Cytomegalovirus in children undergoing haematopoietic stem cell transplantation: a diagnostic and therapeutic approach to antiviral resistance.

Cytomegalovirus (CMV) is a ubiquitous virus which causes a mild illness in healthy individuals. In immunocompromised individuals, such as children receiving haematopoietic stem cell transplantation, CMV can reactivate, causing serious disease and increasing the risk of death. CMV can be effectively treated with antiviral drugs, but antiviral resistance is an increasingly common complication. Available therapies are associated with adverse effects such as bone marrow suppression and renal impairment, making the choice of appropriate treatment challenging. New agents are emerging and require evaluation in children to establish their role. This review will discuss established and emerging diagnostic tools and treatment options for CMV, including antiviral resistant CMV, in children undergoing haematopoietic stem cell transplant.

Incidence of Sinusoidal Obstruction Syndrome/Veno-Occlusive Disease and Treatment with Defibrotide in Allogeneic Transplantation: A Multicenter Australasian Registry Study.

Sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) is an established complication in patients undergoing allogeneic hemopoietic stem cell transplantation (HSCT). Defibrotide is an effective and safe pharmacologic option for treating diagnosed SOS/VOD. By exploring data provided to the Australasian Bone Marrow Transplant Recipient Registry (ABMTRR) by centers in Australia and New Zealand, this study aimed to describe the incidence of SOS/VOD and patterns of defibrotide use from 2016 to 2020. Patients who underwent allogeneic hemopoietic stem cell transplantation between 2016 and 2020 were identified from the ABMTRR. Data were extracted for a total of 3346 patients, 2692 from adult centers and 654 from pediatric centers, with a median follow-up of 21.5 months and 33.3 months, respectively. Descriptive statistics were used to describe the patient population, including the incidence of SOS/VOD and defibrotide use. Comparisons were made between patients without SOS/VOD and those with SOS/VOD, divided into defibrotide and no defibrotide cohorts. Associations with overall survival (OS) and day 100 survival with such variables as sex, age, disease at transplantation, stem cell source, conditioning agents, SOS/VOD diagnosis, and use of defibrotide, were determined. The reported incidence of SOS/VOD was 4.1% in adult centers and 11.5% in pediatric centers. Defibrotide was administered to 74.8% of adult patients and 97.3% of pediatric patients with SOS/VOD. Significant variability in the use, dosage, and duration of defibrotide was seen across the adult centers. The day 100 survival rate and median OS for patients managed with defibrotide was 51.8% and 103 days, respectively, for adult patients and 90.4% and not reached, respectively, for pediatric patients. In adults, older age at transplantation, an HLA-matched nonsibling relative donor, and a diagnosis of SOS/VOD treated with defibrotide were associated with reduced OS. In pediatric patients, the patient and transplantation characteristics associated with reduced OS were a diagnosis of SOS/VOD and a ≥2 HLA-mismatched related donor. A collaborative approach across Australasia to diagnosing and managing SOS/VOD, particularly with respect to consistent defibrotide use, is recommended.

Australia and New Zealand Transplant and Cellular Therapies (ANZTCT) position statement: COVID-19 management in patients with haemopoietic stem cell transplant and chimeric antigen receptor T cell.

Patients with post-haemopoietic stem cell transplant or chimeric antigen receptor T -cell (CAR-T) therapy face a significant risk of morbidity and mortality from coronavirus disease 2019 because of their immunosuppressed state. As case numbers in Australia and New Zealand continue to rise, guidance on management in this high-risk population is needed. Whilst we have learned much from international colleagues who faced high infection rates early in the pandemic, guidance relevant to local health system structures, medication availability and emerging therapies is essential to equip physicians to manage our patients optimally.

Measurable residual disease analysis in paediatric acute lymphoblastic leukaemia patients with ABL-class fusions.

