The prognostic impact of the cytomegalovirus serostatus in patients with chronic hematological malignancies after allogeneic hematopoietic stem cell transplantation: a report from the Infectious Diseases Working Party of EBMT

Prognostic factors in haploidentical transplantation with post-transplant cyclophosphamide for acute myeloid leukemia

BACKGROUND AIMS

Haploidentical hematopoietic stem cell transplantation (haplo-HCT) is an appropriate option when an HLA-matched related or unrelated donor is not available. Haplo-HCT using post-transplant cyclophosphamide (PTCy) is being increasingly performed worldwide due to its effective suppression of GVHD and its safety.

METHODS

We conducted a large nationwide cohort study to retrospectively analyze 366 patients with acute myeloid leukemia undergoing haplo-HCT with PTCy between 2010 and 2019 and to identify prognostic factors.

RESULTS

A multivariate Cox analysis revealed that an older recipient age (≥60 years), a male donor to a male recipient, a cytomegalovirus IgG-negative donor to a cytomegalovirus IgG-positive recipient, a poor cytogenetic risk, a noncomplete remission status at the time of transplantation, and a history of HCT were independently associated with worse overall survival (OS). Based on each hazard ratio, these factors were scored (1-2 points) and stratified by their total score into three groups: favorable (0-1 points), intermediate (2-3 points), and poor (4 points or more) groups, and 2-year OS rates were 79.9%, 49.2%, and 25.1%, respectively (P < 0.001).

CONCLUSIONS

The present study revealed significant prognostic factors in haplo-HCT with PTCy, and a scoring system based on these factors may be used to predict outcomes.

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.

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.

Letermovir for Prophylaxis and Pre-emptive Therapy of Cytomegalovirus Infection in Paediatric Allogeneic Haematopoietic Cell Transplant Patients

BACKGROUND

Cytomegalovirus (CMV) infection is a frequent event in patients undergoing allogeneic haematopoietic cell transplantation (HCT) and is associated with increased morbidity and mortality due to eventual progress to end-organ disease. Letermovir prophylaxis for CMV infections has become a standard of care in adult HCT recipients due to its efficacy and high tolerability. However, it is not yet approved for paediatric patients.

OBJECTIVE

In a retrospective single-centre observational study we evaluated the use of letermovir for prophylaxis or pre-emptive treatment of cytomegalovirus (CMV) infection in seropositive paediatric HCT recipients receiving the compound outside of clinical trials. The primary endpoint was CMV reactivation requiring a change of medication.

METHODS

A total of 17 patients (seven female/ten male; median age 12.2 [range 3.5-19] years, median body weight 39.5 [range 15-63] kg; median follow-up time 463.7 [range 41-1022] days) were identified who were started on oral (14) or intravenous (3) followed by oral (2) letermovir shortly after neutrophil engraftment at doses determined on the basis of age, weight, and concomitant cyclosporine use.

RESULTS

Five patients had no evidence of viral replication (prophylactic use), while 12 patients had varying extents of viral replication (pre-emptive therapy). A change of therapy was required in one patient due to a sustained increase in CMV viral load, and in two patients, letermovir was stopped without later reactivation after initiation of palliative care for recurrent leukaemia. Of the 14 patients who completed treatment, 3 had evidence of transient viral replication after end of treatment that required no further antiviral treatment. No patients (of 17) discontinued letermovir due to an adverse event.

CONCLUSION

Letermovir was effective in controlling CMV infection in seropositive paediatric allogeneic HCT recipients and was overall well tolerated. Pending completion of the still ongoing paediatric investigation plans, letermovir will be an important adjunct to our options for control of infectious complications in this special population.

Improved outcomes over time and higher mortality in CMV seropositive allogeneic stem cell transplantation patients with COVID-19; An infectious disease working party study from the European Society for Blood and Marrow Transplantation registry

Introduction

COVID-19 has been associated with high morbidity and mortality in allogeneic hematopoietic stem cell transplant (allo-HCT) recipients.

Methods

This study reports on 986 patients reported to the EBMT registry during the first 29 months of the pandemic.

