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)

Infectious complications and the utility of serum and cellular markers of infections in the setting of allogeneic hematopoietic stem cell transplantation

INTRODUCTION

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients are severely immunocompromised and susceptible to bacterial, viral, and fungal infections. Despite improved anti-microbial prophylaxis and preemptive strategies, bacterial bloodstream infections (BSIs) occur frequently in allo-HSCT recipients and are associated with increased morbidity and mortality. Cytomegalovirus (CMV) and Epstein Barr virus (EBV) are the most relevant viruses following allo-HSCT and remain major concerns. Fungal infections, including those caused by Candida and Aspergillus species, are persistent and feared complications.

AREAS COVERED

We aim to provide clinicians caring for allo-HSCT recipients with a comprehensive overview of the risk factors that predispose patients to common bacterial, fungal, and viral infections during the first years post-transplant. The focus is on the value of noninvasive diagnostic biomarkers and serological assays in enhancing the early detection and management of these infections.

EXPERT OPINION

Effective management of infectious complications following allo-HSCT relies on continuous immune recovery monitoring and the implementation of advanced diagnostic methods. Utilizing noninvasive diagnostic methods is crucial for early detection and different intervention strategies. The development and integration of reliable microbiological markers into clinical practice is essential for enhancing patient outcomes and mitigating infection-related risks. Emphasizing diagnostic innovation will be pivotal in advancing patient care post-allo-HSCT.

Advances and prospect in herpesviruses infections after haematopoietic cell transplantation: closer to the finish line?

BACKGROUND

Herpesviruses represent common and significant infectious complications after allogeneic haematopoietic cell transplantation (HCT). In the last decade, major advances in the prevention and treatment of these infections were accomplished.

OBJECTIVES

The aim of this paper is to review the recent advances in the prophylaxis and treatment of herpesvirus infections after allogeneic HCT, to assess the persisting challenges, and to offer future directions for the prevention and management of these infections.

SOURCES

We searched PubMed for relevant literature regarding specific herpesviruses complicating allogeneic HCT through March 2024.

CONTENT

The largest advances in this past decade were witnessed for cytomegalovirus (CMV) with the advent of letermovir for primary prophylaxis and the development of maribavir as an option for refractory and/or resistant CMV infections in transplant recipients. For varicella zoster virus, prevention of reactivation with the recombinant zoster vaccine offers an additional prophylactic intervention. Pritelivir is being explored for the treatment of drug-resistant or refractory Herpes simplex virus infections. Although rituximab is now an established option for preemptive therapy for Epstein-Barr virus, Human Herpesvirus-6 remains the most elusive virus of the herpesvirus family, with a lack of evidence supporting the benefit of any agent for prophylaxis or for optimal preemptive therapy.

IMPLICATIONS

Although considerable advances have been achieved for the treatment and prevention of herpes virus infections, most notably with CMV, the coming years should hold additional opportunities to tame the beast in these herpesviruses postallogeneic HCT, with the advent of new antivirals, cell-mediated immunity testing, and cytotoxic T lymphocytes infusions.

Impact of automated nucleic acid extraction platforms on plasma Cytomegalovirus DNA loads quantitated by real-time PCR normalized to the 1st WHO international standard

INTRODUCTION

The extent to which commercially available nucleic acid extraction platforms impact the magnitude of Cytomegalovirus (CMV) DNA loads measured in plasma specimens by 1st WHO standard-normalized real-time PCR assays is uncertain.

METHODS

This retrospective study compares the performance of Abbott m2000sp, Qiagen QIAsymphony SP, and KingFisher Flex platforms using plasma samples from allogeneic hematopoietic stem cell transplant recipients and plasma spiked with the CMV AD169 strain. The Abbott RealTime CMV PCR assay was used for CMV DNA quantitation.

RESULTS

Maximum differences in CMV DNA loads quantified in plasma from 11 allo-HSCT and spiked plasma over a wide range of viral DNA concentrations (2.0-4.0 log10 IU/ml) were ≤0.5 log10 IU/ml.

CONCLUSIONS

The CMV DNA extraction efficiency of the platforms evaluated varies. The impact of these variations on CMV DNA loads quantified in plasma may not be clinically relevant.

Inflammatory factors predict infection risk during chemotherapy in leukemia patients

BACKGROUND

This study explores the novel role of specific inflammatory factors in predicting infection risk among leukemia patients undergoing chemotherapy, providing new insights into managing leukemia-associated infections.

METHODS

This prospective cohort study included 244 leukemia patients suspected of infection, divided into the infected group (n = 194) and the uninfected group (n = 50) based on etiological testing. The infected group was further categorized into bacterial (n = 123), fungal (n = 22), and viral (n = 49) infection subgroups. Inflammatory cytokines including IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, TNF-α, IFN-γ, IL-17A, IL-127P0, and IFN-α were measured using ELISA kits. Additional markers such as hs-CRP, SAA, and PCT were also assessed for the infected group.

RESULTS

The levels of IL-1β, IL-4, IL-5, IL-6, IL-8, IL-10, IFN-γ, IL-12p70, and IFN-α significantly differed between the infected and uninfected groups (P < 0.05). IL-1β, IL-4, IL-6, and IL-10 were significantly higher in the infected group compared to the uninfected group. Significant differences in PCT, IL-2, IL-4, IL-5, and IL-10 levels were observed among patients with bacterial, fungal, and viral infections (P < 0.05). However, none of these inflammatory factors were predictive of infection type.

CONCLUSION

IL-4, IL-6, IL-8, and IL-10 were identified as independent predictors of infection risk. However, no inflammatory factors could be used to distinguish between different types of infections.

Effectiveness of letermovir in preventing cytomegalovirus reactivation after cord blood transplantation

BACKGROUND

Cord blood transplantation (CBT) is associated with a high risk of cytomegalovirus (CMV) infection. Letermovir (LTV) is a prophylactic agent against CMV reactivation after CBT, but data on its effectiveness and the incidence of late CMV reactivation after LTV discontinuation are limited.

METHODS

A single-center retrospective observational study was conducted in 79 adult CMV-seropositive CBT recipients who received their first transplant for acute myeloid leukemia, acute lymphoblastic leukemia, or myelodysplastic syndrome from February 2016 to September 2022. Outcomes were compared between 45 patients who received LTV prophylaxis and 34 patients who did not.

RESULTS

The cumulative incidence of CMV reactivation was significantly lower in patients who received LTV prophylaxis at both day 100 (11.1 % vs. 82.4 %, p < 0.001) and 1 year (45.3 % vs. 82.4 %, p < 0.001). The incidence of late CMV reactivation after LTV discontinuation was 34.2 %. The cumulative incidence of CMV disease was comparable between patients who received and those who did not (0 % vs. 8.8 % at day 100, 2.3 % vs. 8.8 % at 1 year; p = 0.181). Multivariate analysis showed that LTV prophylaxis reduced the cumulative incidence of CMV reactivation (hazard ratio 0.20, 95 % confidence interval 0.09 to 0.42, p < 0.001).

CONCLUSION

LTV prophylaxis is strongly associated with prevention of CMV reactivation after CBT. Due to the high incidence of late CMV reactivation, close monitoring is required after LTV discontinuation and extension of LTV prophylaxis beyond day 100 should be considered.

The emergence of letermovir and maribavir drug-resistant mutations: from clinical trials to real-world studies

PURPOSE OF REVIEW

Cytomegalovirus (CMV) infection is associated with severe clinical disease and high morbidity in immunocompromised hosts. Letermovir and maribavir, are two recently developed antiviral drugs used in the prevention and treatment of resistant and refractory CMV. Following the publication of landmark randomized trials and increased use, both clinical trial data and real-world experience has reported the development of antiviral drug resistance. The aim of this review was to comprehensively review the published literature on letermovir and maribavir drug resistance and to describe the clinical scenarios in which they may emerge.

RECENT FINDINGS

For letermovir, the most frequently detected resistance mutations occur in the UL56 gene (C325Y/W/F) and confer total resistance. Maribavir resistance mutations most often occur in the UL97 gene and resistance-associated variants (RAVs) T409M, H411Y, C480F have all been detected. The clinical context in which letermovir and maribavir resistance occurs include high viral loads at initiation, intensified immunosuppression, subtherapeutic drug exposure because of poor adherence, drug interactions, and inadequate central nervous system (CNS) penetration. Emergence of resistance mutations generally occurs within the first 3 months of initiation.

SUMMARY

The detection of letermovir and maribavir resistance mutations highlights an ongoing clinical challenge in the management of CMV.

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 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.

