Cytomegalovirus infection is associated with AML relapse after allo-HSCT: a meta-analysis of observational studies

Role of cytomegalovirus reactivation on relapse after allogeneic hematopoietic stem cell transplantation in acute lymphoblastic leukemia

Cytomegalovirus reactivation (CMV-R) is a frequent complication post-allogeneic hematopoietic stem cell transplantation (allo-HSCT), associated with poor outcomes. Previous studies have demonstrated the protective effect of CMV-R against relapse after allo-HSCT for acute myeloblastic leukemia (AML). However, this impact remains unclear in acute lymphoblastic leukemia (ALL). We conducted a retrospective study on 81 patients with ALL who received allo-HSCT after myeloablative conditioning regimen from matched sibling donors between 2016 and 2022. All patients underwent weekly monitoring for CMV-R by quantitative polymerase chain reaction assay from engraftment until day +100 post allo-HSCT, and received antiviral prophylaxis with acyclovir from day +1 to 6 months after allo-HSCT. Preemptive treatment was initiated when a viremia was higher than 150 copies/mL. The median age was 20 years (range, 5-50 years). After allo-HSCT, 35% of patients developed CMV-R after a median of 39 days (range, 19-100 days). After a median follow-up of 30 months (range, 1-93 months), CMV-R was an independent factor associated with lower cumulative incidence of relapse (CIR) (OR: 0.17; 95% CI [0.03 - 0.98], p = 0.04) without survival benefit. Further studies are needed to validate the protective effect of CMV-R on ALL relapse.

The indirect effects of CMV reactivation on patients following allogeneic hematopoietic stem cell transplantation: an evidence mapping

Cytomegalovirus (CMV) reactivation following allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains a challenging problem, and the impact on the risk of overall mortality (OM) and non-relapse mortality (NRM) in patients following allo-HSCT is still controversial. Utilizing the evidence mapping method, we aimed to assess the effect of CMV infection on outcomes of patients post-transplantation and identify research gaps through systematic reviews (SRs) and clinical studies. PubMed, EMBASE, Web of Science, and Cochrane library databases were searched from inception until 5 July 2022 to identify relevant literature. After systematic literature screening and data extraction, evidence mapping of the effects of CMV reactivation on patients post-allo-HSCT was conducted. Three SRs and 22 clinical studies were included. In one SR, CMV reactivation was associated with an increased risk of mortality (HR 1.46; 95% CI, 1.24-1.72; P ≤ 0.001). In two SRs, CMV reactivation was associated with NRM. One SR reported CMV reactivation was potentially associated with significant protection against relapse in patients with acute myelocytic leukemia (AML), but no significant correlation with graft-versus-host disease (GVHD) was found. Lastly, in one SR CMV reactivation significantly increased the risk of invasive fungal disease (IFD). Most clinical articles reported that CMV reactivation increased the risk of renal dysfunction, poor graft function, re-hospitalization, and bacterial infections. CMV reactivation following allo-HSCT is associated with an increased risk of OM, NRM, IFD, and renal dysfunction, as well as a reduced risk of relapse in patients with AML.

Efficacy and safety of extended duration letermovir prophylaxis in recipients of haematopoietic stem-cell transplantation at risk of cytomegalovirus infection: a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

In a pivotal phase 3 trial of cytomegalovirus prophylaxis with letermovir for up to 100 days after allogeneic haematopoietic stem-cell transplantation (HSCT), 12% of participants developed clinically significant cytomegalovirus infection after letermovir was discontinued. We aimed to evaluate the efficacy and safety of extending the duration of letermovir prophylaxis for clinically significant cytomegalovirus infection from 100 days to 200 days following HSCT.

METHODS

We conducted a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial at 32 sites in six countries (France, Germany, Italy, Japan, the UK, and the USA). Cytomegalovirus‑seropositive HSCT recipients (aged ≥18 years) who had received letermovir prophylaxis for up to 100 days following HSCT and who remained at high risk of late clinically significant cytomegalovirus infection (with no previous history of clinically significant cytomegalovirus infection, defined as initiation of pre-emptive therapy for documented cytomegalovirus viraemia, onset of cytomegalovirus end-organ disease, or both) were eligible. Participants were randomly assigned (2:1) to receive either an additional 100 days (ie, a total of 200 days; letermovir group) of oral or intravenous letermovir 480 mg once daily, adjusted to 240 mg once daily for participants on cyclosporin A, or 100 days of a placebo comparator for letermovir (ie, a total of 100 days of letermovir; placebo group), following HSCT. Randomisation was done using a central interactive response technology system, stratified by study centre and haploidentical donor (yes or no). Participants, investigators, and sponsor personnel were masked to the treatment allocation. The primary efficacy endpoint was the proportion of participants from randomisation to week 28 (200 days after HSCT) with clinically significant cytomegalovirus infection, analysed using the full analysis set population (ie, those who received at least one dose of study intervention). Safety was analysed in all participants as treated (ie, those who received at least one dose according to the study intervention they were assigned to). This study is registered with ClinicalTrials.gov, NCT03930615, and is complete.

