G. Yanik

Tacrolimus (FK506) and methotrexate as prophylaxis for acute graft-versus-host disease in pediatric allogeneic stem cell transplantation.

Currently, limited data exist on the role of tacrolimus (FK506) in pediatric allogeneic marrow transplantation. Forty-one patients who received tacrolimus as prophylaxis were reviewed, with a median age of 9 years (range 0.2–16 years). Twenty-one patients underwent related donor transplants and 20 underwent unrelated donor transplants. All patients received tacrolimus beginning the day prior to transplant at a dose of 0.03 mg/kg/day by continuous i.v. infusion. When clinically possible, patients were switched to oral therapy in two divided doses, at four times the intravenous dose. Tacrolimus levels were monitored twice a week, and dosages adjusted to maintain serum levels 5–15 ng/ml. Common adverse effects included hypomagnesemia (98%), hypertension (49%), nephrotoxicity (34%), and tremors (32%). Less common side-effects (<10% cases) included seizures and hyperglycemia. The median time to anc recovery (anc >500 × 106/l) was 15 days. For the related donor group, the incidence of grade II–IV acute GVHD was 33%, and grade III–IV GVHD 19%. For the unrelated donor group, the incidence of grade II–IV acute GVHD was 55%, and grade III–IV GVHD 30%. Overall, tacrolimus therapy was well tolerated as prophylaxis for acute GVHD in pediatric patients undergoing allogeneic transplantation. Bone Marrow Transplantation (2000) 26, 161–167.

Stem cell transplantation in patients with severe congenital neutropenia with evidence of leukemic transformation.

Summary:Severe congenital neutropenia (SCN) is a hematologic condition characterized by arrested maturation of myelopoiesis at the promyelocyte stage of development. With appropriate treatment using recombinant human granulocyte-colony-stimulating factor (r-HuG-CSF), SCN patients are now surviving longer, but are at increased risk of developing myelodysplastic syndrome (MDS)/acute myeloid leukemia (AML). Hematopoietic stem cell transplantation (HSCT) is the only curative option for these patients, but transplantation outcomes after malignant transformation are not well established. We report results for six patients with SCN who underwent HSCT for MDS or AML between 1997 and 2001 at two transplant centers. Two patients transplanted for MDS survived. Both of these patients were transplanted without being given induction chemotherapy. Four patients, who all received induction chemotherapy for AML prior to HSCT, died. Administering induction chemotherapy prior to HSCT resulted in significant morbidity. Rapid transplantation should be the goal for the SCN patient once the diagnosis of MDS/AML is established. SCN patients should be monitored carefully for progression to MDS in order to be treated with HSCT as soon as they have progressed and before developing AML. For SCN patients who progress to AML, HSCT should still be considered, even though the risks appear to be greater.

FDG PET imaging of childhood sarcomas.

Positron‐emission tomography (PET) imaging using [18F]fluorodeoxyglucose (FDG) is useful for detection, staging, and monitoring a variety of malignancies, including lymphoma, in adults, but its utility in sarcomas, especially soft tissue sarcomas (STS), in children and young adults is not clear.

Reduced intensity versus full myeloablative stem cell transplant for advanced CLL

CLL remains incurable with the standard therapy. Allogeneic hematopoietic stem cell transplant may be curative. We examined 50 patients with advanced CLL who underwent allogeneic HCT at the University of Michigan between 1996 and 2006. Twenty-one patients received reduced-intensity conditioning (RIC) and twenty-nine patients received full-intensity conditioning (FIC) consisting of CY, etoposide and BCNU (n=20) or BU and CY (n=9). RIC recipients were older than FIC recipients (median age 54 vs 51, P=0.009). There were no statistically significant differences between groups in terms of the number of earlier therapies or patients with adverse cytogenetics. There were more unrelated donors in the RIC group 62% than in the FIC group 31% (P=0.030). Despite their older age and greater use of URD, the 5-year overall survival (OS) rate was 63% in the RIC group as compared with 18% in the FIC group (P=0.006). The primary cause of inferior survival in the FIC recipients was TRM, which was twice as high at day 100 for the FIC group 27% compared with the RIC group 14% (P=0.005). The relapse rate was 15% regardless with the majority of relapses occurring after day 100. These results suggest a favorable outcome for advanced CLL who undergo a RIC regimen compared with FIC.