Results

The median age was 50.3 years (min - max; 1.0 - 80.7). The median time from most recent HCT to diagnosis of COVID-19 was 20 months (min - max; 0.0 - 383.9). The median time was 19.3 (0.0 - 287.6) months during 2020, 21.2 (0.1 - 324.5) months during 2021, and 19.7 (0.1 - 383.9) months during 2022 (p = NS). 145/986 (14.7%) patients died; 124 (12.6%) due to COVID-19 and 21 of other causes. Only 2/204 (1%) fully vaccinated patients died from COVID-19. There was a successive improvement in overall survival over time. In multivariate analysis, increasing age (p<.0001), worse performance status (p<.0001), contracting COVID-19 within the first 30 days (p<.0001) or 30 - 100 days after HCT (p=.003), ongoing immunosuppression (p=.004), pre-existing lung disease (p=.003), and recipient CMV seropositivity (p=.004) had negative impact on overall survival while patients contracting COVID-19 in 2020 (p<.0001) or 2021 (p=.027) had worse overall survival than patients with COVID-19 diagnosed in 2022.

Discussion

Although the outcome of COVID-19 has improved, patients having risk factors were still at risk for severe COVID-19 including death.

Letermovir as Cytomegalovirus Prophylaxis in a Pediatric Cohort: A Retrospective Analysis

Letermovir is an attractive cytomegalovirus (CMV) prophylactic agent, but published data in children are scarce. This retrospective chart review aimed to describe our experience using letermovir as CMV prophylaxis in pediatric hematopoietic cell transplantation (HCT) recipients. Pediatric patients (age <20 years) undergoing allogeneic HCT and receiving letermovir prophylaxis in the Mayo Clinic Pediatric Bone Marrow Transplant Program were eligible for inclusion in this retrospective chart review. Medical records were reviewed to evaluate letermovir dosing, CMV levels, laboratory values, and reports of adverse effects. Between October 2020 and April 2022, 9 patients age 4 to 19 years undergoing allogeneic HCT in the Pediatric Bone Marrow Transplant Program received letermovir prophylaxis, either 240 mg or 480 mg daily at a mean and median dose of 10 mg/kg/day. Letermovir was crushed and administered via nasogastric tube in 4 of 9 patients. Two patients received letermovir for secondary CMV prophylaxis after initial treatment with ganciclovir/valganciclovir, and the remaining 7 received letermovir for primary prophylaxis. One patient, a 20-kg 6-year-old female receiving 240 mg (12 mg/kg), experienced low-level CMV viremia while on letermovir. No other patients experienced CMV reactivation while on letermovir prophylaxis. In 2 patients, transient mild transaminitis was noted within the first weeks of letermovir therapy, which resolved without intervention, and its relationship to letermovir could not be clearly established. Letermovir administration was feasible and well tolerated as CMV prophylaxis in our small cohort of pediatric patients undergoing HCT. Larger, prospective studies are warranted to confirm the safety and efficacy of letermovir in children. © 2022 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

The Ten Most Common Questions on Cytomegalovirus Infection in Hematopoietic Stem Cell Transplant Patients

With the rising number of patients undergoing hematopoietic stem cell transplantation (HSCT), clinicians are more likely to encounter infectious complications in immunocompromised hosts, particularly cytomegalovirus (CMV) infection. Besides the high mortality of CMV end-organ disease, patients with detectable CMV viremia may have worse outcomes and decreased survival even in the absence of end-organ disease. In view of the implications on morbidity and mortality, clinicians should maintain a high index of suspicion and initiate antiviral drugs promptly when CMV infection is confirmed. High-risk patients should be identified in order to provide optimal management. Additionally, novel antiviral agents with a good safety profile and minor adverse events are now available for prophylaxis in high-risk patients and for treatment of resistant or refractory CMV infection. The following review provides concise, yet comprehensive, guidance on the burden and risk factors of CMV in this population, as well as an update on the latest evidence for the management of CMV infection.

Risk factors and incidence of cytomegalovirus viremia and disease in pediatric patients with allogeneic hematopoietic stem cell transplantation: An 8-year single-center experience in Latin America

BACKGROUND

Cytomegalovirus infection represents a significant cause of morbidity and mortality after hematopoietic stem cell transplantation. This study aimed to evaluate the incidence of viremia and disease due to cytomegalovirus and the risk factors in pediatric patients with hematopoietic stem cell transplantation in our institution.

