Th1 cytokines in pediatric acute lymphoblastic leukemia.

Immune milieus play an important role in various types of cancer. The present study focuses on the effect of Th1 cytokines on pediatric acute lymphoblastic leukemia (ALL). The reaction of ALL cell lines and patient-derived xenografts (PDX) to the most important Th1 cytokines TNF-α (tumor necrosis factor alpha) and IFN-γ (interferon gamma) is analyzed and correlated with the respective cytokine receptors and the intracellular signaling molecules. ALL cell lines and ALL PDX display a great heterogeneity in cell death after incubation with TNF-α and IFN-γ. Several samples show a dose-dependent and additive induction of cell death by both cytokines; others do not react at all or even display an increased viability. Apoptosis is the main type of cell death induced by Th1 cytokines in ALL cells. Over all leukemia cells analyzed, IFN-γ receptor (IFNGR) shows a higher expression than both TNF-receptors, resulting in higher phosphorylation of STAT1 (signal transducer and activator of transcription) compared to phosphorylation of NF-κB (nuclear factor kappa-light-chain-enhancer of activated B-cells) in the TNF pathway. The activation of STAT1 correlates with the amount of cell death after stimulation with Th1 cytokines. TNF-α and IFN-γ lead to heterogeneous reactions in ALL cell lines and ALL PDX but are able to induce cell death by apoptosis in the majority of ALL blasts. The correlation of a high expression of IFNGR and following activation of STAT1 with cell death indicates an important role for IFN-γ signaling in this setting.

Low leukemia burden improves blinatumomab efficacy in patients with relapsed/refractory B-cell acute lymphoblastic leukemia.

BACKGROUND: A lower baseline bone marrow blast percentage (bBMB%) is associated with better outcomes in patients with B-cell acute lymphoblastic leukemia (B-ALL) receiving blinatumomab. The objective of this analysis was to investigate the association between bBMB% and treatment outcomes in relapsed/refractory (R/R) B-ALL. METHODS: Data from five trials of blinatumomab for R/R B-ALL were pooled for analyses. Patients were placed in one of three groups: group 1, ≥50% bBMBs; group 2, ≥25% to <50% bBMBs; group 3, ≥5% to <25% bBMBs. Response and survival outcomes were compared between groups. RESULTS: Data from 683 patients (166 pediatric, 517 adult) were analyzed. Collectively, patients in groups 2 and 3 had significantly higher odds of achieving a complete remission (CR) (odds ratio [OR], 3.50 [95% confidence interval (CI), 2.23-5.48] and 3.93 [95% CI, 2.50-6.18], respectively; p < .001) and minimal/measurable residual disease response (OR, 2.61 and 3.37, respectively; p < .001) when compared with group 1 (reference). Groups 2 and 3 had a 37% and 46% reduction in the risk of death (hazard ratio [HR], 0.63 and 0.54, respectively; p < .001) and a 41% and 43% reduction in the risk of an event (relapse or death) (HR, 0.59 and 0.57, respectively; p < .001) compared with group 1. No significant differences in response or survival outcomes were observed between groups 2 and 3. Seven of nine patients whose bBMB% was lowered to <50% with dexamethasone achieved CR with blinatumomab. CONCLUSION: Any bBMB% <50% was associated with improved efficacy following blinatumomab treatment for R/R B-ALL.

Anti-GD2 Antibody Dinutuximab Beta and Low-Dose Interleukin 2 After Haploidentical Stem-Cell Transplantation in Patients With Relapsed Neuroblastoma: A Multicenter, Phase I/II Trial.