BACKGROUND: ABL-class fusions including NUP214-ABL1 and EBF1-PDGFRB occur in high risk acute lymphoblastic leukaemia (ALL) with gene expression patterns similar to BCR-ABL-positive ALL. Our aim was to evaluate new DNA-based measurable residual disease (MRD) tests detecting these fusions and IKZF1-deletions in comparison with conventional immunoglobulin/T-cell receptor (Ig/TCR) markers. METHODS: Precise genomic breakpoints were defined from targeted or whole genome next generation sequencing for ABL-fusions and BCR-ABL1. Quantitative PCR assays were designed and used to re-measure MRD in remission bone marrow samples previously tested using Ig/TCR markers. All MRD testing complied with EuroMRD guidelines. RESULTS: ABL-class patients had 46% 5year event-free survival and 79% 5year overall survival. All had sensitive fusion tests giving high concordance between Ig/TCR and ABL-class fusion results (21 patients, n = 257 samples, r2 = 0.9786, P < 0.0001) and Ig/TCR and IKZF1-deletion results (9 patients, n = 143 samples, r2 = 0.9661, P < 0.0001). In contrast, in BCR-ABL1 patients, Ig/TCR and BCR-ABL1 tests were discordant in 32% (40 patients, n = 346 samples, r2 = 0.4703, P < 0.0001) and IKZF1-deletion results were closer to Ig/TCR (25 patients, n = 176, r2 = 0.8631, P < 0.0001). CONCLUSIONS: MRD monitoring based on patient-specific assays detecting gene fusions or recurrent assays for IKZF1-deletions is feasible and provides good alternatives to Ig/TCR tests to monitor MRD in ABL-class ALL.

Good Engraftment but Quality and Donor Concerns for Cryopreserved Hemopoietic Progenitor Cell Products Collected During the COVID-19 Pandemic.

Changes to donor availability, collection center capacity, and travel restrictions during the early phase of the COVID-19 pandemic led to routine cryopreservation of most unrelated donor products for hematopoietic transplantation prior to the recipient commencing the conditioning regimen. We investigated the effect of this change on unrelated donor product quality and clinical outcomes. Product information was requested from transplantation centers in Australia and New Zealand and clinical outcome data from the Australasian Bone Marrow Transplant Recipient Registry (ABMTRR). In total, 191 products were collected between April 1, 2021, and September 30, 2021, and most (74%) were from international collection centers. Median post-thaw CD34 recovery was 78% (range 25% to 176%) and median post-thaw CD34 viability was 87% (range 34% to 112%). Median time to neutrophil recovery was 17 days (interquartile range 10 to 24 days), and graft failure occurred in 6 patients (4%). These clinical outcomes were similar to those of "fresh" unrelated donor transplants reported to the ABMTRR in 2019. However, recipient transplantation centers reported problems with 29% of products in the form of damage during transit, low cell dose, inadequate labeling, missing representative samples, or missing documentation. These problems were critical in 7 cases (4%). At last follow-up, 22 products (12%) had not been infused. Routine cryopreservation of unrelated donor hemopoietic progenitor cell products has enabled safe continuation of allogeneic transplant services during the COVID-19 pandemic. However, practices for product tracing, documentation, and transportation can be optimized, and measures to reduce the incidence of unused unrelated donor product are required.

Outcomes for Australian children with relapsed/refractory acute lymphoblastic leukaemia treated with blinatumomab.

We report on the Australian experience of blinatumomab for treatment of 24 children with relapsed/refractory precursor B-cell acute lymphoblastic leukaemia (B-ALL) and high-risk genetics, resulting in a minimal residual disease (MRD) response rate of 58%, 2-year progression-free survival (PFS) of 39% and 2-year overall survival of 63%. In total, 83% (n = 20/24) proceeded to haematopoietic stem cell transplant, directly after blinatumomab (n = 12) or following additional salvage therapy (n = 8). Four patients successfully received CD19-directed chimeric antigen receptor T-cell therapy despite prior blinatumomab exposure. Inferior 2-year PFS was associated with MRD positivity (20%, n = 15) and in KMT2A-rearranged infants (15%, n = 9). Our findings highlight that not all children with relapsed/refractory B-ALL respond to blinatumomab and factors such as blast genotype may affect prognosis.

Epidemiology and outcome for viremia in children undergoing bone marrow transplant: A retrospective cohort study.

