Kohorst, Mira A.

ABSTRACT Background Patients at high risk for cytomegalovirus (CMV) infection after allogeneic hematopoietic stem cell transplant (HCT) should receive CMV prophylaxis. Historically, ganciclovir has been the preferred agent. However, its side effect profile, particularly myelosuppression, is undesirable. Letermovir is a newer agent that is not myelosuppressive and has replaced ganciclovir as the preferred agent for CMV prophylaxis in high‐risk adult patients. Methods The primary objective was to compare the incidence of dose modifications or discontinuation of CMV prophylaxis between pediatric patients who received ganciclovir versus letermovir. Secondary objectives included comparing the use of granulocyte colony‐stimulating factor (G‐CSF) support and the incidence of CMV DNAemia. We reviewed records of all pediatric patients who received an HCT at our institution between 2000 and 2024 and received either ganciclovir/valganciclovir or letermovir for CMV prophylaxis. Results Between 2000 and 2024, 65 pediatric patients receiving prophylactic ganciclovir, valganciclovir, or letermovir were evaluated. The median age at transplant was 12.2 years. No patients receiving letermovir required dose modification or discontinuation as opposed to 14 (29.2%) patients receiving ganciclovir ( p = 0.014). After engraftment, 12 (25%) patients receiving ganciclovir required G‐CSF support compared to seven (41.2%) patients receiving letermovir ( p = 0.23). In the ganciclovir group, 10 (20.8%) patients experienced CMV infection versus one (5.9%) patient receiving letermovir ( p = 0.26). Conclusion Compared with those receiving letermovir, a significantly higher proportion of patients in the ganciclovir/valganciclovir group experienced dose modifications or discontinuation of CMV prophylaxis due to adverse effects. Letermovir shows great promise as a CMV prophylactic agent in pediatric HCT patients due to its favorable side effect profile.

ABSTRACTTransplant‐associated thrombotic microangiopathy (TA‐TMA) is an endothelial dysfunction syndrome observed after allogeneic hematopoietic cell transplant (alloHCT). Our aim was to externally validate the impact of high‐risk features on the clinical outcomes of adult patients meeting the updated TA‐TMA harmonizing criteria. Between 2005 and 2022, 99 patients were diagnosed with TA‐TMA at Mayo Clinic Rochester (incidence 6.2%) after a median of 137 days post alloHCT (IQR: 34–283 days). The development of TA‐TMA was associated with an inferior overall survival posttransplant (HR: 3.8, 95% CI: 2.97–4.72). High‐risk features, including concomitant infection, acute graft‐versus‐host disease (GVHD), and organ dysfunction, were associated with poor survival, while LDH elevation was not associated with inferior outcomes. The most common treatment strategy for TA‐TMA was discontinuation of calcineurin or mTOR inhibitors in 80 (81%) patients. Thirty (37.5%) patients experienced worsening of GVHD with this strategy, of which 26 (86.7%) patients had died at last follow‐up. The most common cause of death among these patients was worsening GVHD (69%; n = 18), followed by infection (11%; n = 3), disease relapse (8%; n = 2), other/unknown causes (8%; n = 2), or TA‐TMA (4%; n = 1). Objective response rate (ORR) to initial treatment for the cohort was 56.6%. Eculizumab was used in 11 patients with an observed ORR of 70%, including 5 complete responses. In conclusion, TA‐TMA remains a significant contributor to non‐relapse mortality and is associated with worse survival following alloHCT. Not all high‐risk features, particularly LDH elevation, have consistently demonstrated a negative impact in adult cohorts. Patients with TA‐TMA may benefit from immune suppression dose adjustment, rather than a discontinuation, and the addition of complement‐directed therapy, particularly among high‐risk patients.

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Pediatric Acute Lymphoblastic Leukemia (ALL) were developed as a result of meetings convened by a multidisciplinary panel of pediatric ALL experts, with the goal of providing recommendations on standard treatment approaches based on current evidence. The NCCN Guidelines for pediatric ALL focus on risk assessment and stratification of risk-adapted therapy; treatment strategies for BCR::ABL1 (Philadelphia chromosome [Ph])-negative and BCR::ABL1-positive B-cell lineage, T-cell lineage, and infant ALL; and supportive care considerations. This selection from the NCCN Guidelines for pediatric ALL focuses on the diagnosis of and management of pediatric T-ALL.