METHODS

This was a retrospective cohort of patients under 19 years of age who underwent allogeneic hematopoietic stem cell transplantation due to any indication between 2012 and 2019. The analysis included the diagnosis of cytomegalovirus viremia or disease during post-transplant follow-up, evaluation of risk factors, and outcomes. The statistical analysis included univariate and multivariate analyses, and the cumulative incidence of cytomegalovirus viremia was determined by the Kaplan-Meier method using STATA 14 statistical software.

RESULTS

A total of 182 transplants were included. At 100 days, the cumulative incidence of cytomegalovirus viremia was 70.5%, and that of cytomegalovirus disease was 4.7%. Overall survival at 2 years was 74%, and event-free survival was 64%. The remaining demographic characteristics were not predictors of infection. There was no association between viremia and relapse or survival of the patients. Higher mortality was noted in cytomegalovirus disease.

CONCLUSIONS

During the study period, the incidence of cytomegalovirus disease was similar to that of other pediatric reports, but the incidence of viremia was higher. Pre-emptive therapy has diminished disease rates and death due to infection. Viral load cutoff points should be standardized to guide treatment and avoid myelotoxicity.

Cytomegalovirus viral interleukin-10 (cmvIL-10) in patients with Aspergillus infection and effects on clinical outcome

BACKGROUND

Human cytomegalovirus (CMV) is associated with aspergillosis, but the simultaneous presence of cytomegalovirus viral interleukin-10 (cmvIL-10) and aspergillosis has never been investigated. CmvIL-10 is produced by CMV-infected cells and acts as an immune modulator during CMV infection. The aim of this study was to evaluate cmvIL-10 levels in peripheral blood and its influence on the clinical outcomes of Aspergillus infection.

METHODS

Patients who visited or were admitted to the hospital with suspected Aspergillus infection, including invasive aspergillosis (IA) and chronic pulmonary aspergillosis (CPA), were prospectively enrolled. The cmvIL-10, human IL-10 (hIL-10), IL-1B, IL-6, IL-8, IFN-γ, and TNF-α levels in peripheral blood were measured.

RESULTS

Patients with Aspergillus infection had a higher level of cmvIL-10 than the control group (158±305 vs. 27.9±30.4 pg/mL, p<0.05). The level of cmvIL-10 was not correlated with CMV viremia or end-organ disease. The cmvIL-10 but not hIL-10 level was positively correlated with the IFN-γ level (p<0.05) and marginally negatively correlated with IL-1B and IL-8 levels (p<0.1). In patients with CPA, a high level of cmvIL-10 (≥100 pg/mL) was a poor prognostic factor for long-term survival (p<0.05). In contrast, CMV viremia or end-organ disease was associated with poor survival in patients with IA (p=0.05).

CONCLUSIONS

Aspergillus infection was associated with CMV coinfection with cmvIL-10 in blood. A cmvIL-10 concentration ≥100 pg/mL was a predictor for unfavourable outcome in CPA patients.

Signatures of GVHD and relapse after posttransplant cyclophosphamide revealed by immune profiling and machine learning

The key immunologic signatures associated with clinical outcomes after posttransplant cyclophosphamide (PTCy)-based HLA-haploidentical (haplo) and HLA-matched bone marrow transplantation (BMT) are largely unknown. To address this gap in knowledge, we used machine learning to decipher clinically relevant signatures from immunophenotypic, proteomic, and clinical data and then examined transcriptome changes in the lymphocyte subsets that predicted major posttransplant outcomes. Kinetics of immune subset reconstitution after day 28 were similar for 70 patients undergoing haplo and 75 patients undergoing HLA-matched BMT. Machine learning based on 35 candidate factors (10 clinical, 18 cellular, and 7 proteomic) revealed that combined elevations in effector CD4+ conventional T cells (Tconv) and CXCL9 at day 28 predicted acute graft-versus-host disease (aGVHD). Furthermore, higher NK cell counts predicted improved overall survival (OS) due to a reduction in both nonrelapse mortality and relapse. Transcriptional and flow-cytometric analyses of recovering lymphocytes in patients with aGVHD identified preserved hallmarks of functional CD4+ regulatory T cells (Tregs) while highlighting a Tconv-driven inflammatory and metabolic axis distinct from that seen with conventional GVHD prophylaxis. Patients developing early relapse displayed a loss of inflammatory gene signatures in NK cells and a transcriptional exhaustion phenotype in CD8+ T cells. Using a multimodality approach, we highlight the utility of systems biology in BMT biomarker discovery and offer a novel understanding of how PTCy influences alloimmune responses. Our work charts future directions for novel therapeutic interventions after these increasingly used GVHD prophylaxis platforms. Specimens collected on NCT0079656226 and NCT0080927627 https://clinicaltrials.gov/.