INTRODUCTION: Viral infections pose a serious risk for children undergoing hematopoietic stem cell transplant (HSCT). There are few published case series of prevalence, risk factors, and outcomes examining multiple viruses simultaneously, and no pediatric Australasian data published to date. We describe the real-life experience of viremia in pediatric HSCT in a single tertiary center. METHODS: All episodes of viremia in children undergoing HSCT between 2000 and 2018 were identified by matching HSCT patients' unique identification numbers with positive blood polymerase chain reaction (PCR) results for human adenovirus (HAdV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human herpes virus 6 (HHV-6). Paper or electronic charts and electronic pathology results were used to extract the study variables. RESULTS: Viremia was detected in 177/445 (39.8%) HSCT episodes, of which 46% were allogeneic and 19% autologous transplants. Viremia was disseminated in 96 (21.6%) episodes, with 80 (18%) having more than one virus. HAdV was detected in 108 (24.3% of total episodes) and frequently in autologous transplants, CMV in 71 (16.0%), EBV in 60 (13.5%), and HHV-6 in 38 (8.5%). Of 174 children, 19 (10.9%) died of a viral-associated cause, with viral mortality highest in CMV (18.3%), lowest in HHV-6 (2.6%) with HAdV and EBV similar (6.6% and 6.7%). Adenoviral (but not other virus) dissemination was significantly associated with lower lymphocyte count at time of first detection. CMV dissemination and death were significantly associated with initial and highest CMV viral loads (copies/mL). CONCLUSION: This study presents the first pediatric-specific Australasian data for viremia in HSCT. Findings may help guide clinicians in prophylaxis and treatment decisions.

Diagnosis and management of severe combined immunodeficiency in Australia and New Zealand.

This consensus document outlines the recommendations from the Australasian Society of Clinical Immunology and Allergy Transplantation and Primary Immunodeficiency group for the diagnosis and management of patients with severe combined immunodeficiency. It also provides a proposed framework for the early investigation, management and supportive care prior to haematopoietic stem cell transplantation.

Development of paediatric non-stage prognosticator guidelines for population-based cancer registries and updates to the 2014 Toronto Paediatric Cancer Stage Guidelines.

Population-based cancer registries (PBCRs) generate measures of cancer incidence and survival that are essential for cancer surveillance, research, and cancer control strategies. In 2014, the Toronto Paediatric Cancer Stage Guidelines were developed to standardise how PBCRs collect data on the stage at diagnosis for childhood cancer cases. These guidelines have been implemented in multiple jurisdictions worldwide to facilitate international comparative studies of incidence and outcome. Robust stratification by risk also requires data on key non-stage prognosticators (NSPs). Key experts and stakeholders used a modified Delphi approach to establish principles guiding paediatric cancer NSP data collection. With the use of these principles, recommendations were made on which NSPs should be collected for the major malignancies in children. The 2014 Toronto Stage Guidelines were also reviewed and updated where necessary. Wide adoption of the resultant Paediatric NSP Guidelines and updated Toronto Stage Guidelines will enhance the harmonisation and use of childhood cancer data provided by PBCRs.

Addition of Thiotepa to Total Body Irradiation and Cyclophosphamide Conditioning for Allogeneic Hematopoietic Stem Cell Transplantation in Pediatric Acute Lymphoblastic Leukemia.

Total body irradiation (TBI)/cyclophosphamide (CY) is a standard-of-care conditioning regimen in allogeneic hematopoietic stem cell transplant (HSCT) for pediatric acute lymphoblastic leukemia (ALL). This study sought to identify whether the addition of thiotepa (TT) to TBI/CY improves HSCT outcomes for pediatric patients with ALL. A retrospective analysis was performed on 347 pediatric ALL patients who underwent HSCT between 1995 and 2015, with 242 receiving TBI/CY/TT and 105 patients receiving TBI/CY. There were no statistical differences in age, donor source, or complete remission status between the 2 groups. Comparison of the TBI/CY/TT versus TBI/CY groups demonstrated no difference in transplant-related mortality at 1 (11% versus 11%), 5 (13% versus 16%), or 10 years (16% versus 16%). There was lower relapse in the TBI/CY/TT group at 1 (14% versus 26%), 5 (24% versus 36%), 10 (26% versus 37%), and 15 years (26% versus 37%) (P= .02) but was not statistically significant on multivariate analysis. The TBI/CY/TT group showed a trend toward improved disease-free survival (DFS) at 5 (59% versus 47%), 10 (56% versus 46%), and 15 years (49% versus 40%) (P = .05) but was not statistically significant on multivariate analysis. Comparing overall survival at 5 (62% versus 53%), 10 (57% versus 50%), and 15 years (50% versus 44%) demonstrated no statistical difference between the 2 groups. The addition of thiotepa to TBI/CY demonstrated no increase in transplant-related mortality for pediatric ALL HSCT but was unable to demonstrate significant benefit in disease control. Minimal residual disease status remained the key risk factor impacting both relapse and DFS. More studies are warranted to better clarify the benefits of using thiotepa in conditioning for ALL HSCT.