OBJECTIVE Sepsis is associated with significant morbidity and mortality in pediatric hematology, oncology, and transplant (PHOT) patients. This study characterized PHOT patients who developed hospital-onset sepsis more than 12 hours after admission and identified risk factors for 30-day sepsis-attributable (SA) mortality. PATIENTS AND METHODS We analyzed an existing multicenter database of sepsis collected prospectively over 5 years (2017–2021) as part of the Improving Pediatric Sepsis Outcomes Collaborative. Sepsis was defined using operational elements documented in the health records based on International Classification of Diseases, Tenth Revision codes, treatment, diagnostic tests, and sepsis screen, huddle, or order set use. RESULTS A total of 9604 sepsis episodes in PHOT patients from 49 hospitals were analyzed: 70.5% were identified in the emergency department (ED), 10.9% in inpatient settings less than or equal to 12 hours from admission, and 18.6% were hospital onset. Only 52.5% of patients with hospital-onset sepsis were identified using a sepsis recognition method compared with 87.2% in the ED (P < .001). The overall 30-day SA mortality was 2.2%, with a higher rate (6.9%) among those with hospital-onset sepsis compared with those who developed sepsis at presentation or less than or equal to 12 hours (1.1%, P < .001). CONCLUSIONS Although the difference in SA mortality between hospitalized and nonhospitalized patients may be impacted by nonmeasurable confounders inherent to the type of patients presenting in the different care settings, we reported system-based improvements that may reduce mortality. The 30-day SA mortality was lower in hospitalized PHOT patients when sepsis was detected by early recognition methods, supporting the need for efforts to implement sepsis recognition tools in the inpatient setting.

Germline 3q21 chromosome deletions result in a rare multi-system condition. Of the 14 cases of germline 3q21 deletion syndrome reported, 2 have been reported to develop myelodysplastic syndrome necessitating allogeneic HCT (our patient and one other). Our patient was treated with an allogeneic, matched sibling hematopoietic cell transplantation. Patients with 3q21 deletion have a predilection for myelodysplastic syndrome, likely due to GATA2 deletion. We recommend frequent complete blood count evaluation with annual bone marrow aspiration to monitor for development of MDS in patients with 3q21 deletion.

A 13-year-old male undergoing maintenance chemotherapy with methotrexate and 6-mercaptopurine (6MP), for very high-risk B-cell acute lymphoblastic leukemia (ALL), presented with vomiting due to severe hypoglycemia with metabolic acidosis. While his laboratory values were concerning for a critically ill child, the patient was relatively well appearing. Hypoglycemia is a rare but serious side effect of 6MP with an unexpectedly variable presentation; therefore, a high index of suspicion is needed for its prompt detection and treatment. This patient also had severe metabolic acidosis, likely secondary to hypoglycemia, creating a serious clinical picture despite a well-appearing child. This example of incongruity between laboratory tests and clinical appearance adds nuance to the existing literature. Moreover, although 6MP-associated hypoglycemia is rare, it may be more prevalent than the literature suggests, as symptoms of hypoglycemia—nausea, vomiting, and somnolence—mirror common chemotherapy side effects. 6MP-induced hypoglycemia can be ameliorated with the addition of allopurinol to shunt metabolism in favor of the production of therapeutic metabolites over hepatotoxic metabolites. Additionally, a morning administration of 6MP and frequent snacks may also help to prevent hypoglycemia. Overall, this case adds to the literature of unusual reactions to 6MP including hypoglycemia in an older child without traditional risk factors.

AbstractRelapsed and refractory B‐cell acute lymphoblastic leukemia (B‐ALL) is an aggressive B‐cell neoplasm associated with poor outcomes. Conventional multiagent chemotherapy and bispecific antibody therapy may induce remission; however, relapse rates remain high and overall survival is poor. Chimeric antigen receptor T‐cell (CAR‐T) therapy provides durable, deep complete remission, and long‐term cures in relapsed and refractory B‐ALL. However, with this new treatment modality, 10%–30% of patients do not achieve remission, and over 50% experience relapse after therapy. Currently, there are two approved CD19‐specific CAR‐T cell constructs in B‐ALL, Tisagenlecleucel and Brexucabtagene Autoleucel by the United States Food and Drug Administration, and the European Medicines Agency (EMA). In this review, we discuss patients, disease, and CAR‐T predictors of outcomes in B‐ALL. We describe the two approved CD19‐directed CAR‐T cell products, review the current literature, and discuss factors associated with high risks of therapy failure and future direction in CAR‐T cell therapy for B‐ALL.