Cytomegalovirus-Specific T-Cell-Receptor-like Antibodies Target In Vivo-Infected Human Leukocytes Inducing Natural Killer Cell-Mediated Antibody-Dependent Cellular Cytotoxicity

Cytomegalovirus (CMV) reactivation after stem cell or solid organ transplantation remains a major cause of morbidity and mortality in this setting. T-cell receptor (TCR)-like antibodies bind to intracellular peptides presented in major histocompatibility complex (MHC) molecules on the cell surface and may have the potential to replace T-cell function in immunocompromised patients. Three previously selected CMV-specific, human leukocyte antigen (HLA)-restricted (HLA-A*0101, HLA-A*0201 and HLA-B*0702) Fab-antibodies (A6, C1 and C7) were produced as IgG antibodies with Fc optimization. All antibodies showed specific binding to CMV peptide-loaded tumor cell lines and primary fibroblasts expressing the corresponding MHC-I molecules, leading to specific target cell lysis after the addition of natural killer (NK) cells. When deployed in combination as an antibody pool against target cells expressing more than one matching HLA allele, cytotoxic effects were amplified accordingly. CMV-specific TCR-like antibodies were also able to mediate their cytotoxic effects through neutrophils, which is important considering the delayed recovery of NK cells after stem cell transplantation. When tested on patient blood obtained during CMV reactivation, CMV-specific antibodies were able to bind to and induce cytotoxic effects in lymphocytes. CMV-specific TCR-like antibodies may find application in patients with CMV reactivation or at risk of CMV reactivation. In contrast to previous HLA/peptide-directed therapeutic approaches, the concept of a TCR-like antibody repertoire covering more than one HLA allele would make this therapeutic format available to a much larger group of patients.

A New Tool Supporting the Selection of the Best Hematopoietic Stem Cell Donor by Modelling Local Own Real-World Data

BACKGROUND

The selection of the best donor for each specific patient is crucial for the success of allogeneic hematopoietic stem cell transplantation (HSCT). However, there is debate on the choice of the best donor when multiple suitable donors exist.

METHODS

By using own data from two transplant centers, we have developed a calculator able to provide the patients' 2-year overall survival (OS) associated with each of the potential donor options during the selection process, in order to support the transplant physician during the choice. Data on 737 HSCTs with HLA-identical siblings, and unrelated or related haploidentical donors from January 2010 to July 2022 have been retrospectively obtained.

RESULTS

Patients' age, disease, comorbidity index, and donor type were found to be significant variables able to predict the outcome with robustness (concordance index: 0.677). Estimates are provided within an example in the text showing outcomes with four donor options for a specific patient.

CONCLUSIONS

We present the prototype of a tool supporting the selection of the best donor, guiding transplant physicians during the delicate process of donor selection before HSCT. This approach relies on real data from the centers, reflecting their local clinical experience. Improvements are underway with a larger, ongoing multicenter study.

Role of letermovir therapeutic drug monitoring for cytomegalovirus prophylaxis in allogeneic hematopoietic stem cell transplantation recipients: a prospective study

PURPOSE

The role of therapeutic drug monitoring (TDM) in allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients receiving letermovir has not yet been clarified. This study is to explore letermovir trough concentration (Cmin) correlation with its clinical efficacy and adverse events, and factors affecting its plasma concentrations.

METHODS

A prospective, non-interventional study was performed in allo-HSCT recipients receiving letermovir prophylaxis. Plasma concentrations were determined using high-performance liquid chromatography-tandem mass spectrometry. Data analysis was performed using logistic regression, linear regression, and classification and regression tree (CART) models.

RESULTS

701 trough concentrations from 71 recipients were included, uncovering pronounced intra- and inter-individual variability in letermovir Cmin. During 24-week follow-up, CMV infection incidence was 16.4%. A significant correlation was identified between letermovir Cmin and its clinical efficacy, and the CART model showed an increased risk of CMV infection when Cmin ≤ 2731 ng/mL. However, no clear correlation was found between Cmin and adverse events. Gastrointestinal graft-versus-host disease, cyclosporine Cmin, gender, and concomitant medications, including mycophenolate mofetil, ondansetron, caspofungin, and methylprednisolone, may impact letermovir Cmin. Additionally, coadministration with cyclosporine injection significantly decreased median letermovir Cmin compared with cyclosporine capsules (2311 vs. 3386 ng/mL). Moreover, with the extension of time post-transplant, trough concentrations of both cyclosporine and letermovir significantly decreased.

CONCLUSION

TDM for letermovir may be beneficial in allo-HSCT recipients considering the variability in letermovir Cmin and its correlation with clinical efficacy. Moreover, drug interactions and the effects of changes in cyclosporine dosage forms or concentrations require careful monitoring for their effect on letermovir Cmin.

Mismatched unrelated donors allogeneic hematopoietic stem cell transplantation with antithymocyte globulin for hematological malignancies: a multicenter retrospective study in China

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) utilizing mismatched unrelated donors (MMUD) present a vital option for patients with hematologic malignancies without human leukocyte antigen (HLA)-matched donors. This multicenter retrospective study encompassed 211 adults with hematological malignancies receiving allo-HSCT with antithymocyte globulin (ATG) from ≥1 HLA locus MMUD. The findings revealed cumulative incidences of II-IV acute graft-versus-host disease (GVHD) at 180 days at 26.5%, and III-IV acute GVHD at 12.3%, with 3-year cumulative incidences for total and moderate-severe chronic GVHD at 37.0% and 21.0%. The 3-year non-relapse mortality (NRM) and relapse rates were 19.7% and 25.8%. The study reported a 3-year overall survival (OS) rate of 63.1%, a disease-free survival (DFS) rate of 54.5%, and a GVHD-free, relapse-free survival (GRFS) rate of 40.8%. Administration of a lower-dose ATG-Genzyme (ATG-G, ≤ 6 mg/kg) correlated with improved engraftment without significantly affecting survival, relapse, or viral reactivation rates. The quantity of HLA mismatches did not impact engraftment, GVHD, viral reactivation, OS, DFS, GRFS, relapse, or NRM. In conclusion, MMUD allo-HSCT with ATG demonstrates favorable outcomes for patients with hematological malignancies, with no evident correlation between the degree of mismatch and post-transplantation results. Utilizing a lower dose of ATG-G ( ≤ 6 mg/kg) proved efficacious, delivering comparable clinical advantage.

Monitoring and Management of Cytomegalovirus Reactivations After Allogeneic Hematopoietic Stem Cell Transplantation in Children: Experience from a Single Pediatric Center

BACKGROUND

CMV reactivation represents a frequent complication after HSCT. The aim of this study was to describe the incidence of CMV reactivation in a pediatric HSCT cohort and analyze the potential impact of recipient/donor-related or transplant-related factors on this complication. Furthermore, we analyzed the management of CMV reactivation in order to purpose criteria for pre-emptive therapy.

METHODS

Allogeneic HSCTs, performed at IRCCS Istituto Gaslini between 2012 and 2022, were included in this analysis. CMV-DNAemia was regularly monitored. Risk stratification was based on donor/recipient serological status and additional potential risk factors were considered: haploidentical transplant; any HSCT subsequent to the first; acute and chronic GvHD; steroids; and other immunosuppressive therapies. We described also the approach for pre-emptive therapy during the period 2012-2019.

RESULTS

A total of 214 allogeneic HSCTs were performed in 189 patients. In total, 100 (46.7%) HSCTs were complicated by at least one reactivation. CMV reactivation was significantly associated with high serological risk and steroid treatment. Pre-emptive therapy was administered in 59/69 (85.5%) HSCTs during 2012-2019. In the presence of predefined risk conditions, therapy was started at a median viremia of 2050 copies/mL. No difference was observed in OS between patients with CMV reactivation versus patients who did not present this complication.

CONCLUSIONS

These results suggest the potential effectiveness of the approach used in providing pre-emptive therapy based on viral load monitoring and individualized risk factors.

Comprehensive Herpesviruses Antiviral drug Resistance Mutation Database (CHARMD)

A comprehensive and accessible Herpesvirus drug resistance database was designed to serve as an international reference for diagnosis and clinical studies. This database available at https://www.unilim.fr/cnr-herpesvirus/outils/codexmv/includes both resistance-related mutations and natural polymorphisms. Initially designed for human cytomegalovirus, it will be expanded to include herpes simplex and varicella-zoster viruses. Newly published mutations and new mutations reported by users or collaborating expert laboratories will be reviewed by an international committee of reference laboratories before inclusion in the database. Coupled with the Herpesvirus Sequence Analysis tool (HSA) mutation reports from NGS or Sanger sequences, it will be an open source for researchers in the field of Herpesviruses. We hope to fill this unmet need for the development and standardization of resistance genotyping.

Cytomegalovirus infection risk with alemtuzumab therapy in hematological malignancies: a retrospective cohort study in the non-transplant setting

Alemtuzumab is a potent lymphocyte-depleting immunotherapy used in solid organ transplan-tation (SOT), that is increasingly being applied in diverse lymphoproliferative disorders (LPDs). However, a significant toxicity limiting expanded usage is cytomegalovirus (CMV) infection, for which standardized preventive strategies exist in SOT but not in LPDs due to a poor understanding of infection risk in this population, with early LPD studies largely limited to stem cell transplantation. Using one of the most diverse arrays of LPDs studied to date, our retrospective cohort study of non-transplant patients receiving alemtuzumab over a ten-year period at a large regional cancer center examines the incidence and clinical profile of infected patients. Among 24 patients, we identified a composite CMV infection rate of 42% with a symptomatic rate of 21%. We also noted significant variations in preventive strategies, which alongside a high infection rate presents an opportunity to improve outcomes through further work in standardization.