Single incision laparoscopic assisted double balloon enteroscopy: a novel technique to manage small bowel pathology.

BACKGROUND AND AIMS: Double balloon enteroscopy (DBE) has revolutionised the diagnosis and treatment of small bowel (SB) conditions. However, deep SB insertion can be challenging in patients with a history of abdominal surgery and a two-step procedure is required when findings are not amenable to endoscopic therapy. This case series reports the development of laparoscopically assisted DBE (LA-DBE) using single incision laparoscopic surgery (SILS). METHODS: Retrospective review of LA-DBE procedures performed in a single tertiary centre over 6 years. RESULTS: Seventeen patients (median age: 40 years, male 41%) underwent 17 LA-DBE procedures. The approach was oral in 13 and rectal in 4. Laparoscopic approach was standard (multi-port) in the first four cases, SILS was then used in all subsequent patients (13/17). Indications for LA-DBE were previously failed standard DBE (n = 16) and need for a combined procedure (n = 1). Indications for DBE were Peutz-Jeghers syndrome (PJS) (n = 10), suspected submucosal/polypoid lesion at small bowel imaging (n = 5) and obscure gastrointestinal bleeding (OGIB) with vascular abnormalities seen at capsule endoscopy (n = 2). In 1/17 the suggested pathology on imaging was not identified. Therapy was applied in 15/17 (88%) cases. Diagnoses were PJS polyps (n = 8), neuroendocrine tumour (NET) (n = 2), PJS and NET (n = 1), transmural arteriovenous malformation (n = 1), angioectesia (n = 1), inflammatory polyp (n = 1), leiomyoma (n = 1) and Meckel's diverticulum (n = 1). The median (range) procedure time was 147 (84-210) mins. Median (range) length of stay post-procedure was 2 (1-19) days. Three patients developed complications. The 30-day mortality rate was 0%. CONCLUSIONS: LA-DBE is a safe, effective and minimally invasive procedure that can be applied for the management of selected patients with small bowel pathology. A SILS approach allows all therapeutic modalities to be available, including conversion to intraoperative enteroscopy (IOE), laparoscopic small bowel resection and laparotomy.

Immunogenicity of the inactivated influenza vaccine in children who have undergone allogeneic haematopoietic stem cell transplant.

Influenza vaccination is recommended for children following allogeneic haematopoietic stem cell transplant (HSCT), however there is limited evidence regarding its benefit. A prospective multicentre study was conducted to evaluate the immunogenicity of the inactivated influenza vaccine in children who have undergone HSCT compared with healthy age-matched controls. Participants were vaccinated between 2013 and 2016 according to Australian guidelines. Influenza-specific hemagglutinin inhibition antibody titres were performed prior to each vaccination and 4 weeks following the final vaccination. A nasopharyngeal aspirate for influenza was performed on participants that developed influenza-like illness. There were 86 children recruited; 43 who had undergone HSCT and 43 controls. For the HSCT group, seroprotection and seroconversion rates were 81.4% and 60.5% for H3N2, 41.9% and 32.6% for H1N1, and 44.2% and 39.5% for B strain respectively. There was a significant geometric mean fold increase to the H3N2 (GMFI 5.80, 95% CI 3.68-9.14, p < 0.001) and B (GMFI 3.44, 95% CI 2.36-5.00, p = 0.048) strains. Serological response was superior in age-matched controls to all vaccine strains. There were no serious adverse events following vaccination. For children who underwent HSCT, incidence of laboratory-proven influenza infection was 2.3%. Overall, this study provides evidence to support annual inactivated influenza vaccine administration to children following HSCT.

TCR α+ ß+ /CD19+ cell-depleted hematopoietic stem cell transplantation for pediatric patients.