PURPOSE: Patients with relapsed high-risk neuroblastoma (rHR-NB) have a poor prognosis. We hypothesized that graft-versus-neuroblastoma effects could be elicited by transplantation of haploidentical stem cells (haplo-SCT) exploiting cytotoxic functions of natural killer cells and their activation by the anti-GD2 antibody dinutuximab beta (DB). This phase I/II trial assessed safety, feasibility, and outcomes of immunotherapy with DB plus subcutaneous interleukin-2 (scIL2) after haplo-SCT in patients with rHR-NB. METHODS: Patients age 1-21 years underwent T-/B-cell-depleted haplo-SCT followed by DB and scIL2. The primary end point 'success of treatment' encompassed patients receiving six cycles, being alive 180 days after end of trial treatment without progressive disease, unacceptable toxicity, acute graft-versus-host-disease (GvHD) ≥grade 3, or extensive chronic GvHD. RESULTS: Seventy patients were screened, and 68 were eligible for immunotherapy. Median number of DB cycles was 6 (range, 1-9). Median number of scIL2 cycles was 3 (1-6). The primary end point was met by 37 patients (54.4%). Median observation time was 7.8 years. Five-year event-free survival (EFS) and overall survival from start of trial treatment were 43% (95% CI, 31 to 55) and 53% (95% CI, 41 to 65), respectively. Five-year EFS among patients in complete remission (CR; 52%; 95% CI, 31 to 69) or partial remission (44%; 95% CI, 27 to 60) before immunotherapy were significantly better compared with patients with nonresponse/mixed response/progressive disease (13%; 95% CI, 1 to 42; P = .026). Overall response rate in 43 patients with evidence of disease after haplo-SCT was 51% (22 patients), with 15 achieving CR (35%). Two patients developed GvHD grade 2 and 3 each. No unexpected adverse events occurred. CONCLUSION: DB therapy after haplo-SCT in patients with rHR-NB is feasible, with low risk of inducing GvHD, and results in long-term remissions likely attributable to increased antineuroblastoma activity by donor-derived effector cells.

Evaluating the safety of perioperative dexamethasone treatment: A retrospective analysis of a single center pediatric low-grade glioma cohort.

In addition to surgical management, corticosteroids have proven to be beneficial in the management of acute symptoms related to CNS tumors, and have been widely used for many decades, with dexamethasone (DM) representing the most commonly used agent. However, lately published in vitro data possibly indicates a DM-induced suppression of oncogene-induced senescence (OIS) in a preclinical pediatric low-grade glioma (pLGG) model, which, alongside data associating perioperative DM treatment with reduced event-free survival in adult glioma, raises questions concerning the safety of DM treatment in pLGG. A total of 172 patients with pLGG were retrospectively analyzed concerning the impact of perioperative DM application on postoperative short- and long-term tumor growth velocity and progression-free survival (PFS). Three-dimensional volumetric analyses of sequential MRI follow-up examinations were used for assessment of tumor growth behavior. Mean follow-up period accounted for 60.1 months. Sixty-five patients (45%) were perioperatively treated with DM in commonly used doses. Five-year PFS accounted for 93% following gross-total resection (GTR) and 57% post incomplete resection (IR). Comparison of short- and long-term postoperative tumor growth rates in patients with vs without perioperative DM application showed no significant difference (short-term: 0.022 vs 0.023 cm3 /month, respectively; long-term: 0.019 vs 0.023 cm3 /month, respectively). Comparison of PFS post IR (5-year-PFS: 65% vs 55%, respectively; 10-year-PFS: 52% vs 53%, respectively) and GTR (5- and 10-years-PFS: 91% vs 92%, respectively) likewise showed similarity. This data emphasizes the safety of perioperative DM application in pLGG, adding further evidence for decision making and requested future guidelines.

Resection extent and BRAF V600E mutation status determine postoperative tumor growth velocity in pediatric low-grade glioma: results from a single-center cohort analysis.

PURPOSE: Despite excellent long-term overall survival rates, pediatric low-grade gliomas (pLGG) show high variety of clinical behavior regarding progress or senescence post incomplete resection (IR). This study retrospectively analyzes tumor growth velocity (TGV) of pLGG before surgery and after IR to investigate the impact of surgical extent, tumor location and molecular BRAF status on postoperative residual tumor growth behavior. METHODS: Of a total of 172 patients with pLGG receiving surgical treatment, 107 underwent IR (66%). Fifty-three vs 94 patients could be included in the pre- and post-operative cohort, respectively, and were observed over a mean follow-up time of 40.2 vs 60.1 months. Sequential three-dimensional MRI-based tumor volumetry of a total of 407 MRI scans was performed to calculate pre- and postoperative TGV. RESULTS: Mean preoperative TGV of 0.264 cm3/month showed significant deceleration of tumor growth to 0.085 cm3/month, 0.024 cm3/month and -0.016 cm3/month after 1st, 2nd, and 3rd IR, respectively (p < 0.001). Results remained significant after excluding patients undergoing (neo)adjuvant treatment. Resection extent showed correlation with postoperative reduction of TGV (R = 0.97, p < 0.001). ROC analysis identified a residual cut-off tumor volume > 2.03 cm3 associated with a higher risk of progress post IR (sensitivity 78,6%, specificity 76.3%, AUC 0.88). Postoperative TGV of BRAF V600E-mutant LGG was significantly higher than of BRAF wild-type LGG (0.123 cm3/month vs. 0.016 cm3/month, p = 0.047). CONCLUSION: This data suggests that extensive surgical resection may impact pediatric LGG growth kinetics post incomplete resection by inducing a significant deceleration of tumor growth. BRAF-V600E mutation may be a risk factor for higher postoperative TGV.