Impact of Letermovir Primary Cytomegalovirus Prophylaxis on 1-Year Mortality After Allogeneic Hematopoietic Cell Transplantation: A Retrospective Cohort Study

BACKGROUND

Cytomegalovirus (CMV)-seropositive (R+) hematopoietic cell transplant (HCT) recipients have a survival disparity compared with CMV-seronegative recipient/donor (R-D-) pairs. We hypothesized that primary letermovir prophylaxis (LET) may abrogate this disparity. We investigated the relationship between LET and mortality at 1 year post-HCT.

METHODS

In this retrospective cohort study, we included adult R-D- or R+ patients who received HCT pre-LET (between 1 January 2013 through 15 December 2017) and post-LET (between 16 December 2017 through December 2019). R+ were categorized by LET receipt as R+/LET or R+/no-LET. Cox proportional hazard models were used to estimate the association of LET with all-cause mortality at 1 year after transplantation.

RESULTS

Of 848 patients analyzed, 305 were R-D-, 364 R+/no-LET, and 160 R+/LET. Because of similar mortality (adjusted hazard ratio [aHR], 1.29 [95% confidence interval {CI}, .76-2.18]; P = .353]) between pre-LET/R-D- and post-LET/R-D-, R-D- were combined into 1 group. Compared with R-D-, the aHR for mortality was 1.40 (95% CI, 1.01-1.93) for R+/no-LET and 0.89 (95% CI, .57-1.41) for R+/LET. Among R+, LET was associated with decreased risk of death (aHR, 0.62 [95% CI, .40-.98]); when conventional HCT and T-cell depleted HCT were analyzed separately, the aHR was 0.86 (95% CI, .51-1.43) and 0.21 (95% CI, .07-.65), respectively.

CONCLUSIONS

At 1 year post-HCT, LET was associated with closing the mortality disparity between R-D- and R+. Among all R+, LET was associated with decreased mortality, driven by 79% reduced incidence of death in T-cell depleted HCT.

Risk Factors for CMV Viremia and Treatment-Associated Adverse Events Among Pediatric Hematopoietic Stem Cell Transplant Recipients

BACKGROUND

Cytomegalovirus (CMV) causes substantial morbidity and mortality after hematopoietic stem cell transplantation (HSCT). There are limited data on risk factors for CMV viremia and the safety of antiviral medications used to treat CMV in children.

METHODS

We conducted a single-center retrospective study of children who underwent HSCT between 2000 and 2016. We used log-logistic regression to evaluate associations between clinical characteristics and CMV-free survival at 100 days after HSCT. We compared the incidences of laboratory-defined adverse events (AEs) during treatment with ganciclovir and foscarnet.

RESULTS

Among 969 children, the median (interquartile range) age was 6.5 (3.1-11.5) years, and 80% underwent allogeneic HSCT. Two hundred forty-four (25%) children developed CMV viremia. Older age (odds ratio [OR], 0.95; 95% CI, 0.92-0.98), male sex (OR, 0.71; 95% CI, 0.51-0.99), non-Black, non-White race (OR, 0.56; 95% CI, 0.36-0.87), umbilical cord blood donor source (OR, 0.28; 95% CI, 0.08-0.97), and CMV seropositivity (R-/D+: OR, 0.17; 95% CI, 0.07-0.41; R+/D-: OR, 0.14; 95% CI, 0.09-0.21; R+/D+: OR, 0.08; 95% CI, 0.04-0.15) were associated with lower odds of 100-day CMV-free survival. Compared with foscarnet, ganciclovir was associated with lower incidences of thrombocytopenia (incidence rate ratio [IRR], 0.38; 95% CI, 0.15-0.97), electrolyte AEs (IRR, 0.42; 95% CI, 0.24-0.75), endocrine AEs (IRR, 0.52; 95% CI, 0.34-0.79), and renal AEs (IRR, 0.36; 95% CI, 0.19-0.65).