Understanding Risk Factors for Cytomegalovirus Infection in Pediatric Hematopoietic Stem Cell Transplantation: Insights From a 10-Year Study Comparing Conditioning Regimens

Hematopoietic stem cell transplantation is a curative therapy for pediatric patients with malignancies and blood or immune system disorders. However, recipients are at risk of opportunistic infections, including cytomegalovirus infection, due to immunosuppression from conditioning regimens. This retrospective study analyzed 439 pediatric hematopoietic stem cell transplantation patients to identify risk factors for cytomegalovirus infection and assess the impact of conditioning regimens. Significant factors included graft source, graft versus host disease, and pre-transplant clinically significant cytomegalovirus infection. Myeloablative conditioning regimens and the use of anti-thymocyte globulin increased the risk of clinically significant cytomegalovirus infection. Additionally, the risk of cytomegalovirus infection in patients was found to be statistically significant in the myeloablative subgroup analyses who received anti-thymocyte globulin alone and those who received both anti-thymocyte globulin and total body irradiation. In our study, total body irradiation did not significantly affect the risk of clinically significant cytomegalovirus infection. This study covers a 10-year period and a large pediatric patient population from a single center. Our findings highlight the importance of understanding risk factors for clinically significant cytomegalovirus infection to guide preventive strategies in pediatric HSCT recipients.

Analysis of early and treatment related deaths among children and adolescents with acute myeloid leukemia in Poland: 2005-2023

Background

A personalised approach to the treatment of acute myeloid leukemia (AML) in children and adolescents, as well as the development of supportive therapies, has significantly improved survival. Despite this, some patients still die before starting treatment or in an early phase of therapy before achieving remission. The study analysed the frequency, clinical features and risk factors for early deaths (ED) and treatment related deaths (TRD) of children and adolescents with AML.

Methods

From January 2005 to November 2023, 646 children with AML treated in the centers of the Polish Pediatric Leukemia and Lymphoma Study Group according to three subsequent therapeutic protocols were evaluated: AML-BFM 2004 Interim (385 children), AML-BFM 2012 Registry (131 children) and AML-BFM 2019 (130 children).

Results

Out of 646 children, early death occurred in 30 children, including 15 girls. The median age was 10.7 years (1 day to 18 years). More than half of the patients (53%) were diagnosed with acute myelomonocytic leukemia (M5) and 13% with acute promyelocytic leukemia (M3). The ED rate for the three consecutive AML-BFM protocols was 4.9% vs. 5.3% vs. 3.1%, respectively. In 19 patients, death occurred before the 15th day of treatment, in 11 between the 15th and 42nd day. The most common cause of death before the 15th day (ED15) was leukostasis and bleeding, whereas between the 15th and 42nd day (ED15-42), infections, mainly bacterial sepsis. A significant association was found between ED15 and high leukocyte count (>10 × 109/L), M3 leukemia (p < 0.001), and ED15-42 and age <1 year (p = 0.029). In the univariate analysis only initial high leukocyte count >100 × 109/L, was a significant predictor of early death. The overall TRD for the entire study period was 3.4%. The main cause of death were infections, mainly bacterial sepsis (10 children out of 22, 45.4%).

Conclusions

Hyperleukocytosis remains significant factor of early mortality in patients with AML, despite the introduction of various cytoreductive methods. Infections are still the main cause of treatment related deaths. A more individualized approach by using new targeted drugs may be the therapeutic option of choice in the future.

Use of Specific T Lymphocytes in Treating Cytomegalovirus Infection in Hematopoietic Cell Transplant Recipients: A Systematic Review

Cytomegalovirus (CMV) poses a significant threat to post-hematopoietic cell transplantation (HCT). Control strategies include letermovir prophylaxis or ganciclovir pre-emptive therapy (PET). Without prophylaxis, 65-90% of seropositive recipients develop a clinically significant CMV infection. Due to PET drawbacks, letermovir prophylaxis is preferable, as it reduces CMV-related events and improves overall survival. However, refractory or resistant CMV-CS remains a challenge, with maribavir showing limited efficacy. This systematic review followed the Cochrane Manual and PRISMA guidelines and was registered in PROSPERO. Searches were conducted in PubMed, Scopus, Embase, and Web of Science. Out of 1895 identified records, 614 duplicates were removed, and subsequent screening excluded 1153 studies. Eleven included studies (2012-2024) involved 255 HCT recipients receiving adoptive immunotherapy (AI), primarily CMV-specific T-cell therapy. GvHD occurred in 1.82% of cases. Adverse events occurred in 4.4% of cases, while mild CRS was observed in 1.3% of patients. Efficacy, evaluated in 299 patients across eleven studies, showed an average response rate of 78.2%. CMV-CS recurrence was observed in 24.4% of 213 patients, and death due to CMV was reported in 9.7% of 307 patients across nine studies. Adoptive hCMV-specific T-cell immunotherapy appears to be a safe, effective alternative for refractory CMV-CS in HCT.

[Management of Cytomegalovirus Infection in Allogeneic Hematopoietic Stem Cell Transplant Recipients]

Cytomegalovirus (CMV) is a type of double-stranded deoxyribonucleic acid virus belonging to the herpesviridae family. Following a primary infection, the virus becomes latent in various types of white blood cells. Cytomegalovirus infection can remain latent or become active, especially in immunocompromised individuals, such as those undergoing hematopoietic stem cell transplantation (HSCT), where CMV reactivation can occur. In this context, CMV infection is common and associated with high rates of morbidity and mortality. Pneumonia is one of the most serious complications, with mortality rates exceeding 50%. Additionally, even in the absence of organ-specific disease, CMV infection is related to increased mortality unrelated to hematologic neoplasm recurrence. Given the frequency and severity of this infection in HSCT patients, it is crucial to implement effective strategies for monitoring, prevention, and treatment. This guideline was developed to identify patient groups that benefit from a systematic approach to CMV infection and to define the most appropriate strategy for each group. Monitoring CMV viral load in peripheral blood is crucial, especially in patients at moderate to high risk of active infection. Primary prophylaxis with letermovir (an antiviral drug) is recommended to reduce the incidence of active infection, especially in high-risk patients. Secondary prophylaxis with valganciclovir (antiviral drug) is recommended after an episode of active infection, while preemptive and disease treatment is based on monitoring viral load and clinical response. The aim of this guideline is to improve the approach to CMV infection in HSCT patients, ensuring an effective and safe preventive and therapeutic approach.

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.

Management of cytomegalovirus infections - Swedish recommendations 2023

Cytomegalovirus (CMV) infection, which mostly causes a subclinical infection early in life, has important clinical consequences in certain patient groups. CMV is the most common congenital infection and can cause permanent disabilities such as hearing loss and motor- and cognitive deficits in affected infants. In allogeneic haematopoietic stem cell and solid organ transplant recipients, CMV still is an important infectious complication with a risk for life-threatening disease. The previous Swedish recommendations for the management of CMV infections were updated by an expert group under the guidance of The Swedish Reference Group for Antiviral Treatment (RAV) and published at the website of RAV in August 2023 (https://www.sls.se/rav/rekommendationer/cytomegalovirus/). We here provide a translation of the updated recommendations, with minor modifications regarding diagnosis of CMV pneumonia. In the present recommendations, we discuss aspects of old and new CMV antivirals, including dosing for different age groups, and cover the management of congenital infections and CMV in immunocompromised patients. The recommendations are evidence-graded in accordance with the Oxford Centre for Evidence-Based Medicine.

Microbiological risk factors, ICU survival, and 1-year survival in hematological patients with pneumonia requiring invasive mechanical ventilation

PURPOSE

To identify pathogenic microorganisms and microbiological risk factors causing high morbidity and mortality in immunocompromised patients requiring invasive mechanical ventilation due to pneumonia.

METHODS

A retrospective single-center study was performed at the intensive care unit (ICU) of the Department of Internal Medicine at Heidelberg University Hospital (Germany) including 246 consecutive patients with hematological malignancies requiring invasive mechanical ventilation due to pneumonia from 08/2004 to 07/2016. Microbiological and radiological data were collected and statistically analyzed for risk factors for ICU and 1-year mortality.

RESULTS

ICU and 1-year mortality were 63.0% (155/246) and 81.0% (196/242), respectively. Pneumonia causing pathogens were identified in 143 (58.1%) patients, multimicrobial infections were present in 51 (20.7%) patients. Fungal, bacterial and viral pathogens were detected in 89 (36.2%), 55 (22.4%) and 41 (16.7%) patients, respectively. Human herpesviruses were concomitantly reactivated in 85 (34.6%) patients. As significant microbiological risk factors for ICU mortality probable invasive Aspergillus disease with positive serum-Galactomannan (odds ratio 3.1 (1.2-8.0), p = 0.021,) and pulmonary Cytomegalovirus reactivation at intubation (odds ratio 5.3 (1.1-26.8), p = 0.043,) were identified. 1-year mortality was not significantly associated with type of infection. Of interest, 19 patients had infections with various respiratory viruses and Aspergillus spp. superinfections and experienced high ICU and 1-year mortality of 78.9% (15/19) and 89.5% (17/19), respectively.