Epitope detection in monocytes (EDIM) for liquid biopsy including identification of GD2 in childhood neuroblastoma-a pilot study.

BACKGROUND: Neuroblastoma (NB) is the most common paediatric extracranial solid malignancy. We analysed the role of the epitope detection in monocytes (EDIM) technique for liquid biopsy in NB patients. METHODS: Tumour epitopes transketolase-like 1 (TKTL1), Apo10 (DNaseX) and GD2 were assessed: expression levels in seven NB tumour samples and five NB cell lines were analysed using RT-PCR and flow cytometry. LAN-1 cells were co-cultured with blood and assessed using EDIM. Peripheral blood macrophages of patients with neuroblastoma (n = 38) and healthy individuals (control group, n = 37) were labelled (CD14+/CD16+) and assessed for TKTL1, Apo10 and GD2 using the EDIM technology. RESULTS: mRNA expression of TKTL1 and DNaseX/Apo10 was elevated in 6/7 NB samples. Spike experiments showed upregulation of TKTL1, Apo10 and GD2 in LAN-1 cells following co-culturing with blood. TKTL1 and Apo10 were present in macrophages of 36/38 patients, and GD2 in 15/19 patients. The 37 control samples were all negative. EDIM expression scores of the three epitopes allowed differentiation between NB patients and healthy individuals. CONCLUSIONS: The EDIM test might serve as a non-invasive tool for liquid biopsy in children suffering from NB. Future studies are necessary for assessing risk stratification, tumour biology, treatment monitoring, and early detection of tumour relapses.

Introducing isotonic fluids into pediatric oncology.

Objective: Hypotonic fluids are commonly used in pediatric oncology despite evidence that these fluids can lead to hospital-acquired hyponatremia. This practice is most likely due to lack of data evaluating risks and benefits of isotonic fluids in pediatric oncology. To address this issue, our study investigates the effects of exchanging hypotonic fluids with isotonic fluids in a large pediatric oncology unit. Study Design: Prevalence of laboratory disorders before and after the change to balanced, isotonic fluids for all patients are compared in this retrospective analysis. Disturbances in electrolyte levels, fluid-, acid-base balance and kidney function were examined. Results: The rate of hyponatremia was reduced using isotonic fluids. There were no hypernatremic events. Volume overload might increase the use of furosemide when using isotonic fluids. Potassium and bivalent cation levels increased. The risk of acidosis is greatly reduced, whereas alkalosis was more frequent due to furosemide use. The rate of acute kidney injury did not increase. Conclusion: Using isotonic fluids for hyper-hydration in pediatric oncology lead to a modest reduction of hospital-acquired hyponatremia without causing hypernatremia, but the effects on fluid balance need further investigation. The additional intake of bivalent cations and buffering anions in balanced fluids has measurable effects.

Blinatumomab in Pediatric Acute Lymphoblastic Leukemia-From Salvage to First Line Therapy (A Systematic Review).