TCR α+ ß+ /CD19+ cell depletion is an emerging technique for ex vivo graft manipulation in HSCT. We report 20 pediatric patients who underwent TCR α+ ß+ /CD19+ cell-depleted HSCT in four Australian centers. Conditioning regimen was dependent on HSCT indication, which included immunodeficiency (n = 14), Fanconi anemia (n = 3), and acute leukemia (n = 3). Donor sources were haploidentical parent (n = 17), haploidentical sibling (n = 2), or matched unrelated donor (n = 1). Mean cell dose was 8.2 × 108 /kg TNC, 12.1 × 106 /kg CD34+ cells, and 0.4 × 105 /kg TCR α+ ß+ cells. All patients achieved primary neutrophil and platelet engraftment, with average time to neutrophil engraftment 11 days (range 8-22) and platelet engraftment 24 days (range 12-69). TRM at 1 year was 15%. Rate of grade II-IV aGVHD at 1 year was 20% with no grade III-IV aGVHD seen. CMV reactivation occurred in 81% of CMV-positive recipients, with one patient developing CMV disease. Average time to CD4 recovery (>400 × 106 /L) was 258 days. Overall survival for the cohort at 5 years was 80%. This report highlights the initial experience of TCR α+ ß+ /CD19+ cell-depleted HSCT in Australian centers, with high rates of engraftment, low rates of aGVHD, and acceptable TRM.

Hematopoietic stem cell transplantation for children with acute myeloid leukemia in second remission: A report from the Australasian Bone Marrow Transplant Recipient Registry and the Australian and New Zealand Children's Haematology Oncology Group.

BACKGROUND: Approximately one-third of children with acute myeloid leukemia (AML) relapse, requiring re-treatment and allogeneic hematopoietic stem cell transplantation (HSCT). Although achieving second complete remission (CR2) prior to HSCT is desirable, once CR2 is attained, it is unclear if there is any benefit from further chemotherapy prior to HSCT. Moreover, although pre-HSCT minimal residual disease (MRD) has prognostic value in acute lymphoblastic leukemia, the benefit of MRD reduction after achieving CR prior to HSCT is less clear for AML. PROCEDURE: To address these questions, we analyzed data from pediatric transplant centers in Australia and New Zealand concerning relapsed childhood AML cases occurring between 1998 and 2013. Given the retrospective nature of our analysis and assay data available, we analyzed patients on the basis of measurable residual disease (MeRD) by any methodology, rather than MRD in the conventional sense. RESULTS: We observed improved overall survival (OS) in children receiving two chemotherapy cycles, compared to one cycle or three or more cycles pre-HSCT. Improved OS with two cycles remained significant for patients without MeRD after cycle 1. CONCLUSIONS: These data suggest that a second chemotherapy cycle pre-HSCT may improve survival by lowering disease burden. Prospective trials assessing strategies to reduce pre-HSCT MRD in relapsed childhood AML are warranted.

A prospective randomised study comparing double-balloon colonoscopy and conventional colonoscopy in pre-defined technically difficult cases.

BACKGROUNDS AND AIM: Technically 'difficult' (TD) colonoscopy is associated with incomplete colonoscopy, discomfort and longer procedures. Double-balloon colonoscopy (DBC) may facilitate TD colonoscopy. The primary outcome was to compare the time taken to achieve caecal intubation during conventional colonoscopy (CC) and DBC in patient with a TD colon. METHODS: We performed a prospective, randomised study comparing DBC and CC for TD colonoscopy. Patients were screened for parameters predictive of TD colonoscopy using an original scoring system and randomised to DBC or CC. Pain, sedation dose, colonoscopy completeness, time taken for cecal intubation, procedure completion, recovery time and patient satisfaction were recorded. RESULTS: Forty-four patients were recruited (DBC=22; CC=22). DBC facilitated total colonoscopy in 22 cases whereas 9 CC procedures were incomplete (P=0.019). Median pre-procedure difficulty scores were equal for both groups (4.0 vs. 4.0). Mean patient discomfort, pain scores and recovery time were significantly lower for the DBC group (2.3 vs. 5.5, P=0.001; 2.0 vs. 5.9, P=0.005; 5 vs. 20min, P=0.014 respectively). Mean time taken for cecal intubation was similar (17.5 vs. 14min, P=0.18); CONCLUSION: DBC facilitates colonoscopy completion and may be a more comfortable alternative to CC for TD cases although the time taken to achieve caecal intubation was similar.