Veno-occlusive disease after high-dose busulfan–melphalan in neuroblastoma

Survival Benefit of Myeloablative Therapy with Autologous Stem Cell Transplantation in High-Risk Neuroblastoma: A Systematic Literature Review

BACKGROUND

Multimodal treatment of newly diagnosed high-risk neuroblastoma (HRNB) includes induction chemotherapy, consolidation with myeloablative therapy (MAT) and autologous stem cell transplantation (ASCT), followed by anti-disialoganglioside 2 (GD2) immunotherapy, as recommended by the Children's Oncology Group (COG) and the Society of Paediatric Oncology European Neuroblastoma (SIOPEN). Some centres proposed an alternative approach with induction chemotherapy followed by anti-GD2 immunotherapy, without MAT+ASCT.

OBJECTIVE

The aim of this systematic literature review was to compare survival outcomes in patients with HRNB treated with or without MAT+ASCT and with or without subsequent anti-GD2 immunotherapy.

PATIENTS AND METHODS

The review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. MEDLINE via PubMed and EMBASE databases were systematically searched for randomised controlled trials (RCT) and observational comparative studies in patients with HRNB using search terms for 'neuroblastoma' and ('myeloablative therapy' OR 'stem cell transplantation'). Reporting of at least one survival outcome [event-free survival (EFS), progression-free survival, relapse-free survival and/or overall survival (OS)] was required for inclusion. Outcomes from RCTs were synthesized in meta-analysis, while meta-analysis of non-RCTs was not planned owing to expected heterogeneity.

RESULTS

Literature searches produced 2587 results with 41 publications reporting 34 comparative studies included in the review. Of these, 7 publications reported 4 RCTs, and 34 publications reported 30 non-RCT studies. Studies differed with respect to included populations, induction regimen, response to induction, additional treatments and transplantation procedures. Subsequent treatments of relapse were rarely reported and could not be compared. In the meta-analysis, EFS was in favour of MAT+ASCT over conventional chemotherapy or no further treatment [hazard ratio (HR) = 0.78, 95% confidence interval (CI) 0.67-0.91, p = 0.001] with a trend favouring MAT+ASCT for OS (HR = 0.86, 95% CI 0.73-1.00, p = 0.05). Tandem MAT+ASCT was found to improve EFS compared with the single procedure, with improvement in both EFS and OS in patients treated with anti-GD2 therapy. Non-RCT comparative studies were broadly consistent with evidence from the RCTs; however, not all reported survival benefits of MAT+ASCT (single or tandem). Limited comparative evidence on treatment without MAT+ASCT in patients treated with anti-GD2 immunotherapy suggests an increased risk of relapse. In relapsed patients, MAT+ASCT appears to improve OS, but evidence remains scarce.

CONCLUSIONS

Survival benefits in patients treated with MAT+ASCT confirm that the procedure should remain an integral part of multimodal therapy. In patients treated with anti-GD2 immunotherapy, limited evidence suggests that omitting MAT+ASCT is associated with an increased risk of relapse, and therefore, a change in clinical practice can currently not be recommended. Evidence suggests the use of tandem MAT+ASCT compared with the single procedure, with greater benefits observed in patients treated with anti-GD2 immunotherapy. Limited evidence also suggests improved survival following MAT+ASCT in relapsed patients, which needs to be viewed in light of emerging chemoimmunotherapy in this setting.

The Development of New Agents for Post-Hematopoietic Stem Cell Transplantation Non-Infectious Complications in Children

Hematopoietic stem cell transplantation (HSCT) is often the only curative treatment option for patients suffering from various types of malignant diseases and some non-cancerous conditions. Nevertheless, it is associated with a high risk of complications leading to transplant-related mortality and long-term morbidity. An increasing number of therapeutic and prevention strategies have been developed over the last few years to tackle the complications arising in patients receiving an HSCT. These strategies have been mainly carried out in adults and some are now being translated into children. In this manuscript, we review the recent advancements in the development and implementation of treatment options for post-HSCT non-infectious complications in pediatric patients with leukemia and other non-malignant conditions, with a special attention on the new agents available within clinical trials. We focused on the following conditions: graft failure, prevention of relapse and early interventions after detection of minimal residual disease positivity following HSCT in acute lymphoblastic and myeloid leukemia, chronic graft versus host disease, non-infectious pulmonary complications, and complications of endothelial origin.