Acute lymphoblastic leukemia is by far the most common malignancy in children, and new immunotherapeutic approaches will clearly change the way we treat our patients in future years. Blinatumomab is a bispecific T-cell-engaging antibody indicated for the treatment of relapsed/refractory acute lymphoblastic leukemia (R/R-ALL). The use of blinatumomab in R/R ALL has shown promising effects, especially as a bridging tool to hematopoietic stem cell transplantation. For heavily pretreated patients, the response to one or two cycles of blinatumomab ranges from 34% to 66%. Two randomized controlled trials have very recently demonstrated an improved reduction in minimal residual disease as well as an increased survival for patients treated with blinatumomab compared to standard consolidation treatment in first relapse. Current trials using blinatumomab frontline for high-risk patients or as a consolidation treatment post-transplant will show whether efficacy is even higher in less heavily pretreated patients. Due to the distinct pattern of adverse events compared to high-dose conventional chemotherapy, blinatumomab could play an important role for patients with a risk for severe chemotherapy-associated toxicities. This systematic review discusses all published results for blinatumomab in children as well as all ongoing clinical trials.

An Fc-Optimized CD133 Antibody for Induction of NK Cell Reactivity against B Cell Acute Lymphoblastic Leukemia.

In recent decades, antibody-dependent cellular cytotoxicity (ADCC)-inducing monoclonal antibodies (mAbs) have revolutionized cancer immunotherapy, and Fc engineering strategies have been utilized to further improve efficacy. A promising option is to enhance the affinity of an antibody's Fc-part to the Fc-receptor CD16 by altering the amino acid sequence. Herein, we characterized an S239D/I332E-modified CD133 mAb termed 293C3-SDIE for treatment of B cell acute lymphoblastic leukemia (B-ALL). Flow cytometric analysis revealed CD133 expression on B-ALL cell lines and leukemic cells of 50% (14 of 28) B-ALL patients. 293C3-SDIE potently induced NK cell reactivity against the B-ALL cell lines SEM and RS4;11, as well as leukemic cells of B-ALL patients in a target antigen-dependent manner, as revealed by analysis of NK cell activation, degranulation, and cytotoxicity. Of note, CD133 expression did not correlate with BCR-ABL, CD19, CD20, or CD22, which are presently used as therapeutic targets in B-ALL, which revealed CD133 as an independent target for B-ALL treatment. Increased CD133 expression was also observed in MLL-AF4-rearranged B-ALL, indicating that 293C3-SDIE may constitute a particularly suitable treatment option in this hard-to-treat subpopulation. Taken together, our results identify 293C3-SDIE as a promising therapeutic agent for the treatment of B-ALL.

Arsenic trioxide in pediatric cancer - a case series and review of literature.

Arsenic trioxide (ATO) has become an established component of treatment protocols for acute promyelocytic leukemia (APL) with excellent efficacy and no relevant sustained toxicity. Part of its action has been attributed to the inhibition of Hedgehog signaling (Hh) which enables a possible therapeutic approach as many pediatric tumor entities have been associated with increased Hh activity. We retrospectively analyzed 31 patients with refractory and relapsed pediatric cancer who were treated with ATO at the University Children's Hospital of Tuebingen. Additionally a literature review on the clinical and preclinical use of ATO in pediatric cancer treatment was performed.ATO alone as well as combinations with other drugs have proven effective in vitro and in mouse models of various pediatric malignancies. However, only few data on the clinical use of ATO in pediatric patients besides APL exist. In our patient sample, ATO was overall well tolerated in the treatment of various pediatric cancers, even in combination with other cytostatic drugs. Due to distinct tumor entities, differently progressed disease stages and varying co-medication, no clear statement can be made regarding the efficacy of ATO treatment. However, patients with proven Hh activation in molecular tumor profiling surpassed all other patients, who received ATO in an experimental treatment setting, in terms of survival. As molecular profiling of tumors increases and enhanced Hh activity can be detected at an early stage, ATO might expand its clinical use to other pediatric malignancies beyond APL depending on further clinical studies.

Matched versus Haploidentical Hematopoietic Stem Cell Transplantation as Treatment Options for Primary Immunodeficiencies in Children.