CONCLUSIONS

CMV viremia occurred commonly among children after HSCT, and ganciclovir and foscarnet were associated with distinct toxicity profiles among children with CMV infection. These findings should be considered when developing CMV prevention and treatment strategies for children after HSCT.

Combined Analysis of Early CD4+ T Cell Counts and CMV Serostatus May Improve CMV Risk Assessment after Allogeneic Hematopoietic Cell Transplantation

The incidence and severity of viral complications after cellular therapy are highly variable. Recent publications describe relevant interactions between the human Cytomegalovirus (CMV) and host immunity in recipients of allogeneic hematopoietic cell transplantation (HCT). Although immune monitoring is routinely performed in HCT patients, validated cut-off levels correlating with transplant outcomes such as survival or CMV reactivation are mostly limited to day +100, which is later than the median time for CMV reactivation in the absence of medical prophylaxis. To address this gap in early risk assessment, we applied an unsupervised machine learning technique based on clustering of day +30 CD4⁺ helper T cell count data, and identified relevant cut-off levels within the diverse spectrum of early CD4⁺ reconstitution. These clusters were stratified for CMV recipient serostatus to identify early risk groups that predict clinical HCT outcome. Indeed, the new risk groups predicted subsequent clinical events such as NRM, OS, and high CMV peak titers better than the most established predictor, i.e., the positive CMV recipient serostatus (R+). More specifically, patients from the R+/low CD4⁺ subgroup strongly associated with high CMV peak titers and increased 3-year NRM (subdistribution hazard ratio (SHR) 10.1, 95% CI 1.38–73.8, p = 0.023), while patients from the R-/very high CD4⁺ subgroup showed comparable NRM risks (SHR 9.57, 95% CI 1.12–81.9, p = 0.039) without such an association. In short, our study established novel cut-off levels for early CD4⁺ T cells via unsupervised learning and supports the integration of host cellular immunity into clinical risk-assessment after HCT in the context of CMV reactivation.

The association of cytomegalovirus infection and cytomegalovirus serostatus with invasive fungal infections in allogeneic haematopoietic stem cell transplant recipients: a systematic review and meta-analysis

BACKGROUND

In allogeneic haematopoietic stem cell transplant (allo-HSCT) recipients, the inter-relationship between post-transplant cytomegalovirus (CMV) and subsequent invasive fungal infections (IFIs) is conflicting and the association of CMV serostatus with IFIs has not been evaluated.

OBJECTIVES

To determine the relationship between CMV infection/serostatus and IFIs in allo-HSCT populations.

DATA SOURCES

A systematic literature search was conducted from existence until 11 July 2021 using Medline, Embase and ISI Web of Science databases.

STUDY ELIGIBILITY CRITERIA

Cross-sectional, prospective cohort, retrospective cohort and case-control studies that reported allo-HSCT recipients with CMV and without CMV who developed or did not develop IFIs after CMV infection.

PARTICIPANTS

Allo-HSCT recipients.

INTERVENTIONS

Not applicable.

METHODS

A systematic search, screening, data extracting and assessing study quality were independently conducted by two reviewers. The Newcastle-Ottawa scale was used to assess risk of bias. data were analysed using the pooled effect estimates of a random-effects model.

RESULTS

A total of 18 and 12 studies were included for systematic review and meta-analysis, respectively. Post-transplant CMV infection significantly increased the risk of IFIs with a pooled hazard ratio (pHR) of 2.58 (1.78, 3.74), I² = 75%. Further subgroup analyses by timing of IFIs, CMV definitions, study continents, study design and adjustment of effect estimates showed that post-transplant CMV infection consistently increased the risk of subsequent IFIs. High-risk CMV serostatus (D-/R+) increased the risk of IFIs with a pooled odds ratio (OR) of 1.33 (1.04, 1.71), I² = 0%, but low-risk CMV serostatus (D-/R-) decreased the risk of IFIs with a pOR of 0.69 (0.55, 0.87), I² = 0%.

CONCLUSIONS

Post-transplant CMV infection and high-risk CMV serostatus increased the risk of IFIs, but low-risk CMV serostatus decreased risk of IFIs among allo-HSCT recipients. Further studies are needed to identify at-risk allo-HSCT recipients as well as to focus on fungal diagnostics and prophylaxis to prevent this fungal-after-viral phenomenon.