The Importance of New EBMT Criteria on the Diagnosis of Veno-Occlusive Liver Disease in Children

BACKGROUND

Early recognition and specific therapy facilitate a favorable disease course in hepatic venous-occlusive disease (HVOD) following hematopoietic stem cell transplantation (HCT). Diagnostic and classification criteria, published by the European Society for Blood and Marrow Transplantation (EBMT), better account for clinical differences in disease presentation in pediatric populations.

OBJECTIVES

To compare the course of HVOD in children before and after the implementation of new EBMT criteria.

MATERIAL AND METHODS

The study retrospectively evaluates 26 HVODs in 179 children treated in a single HCT unit (Slovakia) comparing the period of 2014-2017 using the Baltimore and modified Seattle criteria with the period of 2018-2021, when new EBMT criteria were adopted.

RESULTS

No difference in HVOD incidence (11.2% vs. 14.8%, p = 0.46) and in time of diagnosis post-HCT (15.6 days vs. 15.7 days, p = 0.75) was found. With EBMT criteria we observed more frequent anicteric disease at diagnosis (50% vs. 87.5%, p = 0.04), lower serum bilirubin at diagnosis (3.4 mg/dL vs. 1.23 mg/dL, p = 0.045), and non-significant trends of shorter defibrotide treatment (21.7 days vs. 15.6 days, p = 0.73), decreased mortality (30% vs. 6.2%, p = 0.10) and shorter hospitalization (73.1 days vs. 59.6 days, p = 0.54).

CONCLUSIONS

Different time periods around the implementation of new criteria are evaluated, underling that pediatric EBMT criteria for post-transplant HVOD diagnosis appear more sensitive.

Sinusoidal Obstruction Syndrome of the Liver Associated With 6-Mercaptopurine During Maintenance in a Child With T-cell Acute Lymphoblastic Leukemia

Sinusoidal obstruction syndrome (SOS) of the liver is a complication of chemotherapy most often encountered with hematopoietic stem cell transplant due to high-dose conditioning regimens, but it can also occur with regimens outside of the transplant setting. Mild-to-moderate SOS is a well-described 6-thioguanine toxicity; however, it has rarely been reported as secondary to 6-mercaptopurine, a related thiopurine. This report details a case of a 10-year-old male with T-cell acute lymphoblastic leukemia who developed severe SOS during maintenance therapy with 6-mercaptopurine, and a review of the related literature.

Low Plasma Levels of Hyaluronic Acid Might Rule Out Sinusoidal Obstruction Syndrome after Hematopoietic Stem Cell Transplantation

Background

Sinusoidal obstructive syndrome (SOS) is a potentially fatal complication secondary to hematopoietic stem cell transplant (HSCT) conditioning. Endothelial damage plasma biomarkers such as plasminogen activator inhibitor-1 (PAI-1), hyaluronic acid (HA), and vascular adhesion molecule-1 (VCAM1) represent potential diagnostic tools for SOS.

Methods

We prospectively collected serial citrated blood samples (baseline, day 0, day 7, and day 14) in all adult patients undergoing HSCT at La Paz Hospital, Madrid. Samples were later analyzed by ELISA (enzyme-linked immunosorbent assay) for HA, VCAM1, and PAI-1 concentrations.

Results

During sixteen months, we prospectively recruited 47 patients. Seven patients (14%) were diagnosed with SOS according to the EBMT criteria for SOS/VOD diagnosis and received treatment with defibrotide. Our study showed a statistically significant elevation of HA on day 7 in SOS patients, preceding clinical SOS diagnosis, with a sensitivity of 100%. Furthermore, we observed a significant increase of HA and VCAM1 levels on day 14. Regarding risk factors, we observed a statistically significant association between SOS diagnosis and the fact that patients received 3 or more previous lines of treatment before HSCT.