Primary immunodeficiencies (PIDs) are inherited disorders of the immune system with allogeneic hematopoietic stem cell transplantation (HSCT) as the only curative treatment in some of them. In case an HLA-matched donor is not available, HSCT from a haploidentical family donor may be considered. We compared the outcomes of HSCT from HLA-matched unrelated or related donors (MUDs or MRDs) and mismatched related haploidentical donors (MMRDs) in patients with a variety of PIDs in 2 centers. A total of 44 pediatric patients were evaluated. We reviewed the outcomes of 25 children who underwent transplantation with HLA-matched grafts (MRD, n = 13; MUD, n = 12) and 19 patients receiving haploidentical stem cells. Bone marrow (BM) was transplanted in 85% (MRD) and 75% (MUD) of the matched cohort and peripheral blood stem cells (PBSCs) in 15% (MRD), 25% (MUD), and 100% (MMRD). All but 9 patients (MRD, n = 6; MMRD, n = 3) with severe combined immunodeficiency (SCID) received a chemotherapy-based conditioning regimen. Immune reconstitution of T, B, and natural killer cells was comparable for all groups with an advantage of recipients of MRD grafts in early CD4 reconstitution. However, deaths due to viral infections occurred more often in the haploidentical cohort. The disease-free survival was 91.7% (MRD), 66.7% (MUD), and 62.7% (MMRD), respectively. Grade II to IV acute graft-versus-host disease (GVHD) occurred in 15% (MRD), 8% (MUD), and 21% (MMRD) of the patients. Only 1 patient had severe grade IV GVHD in the MRD group, whereas no grade >II GVHD was observed in the MUD or MMRD cohort. These data indicate that in the absence of a suitable HLA-identical family donor, haploidentical HSCT may be a viable option for patients with life-threatening disease and urgent need of HSCT.

Blinatumomab in pediatric patients with relapsed/refractory B-cell precursor acute lymphoblastic leukemia.

OBJECTIVE: Pediatric patients with relapsed or refractory acute lymphoblastic leukemia have a poor prognosis. We here assess the response rates, adverse events, and long-term follow-up of pediatric patients with relapsed/refractory acute lymphoblastic leukemia receiving blinatumomab. METHODS: Retrospective analysis of a single-center experience with blinatumomab in 38 patients over a period of 10 years. RESULTS: The median age at onset of therapy was 10 years (1-21 years). Seventy-one percent of patients had undergone at least one hematopoietic stem cell transplantation (HSCT) prior to treatment with blinatumomab. We observed a response to blinatumomab in 13/38 patients (34%). The predominant side effect was febrile reactions, nearly half of the patients developed a cytokine release syndrome. Eight events of neurotoxicity were registered over the 78 cycles (15%). To date, nine patients (24%) are alive and in complete molecular remission. All survivors underwent haploidentical HSCT after treatment with blinatumomab. CONCLUSIONS: Despite heavy pretreatment of most of our patients, severe adverse events were rare and response rates encouraging. Blinatumomab is a valuable bridging salvage therapy for relapsed or refractory patients to a second or even third HSCT.

Antiemetic Prophylaxis with Fosaprepitant and 5-HT3-Receptor Antagonists in Pediatric Patients Undergoing Autologous Hematopoietic Stem Cell Transplantation.

BACKGROUND: High-dose myeloablative conditioning prior to autologous hematopoietic stem cell transplantation (autoHSCT) in pediatric patients is usually highly emetogenic. The antiemetic neurokinin-1 receptor antagonist fosaprepitant was safe and effective in children receiving highly emetogenic chemotherapy. Data on fosaprepitant during autoHSCT in children are currently not available. METHODS: A total of 35 consecutive pediatric patients, who received an antiemetic prophylaxis with fosaprepitant (4 mg/kg; single dose, max. 1 x 150 mg/kg BW) and ondansetron (24-hours continuous infusion; 8-32 mg/24h) or granisetron (2 x 40 µg/kg∙d-1) during highly emetogenic conditioning chemotherapy before autoHSCT were retrospectively analyzed, and their results were compared with a control group comprising 35 consecutive pediatric patients, who received granisetron or ondansetron only. The antiemetic efficacy and the safety of the two prophylaxis regimens were compared with respect to three time periods after the first chemotherapy administration (0-24h, >24-120h, >120-240h). RESULTS: Clinical adverse events and clinically relevant increases/decreases of laboratory markers were similarly low and did not significantly differ between the two study groups (p>0.05). The registered number of vomiting events was significantly higher in the control group in the time periods of 0-24h (64 vs 22 events; p<0.01), >24-120h (135 vs 78 events; p<0.0001), >120-240h (268 vs 105 events; p<0.0001), and the whole observation period 0-240h (467 vs 205 events; p<0.0001). The percentage of patients experiencing vomiting was higher in the control group during the time period of >24-120h (100% vs 74.3%) but not the other analyzed time periods (p>0.05). CONCLUSION: The fosaprepitant-based antiemetic prophylaxis was safe, well tolerated and significantly reduced vomiting in children undergoing highly emetogenic chemotherapy prior to autoHSCT. Prospective randomized trials are necessary to confirm these results.

