Effective CMV prophylaxis with high-dose valaciclovir in allogeneic hematopoietic stem-cell recipients at a high risk of CMV infection.

BACKGROUND: Cytomegalovirus (CMV) infection increases mortality and morbidity following allogeneic hematopoietic stem-cell transplantation (alloHSCT). Universal antiviral prophylaxis with letermovir is effective but unsubsidized in Australia. Valaciclovir demonstrates anti-CMV activity in high doses, but few current real-world studies explore its use as primary prophylaxis in high-risk patients post-alloHSCT. METHODS: We performed a retrospective analysis of alloHSCT recipients at high risk of clinically significant CMV infection (cs-CMVi), defined as a plasma CMV DNA viral load of >400 IU/ml requiring preemptive therapy, or CMV disease. High-risk recipients were CMV seropositive and underwent T-cell depleted, haploidentical or umbilical cord stem-cell transplants. Consecutive patients transplanted from July 2018 to January 2020, treated with valaciclovir 2 g TDS from day +7 to +100 (HD-VALA), were compared to a historical cohort (July 2017-June 2018) who only received preemptive CMV therapy, and standard valaciclovir (SD-VALA) for varicella/herpes prophylaxis. We compared incidence of and time to cs-CMVi. RESULTS: In the SD-VALA cohort (n = 27, median CMV follow-up duration 259 days), 23/27 (85%) developed cs-CMVi at a median of 39 days. For the HD-VALA cohort (n = 35, median CMV follow-up duration 216 days), 19/35 (54%) developed cs-CMVi, at a median of 68 days. Time to cs-CMVi was significantly longer in HD-VALA cohort (p < .0001). On multivariate analysis, HD VALA reduced the risk of cs-CMVi (HR 0.32, p = .0005). CONCLUSIONS: In alloHSCT recipients at high risk for cs-CMVi, HD-VALA resulted in lower cumulative reactivation, and delayed reactivation, reducing requirement for preemptive CMV therapy in the early post-engraftment period.

Outcome of an elective readmission policy in patients receiving acute myeloid leukaemia consolidation therapy and implications for an outpatient management programme.

Safe outpatient management of acute leukaemia consolidation cycles may enable substantial savings in admission costs. Safety involves the prompt administration of antibiotics in patients with neutropenic fever. Our unit in a metropolitan tertiary referral hospital analysed a cohort of patients spanning a 10-year period, with two key observations: (i) a high proportion of patients living a substantial distance from hospital and (ii) the high incidence and generally prompt onset of fever after severe neutropenia, suggesting this broad applicability of this approach is unfeasible without addressing travel issues and potentially reducing and/or delaying neutropenic fever with prophylactic antibiotics.

Prognostic markers in core-binding factor AML and improved survival with multiple consolidation cycles of intermediate-/high-dose cytarabine.

OBJECTIVES: Core-binding factor acute myeloid leukaemia (CBF AML) defined by t(8;21)(q22;q22) or inv(16)(p13q22)/t(16;16)(p13;q22) has a favourable prognosis; however, 30%-40% of patients still relapse after chemotherapy. We sought to evaluate the risk factors for relapse in a de novo CBF AML cohort. PATIENTS/MATERIALS/METHODS: A retrospective review of patients from four Australian tertiary centres from 2001 to 2012, comprising 40 t(8;21) and 30 inv(16) AMLs. RESULTS: Multivariate analysis identified age (P = .032) and white cell count (WCC)>40 (P = .025) as significant predictors for inferior OS and relapse, respectively. Relapse risk was higher in the inv(16) group vs the t(8;21) group (57% vs 18%, HR 4.31, 95% CI: 1.78-10.42, P = .001). Induction therapy had no bearing on OS or relapse-free survival (RFS); however, consolidation treatment with >3 cycles of intermediate-/high-dose cytarabine improved OS (P = .035) and RFS (P = .063). Five patients demonstrated post-treatment stable q PCR positivity without relapse. CONCLUSIONS: >3 consolidation cycles of intermediate-/high-dose cytarabine improves patient outcomes Age and inv(16) CBF AML subtype are predictors of inferior OS and RFS, respectively. Stable low-level MRD by qPCR does not predict relapse Similar OS in the inv(16) cohort compared to the t(8;21) cohort, despite a higher relapse rate, confirms salvageability of relapsed disease.