CMV Infection in Hematopoietic Stem Cell Transplantation: Prevention and Treatment Strategies

Purpose of Review

Cytomegalovirus (CMV) remains a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (Allo-HSCT). New strategies and methods for prevention and management of CMV infection are urgently needed. We aim to review the new developments in diagnostics, prevention, and management strategies of CMV infection in Allo-HSCT recipients.

Recent Findings

The approval of the novel anti-CMV drug letermovir in 2017 has led to an increase in the use of antiviral prophylaxis as a preferred approach for prevention in many centers. Real-world studies have shown efficacy similar to the clinical trial. CMV-specific T cell-mediated immunity assays identify patients with immune reconstitution and predict disease progression. Phase 2 trials of maribavir have shown its efficacy as preemptive therapy and treatment of resistant and refractory CMV infections. Adoptive T cell therapy is an emerging option for treatment of refractory and resistant CMV. Of the different CMV vaccine trials, PepVax has shown promising results in a phase 1 trial.

Summary

CMV cell-mediated immunity assays have potential to be used as an adjunctive test to develop individualized management plan by identifying the patients who develop immune reconstitution; however, further prospective interventional studies are needed. Maribavir and adoptive T cell therapy are promising new therapies for treatment of CMV infections. CMV vaccine trials for prevention are also under way.

The Roles of γδ T Cells in Hematopoietic Stem Cell Transplantation

The αβ T-cell-depleted hematopoietic stem cell transplantation (HSCT) leads to lower relapse and better outcome, and may correlate strongly with expansion of donor-derived γδ T cells. γδ T cells play an important role in immune reconstitution and can exert a graft-versus-leukemia effect after HSCT. This review showed the recent literature on immune functions of γδ T cells after HSCT. The discrepancies between studies of γδ T cells in graft-versus-host disease may cause by its heterogeneous and various distinct subsets. And reconstitution of γδ T cells may play a potential immunoregulatory role in the infections after HSCT.

Insight for Immunotherapy of HCMV Infection

Human cytomegalovirus (HCMV), a ubiquitous in humans, has a high prevalence rate. Young people are susceptible to HCMV infection in developing countries, while older individuals are more susceptible in developed countries. Most patients have no obvious symptoms from the primary infection. Studies have indicated that the virus has gradually adapted to the host immune system. Therefore, the control of HCMV infection requires strong immune modulation. With the recent advances in immunotherapy, its application to HCMV infections is receiving increasing attention. Here, we discuss the immune response to HCMV infection, the immune escape mechanism, and the different roles that HCMV plays in various types of immunotherapy, including vaccines, adoptive cell therapy, checkpoint blockade therapy, and targeted antibodies.

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.

Cytomegalovirus management after allogeneic hematopoietic stem cell transplantation: A mini-review

Because of the high incidence of cytomegalovirus (CMV) seropositivity in the population, CMV infection is a common and severe complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in Taiwan. Here we propose a CMV management strategy for patients undergoing allo-HSCT from the Taiwanese perspective, which focuses on the epidemiology, diagnosis, monitoring, prophylaxis, and treatment of CMV infection after allo-HSCT. In terms of CMV monitoring, weekly CMV monitoring with the COBAS® AmpliPrep system is the standard approach because the pp65 CMV antigenemia assay has a lower sensitivity than CMV monitoring with the COBAS® AmpliPrep system. However, pp65 CMV antigenemia assay has a better correlation with clinical symptoms in immunocompromised patients. A 14-week prophylactic course of letermovir is recommended for allo-HSCT recipients in Taiwan, especially for recipients of hematopoietic stem cells from mismatched unrelated and haploidentical donors. Preemptive ganciclovir therapy should be initiated when the CMV viral load exceeds 1000 copies/mL, and should not be discontinued until CMV DNA is no longer detected in the blood. For allo-HSCT recipients who have CMV-related diseases, ganciclovir with or without CMV-specific intravenous immunoglobulin is the standard of care. The limited availability of foscarnet, an alternative for patients who are not responsive to or cannot tolerate ganciclovir, is a crucial issue in Taiwan. For pediatric allo-HSCT recipients, more data are needed to propose a CMV management recommendation.