Efficacy, Safety And Feasibility Of Antiemetic Prophylaxis With Fosaprepitant, Granisetron And Dexamethasone In Pediatric Patients With Hemato-Oncological Malignancies.

BACKGROUND: Chemotherapy-induced nausea and vomiting (CINV) are a major burden for patients undergoing emetogenic chemotherapy. International guidelines recommend an antiemetic prophylaxis with corticosteroids, 5-HT3R-antagonists and NK1R-antagonists. The NK1R-antagonist fosaprepitant has shown favorable results in pediatric and adult patients. There is little pediatric experience with fosaprepitant. METHODS: This non-interventional observation study analyzed 303 chemotherapy courses administered to 83 pediatric patients with a median age of 9 years (2-17 years), who received antiemetic prophylaxis either with fosaprepitant and granisetron with or without dexamethasone (fosaprepitant group/FG; n=41), or granisetron with or without dexamethasone (control group/CG; n=42), during moderately (CINV risk 30-90%) or highly (CINV risk>90%) emetogenic chemotherapy. The two groups' results were compared with respect to the safety and efficacy of the antiemetic prophylaxis during the acute (0-24hrs after chemotherapy), delayed (>24-120hrs after chemotherapy) and both CINV phases. Laboratory and clinical adverse events were compared between the two cohorts. RESULTS: Adverse events were not significantly different in the two groups (p>0.05). Significantly fewer vomiting events occurred during antiemetic prophylaxis with fosaprepitant in the acute (23 vs 142 events; p<0.0001) and the delayed (71 vs 255 events; p<0.0001) CINV phase. In the control group, the percentage of chemotherapy courses with vomiting was significantly higher during the acute (24%/FG vs 45%/CG; p<0.0001) and delayed CINV phase (28%/FG vs 47%/CG; p=0.0004). Dimenhydrinate (rescue medication) was administered significantly more often in the CG, compared to the FG (114/FG vs 320/CG doses; p<0.0001). Likewise, in the control group, dimenhydrinate was administered in significantly more (p<0.0001) chemotherapy courses during the acute and delayed CINV phases (79 of 150; 52.7%), compared to the fosaprepitant group (45 of 153; 29.4%). CONCLUSION: Antiemetic prophylaxis with fosaprepitant and granisetron with or without dexamethasone was well tolerated, safe and effective in pediatric patients. However, larger prospective trials are needed to evaluate these findings.

Comparison of procalcitonin and C-reactive protein as early diagnostic marker for the identification of transplant-related adverse events after allogeneic hematopoietic stem cell transplantation in pediatric patients.

PURPOSE: To evaluate serum procalcitonin (PCT) and C-reactive protein (CRP) as diagnostic biomarkers of transplant-related adverse events (TRAE) in pediatric patients undergoing hematopoietic stem cell transplantation (HSCT). METHODS: This study analyzed PCT and CRP levels of 214 pediatric patients with a median age of 8.5 years (0.4-17.8 years) undergoing allogeneic HSCT with respect to major TRAE. RESULTS: 26 patients (12.1%) did not experience TRAE (control group), and 188 (87.9%) experienced median 2 (range 1-4) TRAE. Median CRP and PCT were highly and significantly increased during sepsis/SIRS and bacteremia (17.24 mg/dl | 6.30 ng/ml; p < 0.0001 vs. prior values), graft rejection (14.73 mg/dl | 3.20 ng/ml; p < 0.0001), and liver GvHD (6.88 mg/dl | 2.29 ng/ml; p < 0.01). Strong CRP increases and slight/minimal/no PCT increases occurred during fungemia (8.85 mg/dl | 0.72 ng/ml; p < 0.001), intestinal GvHD (8.73 mg/dl | 1.06 ng/ml; p < 0.0001), VOD (10.84 mg/dl | 0.59 ng/ml; p < 0.01), mucositis (8.84 mg/dl | 0.81 ng/ml; p < 0.0001), and viremia (3.62 mg/dl; p < 0.0001 | 0.43 ng/ml; below normal limit). During skin GvHD, CRP and PCT were slightly increased (2.03 mg/dl | 0.93 ng/ml; p < 0.0001). CONCLUSIONS: CRP and PCT did not show congruent changes during TRAE. PCT was a clinically relevant marker for the early detection and differentiation of severe mucositis and sepsis/SIRS and bacteremia during the critical neutropenic period after HSCT. PCT helped to discriminate acute intestinal GvHD from adenovirus viremia and liver GvHD from hepatic VOD. Thus, PCT may be a valuable parameter to enable a prompt and appropriate treatment during these complications, improving patient outcomes.