CONCLUSIONS

Patients with hematological malignancies requiring invasive mechanical ventilation due to pneumonia showed high ICU and 1-year mortality. Pulmonary Aspergillosis and pulmonary reactivation of Cytomegalovirus at intubation were significantly associated with negative outcome.

Cytomegalovirus in haematopoietic cell transplantation - The troll is still there

Patients undergoing allogeneic haematopoietic cell transplantation are prone to complications caused by viral infections. Cytomegalovirus (CMV) considerably impacts transplantation as it frequently requires antiviral intervention that evokes substantial side effects depending on the antiviral drug. Intermittent antiviral treatment may become necessary if CMV DNAemia cannot be permanently suppressed, and drug resistance may emerge that hampers and prolongs treatment. Despite sedulous endeavours, vaccination against CMV is not yet available. This review concisely summarises current approaches in managing CMV infection comprising risk factors, diagnostics including indications for resistance testing, and therapeutic options from antiviral drugs to virus-specific T cells.

Long-term outcome after allogeneic stem cell transplantation for GATA2 deficiency: An analysis of 67 adults and children from France and Belgium

Modalities and timing of haematopoietic stem cell transplant (HSCT) in patients with GATA2 deficiency are still subject to debate. On June 2022, 67 patients (median age 20.6 years) underwent a first allogeneic HSCT among 21 centres. Indications for HSCT were myelodysplastic syndrome (MDS) ≤5% blasts ± immunodeficiency (66%), MDS >5% blasts (15%), acute myeloid leukaemia (19%). Conditioning regimen was myeloablative in 85% and anti-thymocyte globulins were used in 67%. The cumulative incidence (CInc) of acute graft versus host disease (GvHD) grade II-IV and III-IV at day 100 were 42% and 13%, and CInc of chronic and extensive chronic GvHD at 2 years were 42% and 23%. CInc of relapses was 3% and 11% at 1 and 5 years. Overall survival (OS) at 1 and 5 years was 83% and 72% (median follow-up 5.6 years). The factors associated with worse OS in multivariable analysis were the year of HSCT, a history of excess blasts before transplant and peripheral blood stem cell (PBSC) grafts. Age at HSCT, non-myeloablative conditioning and PBSC grafts were associated with increased non-relapse mortality. In conclusion, bone marrow monitoring to identify clonal evolution and perform HSCT before the appearance of excess blast is mandatory.

QuantiFERON monitor predicts early cytomegalovirus infection and viral burden in allogeneic hematopoietic stem cell transplantation

INTRODUCTION

Cytomegalovirus (CMV) infection is a major cause of transplantation-related morbidity and mortality. This study assessed the utility of the QuantiFERON monitor (QFM; Qiagen) for the prediction of early CMV infection and viral burden.

METHODS

QuantiFERON-CMV (QF-CMV; Qiagen) and QFM were measured at the post-allogeneic hematopoietic stem cell transplantation (HSCT) week 4. CMV DNA was measured at every visit until post-HSCT week 24. The QFM cutoff specific to CMV infection was established.

RESULT

At the post-HSCT week 4, the QFM cutoff predicting CMV infection was 86.95 IU/mL. While QF-CMV results at the post-HSCT week 4 were associated with high-level CMV infection (CMV DNA ≥ 5,000 IU/mL) but not with CMV infection (CMV DNA ≥ 500 IU/mL), QFM was associated with both CMV infection and high-level CMV infection. Both indeterminate QF-CMV and nonreactive QFM were associated with increased peak CMV DNA.

CONCLUSION

Low QFM is a risk factor for CMV infection and increased CMV viral loads. QFM at post-HSCT week 4 can be utilized as an assay to predict the risk and burden of early CMV infection in HSCT recipients, in conjunction with other risk factors.

The plasma viral communities associate with clinical profiles in a large-scale haematological patients cohort

BACKGROUND

Haematological patients exhibit immune system abnormalities that make them susceptible to viral infections. Understanding the relationship between the virome in the blood plasma of haematological patients and their clinical characteristic is crucial for disease management. We aimed to explore the presence of viral pathogens and identify close associations between viral infections and various clinical features.

RESULTS

A total of 21 DNA viruses and 6 RNA viruses from 12 virus families were identified from 1383 patients. Patients with haematological diseases exhibited significantly higher diversity, prevalence, and co-detection rates of viral pathogens. During fever episodes, pathogen detection was notably higher, with Epstein-Barr virus (EBV) and Mucorales infections being the most probable culprits for fever symptoms in non-haematological patients. The detection rate of torque teno virus (TTV) significantly increases in haematological patients after transplantation and during primary lung infections. Additionally, TTV-positive patients demonstrate significantly higher absolute neutrophil counts, while C-reactive protein and procalcitonin levels are notably lower. Furthermore, TTV, cytomegalovirus, and parvovirus B19 (B19V) were found to be more prevalent in non-neutropenic patients, while non-viral pathogenic infections, such as Gram-negative bacteria and Mucorales, were more common in neutropenic patients. Pegivirus C (HPgV-C) infection often occurred post-transplantation, regardless of neutropenia. Additionally, some viruses such as TTV, B19V, EBV, and HPgV-C showed preferences for age and seasonal infections.

CONCLUSIONS

Analysis of the plasma virome revealed the susceptibility of haematological patients to plasma viral infections at specific disease stages, along with the occurrence of mixed infections with non-viral pathogens. Close associations were observed between the plasma virome and various clinical characteristics, as well as clinical detection parameters. Understanding plasma virome aids in auxiliary clinical diagnosis and treatment, enabling early prevention to reduce infection rates in patients and improve their quality of life. Video Abstract.

Late cytomegalovirus disease after hematopoietic cell transplantation: significance of novel transplantation techniques

ABSTRACT

Preemptive therapy (PET) and letermovir prophylaxis are effective in preventing cytomegalovirus (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 203 episodes of late CMV disease among 2469 day 100 survivors, and the estimated cumulative incidence of first late CMV disease was 7.2% (95% confidence interval [CI], 6.2-8.3) with no difference between the PET (7.4%; 95% CI, 6.4-8.6) and the letermovir group (5.4%; 95% CI, 3.2-8.3). Thirty-seven patients (1.5%) had a second episode of CMV disease. In multivariable Cox regression models, posttransplant cyclophosphamide was associated with an increased risk of gastrointestinal CMV disease. CMV viremia or disease detected before day 100, corticosteroid treatment after day 100 at dose ≥1 mg/kg, acute and chronic graft-versus-host disease, lymphopenia, HLA-mismatched related donor status, 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 2 years after HCT. In summary, late CMV disease continues to occur in the present era. Improved prevention strategies for late CMV disease are needed.

Clinical characteristics and outcomes of immunocompromised critically ill patients with cytomegalovirus end-organ disease: a multicenter retrospective cohort study

BACKGROUND

Cytomegalovirus (CMV) infection in patients with cellular immune deficiencies is associated with significant morbidity and mortality. However, data on CMV end-organ disease (CMV-EOD) in critically ill, immunocompromised patients are scarce. Our objective here was to describe the clinical characteristics and outcomes of CMV-EOD in this population.

METHODS

We conducted a multicenter, international, retrospective, observational study in adults who had CMV-EOD and were admitted to any of 18 intensive care units (ICUs) in France, Israel, and Spain in January 2010-December 2021. Patients with AIDS were excluded. We collected the clinical characteristics and outcomes of each patient. Survivors and non-survivors were compared, and multivariate analysis was performed to identify risk factors for hospital mortality.

RESULTS

We studied 185 patients, including 80 (43.2%) with hematologic malignancies, 55 (29.7%) with solid organ transplantation, 31 (16.8%) on immunosuppressants, 16 (8.6%) with solid malignancies, and 3 (1.6%) with primary immunodeficiencies. The most common CMV-EOD was pneumonia (n = 115, [62.2%] including 55 [47.8%] with a respiratory co-pathogen), followed by CMV gastrointestinal disease (n = 64 [34.6%]). More than one organ was involved in 16 (8.8%) patients. Histopathological evidence was obtained for 10/115 (8.7%) patients with pneumonia and 43/64 (67.2%) with GI disease. Other opportunistic infections were diagnosed in 69 (37.3%) patients. Hospital mortality was 61.4% overall and was significantly higher in the group with hematologic malignancies (75% vs. 51%, P = 0.001). Factors independently associated with higher hospital mortality were hematologic malignancy with active graft-versus-host disease (OR 5.02; 95% CI 1.15-27.30), CMV pneumonia (OR 2.57; 95% CI 1.13-6.03), lymphocytes < 0.30 × 109/L at diagnosis of CMV-EOD (OR 2.40; 95% CI 1.05-5.69), worse SOFA score at ICU admission (OR 1.18; 95% CI 1.04-1.35), and older age (OR 1.04; 95% CI 1.01-1.07).

CONCLUSIONS

Mortality was high in critically ill, immunocompromised patients with CMV-EOD and varied considerably with the cause of immunodeficiency and organ involved by CMV. Three of the four independent risk factors identified here are also known to be associated with higher mortality in the absence of CMV-EOD. CMV pneumonia was rarely proven by histopathology and was the most severe CMV-EOD.