Conclusions

The early significant increase in HA levels observed opens the door to a noninvasive peripheral blood test which could have the potential to improve diagnosis and facilitate prophylactic and therapeutic management of SOS before clinical/histological damage is established.

Paediatric gastrointestinal and hepatobiliary radiology: why do we need subspecialists, and what is new?

We present the case for subspecialisation in paediatric gastrointestinal and hepato-pancreatico-biliary radiology. We frame the discussion around a number of questions: What is different about the paediatric patient and paediatric gastrointestinal system? What does the radiologist need to do differently? And finally, what can be translated from these subspecialty areas into everyday practice? We cover conditions that the sub-specialist might encounter, focusing on entities such as inflammatory bowel disease and hepatic vascular anomalies. We also highlight novel imaging techniques that are a focus of research in the subspecialties, including contrast-enhanced ultrasound, MRI motility, magnetisation transfer factor, and magnetic resonance elastography.

Review of the Pharmacokinetics and Pharmacodynamics of Intravenous Busulfan in Paediatric Patients

We aimed to review the pharmacokinetics (PK) of intravenous busulfan in paediatric patients, identify covariate factors influencing exposure, investigate evidence of changes in PK behaviour over time, and correlate exposure with efficacy and toxicity outcomes. A literature review was undertaken of original research published between 2007 and 2019, investigating the PK and pharmacodynamics (PD) of intravenous busulfan in patients ≤ 18 years of age. The review identified 41 publications characterising the PK, and 45 publications describing the PD, of busulfan. Median typical clearance (CL) was 0.22 L/h/kg and median typical volume of distribution was 0.69 L/kg. Patient weight, age, glutathione-S-transferase A1 (GSTA1) genotype and busulfan dosing day/time were the most commonly identified factors affecting CL. Of nine studies investigating changes in CL, seven reported reduced CL over the 4-day course of treatment. Exposure monitoring methods and therapeutic targets were heterogeneous across studies. Relationships between busulfan exposure and patient outcomes were observed in five studies. One study observed a cumulative area under the concentration-time curve over all days of treatment of between 78 and 101 mg/L·h, and two studies observed an average concentration at first dose of < 600 ng/mL improved overall survival, transplant-related mortality, or relapse. One study observed increased sinusoidal obstructive syndrome with maximum busulfan concentration > 1.88 ng/mL. Patient weight, age and GSTA1 genotype are important covariates to consider when individualising busulfan therapy. Reduced busulfan CL over time may need to be accounted for, particularly in patients not receiving phenytoin co-therapy. Standardised monitoring of busulfan exposure over the entire course of treatment and further investigation of the role of busulfan metabolites and pharmacogenomics is warranted.

Prognosis of pediatric patients with anicteric and late-onset sinusoidal obstruction syndrome after hematopoietic stem cell transplantation

BACKGROUND

Sinusoidal obstruction syndrome (SOS) is a life-threatening complication after hematopoietic stem cell transplantation (HSCT). Most adult patients with SOS present with jaundice, whereas hyperbilirubinemia does not always occur in children. Additionally, while late-onset SOS is rare in adults, 15-20% of SOS cases develop beyond day 30 after HSCT in children.

PROCEDURE

We investigated the incidence and prognosis of children with anicteric and late-onset SOS. We retrospectively analyzed the data of patients who developed SOS after HSCT conducted at our center between 2000 and 2016.

RESULTS

A total of 22 patients with a median age of 6.5 years (range: 0-16), including 14 males and eight females, developed SOS. Eight of the twenty-two patients were diagnosed as having anicteric SOS, and nine as having late-onset SOS. Patients with anicteric SOS had significantly lower incidence of SOS-related death at 100 days after HSCT (12.5% vs 64.3%, P = 0.03) and higher 2-year overall survival (OS) rate (60.0% vs 14.3%, P = .04) than patients with icteric SOS. One patient with anicteric SOS died from progression of SOS. There were no significant differences observed in these endpoints between patients who developed SOS before and after 21 days from HSCT.