Evaluation of Norepinephrine Transporter Expression and Metaiodobenzylguanidine Avidity in Neuroblastoma: A Report from the Children's Oncology Group

Purpose. 123I-metaiodobenzylguanidine (MIBG) is used for the diagnostic evaluation of neuroblastoma. We evaluated the relationship between norepinephrine transporter (NET) expression and clinical MIBG uptake. Methods. Quantitative reverse transcription PCR (N = 82) and immunohistochemistry (IHC; N = 61) were performed for neuroblastoma NET mRNA and protein expression and correlated with MIBG avidity on diagnostic scans. The correlation of NET expression with clinical features was also performed. Results. Median NET mRNA expression level for the 19 MIBG avid patients was 12.9% (range 1.6–73.7%) versus 5.9% (range 0.6–110.0%) for the 8 nonavid patients (P = 0.31). Median percent NET protein expression was 50% (range 0–100%) in MIBG avid patients compared to 10% (range 0–80%) in nonavid patients (P = 0.027). MYCN amplified tumors had lower NET protein expression compared to nonamplified tumors (10% versus 50%; P = 0.0002). Conclusions. NET protein expression in neuroblastoma correlates with MIBG avidity. MYCN amplified tumors have lower NET protein expression.

FLT3 mutational status is an independent risk factor for adverse outcomes after allogeneic transplantation in AML.

Allogeneic hematopoietic cell transplantation (HCT) has been increasingly used in the setting of FMS-like tyrosine kinase-3 (FLT3)-mutated AML. However, its role in conferring durable relapse-free intervals remains in question. Herein we sought to investigate FLT3 mutational status on transplant outcomes. We conducted a retrospective cohort study of 262 consecutive AML patients who underwent first-time allogeneic HCT (2008–2014), of whom 171 had undergone FLT3-ITD (internal tandem duplication) mutational testing. FLT3-mutated AML was associated with nearly twice the relapse risk (RR) compared with those without FLT3 mutation 3 years post-HCT (63% vs 37%, P<0.001) and with a shorter median time to relapse (100 vs 121 days). FLT3 mutational status remained significantly associated with this outcome after controlling for patient, disease and transplant-related risk factors (P<0.05). Multivariate analysis showed a significant association of FLT3 mutation with increased 3-year RR (hazard ratio (HR) 3.63, 95% confidence interval (CI): 2.13, 6.19, P<0.001) and inferior disease-free survival (HR 2.05, 95% CI: 1.29, 3.27, P<0.01) and overall survival (HR 1.92, 95% CI: 1.14, 3.24, P<0.05). These data demonstrate high risk of early relapse after allogeneic HCT for FLT3-mutated AML that translates into adverse disease-free and overall survival outcomes. Additional targeted and coordinated interventions are needed to maintain durable remission after allogeneic HCT in this high-risk population.

Vorinostat plus tacrolimus/methotrexate to prevent GVHD after myeloablative conditioning, unrelated donor HCT

The oral histone deacetylase (HDAC) inhibitor (vorinostat) is safe and results in low incidence of acute graft-versus-host disease (GVHD) after reduced-intensity conditioning, related donor hematopoietic cell transplantation (HCT). However, its safety and efficacy in preventing acute GVHD in settings of heightened clinical risk that use myeloablative conditioning, unrelated donor (URD), and methotrexate are not known. We conducted a prospective, phase 2 study in this higher-risk setting. We enrolled 37 patients to provide 80% power to detect a significant difference in grade 2 to 4 acute GVHD of 50% compared with a reduction in target to 28%. Eligibility included adults with a hematological malignancy to receive myeloablative HCT from an available 8/8-HLA matched URD. Patients received GVHD prophylaxis with tacrolimus and methotrexate. Vorinostat (100 mg twice daily) was started on day -10 and continued through day +100 post-HCT. Median age was 56 years (range, 18-69 years), and 95% had acute myelogenous leukemia or high-risk myelodysplastic syndrome. Vorinostat was safe and tolerable. The cumulative incidence of grade 2 to 4 acute GVHD at day 100 was 22%, and for grade 3 to 4 it was 8%. The cumulative incidence of chronic GVHD was 29%; relapse, nonrelapse mortality, GVHD-free relapse-free survival, and overall survival at 1 year were 19%, 16%, 47%, and 76%, respectively. Correlative analyses showed enhanced histone (H3) acetylation in peripheral blood mononuclear cells and reduced interleukin 6 (P = .028) and GVHD biomarkers (Reg3, P = .041; ST2, P = .002) at day 30 post-HCT in vorinostat-treated subjects compared with similarly treated patients who did not receive vorinostat. Vorinostat for GVHD prevention is an effective strategy that should be confirmed in a randomized phase 3 study. This trial was registered at www.clinicaltrials.gov as #NCT01790568.