FINDINGS

Between June 21, 2019, and March 16, 2022, 255 patients were screened for eligibility and 220 (86%) were randomly assigned (145 [66%] in the letermovir group and 75 [34%] in the placebo group). Between randomisation and week 28, four (3%) of 144 participants in the letermovir group and 14 (19%) of 74 in the placebo group developed clinically significant cytomegalovirus infection (treatment difference -16·1% [95% CI -25·8 to -6·5]; p=0·0005). The most common adverse events among participants in the letermovir group versus the placebo group were graft-versus-host disease (43 [30%] vs 23 [31%]), diarrhoea (17 [12%] vs nine [12%]), nausea (16 [11%] vs 13 [18%]), pyrexia (13 [9%] vs nine [12%]), and decreased appetite (six [4%] vs nine [12%]). The most frequently reported serious adverse events were recurrent acute myeloid leukaemia (six [4%] vs none) and pneumonia (three [2%] vs two [3%]). No deaths were considered to be drug-related by the investigator.

INTERPRETATION

Extending the duration of letermovir prophylaxis to 200 days following HSCT is efficacious and safe in reducing the incidence of late clinically significant cytomegalovirus infection in patients at risk.

FUNDING

Merck Sharp & Dohme LLC.

Features of the TCR repertoire associate with patients' clinical and molecular characteristics in acute myeloid leukemia

Background

Allogeneic hematopoietic stem cell transplant remains the most effective strategy for patients with high-risk acute myeloid leukemia (AML). Leukemia-specific neoantigens presented by the major histocompatibility complexes (MHCs) are recognized by the T cell receptors (TCR) triggering the graft-versus-leukemia effect. A unique TCR signature is generated by a complex V(D)J rearrangement process to form TCR capable of binding to the peptide-MHC. The generated TCR repertoire undergoes dynamic changes with disease progression and treatment.

Method

Here we applied two different computational tools (TRUST4 and MIXCR) to extract the TCR sequences from RNA-seq data from The Cancer Genome Atlas (TCGA) and examine the association between features of the TCR repertoire in adult patients with AML and their clinical and molecular characteristics.

Results

We found that only ~30% of identified TCR CDR3s were shared by the two computational tools. Yet, patterns of TCR associations with patients' clinical and molecular characteristics based on data obtained from either tool were similar. The numbers of unique TCR clones were highly correlated with patients' white blood cell counts, bone marrow blast percentage, and peripheral blood blast percentage. Multivariable regressions of TCRA and TCRB median normalized number of unique clones with mutational status of AML patients using TRUST4 showed significant association of TCRA or TCRB with WT1 mutations, WBC count, %BM blast, and sex (adjusted in TCRB model). We observed a correlation between TCRA/B number of unique clones and the expression of T cells inhibitory signal genes (TIGIT, LAG3, CTLA-4) and foxp3, but not IL2RA, CD69 and TNFRSF9 suggestive of exhausted T cell phenotypes in AML.

Conclusion

Benchmarking of computational tools is needed to increase the accuracy of the identified clones. The utilization of RNA-seq data enables identification of highly abundant TCRs and correlating these clones with patients' clinical and molecular characteristics. This study further supports the value of high-resolution TCR-Seq analyses to characterize the TCR repertoire in patients.

Prognostic factors and impact of CMV reactivation on acute myeloid leukemia patients after HLA-matched myeloablative allogeneic stem cell transplantation in a high CMV prevalence country

INTRODUCTION

Relapse of acute myeloid leukemia (AML) after allogeneic stem cell transplantation (allo-SCT) leads to dismal outcomes. This study aimed to identify high-risk patients and explore the effects of cytomegalovirus (CMV) reactivation in a high CMV-seropositive population.