Leukemia reconstitution in vivo is driven by cells in early cell cycle and low metabolic state.

In contrast to well-established hierarchical concepts of tumor stem cells, leukemia-initiating cells in B-cell precursor acute lymphoblastic leukemia have not yet been phenotypically identified. Different subpopulations, as defined by surface markers, have shown equal abilities to reconstitute leukemia upon transplantation into immunodeficient mice. Using a non-obese diabetes/severe combined immunodeficiency human acute lymphoblastic leukemia mouse model and cell cycle analysis annotating cells to distinct cycle phases, we functionally characterized leukemia-initiating cells and found that cells in all stages of the cell cycle are able to reconstitute leukemia in vivo, with early cycling cells (G1blow population) exhibiting the highest leukemia-initiating potential. Interestingly, cells of the G2/M compartment, i.e. dividing cells, were less effective in leukemia reconstitution. Moreover, G1blow cells were more resistant to spontaneous or drug-induced cell death in vitro, were enriched for stem cell signatures and were less metabolically active, as determined by lower levels of reactive oxygen species, compared to G2/M stage cells. Our data provide new information on the biological properties of leukemia-initiating cells in B-cell precursor acute lymphoblastic leukemia and underline the concept of a stochastic model of leukemogenesis.

Immunotargeting relapsed or refractory precursor B-cell acute lymphoblastic leukemia - role of blinatumomab.

Patients with refractory or relapsed (R/R) acute lymphoblastic leukemia (ALL) have a dismal prognosis of around 5% long-term survival when treated with cytotoxic chemotherapy and allogenic stem cell transplantation. T-cell immunobased strategies open up new therapeutic perspectives. Blinatumomab is the first of a new class of antibody constructs that was labeled bispecific T-cell engager (BiTE): it consists of two single chain variable fragment connected with a flexible linker, one side binding CD3, the other CD19. The tight binding and the close proximity to the CD19-positive B-cells and leukemic cells leads to non-major histocompatibility complex-restricted T-cell activation, polyclonal T-cell expansion and direct target cell killing. Applied by continuous infusion, blinatumomab achieves morphological complete response rates ranging from 39% to 69% in R/R ALL patients (compared to 25% after second-line chemotherapy) with prolonged overall survival (blinatumomab median overall survival, 7.7 months vs chemotherapy, 4.0 months). In comparison to conventional cytotoxic second-line protocols blinatumomab has a favorable safety profile. The main adverse event is related to the mode of action of blinatumomab: the induction of a cytokine-release syndrome that can be managed by interruption and/or the application of steroids or tocilizumab. Another typical complication is the occurrence of neurological side effects, such as seizures and encephalopathy. This neurotoxicity is reversible after application of steroids and/or withdrawal of blinatumomab. Blinatumomab has proven to be a powerful therapeutic option in R/R ALL patients both adult and pediatric because of its efficacy and limited toxicity.

Neurotoxic side effects in children with refractory or relapsed T-cell malignancies treated with nelarabine based therapy.

