelodysplastic syndrome who received CD34⁺ selected, peripheral blood HCT at Memorial Sloan Kettering Cancer Center from March 2012 through December 2014. Patients were prospectively monitored by quantitative PCR assays for CMV, ADV, HHV6, and EBV in whole blood or plasma. The cumulative incidence of viremia(s) at day +180, EOD at 1 year, and OS at 1 year were estimated by the Kaplan-Meier method and compared by the log-rank test among patient with and without viremia/EOD. Standardized incidence ratios were used to compare overall length of hospital stay (LOS), number of readmissions after HCT, and length of readmissions through day +180. Of 156 patients, 96 (62%) were CMV recipient seropositive. Forty-two patients received grafts from matched related (27%), 86 from matched unrelated (55%), and 28 from mismatched (18%) donors. Overall, 132 patients (85%) had ≥1 viremia and 52 (33%) ≥2 viremias by day +180. The cumulative incidences for CMV, HHV6, ADV, and EBV viremia were 44%, 61%, 7%, and 16%, respectively, with median times of onset 28 days (interquartile range [IQR], 25 to 33), 33 days (IQR, 25 to 47), 60 days (IQR, 19 to 84), and 79 days (IQR, 54 to 106) post-HCT, respectively. Twenty-eight patients (18%) developed EOD by dsDNA viruses at 1 year post-HCT. Treatment for CMV accounted for 91% total antiviral treatment-days. Compared with patients with no viremia, patients with CMV viremia, HHV6 viremia, or ≥2 viremias experienced longer LOS (P <.001) and a higher number of readmissions (P <.001) by day +180. OS rate at 1 year was 79% and was similar between patients with or without dsDNA viremias. EOD was associated with lower 1-year OS rates (63.4%) versus without EOD (81.1%) (P = .02). Of 33 patients who died, 10 died due to infection, and 7 of these infection-related deaths were due to dsDNA viruses. Viremia by dsDNA viruses occurred in 85% of TCD HCT recipients by day +100 and 33% of patients experienced ≥2 viremias by day +180. CMV accounted for most antiviral use. CMV, HHV6, or ≥2 viremias were associated with more readmissions and longer LOS. One year OS rate was 78%. EOD by dsDNA viruses was associated with decreased 1-year OS. Infections by dsDNA viruses pose a substantial burden after TCD HCT.

Evaluation of COBAS AmpliPrep/COBAS TaqMan CMV Test for use in hematopoietic stem cell transplant recipients

INTRODUCTION

Cytomegalovirus (CMV) is a common opportunistic infection that contributes to poor outcomes in hematopoietic stem cell transplant (HSCT) recipients. Prevention of CMV end-organ disease in allogeneic HSCT recipients is commonly achieved by preemptive antiviral therapy of asymptomatic CMV reactivation that is detected by serial nucleic acid testing (NAT). However, there was no standardized CMV NAT until the development of the World Health Organization (WHO) International Standard. Areas covered: This article provides a comprehensive review on COBAS AmpliPrep/TaqMan (CAP/CTM) CMV assay (Roche) and emphasizes the limitations in the clinical use of CMV NAT in HSCT recipients. Expert commentary: The CAP/CTM CMV Test is the first US FDA approved commercial quantitative NAT for CMV viral load monitoring of plasma samples in solid organ transplant and HSCT recipients. The CAP/CTM assay has wide linear range of DNA quantification and demonstrates colinearity to the WHO International Standard. Studies of CAP/CTM CMV assay in HSCT recipients are still limited, but are now being reported to define viral thresholds for diagnosis, surveillance and monitoring. Results from these early studies in HSCT recipients suggest that, while the WHO IS has improved the inter-laboratory result variances, there are still important factors that continue to contribute to assay variability. This lack of harmony among NAT highlights the need for further standardization.

Comparison of Two Commercial Automated Nucleic Acid Extraction and Integrated Quantitation Real-Time PCR Platforms for the Detection of Cytomegalovirus in Plasma

Quantitation of cytomegalovirus (CMV) viral load in the transplant patients has become a standard practice for monitoring the response to antiviral therapy. The cut-off values of CMV viral load assays for preemptive therapy are different due to the various assay designs employed. To establish a sensitive and reliable diagnostic assay for preemptive therapy of CMV infection, two commercial automated platforms including m2000sp extraction system integrated the Abbott RealTime (m2000rt) and the Roche COBAS AmpliPrep for extraction integrated COBAS Taqman (CAP/CTM) were evaluated using WHO international CMV standards and 110 plasma specimens from transplant patients. The performance characteristics, correlation, and workflow of the two platforms were investigated. The Abbott RealTime assay correlated well with the Roche CAP/CTM assay (R² = 0.9379, P<0.01). The Abbott RealTime assay exhibited higher sensitivity for the detection of CMV viral load, and viral load values measured with Abbott RealTime assay were on average 0.76 log₁₀ IU/mL higher than those measured with the Roche CAP/CTM assay (P<0.0001). Workflow analysis on a small batch size at one time, using the Roche CAP/CTM platform had a shorter hands-on time than the Abbott RealTime platform. In conclusion, these two assays can provide reliable data for different purpose in a clinical virology laboratory setting.

Laboratory Diagnosis of Infections in Cancer Patients: Challenges and Opportunities

Infections remain a significant cause of morbidity and mortality in cancer patients. The differential diagnosis for these patients is often wide, and the timely selection of the right clinical tests can have a significant impact on their survival. However, laboratory findings with current methodologies are often negative, challenging clinicians and laboratorians to continue the search for the responsible pathogen. Novel methodologies are providing increased sensitivity and rapid turnaround time to results but also challenging our interpretation of what is a clinically significant pathogen in cancer patients. This minireview provides an overview of the most common infections in cancer patients and discusses some of the challenges and opportunities for the clinical microbiologist supporting the care of cancer patients.