Introduction: Immune-mediated graft failure (also termed graft rejection) is a feared complication of hematopoietic stem cell transplant (HSCT) and there is no effective intervention. Multiple pre-transplant risk factors for graft failure are known and recent studies from our groups identified interferon gamma (IFNγ) as a mechanistically important and pharmacologically targetable cytokine involved in graft failure pathophysiology. CXCL9, a downstream marker of IFNγ production, was also identified as a biomarker. We describe an international multicenter retrospective pooled analysis of emapalumab (EMA), an IFNγ neutralizing agent, for the prevention/treatment of immune-mediated graft failure after HSCT. Methods: The safety and preliminary efficacy of EMA were studied in predominantly pediatric patients who received EMA using two different strategies: 1) graft failure treatment and 2) graft failure prophylaxis. Patients at US centers were treated with EMA if they developed clinical and laboratory signs of graft failure after HSCT. All treatment patients met 2 or more of the following criteria: 1) HLA mismatched donor and/or prior graft failure, 2) unexplained fever >39°C (or >38°C if prior history of graft failure) after HSCT, 3) absolute neutrophil count decline after initial engraftment, 4) delayed neutrophil engraftment after HSCT, 5) real-time CXCL9 > 2.5x upper limit of normal (ULN). Temperature and CXCL9 cutoffs were based on a prior graft failure biomarker publication (Sabulski et al, Blood Advances 2021). Patients treated at European centers received prophylactic EMA to prevent graft failure if they were deemed at high-risk prior to transplant. High-risk patients had a prior history of graft failure after HSCT or had two or more of the following established risk factors: a) affected by a disease with high risk of graft failure, including acquired severe aplastic anemia, thalassemia, primary HLH; b) ex-vivo T cell-depleted stem cell product; c) transplant from unrelated cord blood unit or mismatched related/unrelated donor. Results: Thirty-six HSCTs used EMA for graft failure treatment or prophylaxis and were included in this study.EMA was used for graft failure treatment in 25 HSCTs wherein patients developed clinical and laboratory signs of graft failure (Table 1). Most HSCTs in the treatment cohort were performed for bone marrow failure syndromes (n=16). All patients tolerated EMA without complications and no side effects or infections were attributed to EMA. Fifty six percent (14/25) of patients treated with EMA for impending graft failure engrafted and had resolution of graft failure concerns, while the remaining 44% suffered graft failure. Responders had a median ANC of 0.29 x10 3 cells/μL (range 0.05-0.79) prior to EMA, which increased to a median of 0.6 x10 3cells/μL (range, 0-5.1) and 2.97 x10 3 cells/μL (range, 0.85-8.7) on days 3 and 7 after EMA dosing. Eighty percent (20/25) of CXCL9 levels were elevated in the treatment cohort prior to EMA dosing. The median CXCL9 level prior to EMA dosing was elevated 2.4 x ULN (range, 0.3-157.8). The median pre-EMA CXCL9 level in patients who ultimately suffered graft failure in the treatment cohort was 3.3x ULN (range, 0.7-157.8) compared to a median of 2.2x ULN (range, 0.3-30.4) in subjects who had signs of graft failure but did not suffer graft failure (p=0.24). Eleven patients received prophylactic EMA based on a prior history of graft failure or other pre-transplant risk factors. EMA was well tolerated in these patients and 91% (10/11) of patients engrafted while one patient with prior history of graft failure suffered recurrent graft failure. The pre-HSCT (day -2) CXCL9 level in the lone prophylactic patient who suffered graft failure was 4x the ULN. Conclusions: This study reports the largest cohort of HSCTs that used EMA therapy for the novel purpose of treating or preventing graft failure. EMA was well tolerated in all patients. Efficacy conclusions are preliminary and limited by the study design, however our treatment study successfully identified a cohort of patients with a markedly high graft failure rate (44%) and we show preliminary evidence to suggest emaplaumab prevented graft failure in patients who had signs of impending graft failure at the time of treatment. The safety and preliminary efficacy observations in this study support a larger prospective study of IFNγ blockade for graft failure prevention after HSCT.