CONCLUSIONS

Careful monitoring is needed for the development of SOS even in the absence of jaundice, and even at 3 weeksafter HSCT in children.

Effect of Sirolimus levels between days 11 and 20 after allogeneic stem cell transplantation on the risk of hepatic sinusoidal obstruction syndrome

Sinusoidal obstruction syndrome (SOS) is a serious complication of hematopoietic stem cell transplantation (HSCT). Sirolimus plus tacrolimus is an accepted regimen for graft-versus-host disease (GVHD) prophylaxis, with both agents implicated as risk factors for SOS. We analyzed 260 consecutive patients who underwent allogeneic HSCT following myeloablative conditioning using total body irradiation (TBI)-based (n = 151) or chemotherapy only (n = 109) regimens, with sirolimus plus tacrolimus for GVHD prophylaxis. SOS occurred in 28 patients at a median of 22 (range, 12-58) days. Mean sirolimus trough levels were higher between days 11 and 20 following transplant in patients who developed SOS (10.3 vs. 8.5 ng/ml, P = 0.008), with no significant difference in mean trough levels between days 0 and 10 (P = 0.67) and days 21-30 (P = 0.37). No differences in mean tacrolimus trough levels during the same time intervals were observed between those developing SOS and others. On multivariable analysis, a mean sirolimus trough level ≥ 9 ng/ml between days 11 and 20 increased the risk of SOS (hazard ratio 3.68, 95% CI: 1.57-8.67, P = 0.003), together with a longer time from diagnosis to transplant (P = 0.004) and use of TBI (P = 0.006). Our results suggest that mean trough sirolimus levels ≥ 9 ng/mL between days 11 and 20 post transplant may increase the risk of SOS and should be avoided.

Feasibility and effectiveness of treatment strategy of tandem high-dose chemotherapy and autologous stem cell transplantation in combination with 131 I-MIBG therapy for high-risk neuroblastoma

This study was performed to evaluate the safety and effectiveness of tandem HDCT/ASCT combined with targeted radiotherapy using ¹³¹ I-MIBG for high-risk neuroblastoma. Patients with high-risk neuroblastoma were treated with 8 to 10 cycles of induction chemotherapy before tandem HDCT/ASCT. Patients received ¹³¹ I-MIBG treatment before the second HDCT/ASCT. Local radiotherapy and maintenance therapy were performed after tandem HDCT/ASCT. Between 2012 and 2016, 19 patients were diagnosed with high-risk neuroblastoma in our institution and 18 of them received tandem HDCT/ASCT combined with ¹³¹ I-MIBG therapy. For the first HDCT/ASCT regimen, 12 patients received busulfan/melphalan and six patients received melphalan/etoposide/carboplatin. The second HDCT included ThioCy. The median dose of ¹³¹ I-MIBG was 17.2 mCi/kg for the first eight patients, while 12 patients in the latter period of the study received reduced dose of 10.7 mCi/kg. The 5-year OS and EFS rates were 79% and 61%, respectively, for all 19 patients with high-risk neuroblastoma, and 83% and 64%, respectively, for 18 patients who completed tandem HDCT/ASCT combined with ¹³¹ I-MIBG therapy. Six patients experienced disease relapse and five patients died. Treatment-related mortality was not observed. Among 15 evaluable patients, 11 patients (73%) developed hypothyroidism, six patients (40%) had CKD, and six patients (40%) had growth failure. Hypothyroidism and growth failure were less frequent in patients who received reduced doses of ¹³¹ I-MIBG therapy. Tandem HDCT/ASCT combined with HD ¹³¹ I-MIBG therapy could be feasible for patients with high-risk neuroblastoma with acceptable toxicity profiles and favorable outcomes.