Dynamic monitoring of viral gene expression reveals rapid antiviral effects of CD8 T cells recognizing the HCMV-pp65 antigen

Introduction

Human Cytomegalovirus (HCMV) is a betaherpesvirus that causes severe disease in immunocompromised transplant recipients. Immunotherapy with CD8 T cells specific for HCMV antigens presented on HLA class-I molecules is explored as strategy for long-term relief to such patients, but the antiviral effectiveness of T cell preparations cannot be efficiently predicted by available methods.

Methods

We developed an Assay for Rapid Measurement of Antiviral T-cell Activity (ARMATA) by real-time automated fluorescent microscopy and used it to study the ability of CD8 T cells to neutralize HCMV and control its spread. As a proof of principle, we used TCR-transgenic T cells specific for the immunodominant HLA-A02-restricted tegumental phosphoprotein pp65. pp65 expression follows an early/late kinetic, but it is not clear at which stage of the virus cycle it acts as an antigen. We measured control of HCMV infection by T cells as early as 6 hours post infection (hpi).

Results

The timing of the antigen recognition indicated that it occurred before the late phase of the virus cycle, but also that virion-associated pp65 was not recognized during virus entry into cells. Monitoring of pp65 gene expression dynamics by reporter fluorescent genes revealed that pp65 was detectable as early as 6 hpi, and that a second and much larger bout of expression occurs in the late phase of the virus cycle by 48 hpi. Since transgenic (Tg)-pp65 specific CD8 T cells were activated even when DNA replication was blocked, our data argue that pp65 acts as an early virus gene for immunological purposes.

Discussion

ARMATA does not only allow same day identification of antiviral T-cell activity, but also provides a method to define the timing of antigen recognition in the context of HCMV infection.

Performance evaluation of the Alinity m system for quantifying cytomegalovirus DNA in samples of the respiratory, gastrointestinal, and urinary tract

Quantitation of cytomegalovirus (CMV) DNA load in specimens other than blood such as bronchoalveolar lavages, intestinal biopsies, or urine has become a common practice as an ancillary tool for the diagnosis of CMV pneumonitis, intestinal disease, or congenital infection, respectively. Nevertheless, most commercially available CMV PCR platforms have not been validated for CMV DNA detection in these specimen types. In this study, a laboratory-developed test based on Alinity m CMV ("Alinity LDT") was evaluated. Reproducibility assessment using spiked bronchial aspirate (BAS) or urine samples showed low standard deviations of 0.08 and 0.27 Log IU/mL, respectively. Evaluating the clinical performance of Alinity LDT in comparison to a laboratory-developed test based on RealTime CMV ("RealTime LDT") showed good concordance across 200 clinical specimens including respiratory specimens, intestinal biopsies, urine, and stool. A high Pearson's correlation coefficient of r = 0.92, a low mean bias of -0.12 Log IU/mL, a good qualitative agreement of 90%, and a Cohen's kappa value of 0.76 (substantial agreement) were observed. In separate analyses of the sample types BAS, tracheal aspirates, bronchoalveolar lavage, biopsies, and urine, the assay results correlated well between the two platforms with r values between 0.88 and 0.99 and a bias <0.5 Log IU/mL. Overall, the fully automated, continuous, random access Alinity LDT yielded good reproducibility, high concordance, and good correlation to RealTime LDT in respiratory, gastrointestinal, and urine samples and may enhance patient management with rapid result reporting.IMPORTANCEIn transplant recipients, a major cause for morbidity and mortality is end-organ disease by primary or secondary CMV infection of the respiratory or gastrointestinal tract. In addition, sensorineural hearing loss and neurodevelopmental abnormalities are frequent sequelae of congenital CMV infections in newborns. Standard of care for highly sensitive detection and quantitation of the CMV DNA load in plasma and whole blood specimens is real-time PCR testing. Beyond that, there is a need for quantitative determination of CMV DNA levels in respiratory, gastrointestinal, and urinary tract specimens using a highly automated, random access CMV PCR assay with a short turnaround time to enable early diagnosis and treatment. In the present study, clinical performance of the fully automated Alinity m analyzer in comparison to the current RealTime LDT assay was evaluated in eight different off-label sample types.

Impact of Early Cytomegalovirus Reactivation After Allogeneic Hematopoietic Stem Cell Transplantation on Relapse in Patients With Myelodysplastic Syndrome: A Nationwide Retrospective Study From Adult Myelodysplastic Syndrome Working Group of the JSTCT

Cytomegalovirus (CMV) reactivation is a prominent complication associated with adverse outcomes in allogeneic hematopoietic stem cell transplantation (HSCT). However, CMV reactivation after allogeneic HSCT may be associated with a lower incidence of relapse in some hematological malignancies. This study analyzed the Japanese registry data from 1082 patients with myelodysplastic syndrome (MDS) who underwent their first allogeneic HSCT and survived for 100 days after transplantation without graft failure or disease relapse to investigate this association. Patients who received cord blood transplants, demonstrated in vivo T cell depletion, underwent prophylactic anti-CMV treatment, or diagnosed with secondary MDS were excluded. CMV reactivation measured by pp65 antigenemia within 100 days after allogeneic HSCT was observed in 57.5% of patients, with a median time of 46 days from transplant. The 5-yr overall survival and cumulative incidence of relapse (CIR) in the cohort were 60.5% and 15.6%, respectively. The 5-yr CIR showed no significant difference between patients with and without CMV reactivation (14.4% versus 17.2%; P = .185). Interestingly, CMV reactivation within 100 days was significantly associated with a lower 5-yr CIR (7.6% versus 16.4%; P = .002) in patients with <5% myeloblasts in the bone marrow (BM) just before HSCT. Furthermore, this relevancy confirmed even when excluding patients with Grade II to IV acute GVHD (Hazard ratio: 0.38; 95% confidential intervals: 0.18-0.801; P = .011). Our findings indicate a correlation between early CMV reactivation and MDS relapse, based on the proportion of myeloblasts in the BM. These results may contribute to the development of effective CMV prophylaxis post-HSCT.

Cytomegalovirus infection and disease in systemic lupus erythematosus patients at a high-complexity hospital in southwestern Colombia

Cytomegalovirus (CMV) infection and disease is a condition usually described in immunocompromised patients, but among them, those with connective tissue diseases are poorly represented. Here we present the clinical, laboratory characteristics, management and outcomes of systemic lupus erythematosus (SLE) patients who presented with a CMV infection/disease to a high complexity hospital in southwestern Colombia between 2011 and 2020. 16 SLE patients were found to have a CMV infection. SLE was predominantly characterized by renal involvement (10 patients; 62.50%), and 14 patients (87.5%) were receiving steroids previous to the CMV infection. The entire sample required hospital admission, mainly related to acute kidney injury, and nine patients were admitted to the intensive care unit (ICU). Gastrointestinal organ damage was the most common CMV disease manifestation. All patients received ganciclovir, five of them (31.25%) suffered from septic shock, and seven (43.75%) died. Age ≥38 years and the presence of septic shock at admission were correlated to the mortality outcome. To our knowledge, this is the first publication evaluating SLE patients with CMV infection/disease in a Colombian population.

Clinical Pharmacokinetics and Pharmacodynamics of Letermovir in Allogenic Hematopoietic Cell Transplantation

Letermovir is a newly developed antiviral agent used for the prophylaxis of human cytomegalovirus infections in patients undergoing allogeneic hematopoietic cell transplantation. This novel anti-cytomegalovirus drug, used for the prophylaxis of cytomegalovirus reactivation until approximately 200 days after transplantation, effectively reduces the risk of clinically significant cytomegalovirus infection. No human counterpart exists for the terminase complex; letermovir is virus specific and lacks some toxicities previously observed with other anti-cytomegalovirus drugs, such as cytopenia and nephrotoxicity. The absolute bioavailability of letermovir in healthy individuals is estimated to be 94% based on a population-pharmacokinetic analysis. In contrast, oral administration of letermovir to patients undergoing hematopoietic cell transplantation results in lower exposure than that in healthy individuals. Renal or hepatic impairment does not influence the intrinsic clearance of letermovir. Co-administration of letermovir may alter the plasma concentrations of other drugs, including itself, as it acts as a substrate and inhibitor/inducer of several drug-metabolizing enzymes and transporters. In particular, attention should be paid to the drug-drug interactions between letermovir and calcineurin inhibitors or azole antifungal agents, which are commonly used in patients undergoing hematopoietic cell transplantation. This article reviews and summarizes the clinical pharmacokinetics and pharmacodynamics of letermovir, focusing on patients undergoing hematopoietic cell transplantation, healthy individuals, and specific patient subsets.