METHODS

The study involved a single-center retrospective cohort in Thailand, analyzing clinical risk factors and CMV-mediated immune responses, correlated with transplant outcomes in AML patients.

RESULTS

Eighty-five patients with AML in complete remission (CR) undergoing HLA-matched myeloablative allo-SCT between 2011 and February 2021 were enrolled. The relapse rate was 27.1% with the median time of 7 months after transplantation. The 3-year relapse-free-survival (RFS) and overall-survival (OS) were 72.2% and 80.8%, respectively. The disease status (>CR1) and absence of chronic graft-versus-host disease (cGVHD) were independently significant adverse prognostic factors of RFS and OS. Ninety-two percent of recipient-donor pairs were both CMV seropositive. The CMV reactivation occurred in 54.1% of the patients. The clinically significant CMV infection rate was 49.4%. No CMV syndrome/disease or CMV-related mortality occurred. One-year cumulative incidence of relapse among CMV-reactivation and non-reactivation groups were 14.3% and 25.6%, respectively, without a statistically significant difference. Transplantation-related mortality was 11.1%.

CONCLUSIONS

The transplantation beyond CR1 and absence of cGVHD are powerful prognostic factors associated with inferior RFS and OS. In a high CMV prevalence country, there appears to be no impact of CMV reactivation on relapse in AML patients undergoing an allo-SCT.

Cytomegalovirus infection is associated with rapid NK differentiation and reduced incidence of relapse in HLA matched sibling donor transplant patients

The effect of cytomegalovirus (CMV) infection on leukemia relapse and the potential mechanism remains controversial. In this retrospective study, we evaluated the association among CMV infection, NK reconstitution and clinical outcomes in consecutive patients with hematologic malignancy who underwent HLA matched sibling donor transplantation (MST). In total, 228 patients were enrolled in the study between January 2010 and December 2011. The cumulative incidence of CMV infection on day 100 post-HSCT was 13.6 ± 4.9%. The probabilities of OS and DFS were 45.4% vs. 71.7% (P = 0.004) and 43.9% vs. 64.2% (P = 0.050) in the patients with CMV infection and without CMV infection, respectively. The cumulative incidence of treatment-related mortality (TRM) and relapse at 5 years was 48.6 ± 9.6% vs. 11.5 ± 2.9% (P < 0.001) and 6.2 ± 4.3% vs. 29.2 ± 3.9% (P = 0.024) in the patients with CMV infection and without CMV infection, respectively. In the multivariate analysis, CMV infection was associated with higher TRM, lower OS, and lower DFS. In addition, we found that CMV infection may promote the recovery of the absolute number of NK cells and promote the differentiation of NK cells post-MST. In conclusion, CMV infection may promote the recovery and differentiation of NK cells and was correlated with a lower relapse rate post-MST.

Clinical and healthcare burden of disease associated with cytomegalovirus in allogeneic hematopoietic stem cell transplantation - A retrospective single-center study

BACKGROUND

CMV infection is a common complication in allogeneic hematopoietic stem cell transplantation (HSCT). We investigated the association of clinically significant CMV (CS-CMV) infection with clinical outcomes and healthcare resource utilization in allogeneic HSCT patients in Finland.

METHODS

This retrospective study included adult patients who received their first allogeneic HSCT between January 1, 2013, and December 31, 2018, at the Turku University Hospital. Data were collected from the hospital data lake. Clinical and healthcare outcomes were investigated at one year and mortality up to three years.

RESULTS

The study included 251 patients. CMV seroprevalence was 69.7%. CS-CMV infection occurred in 59.0% of the patients, and of those, 14.2% had ≥2 infections. The median time to CS-CMV infection was 34.5 days (Q₁ -Q₃ , 27.0-45.0). Recipient and donor seropositivity, and lymphoproliferative diseases were associated with higher, and HLA identical sibling donors with lower CS-CMV infection risk. CS-CMV infection was not associated with mortality in three years of follow-up. One hundred thirty-three (89.8%) and 75 (72.8%) patients with and without CS-CMV infection, respectively, were readmitted to the hospital. Patients with CS-CMV infection had more hospital readmissions (incidence rate ratio [IRR] 1.38, 95% confidence interval [CI] 1.10-1.73, p = .005) and patients with one CS-CMV infection (IRR 1.48, 95% CI 1.12-1.94, p = .005) or ≥2 infections had longer length of hospital stay (IRR 2.71, 95% CI 1.76-4.35, p < .001).