The prognosis in children with refractory or relapsed (r/r) T-cell acute lymphoblastic leukaemia (T-ALL) or lymphoblastic lymphoma (T-LBL) is poor. Nelarabine (Ara-G) has successfully been used as salvage therapy in these children, but has been associated with significant, even fatal, neurotoxicities. We retrospectively analysed 52 patients with r/r T-ALL/T-LBL aged ≤19 years who were treated with Ara-G alone (n = 25) or in combination with cyclophosphamide and etoposide (n = 27). The majority of patients (45/52) received 1-2 cycles of Ara-G. Seventeen patients (32·7%) had refractory disease, 28 (53·8%) were in first relapse and 7 (13·5%) were in second relapse. A response to Ara-G was achieved in 20 patients and 15 (28·8%) were in remission at last follow-up. Twelve patients (23·1%) had neurotoxic adverse effects (neuro-AE) of any grade, of whom 7 (13·5%) developed neurotoxicity ≥ grade III. The most frequent neuro-AEs were peripheral motor neuropathy (19·2%), peripheral sensory neuropathy (11·5%) and seizures (9·6%). Three patients died of central neuro-AE after 1-2 cycles of combination therapy. Patients with neurotoxicity were significantly older (median 15·17 years) than those without (10·34 years, P = 0·017). No differences were observed between mono- and combination therapy concerning outcome and neuro-AE. The incidence of neuro-AE was not associated with concurrent intrathecal therapy or prior central nervous system irradiation.

Efficacy, safety and feasibility of antifungal prophylaxis with posaconazole tablet in paediatric patients after haematopoietic stem cell transplantation.

PURPOSE: Paediatric recipients of haematopoietic stem cell transplantation (HSCT) have a high risk for invasive fungal infections. Posaconazole oral suspension has proven to be effective in antifungal prophylaxis in adult and paediatric patients. A new posaconazole tablet formulation with absorption independent of the gastric conditions was approved by the FDA in 2013. This is the first report on the use of posaconazole tablets in paediatric patients. METHODS: This single-centre study included 63 paediatric patients with haemato-oncological malignancies who received posaconazole for antifungal prophylaxis after HSCT. They were analysed for efficacy, feasibility and the safety of posaconazole. Out of 63 patients, 31 received posaconazole oral suspension and 32 received posaconazole tablets up to 200 days after transplantation. Analyses of the posaconazole trough levels were determined. RESULTS: No possible, probable or proven invasive fungal infection was observed in either group. Posaconazole trough levels were significantly higher in the tablet group than in the suspension group at all analysed time points. Drug-related adverse events were similarly low in both groups. CONCLUSIONS: Posaconazole tablets are effective in preventing invasive fungal infections in paediatric patients. As early as day 3 after starting posaconazole tablets, over 50% of the posaconazole trough levels were >500 ng/mL, while this was observed on day 14 after start with posaconazole suspension. The administration of posaconazole tablets was safe, effective and feasible as antifungal prophylaxis in paediatric patients after HSCT.

Ferritin as an early marker of graft rejection after allogeneic hematopoietic stem cell transplantation in pediatric patients.

Diagnosis of adverse events following hematopoietic stem cell transplantation (HSCT) is mainly assigned to clinical symptoms or biopsies and thus rather unspecific and/or invasive. Studies indicate a distinct role of serum ferritin in HSCT and its correlation with adverse events such as graft-versus-host disease (GvHD), veno-occlusive disease (VOD), or infections. However, published data on the relevance of ferritin as a prognostic marker for post-transplant adverse events is rare, especially in pediatric patients. The present study analyzes ferritin plasma concentrations of 138 pediatric patients after HSCT between 2007 and 2010 including the control group (n = 21). Given the initial results regarding ferritin as a significant predictor for acute graft rejection after allogeneic HSCT in 9 of the 138 pediatric patients, serum ferritin of all pediatric patients (n = 27) who experienced graft rejection between 2007 and 2014 was analyzed. In addition, laboratory parameters including C-reactive protein (CRP), lactate dehydrogenase (LDH), fibrinogen, and D-dimer as possible differentiation markers for graft rejection were determined. In 24 (88.9 %) of the 27 pediatric patients with graft rejection, a significant increase of ferritin levels was observed 1 to 7 days prior to (P < 0.0001) and at the time of graft rejection (P < 0.0001). Moreover, there was an increase of D-dimer, CRP, LDH, and fibrinogen 1-7 days before graft rejection. Ferritin increased significantly at time of VOD (P = 0.0067), at time of intestinal (P < 0.0001) and skin GvHD (P < 0.0001), and at time of sepsis (P = 0.0005) and bacteremia (P = 0.0029). Ferritin might serve as a readily available identification marker for differentiation and identification of adverse events after HSCT in combination with other laboratory markers.