The use of laparoscopic liver biopsies in pediatric patients with hepatic dysfunction following allogeneic hematopoietic stem cell transplantation

Summary:Hepatic dysfunction following hematopoietic stem cell transplantation (HSCT) is common, but making the correct diagnosis can be challenging. Liver biopsies can serve as an important diagnostic tool when the etiology cannot be clearly determined by laboratory data, physical examination, and imaging studies. We reviewed 12 consecutive pediatric patients (seven males, five females, age 9–23 years) who received allogeneic HSCT and underwent a laparoscopic-guided liver biopsy for hepatic dysfunction of unknown etiology from 1998 to 2005. Biopsies were performed using a single-port technique with a 16 or 18 gauge, spring-loaded biopsy gun. The time from HSCT to biopsy ranged from 31 days to 821 days (median 92 days). No intra- or postoperative complications were observed. The initial clinical diagnosis was confirmed in seven patients, whereas the initial working diagnosis was inaccurate in the remaining five patients. Our results suggest that laparoscopic-guided liver biopsy is an informative and safe procedure in pediatric HSCT recipients; this approach helped delineate the true cause of hepatic dysfunction and changed our therapeutic approach in approximately 40% of the patients reviewed. While the safety record at our institution appears promising, a larger multi-institutional study would be necessary to more accurately describe the overall efficacy of this procedure in pediatric HSCT patients.

Analytic morphomics: A novel CT imaging approach to quantify adipose tissue and muscle composition in allogeneic hematopoietic cell transplantation

Analytic morphomics is a novel methodology that uses high-throughput computed tomography (CT) processing techniques to generate reproducible body measurements (Supplementary Table).1, 2, 3, 4 Body mass index is widely used in clinical and public health studies to predict mortality risk.5 Indeed, we recently examined its impact in allogeneic hematopoietic cell transplantation (HCT) and found that obese patients were at significantly greater risk of mortality compared with normal weight individuals.6 Unfortunately, body mass index does not reliably distinguish adipose tissue mass from muscle mass.7 Therefore, we sought to index patient size using CT measurements.2 The aim of the current study was to apply analytic morphomics in a cohort of allogeneic HCT patients and correlate with clinical outcomes.

Pulmonary Metagenomic Sequencing Suggests Missed Infections in Immunocompromised Children

Abstract Background Despite improved diagnostics, pulmonary pathogens in immunocompromised children frequently evade detection, leading to significant mortality. Therefore, we aimed to develop a highly sensitive metagenomic next-generation sequencing (mNGS) assay capable of evaluating the pulmonary microbiome and identifying diverse pathogens in the lungs of immunocompromised children. Methods We collected 41 lower respiratory specimens from 34 immunocompromised children undergoing evaluation for pulmonary disease at 3 children’s hospitals from 2014–2016. Samples underwent mechanical homogenization, parallel RNA/DNA extraction, and metagenomic sequencing. Sequencing reads were aligned to the National Center for Biotechnology Information nucleotide reference database to determine taxonomic identities. Statistical outliers were determined based on abundance within each sample and relative to other samples in the cohort. Results We identified a rich cross-domain pulmonary microbiome that contained bacteria, fungi, RNA viruses, and DNA viruses in each patient. Potentially pathogenic bacteria were ubiquitous among samples but could be distinguished as possible causes of disease by parsing for outlier organisms. Samples with bacterial outliers had significantly depressed alpha-diversity (median, 0.61; interquartile range [IQR], 0.33–0.72 vs median, 0.96; IQR, 0.94–0.96; P < .001). Potential pathogens were detected in half of samples previously negative by clinical diagnostics, demonstrating increased sensitivity for missed pulmonary pathogens (P < .001). Conclusions An optimized mNGS assay for pulmonary microbes demonstrates significant inoculation of the lower airways of immunocompromised children with diverse bacteria, fungi, and viruses. Potential pathogens can be identified based on absolute and relative abundance. Ongoing investigation is needed to determine the pathogenic significance of outlier microbes in the lungs of immunocompromised children with pulmonary disease.