CONCLUSION

CMV seroprevalence is relatively high among Finnish allogeneic HSCT patients. CS-CMV infection was common and associated with a higher readmission rate and longer length of hospital stay.

Different recovery patterns of CMV-specific and WT1-specific T cells in patients with acute myeloid leukemia undergoing allogeneic hematopoietic cell transplantation: Impact of CMV infection and leukemia relapse

In allogeneic hematopoietic cell transplantation (allo-HSCT), both virus-specific T cells and leukemia-specific T cells need to be reconstituted to protect patients from virus infections and primary disease relapse. Cytomegalovirus (CMV) infection remains an important cause of morbidity and mortality after allo-HSCT. Emerging data indicate that CMV reactivation is associated with reduced risk of leukemia relapse in patients with acute myeloid leukemia (AML) undergoing allo-HSCT. In a cohort of 24 WT1+ AML patients during the first year following HSCT, CMV specific CD8+ T cells (CMV-CTL) reconstituted much faster than WT1-specific CD8+ T cell (WT1-CTL) after allo-SCT. Moreover, CMV-CTL expressed lower levels of exhaustion markers and were more functional as identified by production of IFN-γ/TNF-α and expression of Eomes/T-bet. Interestingly, our patients with CMV reactivation presented higher frequency of CMV-CTL, lower levels of Eomes+T-bet- and higher levels of Eomes+T-bet+ expression in response to WT1 and CMV pp65 antigen during the first year after transplantation as compared to patients without CMV reactivation. Kinetics of CMV-CTL and WT1-CTL after transplantation might be associated with measurable residual disease and later leukemia relapse. Our results support that CMV reactivation, aside from the CMV-CTL reconstitution, could influence WT1-CTL reconstitution after allo-HSCT, thus potentially contributing to the remission/relapse of AML.

Cytomegalovirus in Haematological Tumours

The exquisite coupling between herpesvirus and human beings is the result of millions of years of relationship, coexistence, adaptation, and divergence. It is probably based on the ability to generate a latency that keeps viral activity at a very low level, thereby apparently minimising harm to its host. However, this evolutionary success disappears in immunosuppressed patients, especially in haematological patients. The relevance of infection and reactivation in haematological patients has been a matter of interest, although one fundamentally focused on reactivation in the post-allogeneic stem cell transplant (SCT) patient cohort. Newer transplant modalities have been progressively introduced in clinical settings, with successively more drugs being used to manipulate graft composition and functionality. In addition, new antiviral drugs are available to treat CMV infection. We review the immunological architecture that is key to a favourable outcome in this subset of patients. Less is known about the effects of herpesvirus in terms of mortality or disease progression in patients with other malignant haematological diseases who are treated with immuno-chemotherapy or new molecules, or in patients who receive autologous SCT. The absence of serious consequences in these groups has probably limited the motivation to deepen our knowledge of this aspect. However, the introduction of new therapeutic agents for haematological malignancies has led to a better understanding of how natural killer (NK) cells, CD4+ and CD8+ T lymphocytes, and B lymphocytes interact, and of the role of CMV infection in the context of recently introduced drugs such as Bruton tyrosine kinase (BTK) inhibitors, phosphoinosytol-3-kinase inhibitors, anti-BCL2 drugs, and even CAR-T cells. We analyse the immunological basis and recommendations regarding these scenarios.

CMV Infection and CMV-Specific Immune Reconstitution Following Haploidentical Stem Cell Transplantation: An Update

Haploidentical stem cell transplantation (haploSCT) has advanced to a common procedure for treating patients with hematological malignancies and immunodeficiency diseases. However, cure is seriously hampered by cytomegalovirus (CMV) infections and delayed immune reconstitution for the majority of haploidentical transplant recipients compared to HLA-matched stem cell transplantation. Three major approaches, including in vivo T-cell depletion (TCD) using antithymocyte globulin for haploSCT (in vivo TCD-haploSCT), ex vivo TCD using CD34 + positive selection for haploSCT (ex vivo TCD-haploSCT), and T-cell replete haploSCT using posttransplant cyclophosphamide (PTCy-haploSCT), are currently used worldwide. We provide an update on CMV infection and CMV-specific immune recovery in this fast-evolving field. The progress made in cellular immunotherapy of CMV infection after haploSCT is also addressed. Groundwork has been prepared for the creation of personalized avenues to enhance immune reconstitution and decrease the incidence of CMV infection after haploSCT.