Frequency and clinical impact of viraemia in paediatric patients undergoing therapy for cancer

In contrast to transplant recipients, there is a paucity of data regarding frequency and clinical significance of viraemia in children receiving conventional chemotherapy. In a prospective observational study, we assessed the frequency of and clinical impact of viraemia with cytomegalovirus (CMV), Epstein-Barr virus (EBV), adenovirus, human herpesvirus-6 (HHV6) and herpes-simplex virus 1/2 (HSV1/2) in paediatric cancer patients at diagnosis, at a routine examination during intensive chemotherapy, and during febrile neutropenia (FN). Seventy-nine patients (median age 6 years; 66 children with haematological malignancies) were included in the study. Overall, 362 blood samples were analysed, 72 from the time at diagnosis (11.1% with positive PCR result), 118 during a regular control after chemotherapy (11.0% positive), and 159 during FN (8.8% positive). The overall positivity rate was 9.6% (CMV 3.3%, HHV6 2.7%, HSV 2.2%, EBV 0.8% and adenovirus 0.3%). There were no significant differences between FN episodes with and without viraemia in terms of duration of fever or neutropenia/lymphopenia, severity of mucositis (> II0), incidence of diarrhea and ICU admission. Our results indicate that viraemia in paediatric cancer patients generally does not have a major clinical impact, and may help in the decision regarding the indication of routine evaluation for viraemia in febrile neutropenic, but otherwise asymptomatic children.

Reactivation of cytomegalovirus and bloodstream infection and its impact on early survival after allogeneic haematopoietic stem cell transplantation: a multicentre retrospective study

Cytomegalovirus reactivation (CMVr) and bloodstream infections (BSI) are the most common infectious complications in patients after allogeneic haematopoietic stem cell transplantation (allo-HSCT). Both are associated with great high morbidity whilst the BSI is the leading cause of mortality. This retrospective study evaluated the incidence of CMVr and BSI, identified associated risk factors, assessed their impact on survival in allo-HSCT recipients during the first 100 days after transplantation. The study comprised 500 allo-HSCT recipients who were CMV DNA-negative and CMV IgG-positive before allo-HSCT. Amongst them, 400 developed CMVr and 75 experienced BSI within 100 days after allo-HSCT. Multivariate regression revealed that graft failure and acute graft-versus-host disease were significant risk factors for poor prognosis, whereas CMVr or BSI alone were not. Amongst all 500 patients, 56 (14%) developed both CMVr and BSI in the 100 days after HSCT, showing significantly reduced 6-month overall survival (p = 0.003) and long-term survival (p = 0.002). Specifically, in the initial post-transplant phase (within 60 days), BSI significantly elevate mortality risk, However, patients who survive BSI during this critical period subsequently experience a lower mortality risk. Nevertheless, the presence of CMVr in patients with BSI considerably diminishes their long-term survival prospects. This study provides real-world data on the impact of CMVr and BSI following transplantation on survival, particularly in regions such as China, where the prevalence of CMV IgG-positivity is high. The findings underscore the necessity for devising and executing focused prevention and early management strategies for CMVr and BSI to enhance outcomes for allo-HSCT recipients.

Expansion of effector memory Vδ2neg γδ T cells associates with cytomegalovirus reactivation in allogeneic stem cell transplant recipients

Background

Cytomegalovirus (CMV) reactivation is a significant concern following allogeneic stem cell transplantation. While previous research has highlighted the anti-CMV reactivation effect of γδ T cells in immunocompromised transplant patients, their characterization in recipients at high risk of CMV reactivation remains limited.

Methods

This study focused on D+/R+ recipients (where both donor and recipient are CMV seropositive) at high risk of CMV reactivation. We analyzed 28 patients who experienced CMV recurrence within 100 days post-allogeneic hematopoietic stem cell transplantation, along with 36 matched recipients who did not experience CMV recurrence. Clinical data from both groups were compared, and risk factors for CMV reactivation were identified. Additionally, CMV viral load was measured, and flow cytometric analysis was conducted to assess changes in peripheral blood γδ T cell proportions, subpopulation distribution, and differentiation status. We also analyzed the CDR3 repertoire of the TCR δ chain in different γδ T cell subsets. Functional analysis was performed by measuring the lysis of CMV-infected cells upon stimulation.

Results

CMV reactivation post-transplantation was associated with acute graft-versus-host disease (aGvHD) and reactivation of non-CMV herpesviruses. Notably, CMV reactivation led to sustained expansion of γδ T cells, primarily within the Vδ2neg γδ T cell subpopulation, with a trend toward differentiation from Naive to effector memory cells. Analysis of the δ chain CDR3 repertoire revealed a delay in the reconstitution of clonal diversity in Vδ2neg γδ T cells following CMV reactivation, while Vδ2pos T cells remained unaffected. Upon stimulation with CMV-infected MRC5 cells, the Vδ2neg γδ T cell subpopulation emerged as the primary effector cell group producing IFN-γ and capable of lysing CMV-infected cells. Moreover, our findings suggest that NKG2D is not necessary involved in Vδ2neg γδ T cell-mediated anti-CMV cytotoxicity.

Conclusion

This study provides novel insights into the role of γδ T cells in the immune response to CMV reactivation in transplantation recipients at high risk of CMV infection. Specifically, the Vδ2neg γδ T cell subpopulation appears to be closely associated with CMV reactivation, underscoring their potential role in controlling infection and reflecting CMV reactivation in HSCT patients.

Comparison of valganciclovir versus foscarnet for the treatment of cytomegalovirus viremia in adult acute leukemia patients after allogeneic hematopoietic cell transplantation

Cytomegalovirus (CMV) reactivation increases treatment-related mortality (TRM) after allogeneic hematopoietic cell transplantation (allo-HCT). We analyzed 141 adult acute leukemia (AL) patients suffered allo-HCT between 2017 and 2021, who developed CMV viremia post-HCT and treated with valganciclovir or foscarnet, to evaluate effectiveness and safety of both drugs. Viremia clearance rates (14 and 21 d post treatment) and toxicities were similar in two groups. However, valganciclovir was associated with a lower cumulative incidence of CMV recurrence within 180 days (16.7% vs. 35.7%, p=0.029) post CMV clearance. Finally, 2-year TRM was lower in valganciclovir group (9.7% ± 0.2% vs. 26.2% ± 0.3%, p = 0.026), result a superior 2-year overall survival (OS; 88.1% ± 5.2% vs. 64.4% ± 5.5%, p = 0.005) and leukemia-free survival (LFS; 82.0% ± 5.9% vs. 58.9% ± 5.6%, p = 0.009). Valganciclovir might decrease CMV viremia recurrence and led to better long-term outcome than foscarnet in adult AL patients developed CMV viremia post-HCT. Considering the inherent biases of retrospective study, well-designed trials are warranted to validate our conclusion.

Clinical and Economic Impact of CMV Infection in Allogeneic Hematopoietic Stem Cell Transplantation: Perspectives from a Middle-Income Nation

BACKGROUND

Cytomegalovirus infection (CMV) is a common complication after allogeneic hematopoietic stem cell transplantation (AHSCT). CMV infection increases transplantation costs; however, the extent of the financial burden may vary in different countries. This study aims to determine the clinical and economic impact of CMV infection in patients undergoing AHSCT in a middle-income country.

METHODS

A total of 150 adult and pediatric patients post-AHSCT were included for analysis. In addition to incidence of CMV infections, data on graft versus host disease (GVHD) were also collected. Standard hospital charges for AHSCT and any additional transplantation-related expenditure within 12 months were also retrieved in 104 patients.

RESULTS

CMV infection, acute GVHD and chronic GVHD occurred in 38.7%, 60.7%, and 22.0% of patients, respectively. Patients with CMV infections had higher readmission rates compared to those who did not (67.2% vs. 47.8%; p = 0.020). Additional expenditure was seen in HLA-haploidentical AHSCT and CMV infection (MYR11 712.25/USD2 504.49; p < 0.0001 and MYR5 807.24/USD1 241.79; p = 0.036), respectively.

CONCLUSION

This single-center study demonstrated that patients who underwent HLA-haploidentical AHSCT and subsequently developed CMV infection had higher transplantation expenditures compared to those who had matched-related transplantation. Further studies should be conducted to evaluate if primary prophylaxis against CMV is cost-effective, especially in patients who undergo HLA-haploidentical AHSCT.

Case Report: Approaches for managing resistant cytomegalovirus in pediatric allogeneic hematopoietic cell transplantation recipients

The instructional case is a pediatric haploidentical TCRαβ+/CD19+ depleted allogeneic hematopoietic cell transplantation recipient who developed early onset CMV infection, which was complicated by resistant CMV (both UL97 and UL54) and successfully managed with maribavir and haploidentical CMV-specific T lymphocytes. Novel approaches to resistant CMV infection are reviewed and effective utilization of recent advances in diagnosis and management of resistant CMV in pediatric HCT are highlighted.

Letermovir Primary Cytomegalovirus Prophylaxis in Allogeneic Hematopoietic Cell Transplant Recipients: Real-Life Data from a University Hospital in Argentina

Background

Cytomegalovirus (CMV) infection remains the most common clinically significant infection after allogeneic hematopoietic stem cell transplantation (allo-HCT) and is associated with considerable morbidity and mortality.

Objectives

The present study was designed to describe and compare the incidence of untreated CMV reactivation (uCMVr), clinically significant infection (cs-CMVi) and disease (CMVd), as well as CMV-related hospitalization and outcome of allo-HCT patients, either treated with letermovir (LET) primary prophylaxis or managed with preemptive therapy (PET).