Cytomegalovirus (CMV) management in allogeneic hematopoietic cell transplantation: Pre-transplant predictors of survival, reactivation, and spontaneous clearance

BACKGROUND

Cytomegalovirus (CMV) reactivation is a frequent complication after allogeneic hematopoietic cell transplant (alloHCT).

METHOD

We analyzed 159 alloHCT recipients with 4409 quantitative CMV viral loads to determine pre-transplant predictors of CMV reactivation, clinically significant CMV infection (cs-CMVi, defined as CMV viral load >1000 IU/mL), CMV disease, kinetics of spontaneous clearance of CMV, and survival using a standardized pre-emptive therapy approach to identify at-risk groups to target prevention strategies.

RESULTS

Cs-CMVi was most common in D-/R+ unrelated donor transplants (URD). Spontaneous CMV clearance occurred in 26% of patients who reached a viral load of 56-137 IU/mL, 6% at 138-250 IU/mL and in one patient >250 IU/mL. Median time between the first CMV reactivation (>56 IU/mL) and a viral load >250 IU/mL was 13 days, whereas the time from the first viral load >250 IU/mL to reach a vial load >1000 IU/mL was 4 days. Cs-CMVi was associated with a significant increase in non-relapse mortality (NRM) on multivariate analysis.

CONCLUSIONS

Overall, this study indicates that D-/R+ URD recipients are at high-risk for cs-CMVi- and CMV-related mortality, and are potential candidates for targeted CMV prophylaxis. Spontaneous clearance of CMV beyond a viral load of 250 IU/mL is uncommon, suggesting that this could be used as an appropriate threshold to initiate pre-emptive therapy.

How I treat CMV reactivation after allogeneic hematopoietic stem cell transplantation

Cytomegalovirus (CMV) reactivation remains one of the most common and life-threatening infectious complications following allogeneic hematopoietic stem cell transplantation, despite novel diagnostic technologies, several novel prophylactic agents, and further improvements in preemptive therapy and treatment of established CMV disease. Treatment decisions for CMV reactivation are becoming increasingly difficult and must take into account whether the patient has received antiviral prophylaxis, the patient's individual risk profile for CMV disease, CMV-specific T-cell reconstitution, CMV viral load, and the potential drug resistance detected at the time of initiation of antiviral therapy. Thus, we increasingly use personalized treatment strategies for the recipient of an allograft with CMV reactivation based on prior use of anti-CMV prophylaxis, viral load, the assessment of CMV-specific T-cell immunity, and the molecular assessment of resistance to antiviral drugs.

Clinical and economic impact of treated CMV infection in adult CMV-seropositive patients after allogeneic hematopoietic cell transplantation

OBJECTIVE

Recipients of allogeneic hematopoietic stem cell transplantation (allo-HCT) with positive cytomegalovirus (CMV) serology are at increased risk of morbidity and mortality. The primary objective of this study was to assess the association between treated CMV infection and overall mortality within 1 year after allo-HCT in adult CMV-seropositive Recipients (R+). Secondary objectives included overall 5-year mortality after allo-HCT, risk factors for treated CMV infection, associations between treated CMV infection and allo-HCT complications and medical costs.

METHODS

A multicenter retrospective cohort study was conducted in adult CMV-seropositive recipients (R+) who underwent to allo-HCT between 1st January 2010 and 31st December 2014.

RESULTS

Five hundred seventy two CMV-seropositive patients (mean age, 50.2 years) undergoing allo-HCT between 2010 and 2014 were included; 55.9% of donors were CMV seropositive. CMV infection treated with antiviral therapy was reported in 227 patients (39.7%) after transplantation. One-year overall mortality was significantly increased in patients with treated CMV infections (hazard ratio, 1.86; 95% CI, 1.16-3.00; P = .011). Mean medical costs during the first post-HCT year were higher in patients with CMV infection (€46 853 vs €31 318; P < .0001).

CONCLUSION

In this large cohort of CMV-seropositive patients undergoing allo-HCT, treated CMV infection was significantly associated with an increased 1-year risk of overall mortality, with increased length of stay and with hospitalization cost. The burden of CMV disease in allo-HCT could be reduced in the future by appropriate prophylactic strategies.