Genetic Susceptibility to Hepatic Sinusoidal Obstruction Syndrome in Pediatric Patients Undergoing Hematopoietic Stem Cell Transplantation

Sinusoidal obstruction syndrome (SOS) is a well-recognized and potentially life-threatening complication of hematopoietic stem cell transplantation (HSCT). SOS arises from endothelial cell damage and hepatocellular injury mostly due to the transplantation conditioning regimens but also to other patient, disease, and treatment-related factors. Understanding risk factors associated with the development of SOS is critical for early initiation of treatment or prophylaxis. The knowledge about genetic contribution is limited; few studies investigated so far selected a set of genes. To get more comprehensive insight in the genetic component, we performed an exome-wide association study using genetic variants derived from whole-exome sequencing. The analyses were performed in a discovery cohort composed of 87 pediatric patients undergoing HSCT following a busulfan-containing conditioning regimen. Eight lead single-nucleotide polymorphisms (SNPs) were identified after correction for multiple testing and subsequently analyzed in a validation cohort (n = 182). Three SNPs were successfully replicated, including rs17146905 (P = .001), rs16931326 (P = .04), and rs2289971 (P = .03), located respectively in the UGT2B10, BHLHE22, and KIAA1715 genes. UGT2B10 and KIAA1715 were retained in a multivariable model while controlling for nongenetic covariates and previously identified risk variants in the GSTA1 promoter. The modulation of associations by conditioning regimens was noted; KIAA1715 was dependent on the intensity of the conditioning regimen, whereas the effect of UGT2B10 was equally applicable to all of them. Combined effect of associated loci was also observed (P = .00006) with a genotype-related SOS risk of 9.8. To our knowledge, this is the first study addressing the genetic component of SOS at an exome-wide level and identifying novel genetic variations conferring a higher risk of SOS, which might be useful for personalized prevention and treatment strategies.

Transplant-Associated Thrombotic Microangiopathy in Pediatric Hematopoietic Cell Transplant Recipients: A Practical Approach to Diagnosis and Management

Transplant-associated thrombotic microangiopathy (TA-TMA) is an endothelial damage syndrome that is increasingly identified as a complication of both autologous and allogeneic hematopoietic cell transplantation (HCT) in children. If not promptly diagnosed and treated, TA-TMA can lead to significant morbidity (e.g., permanent renal injury) or mortality. However, as the recognition of the early stages of TA-TMA may be difficult, we propose a TA-TMA "triad" of hypertension, thrombocytopenia (or platelet transfusion refractoriness), and elevated lactate dehydrogenase (LDH). While not diagnostic, this triad should prompt further evaluation for TA-TMA. There is increased understanding of the risk factors for the development of TA-TMA, including those which are inherent (e.g., race, genetics), transplant approach-related (e.g., second HCT, use of HLA-mismatched donors), and related to post-transplant events (e.g., receipt of calcineurin inhibitors, development of graft-vs. -host-disease, or certain infections). This understanding should lead to enhanced screening for TA-TMA signs and symptoms in high-risk patients. The pathophysiology of TA-TMA is complex, resulting from a cycle of activation of endothelial cells to produce a pro-coagulant state, along with activation of antigen-presenting cells and lymphocytes, as well as activation of the complement cascade and microthrombi formation. This has led to the formulation of a "Three-Hit Hypothesis" in which patients with either an underlying predisposition to complement activation or pre-existing endothelial injury (Hit 1) undergo a toxic conditioning regimen causing endothelial injury (Hit 2), and then additional insults are triggered by medications, alloreactivity, infections, and/or antibodies (Hit 3). Understanding this cycle of injury permits the development of a specific TA-TMA treatment algorithm designed to treat both the triggers and the drivers of the endothelial injury. Finally, several intriguing approaches to TA-TMA prophylaxis have been identified. Future work on the development of a single diagnostic test with high specificity and sensitivity, and the development of a robust risk-scoring system, will further improve the management of this serious post-transplant complication.