Methods

This is a prospective observational cohort study of adult CMV seropositive allo-HCT patients who either received primary prophylaxis with LET within the first 100 days after HCT or were managed with PET.

Results

The study population comprised 105 patients (28 in the LET group and 77 in the PET group). Compared to the PET group, patients in the LET group received more allo-HCT from alternative donors (54.5% vs. 82.14%, P=0.012). More than half of the patients in both groups were classified as high risk for CMVd. In the LET vs. PET group, cs-CMVi and CMVd developed respectively in 0 vs. 50 (64.94%), P=<0.0001, and 0 vs. 6 (7.79%), P=0.18. In the LET group, uCMVr occurred in 5 (17.8%) and were all considered blips. Hospital admissions related to cs-CMVi or CMVd in the PET group vs. LET group were 47 (61.04%) vs. 0, respectively, P=<0.0001. No differences were observed in 100-day mortality.

Conclusions

LET primary prophylaxis proved effective in preventing cs-CMVi and CMVd and reducing hospitalizations in allo-HCT adults. Blips can occur during prophylaxis and do not require LET discontinuation.

Cytomegalovirus Reactivations in Allogeneic Hematopoietic Stem Cell Transplantation from HLA-Matched and Haploidentical Donors with Post-Transplantation Cyclophosphamide

Cytomegalovirus (CMV) reactivations cause significant morbidity in allogeneic hematopoietic stem cell transplantation (HSCT) recipients. Graft-versus-host disease (GVHD) prophylaxis with post-transplantation cyclophosphamide (PTCy) is associated with an increased risk of CMV infections. Data are limited comparing HSCT with PTCy performed from matched sibling donors (MSDs), matched unrelated donors (MUDs), and haploidentical (Haplo) donors. In the present study, we aimed to characterize CMV reactivation and recurrence in patients with hematologic malignancies undergoing HSCT from MSD, MUD, and Haplo donors using PTCy as GVHD prophylaxis in the pre-letermovir era. We also analyzed risk factors of CMV reactivation, including GVHD as a time-dependent variable, on the incidence and mortality associated with CMV infections. We analyzed CMV reactivation in patients undergoing HSCT from 160 MSDs, 124 MUDs, and 82 Haplo donors from a single institution. Uniform GVHD prophylaxis with PTCy, sirolimus, and mycophenolate mofetil was given irrespective of donor type. Overall, 46% of patients had at least 1 CMV reactivation. The 1-year cumulative incidence of CMV infection was 39% for MSD, 44% for MUD, and 62% for Haplo donors (P < .001), with 96% of reactivations occurring before day +100. Multivariate analysis identified factors associated with the first CMV reactivation, including Haplo donor, positive recipient CMV serology, older patient age, and grade II-IV acute GVHD. The 1-year cumulative incidence of second reactivation from HSCT was 13%. Recipient CMV seropositivity, older patient age, and grade II-IV acute GVHD, but not type of donor, were identified as adverse factors for second CMV reactivation in multivariate analysis. The 1-year cumulative incidence of a third reactivation post HSCT was 4.4%. Ten cases of CMV disease were recorded, with no attributable deaths. Nevertheless, the risk for nonrelapse mortality was greater for patients who experienced CMV reactivation in multivariate time-dependent Cox model analysis. CMV reactivation is frequent in HSCT with PTCy in patients not receiving letermovir prophylaxis. Identified risk factors include the use of a Haplo donor, recipient CMV seropositivity, and grade II-IV acute GVHD. The prevalence of recurrent CMV reactivations is a noteworthy issue, especially after acute GVHD, warranting trials of secondary prophylaxis strategies.

Prevention and management of infectious complications in patients with chronic lymphocytic leukemia (CLL) treated with BTK and BCL-2 inhibitors, focus on current guidelines

CLL is associated with an increased risk of infectious complications. Treatment with BTK or BCL-2 inhibitors does not seem to increase significantly the risk of opportunistic infections, but the role of combination therapies including BTK and/or BCL-2 inhibitors remains to be established. Various infectious complications can be successfully prevented with appropriate risk management strategies. In this paper we reviewed the international guidelines on prevention and management of infectious complications in patients with CLL treated with BTK or BCL-2 inhibitors. Universal pharmacological anti-herpes, antibacterial or antifungal prophylaxis is not warranted. Reactivation of HBV should be prevented in HBsAg-positive subjects. For HBsAg-negative/HBcAb-positive patients recommendations differ, but in case of combination treatment should follow those for other, particularly anti-CD20, agent. Immunization should be provided preferably before the onset of treatment. Immunoglobulin therapy has favourable impact on morbidity but not mortality in patients with hypogammaglobulinemia and severe or recurrent infections. Lack of high-quality data and heterogeneity of patients or protocols included in the studies might explain differences among the main guidelines. Better data collection is warranted.

Molecular monitoring of viral infections in immunocompromised patients in a large university hospital in Italy: reflections after thirteen years of real-life activity

PURPOSE

This study aimed to investigate the prevalence and viral reactivations of clinical interest in the immunocompromised patient with particular focus on hematologic and solid organ transplant recipients.

METHODS

Molecular screening data of CMV, EBV, JCV and BKV from 2011 to 2023 were analyzed. This extensive time span allowed the access to more than 100,000 samples from over 20,000 patients treated at Policlinico Umberto I. It was possible to temporally investigate patient attendance patterns, average age distribution, seasonality of infections, and positivity rates of the analyzed viruses.

RESULTS

Between 2019 and 2022 a significant reduction in organ transplants performed and in the positive molecular detection of EBV, JCV and BKV was observed. Additionally, there has been a noteworthy decrease in CMV reactivations, with a reduction of up to 50% starting in 2019. A remarkable reduction of 39% in the rate of CMV viral reactivation has been also achieved in SOT between 2016 and 2023.

CONCLUSION

The years following 2019 were profoundly impacted by the COVID-19 pandemic era. This period resulted in a substantial reduction in healthcare services and hospital visits. Furthermore, the introduction of the drug Letermovir in Italy in 2019 demonstrated remarkable efficacy, evidenced by a reduction in CMV reactivations. Additionally, the adoption of a novel clinical approach centered on personalized therapy facilitated improved management of immunocompromised patients.

Retrospective Evaluation of Cystatin C as a Measure of Renal Function in Pediatric Hematopoietic Stem Cell Transplant Patients Receiving Foscarnet for Cytomegalovirus Reactivation

BACKGROUND

Cytomegalovirus (CMV) infection following allogeneic hematopoietic cell transplantation has considerable morbidity and mortality, and foscarnet is a treatment option that requires renal dose adjustment. Serum creatinine (SCr)-based estimated glomerular filtration rate (eGFR) equations are used to estimate renal function for patients receiving foscarnet, but cystatin C (cysC) has been shown as a possible alternative. Data examining cysC-based eGFR in this population is sparse. Our primary objective was to evaluate outcomes of patients treated with foscarnet dosed utilizing cysC-based eGFR versus SCr-based eGFR.

METHODS

We analyzed patients on the transplantation and cellular therapies service at Memorial Sloan Kettering Kids from January 2011 to September 2021 who received allogeneic hematopoietic cell transplantation and ≥14 days of foscarnet for CMV infection. Patients with cysC-based eGFR were compared to a historical cohort of patients who only had SCr-based eGFR. Outcomes included time to CMV clearance, death or change in anti-CMV therapy. Cumulative incidence curves and cause-specific hazards model were used for analysis.

RESULTS

In 61 analyzed patients, no differences were found between the cohorts in cumulative incidence of change in anti-CMV therapy ( P = 0.17) or death ( P = 0.69). After adjustment for multiple confounders, patients in the SCr cohort seemed to have a higher chance of CMV clearance compared with the cysC cohort, but the difference was not statistically significant (hazard ratio = 2.42, P = 0.089). Patients who received corticosteroids appeared to have lower incidence of CMV clearance ( P = 0.056).

CONCLUSIONS

We did not find differences in outcomes when dosing foscarnet using cysC versus SCr for treatment of CMV infection.

Individualized dose of anti-thymocyte globulin based on weight and pre-transplantation lymphocyte counts in pediatric patients: a single center experience

Anti-thymocyte globulin (ATG) has become a standard in preventing GVHD in related and unrelated donor transplantation, but there is no consensus on the best administration schedule. The PARACHUTE trial reported excellent CD4 immune reconstitution (CD4 IR) using a dosing schedule based on the patient's weight and pre-conditioning absolute lymphocyte count (ALC). In 2015 we introduced the PARACHUTE dosing schedule for pediatric patients at our center. One hundred one patients were transplanted for malignant and non-malignant diseases. In this non-concurrent cohort CD4 IR+, defined by a single CD4 count >50/µL on day 90, was seen in 81% of patients. The incidence of grade II-IV and III to IV aGvHD was 26.6% and 15.3% and 5% for cGvHD with no severe cases. We found no difference in aGvHD between donor type and stem cell sources. Five-year EFS and OS were 77.5% and 83.5%. Grade III-IV GFRS was 75.2%. CD4 IR+ patients had better EFS (93.1% vs. 77.7%, p = 0.04) and lower non-relapse mortality (2.7% vs. 22.2%, p = 0.002). The PARACHUTE ATG dosing schedule individualized by weight and ALC results in good early immune reconstitution, low incidence of cGvHD, and favorable survival for patients with different disease groups, donor types, and stem cell sources.