Spatial proteomics identifies a spectrum of immune dysregulation in acquired bone marrow failure syndromes.

Poor graft function (PGF), manifested by multilineage cytopenias and complete donor chimerism post-allogeneic stem cell transplantation (alloSCT), and acquired aplastic anaemia (AA) are immune-mediated acquired bone marrow (BM) failure syndromes with a similar clinical presentation. In this study, we used spatial proteomics to compare the immunobiology of the BM microenvironment and identify common mechanisms of immune dysregulation under these conditions. Archival BM trephines from patients exhibited downregulation of the immunoregulatory protein VISTA and the M2 macrophage marker and suppressor of T-cell activation ARG1 with increased expression of the immune checkpoint B7-H3 compared to normal controls. Increased CD163 and CD14 expression suggested monocyte/macrophage skewing, which, combined with dysregulation of STING and VISTA, is indicative of an environment of reduced immunoregulation resulting in the profound suppression of hematopoiesis in these two conditions. There were no changes in the immune microenvironment between paired diagnostic AA and secondary MDS/AML samples suggesting that leukaemic clones develop in the impaired immune microenvironment of AA without the need for further alterations. Of the eight proteins with dysregulated expression shared by diagnostic AA and PGF, the diagnostic AA samples had a greater fold change in expression than PGF, suggesting that these diseases represent a spectrum of immune dysregulation. Unexpectedly, analysis of samples from patients with good graft function post-alloSCT demonstrated significant changes in the immune microenvironment compared to normal controls, with downregulation of CD44, STING, VISTA, and ARG1, suggesting that recovery of multilineage haematopoiesis post-alloSCT does not reflect recovery of immune function and may prime patients for the development of PGF upon further inflammatory insult. The demonstrable similarities in the immunopathology of AA and PGF will allow the design of clinical interventions that include both patient cohorts to accelerate therapeutic discovery and translation.

Clinical features, pathophysiology, and therapy of poor graft function post-allogeneic stem cell transplantation.

Poor graft function (PGF), defined by the presence of multilineage cytopenias in the presence of 100% donor chimerism, is a serious complication of allogeneic stem cell transplant (alloSCT). Inducers or potentiators of alloimmunity such as cytomegalovirus reactivation and graft-versus-host disease are associated with the development of PGF, however, more clinical studies are required to establish further risk factors and describe outcomes of PGF. The pathophysiology of PGF can be conceptualized as dysfunction related to the number or productivity of the stem cell compartment, defects in bone marrow microenvironment components such as mesenchymal stromal cells and endothelial cells, or immunological suppression of post-alloSCT hematopoiesis. Treatment strategies focused on improving stem cell number and function and microenvironment support of hematopoiesis have been attempted with variable success. There has been limited use of immune manipulation as a therapeutic strategy, but emerging therapies hold promise. This review details the current understanding of the causes of PGF and methods of treatment to provide a framework for clinicians managing this complex problem.

Non-relapse cytopenias following allogeneic stem cell transplantation, a case based review.

The development of non-relapse cytopenias (NRC) is a relatively common occurrence post allogeneic stem cell transplant (alloSCT). Whilst there have been attempts to classify post alloSCT cytopenias by transplantation groups, ambiguity of definitions in prior publications compounded by a lack of availability of high-quality evidence, provide challenges to clinicians attempting to manage these complex patients. In this review we describe 3 cases of NRC, (1) Graft Failure with graft rejection representing cytopenias with minimal donor chimerism (2) Poor Graft Function representing cytopenias with complete donor chimerism and (3) Cytopenias with mixed donor chimerism. This case-based review will evaluate the currently available evidence regarding the pathophysiology of each entity as well as the evidence for current therapies with the aim of providing guidance to clinicians managing these complex patients.