Effective Immunosurveillance After Allogeneic Hematopoietic Stem Cell Transplantation in Acute Myeloid Leukemia

The number of patients receiving allogeneic hematopoietic stem cell transplantation (alloHCT) has increased constantly over the last years due to advances in transplant technology development, supportive care, transplant safety, and donor availability. Currently, acute myeloid leukemia (AML) is the most frequent indication for alloHCT. However, disease relapse remains the main cause of therapy failure. Therefore, concepts of maintaining and, if necessary, reinforcing a strong graft-versus-leukemia (GvL) effect is crucial for the prognosis and long-term survival of the patients. Over the last decades, it has become evident that effective immunosurveillance after alloHCT is an entangled complex of donor-specific characteristics, leukemia-associated geno- and phenotypes, and acquired resistance mechanisms. Furthermore, adoption of effector cells such as natural killer (NK) cells, alloreactive and regulatory T-cells with their accompanying receptor repertoire, and cell–cell interactions driven by messenger molecules within the stem cell and the bone marrow niche have important impact. In this review of pre- and posttransplant elements and mechanisms of immunosurveillance, we highlight the most important mechanisms after alloHCT.

Selection of matched unrelated donors moving forward: from HLA allele counting to functional matching

Matched unrelated donors (URD) are the most frequent source of stem cells for allogeneic hematopoietic cell transplantation (HCT) to date, with HCT performed mainly under conventional immunosuppression by methotrexate and cyclosporine. In this setting, every single allelic donor-recipient mismatch for HLA-A, -B, -C, -DRB1 (8/8), but not for HLA-DQB1, -DPB1, has a significant negative effect on overall survival (OS). When several 8/8 HLA-matched URD are available, donor age is the most important factor impacting OS. Moving forward from the traditional way of counting the number of donor-recipient HLA allele mismatches to biology-driven algorithms for functional matching has led to the unraveling of an association between permissive, low-risk HLA-DPB1 mismatches and improved outcome after URD HCT for malignant disease but not for nonmalignant disease. Functional HLA matching might prove to have increasing importance for URD selection in the era of new immunosuppressive regimens that have the potential to substantially reshuffle the role of HLA mismatches in URD HCT.

Cytomegalovirus in Allogeneic Hematopoietic Transplantation: Impact on Costs and Clinical Outcomes Using a Preemptive Strategy

Cytomegalovirus (CMV) results in significant morbidity and mortality following hematopoietic cell transplantation (HCT). Establishing the cost and clinical impact is imperative to the selection of appropriate CMV preventative strategies. This is a retrospective cohort study of consecutive patients undergoing their first allogeneic HCT between January 1, 2009, and December 31, 2013. Detailed clinical and institutional cost data were obtained from the start of conditioning through 1-year post-transplantation. Baseline characteristics, resource utilization, costs, and outcomes were compared between patients with and without clinically significant CMV infection (csCMVi). One hundred seventy out of 388 patients (44%) developed csCMVi within 1 year after HCT. Within the first year post-HCT, patients with csCMVi had a significantly longer transplantation-related length of stay (mean, 91.7 days versus 78.3 days; P < .0001) and more frequent and prolonged hospitalizations (mean, 2.4 versus 1.7 admissions [P < .0001]; mean, 39.1 versus 31.5 inpatient days [P = .001]) without significantly more admissions to the intensive care unit (28.2% versus 21.6%; P = .408). The use of granulocyte colony-stimulating factor was greater in patients with csCMVi (73.5% versus 54.1%; P = .0001), although no significant differences were demonstrated in mean platelet or red blood cell (RBC) transfusions. Total costs were also higher in patients with csCMVi (mean cost difference, $45,811; 95% CI, $26,385 to $67,544). However, the incidence of graft-versus-host disease (GVHD) and selected infectious complications was not significantly different between the 2 groups. There were no significant differences in 1-year and 5-year post-transplantation overall survival (OS) or nonrelapse mortality (NRM) between those with and those without csCMVi, although relapse of underlying disease was significantly lower in the csCMVi group. Overall, our data show that allogeneic HCT recipients with csCMVi had significantly greater medical resource utilization and costs than those without csCMVi. However, clinical outcomes, including GVHD, infections, and mortality, were similar in the 2 groups. Further study is needed to determine the cost-effectiveness of CMV preventive modalities.