Extended letermovir administration, beyond day 100, is effective for CMV prophylaxis in patients with graft versus host disease

BACKGROUND

Cytomegalovirus (CMV) reactivation is associated with significant morbidity and mortality after an allogeneic hematopoietic cell transplant (AHCT), and graft versus host disease (GVHD) increases the risk of CMV reactivation. Letermovir is approved for CMV prophylaxis in CMV-seropositive patients, but has only been studied through day 100 post-transplantation in the registration trial. Its efficacy in preventing CMV in patients with GVHD requiring treatment beyond the day 100 milestone has not been studied.

METHODS

We retrospectively analyzed all patients who underwent an AHCT at a single center over a period of 24 months, and identified a cohort of 20 patients who received extended duration of letermovir (beyond 100 days) after the diagnosis of GVHD. The primary end point was the incidence of clinically significant CMV infection, defined as onset of CMV disease or initiation of preemptive therapy with alternative antiviral agents.

RESULTS

In this high-risk cohort, only one patient (5%) developed a clinically significant CMV infection, requiring preemptive therapy. No patients developed CMV organ disease. Three additional patients developed CMV viremia of ≥150 IU/mL while on letermovir and after the onset of GVHD, and none required additional treatment. Receipt of post-transplant cyclophosphamide (PTCy) and low CD4 count after the development of GVHD were associated with breakthrough CMV viremia while on extended duration letermovir.

CONCLUSIONS

Extended duration letermovir was efficacious in preventing clinically significant CMV infections in patients with GVHD.

Hematopoietic cell transplant outcomes after myeloablative conditioning with fludarabine, busulfan, low-dose total body irradiation, and rabbit antithymocyte globulin

Optimal conditioning and graft-vs-host disease (GVHD) prophylaxis for hematopoietic cell transplantation (HCT) are unknown. Here, we report on outcomes after low toxicity, myeloablative conditioning consisting of fludarabine, busulfan, and 4 Gy total body irradiation, in combination with thymoglobulin and post-transplant methotrexate and cyclosporine. We retrospectively studied 700 patients with hematologic malignancies who received blood stem cells from 7 to 8/8 HLA-matched unrelated or related donors. Median follow-up of surviving patients was 5 years. At 5 years, overall survival (OS), relapse-free survival (RFS), and chronic GVHD/relapse-free survival (cGRFS) were 58%, 55%, and 40%. Risk factors for poor OS, RFS, and cGRFS were (1). high to very high disease risk index (DRI), (2). high recipient age, and (3). cytomegalovirus (CMV)-seropositive recipient with seronegative donor (D-R+). The latter risk factor applied particularly to patients with lymphoid malignancies. Neither donor other than HLA-matched sibling (7-8/8 unrelated) nor one HLA allele mismatch was risk factors for poor OS, RFS, or cGRFS. In conclusion, the above regimen results in excellent long-term outcomes. The outcomes are negatively impacted by older age, high or very high DRI, and CMV D-R+ serostatus, but not by donor unrelatedness or one HLA allele mismatch.

Assessment and prevention of cytomegalovirus infection in allogeneic hematopoietic stem cell transplant and in solid organ transplant: A multidisciplinary consensus conference by the Italian GITMO, SITO, and AMCLI societies

Cytomegalovirus (CMV) remains a major cause of morbidity and mortality in allogeneic hematopoietic stem cell transplantation (allo-HSCT) and solid organ transplantation (SOT) recipients. In view of the uncertainties on the assessment and prevention of CMV infection in both transplant procedures, three Italian scientific societies for HSCT and SOT and for Clinical Microbiology appointed a panel of experts to compose a framework of recommendations. Recommendations were derived from a comprehensive analysis of the scientific literature and from a multidisciplinary consensus conference process. The lack of adequate clinical trials focused on certain diagnostic procedures, and antiviral intervention forced the panel to use the methods of consensus for shaping some recommendations. Recommendations concerning the two types of transplant were given for the following issues: assessment of pretransplant CMV serostatus, immunological monitoring after transplant, CMV prophylaxis with antivirals, CMV preemptive strategy, and CMV prophylaxis with immunoglobulin infusion and with adoptive immunotherapy. The questions raised by and the recommendations resulting from this consensus conference project may contribute to the improvement of certain crucial aspects of the management of CMV infections in allo-HSCT and in SOT populations.