Evaluation of risk factors for and subsequent mortality from poor graft function (PGF) post allogeneic stem cell transplantation.

Poor Graft Function (PGF) is defined by multi-lineage cytopenias with complete donor chimerism post allogeneic transplantation, Risk factors for and subsequent mortality from PGF were assessed in our transplant cohort. Non-sibling donor [OR 1.97; 95% CI 1.02-3.70], ICU admission [OR 5.28; 95% CI 2.29-11.88] or blood culture positivity within the first 30 days [OR 1.67; 95% CI 1.07-2.62], grade III-IV acute graft vs host disease (GVHD) [OR 4.082; 95% CI 2.31-7.16] and CMV viremia [OR 2.43; 95% CI 1.53-3.88] and were significantly associated with development of PGF. PGF patients without count recovery had a 2 year OS of 6%. Severe GVHD, thrombocytopenia and anemia portended inferior survival and were used to develop a prognostic score for mortality from PGF. This analysis identifies risk factors predictive of PGF and poor survival in those without recovery.

Venetoclax or Ruxolitinib in Pre-Transplant Conditioning Lowers the Engraftment Barrier by Different Mechanisms in Allogeneic Stem Cell Transplant Recipients.

Allogeneic stem cell transplantation (alloSCT) is utilised to cure haematological malignancies through a combination of conditioning regimen intensity and immunological disease control via the graft versus tumour (GVT) effect. Currently, conventional myeloablative chemotherapeutic or chemoradiation conditioning regimens are associated with significant side effects including graft versus host disease (GVHD), infection, and organ toxicity. Conversely, more tolerable reduced intensity conditioning (RIC) regimens are associated with unacceptably higher rates of disease relapse, partly through an excess incidence of mixed chimerism. Improvement in post-alloSCT outcomes therefore depends on promotion of the GVT effect whilst simultaneously reducing conditioning-related toxicity. We have previously shown that this could be achieved through BCL-2 inhibition, and in this study, we explored the modulation of JAK1/2 as a strategy to lower the barrier to donor engraftment in the setting of RIC. We investigated the impact of short-term treatment of BCL2 (venetoclax) or JAK1/2 (ruxolitinib) inhibition on recipient natural killer and T cell immunity and the subsequent effect on donor engraftment. We identified striking differences in mechanism of action of these two drugs on immune cell subsets in the bone marrow of recipients, and in the regulation of MHC class-II and interferon-inducible gene expression, leading to different rates of GVHD. This study demonstrates that the repurposed use of ruxolitinib or venetoclax can be utilised as pre-transplant immune-modulators to promote the efficacy of alloSCT, whilst reducing its toxicity.

Dissection of the bone marrow microenvironment in hairy cell leukaemia identifies prognostic tumour and immune related biomarkers.

Hairy cell leukaemia (HCL) is a rare CD20+ B cell malignancy characterised by rare "hairy" B cells and extensive bone marrow (BM) infiltration. Frontline treatment with the purine analogue cladribine (CDA) results in a highly variable response duration. We hypothesised that analysis of the BM tumour microenvironment would identify prognostic biomarkers of response to CDA. HCL BM immunology pre and post CDA treatment and healthy controls were analysed using Digital Spatial Profiling to assess the expression of 57 proteins using an immunology panel. A bioinformatics pipeline was developed to accommodate the more complex experimental design of a spatially resolved study. Treatment with CDA was associated with the reduction in expression of HCL tumour markers (CD20, CD11c) and increased expression of myeloid markers (CD14, CD68, CD66b, ARG1). Expression of HLA-DR, STING, CTLA4, VISTA, OX40L were dysregulated pre- and post-CDA. Duration of response to treatment was associated with greater reduction in tumour burden and infiltration by CD8 T cells into the BM post-CDA. This is the first study to provide a high multiplex analysis of HCL BM microenvironment demonstrating significant immune dysregulation and identify biomarkers of response to CDA. With validation in future studies, prospective application of these biomarkers could allow early identification and increased monitoring in patients at increased relapse risk post CDA.