Cytomegalovirus Infection after CD34(+)-Selected Hematopoietic Cell Transplantation

The effectiveness of preemptive treatment (PET) for cytomegalovirus (CMV) in recipients of ex vivo T cell-depleted (TCD) hematopoietic cell transplantation (HCT) by CD34(+) selection is not well defined. We analyzed 213 adults who received TCD-HCT at our institution from June 2010 through May 2014. Patients were monitored by a CMV quantitative PCR assay if recipient (R) or donor (D) were CMV seropositive. CMV viremia occurred early (median, 27 days after HCT) in 91 of 213 (42.7%) patients for a 180-day cumulative incidence of 84.5%, 61.8%, and 0 for R+/D+, R+/D-, and R-/D+ patients, respectively. CMV disease occurred in 5% of patients. In Cox regression analysis, R+/D+ status was associated with increased risk for CMV viremia compared with R+/D- (hazard ratio [HR], 1.79, 95% confidence interval [CI], 1.16 to 2.76, P = .01), whereas matched unrelated donor allograft was associated with decreased risk (HR, .62; 95% CI, .39 to .97, P = .04). Of 91 patients with CMV viremia, 52 (57%) had persistent viremia (>28 days duration). Time lag from detection of CMV viremia to PET was associated with incremental risk for persistent viremia (HR, 1.09; 95% CI, 1.01 to 1.18; P = .03). Overall, 166 of 213 (77.9%) patients were alive 1 year after HCT, with no difference between patients with and without CMV viremia or among the different CMV serostatus pairs (P = not significant). CMV viremia occurred in 70% of R + TCD-HCT. Delay in PET initiation was associated with persistent viremia. With PET, CMV R/D serostatus did not adversely impact survival in TCD-HCT on 1-year survival in the present cohort.

Development and optimization of a sensitive TaqMan® real-time PCR with synthetic homologous extrinsic control for quantitation of Human cytomegalovirus viral load

Human cytomegalovirus (Human herpesvirus 5, HCMV) causes frequent asymptomatic infections in the general population. However, in immunosuppressed patients or congenitally infected infants, HCMV is related to high morbidity and mortality. In such cases, a rapid viral detection is crucial for monitoring the clinical outcome and the antiviral treatment. In this study, we optimized a sensitive biplex TaqMan® real-time PCR for the simultaneous detection and differentiation of a partial HCMV UL97 sequence and homologous extrinsic control (HEC) in the same tube. HEC was represented by a plasmid containing a modified HCMV sequence retaining the original primer binding sites, while the probe sequence was substituted by a phylogenetically divergent one (chloroplast CF0 subunit plant gene). It was estimated that the optimal HEC concentration, which did not influence the HCMV amplification is 1,000 copies/reaction. The optimized TaqMan® PCR demonstrated high analytical sensitivity (6.97 copies/reaction, CI = 95%) and specificity (100%). Moreover, the reaction showed adequate precision (repeatability, CV = 0.03; reproducibility, CV = 0.0027) and robustness (no carry-over or cross-contamination). The diagnostic sensitivity (100%) and specificity (97.8%) were adequate for the clinical application of the molecular platform. The optimized TaqMan® real-time PCR is suitable for HCMV detection and quantitation in predisposed patients and monitoring of the applied antiviral therapy. J. Med. Virol. 88:1604-1612, 2016. © 2016 Wiley Periodicals, Inc.

Molecular and Culture-Based Bronchoalveolar Lavage Fluid Testing for the Diagnosis of Cytomegalovirus Pneumonitis

Background.  Cytomegalovirus (CMV) is a major cause of morbidity and mortality in immunocompromised patients, with CMV pneumonitis among the most severe manifestations of infection. Although bronchoalveolar lavage (BAL) samples are frequently tested for CMV, the clinical utility of such testing remains uncertain. Methods.  Retrospective analysis of adult patients undergoing BAL testing via CMV polymerase chain reaction (PCR), shell vial culture, and conventional viral culture between August 2008 and May 2011 was performed. Cytomegalovirus diagnostic methods were compared with a comprehensive definition of CMV pneumonitis that takes into account signs and symptoms, underlying host immunodeficiency, radiographic findings, and laboratory results. Results.  Seven hundred five patients underwent 1077 bronchoscopy episodes with 1090 BAL specimens sent for CMV testing. Cytomegalovirus-positive patients were more likely to be hematopoietic cell transplant recipients (26% vs 8%, P < .0001) and less likely to have an underlying condition not typically associated with lung disease (3% vs 20%, P < .0001). Histopathology was performed in only 17.3% of CMV-positive bronchoscopy episodes. When CMV diagnostic methods were evaluated against the comprehensive definition, the sensitivity and specificity of PCR, shell vial culture, and conventional culture were 91.3% and 94.6%, 54.4% and 97.4%, and 28.3% and 96.5%, respectively. Compared with culture, PCR provided significantly higher sensitivity and negative predictive value (P ≤ .001), without significantly lower positive predictive value. Cytomegalovirus quantitation did not improve test performance, resulting in a receiver operating characteristic curve with an area under the curve of 0.53. Conclusions.  Cytomegalovirus PCR combined with a comprehensive clinical definition provides a pragmatic approach for the diagnosis of CMV pneumonitis.