Efficacy, Safety, and Cost-effectiveness Analysis of Antiviral Agents for Cytomegalovirus Prophylaxis in Allogeneic Hematopoietic Stem Cell Transplantation Recipients

BACKGROUND

Cytomegalovirus (CMV) infection is associated with higher non-relapse mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). But the preferred drug for preventing cytomegalovirus infection is still controversial. We evaluate the efficacy, safety, and cost-effectiveness of antiviral agents based on the most recent studies.

METHODS

A pairwise and network meta-analysis was conducted to obtain direct and indirect evidence of antivirals. The cost of allo-HSCT recipients in a teaching hospital was collected, and a cost-effectiveness analysis using a decision tree combined with Markov model was completed from the perspective of allo-HSCT recipients over a lifetime horizon.

RESULTS

A total of 19 RCTs involving 3565 patients (8 antivirals) were included. In the network meta-analysis, relative to placebo, letermovir, valacyclovir, and ganciclovir significantly reduced CMV infection incidence; ganciclovir significantly reduced CMV disease incidence; ganciclovir significantly increased the incidence of serious adverse event; none of antivirals significantly reduced all-cause mortality. Based on meta-analysis and Chinese medical data, the incremental cost-effectiveness ratios (ICER) per quality-adjusted life year (QALY) saved for maribavir, acyclovir, valacyclovir, ganciclovir, and letermovir relative to placebo corresponded to US$216 635.70, US$11 590.20, US$11 816.40, US$13 049.90, and US$12 189.40, respectively. One-way sensitivity analysis showed the most influential parameter was discount rate. The probabilistic sensitivity analysis indicated a 53.0% probability of letermovir producing an ICER below the willingness-to-pay threshold of US$38 824.23/QALY. The scenario analysis demonstrated prophylaxis with letermovir is considered cost-effective in the United States.

CONCLUSIONS

Currently, letermovir is an effective and well-tolerated treatment for preventing CMV infection, and it might be a cost-effective choice in allo-HSCT recipients in China.

Risk factors for hemorrhagic cystitis after allogeneic hematopoietic stem cell transplantation in a letermovir-exposed CMV-free population receiving PTCy

Hemorrhagic cystitis (HC) is a highly impacting complication in allogeneic hematopoietic stem cell transplantation (HSCT), occurring in 12%-37% of patients. The impact of transplant- and patient-specific variables has been described, with a possible role for JCV and BKV, which may be cooperating with cytomegalovirus (CMV). Here, we analyze 134 letermovir-exposed, CMV-free patients, treated with the same cyclophosphamide-based graft-versus-host disease (GVHD) prophylaxis, describing risk factors for HC. The overall incidence of HC was 23%. Patients with HLA mismatched transplant, higher comorbidity score, and receiving three alkylating agents with TBF (thiotepa, busulfan, and fludarabine) conditioning regimen had a higher risk of HC in multivariate analysis (OR: 4.48, 6.32, and 1.32, respectively). A HC-score including male gender, TBF conditioning, and HLA-mismatch stratifies the risk of HC in the first 100 days after HSCT. The role of BKV and JCV was not highly impacting in those patients, suggesting a possible synergistic effect between CMV and JCV in causing HC. HC can be interpreted as the combination of patient-related factors, chemotherapy-related toxicities-especially due to alkylating agents-and immunological elements.

Evaluation of an automated real-time transcription-mediated amplification (TMA) assay for detection and quantification of cytomegalovirus DNA in different clinical specimens

BACKGROUND

Reliable and fast detection and quantification of human cytomegalovirus (CMV) DNA in various diagnostic specimens is essential for care of immunocompromised or congenitally infected individuals.

OBJECTIVES

To evaluate the analytical and clinical performance of the Panther Aptima® CMV (Hologic) quantitative real-time transcription mediated amplification (TMA) assay.

STUDY DESIGN

Performance of the TMA assay run on the Hologic Panther Fusion was analysed for 32 proficiency testing samples and 21 quantitative reproducibility panel samples; additionally, we compared results of TMA assay and routine quantitative real-time PCR assays ("PCR-A"= Biomérieux CMV R-gene® or "PCR-B"= Laboratory-developed CMV-PCR) in 518 diagnostic specimens (254 plasma, 120 EDTA whole blood, 43 urine, 45 amniotic fluid and 56 breast milk) at two university hospital laboratories.

RESULTS

All proficiency panel samples were correctly identified and quantified by the TMA assay; replicate testing of the reproducibility panel samples showed good reproducibility within and between the two laboratories. Sensitivity in plasma and WB was higher for the TMA assay detecting low-level CMV-DNAemia in samples tested negative by routine PCR. Quantitative CMV-DNAemia values correlated well between TMA and real-time PCR. Similarly, urine, AF and BM specimens showed a high rate of concordant results (91%, 98% and 98%, respectively) among TMA and PCR with good correlation of quantitative values.

CONCLUSION

The performance of the Aptima® CMV TMA assay for viral blood load testing compared well to established real-time PCRs. In addition, it can be useful for diagnostics in urine, amniotic fluid and breast milk specimens.

Letermovir for Cytomegalovirus infection in pediatric patients undergoing allogenic hematopoietic stem cell transplantation: a real-life study by the Infectious Diseases Working Group of Italian Association of Pediatric Hematology-Oncology (AIEOP)

Letermovir prophylaxis revolutionized the approach to Cytomegalovirus infection in adult hematopoietic stem cell transplant (HCT), while data in pediatric setting are still lacking. We retrospectively analyzed 87 HCT children transplanted in 11 AIEOP centers receiving letermovir as off-label indication between January 2020 and November 2022. Letermovir was used as primary, secondary prophylaxis or CMV treatment in 39, 26 and 22 cases, respectively; no discontinuation due to toxicity was reported. Median duration was 100 days (14-256) for primary and 96 days (8-271) for secondary prophylaxis, respectively. None of the patients experienced CMV-clinically significant reactivation during Letermovir primary prophylaxis; one patient developed breakthrough infection during secondary prophylaxis, and 10 and 1 patient experienced asymptomatic CMV-reactivation and CMV-primary infection after drug discontinuation, respectively. Median duration of letermovir in CMV treatment was 40 days (7-134), with 4/22 patients suffering CMV-pneumonia, with an overall response rate of 86.4%. With a median follow-up of 10.7 months (8.2-11.8), estimated 1-year overall survival was 86%; no CMV-related deaths were reported in prophylaxis groups. This is the largest report on Letermovir use in pediatric HCT; real-life data confirm an excellent toxicity profile, with high efficacy as CMV prophylaxis; results in CMV-infection treatment should be investigated in larger, prospective trials.

Treatment for First Cytomegalovirus Infection Post-Hematopoietic Cell Transplant in the AURORA Trial: A Multicenter, Double-Blind, Randomized, Phase 3 Trial Comparing Maribavir With Valganciclovir

BACKGROUND

Neutropenia may limit the use of valganciclovir treatment for cytomegalovirus (CMV) infection following hematopoietic cell transplant (HCT). A phase 2 study indicated efficacy of maribavir with fewer treatment-limiting toxicities than valganciclovir.

METHODS

In this multicenter, double-blind, phase 3 study, patients with first asymptomatic CMV infection post-HCT were stratified and randomized 1:1 to maribavir 400 mg twice daily or valganciclovir (dose-adjusted for renal clearance) for 8 weeks with 12 weeks of follow-up. The primary endpoint was confirmed CMV viremia clearance at week 8 (primary hypothesis of noninferiority margin of 7.0%). The key secondary endpoint was a composite of the primary endpoint with no findings of CMV tissue-invasive disease at week 8 through week 16. Treatment-emergent adverse events (TEAEs) were assessed.

RESULTS

Among patients treated (273 maribavir; 274 valganciclovir), the primary endpoint of noninferiority of maribavir was not met (maribavir, 69.6%; valganciclovir, 77.4%; adjusted difference: -7.7%; 95% confidence interval [CI]: -14.98, -.36; lower limit of 95% CI of treatment difference exceeded -7.0%). At week 16, 52.7% and 48.5% of patients treated (maribavir and valganciclovir, respectively) maintained CMV viremia clearance without tissue-invasive disease (adjusted difference: 4.4%; 95% CI: -3.91, 12.76). With maribavir (vs valganciclovir), fewer patients experienced neutropenia (16.1% and 52.9%) or discontinued due to TEAEs (27.8% and 41.2%). Discontinuations were mostly due to neutropenia (maribavir, 4.0%; valganciclovir, 17.5%).

CONCLUSIONS

Although noninferiority of maribavir to valganciclovir for the primary endpoint was not achieved based on the prespecified noninferiority margin, maribavir demonstrated comparable CMV viremia clearance during post-treatment follow-up, with fewer discontinuations due to neutropenia. Clinical Trials Registration. NCT02927067 [AURORA].