Tisagenlecleucel in Children and Young Adults with B-Cell Lymphoblastic Leukemia

BACKGROUND

In a single-center phase 1-2a study, the anti-CD19 chimeric antigen receptor (CAR) T-cell therapy tisagenlecleucel produced high rates of complete remission and was associated with serious but mainly reversible toxic effects in children and young adults with relapsed or refractory B-cell acute lymphoblastic leukemia (ALL).

METHODS

We conducted a phase 2, single-cohort, 25-center, global study of tisagenlecleucel in pediatric and young adult patients with CD19+ relapsed or refractory B-cell ALL. The primary end point was the overall remission rate (the rate of complete remission or complete remission with incomplete hematologic recovery) within 3 months.

RESULTS

For this planned analysis, 75 patients received an infusion of tisagenlecleucel and could be evaluated for efficacy. The overall remission rate within 3 months was 81%, with all patients who had a response to treatment found to be negative for minimal residual disease, as assessed by means of flow cytometry. The rates of event-free survival and overall survival were 73% (95% confidence interval [CI], 60 to 82) and 90% (95% CI, 81 to 95), respectively, at 6 months and 50% (95% CI, 35 to 64) and 76% (95% CI, 63 to 86) at 12 months. The median duration of remission was not reached. Persistence of tisagenlecleucel in the blood was observed for as long as 20 months. Grade 3 or 4 adverse events that were suspected to be related to tisagenlecleucel occurred in 73% of patients. The cytokine release syndrome occurred in 77% of patients, 48% of whom received tocilizumab. Neurologic events occurred in 40% of patients and were managed with supportive care, and no cerebral edema was reported.

CONCLUSIONS

In this global study of CAR T-cell therapy, a single infusion of tisagenlecleucel provided durable remission with long-term persistence in pediatric and young adult patients with relapsed or refractory B-cell ALL, with transient high-grade toxic effects. (Funded by Novartis Pharmaceuticals; ClinicalTrials.gov number, NCT02435849 .).

Transcription of class III genes: formation of preinitiation complexes

Class III genes require multiple cellular factors for transcription by RNA polymerase III; these genes form stable transcription complexes, which in the case of Xenopus 5S genes are correlated with differential expression in vivo. The minimal number and identity of the factors required to form both stable and metastable complexes on three class III genes (encoding, respectively, 5S RNA, transfer RNA, and adenovirus VA RNA species) were determined. Stable complex formation requires one common factor, whose recognition site was analyzed, and either no additional factors (the VA gene), a second common factor (the transfer RNA gene), or a third gene-specific factor (the 5S gene). The mechanism of stable complex formation and its relevance to transcriptional regulation were examined in light of the various factors and the promoter sequences recognized by these factors.

Cord-blood transplants from unrelated donors in patients with Hurler's syndrome

BACKGROUND

Hurler's syndrome (the most severe form of mucopolysaccharidosis type I) causes progressive deterioration of the central nervous system and death in childhood. Allogeneic bone marrow transplantation before the age of two years halts disease progression and prolongs life, but many children lack a bone marrow donor. We investigated the feasibility of using cord-blood transplants from unrelated donors and a myeloablative preparative regimen that did not involve total-body irradiation in young children with Hurler's syndrome.

METHODS

Between December 1995 and October 2002, 20 consecutive children with Hurler's syndrome received busulfan, cyclophosphamide, and antithymocyte globulin before receiving cord-blood transplants from unrelated donors. The children were subsequently evaluated for engraftment, adverse effects, and effects on disease symptoms.

RESULTS

Cord-blood donors had normal alpha-L-iduronidase activity (mean number of cells, 10.53x10(7) per kilogram of body weight) and were discordant for up to three of six HLA markers. Neutrophil engraftment occurred a median of 24 days after transplantation. Five patients had grade II or grade III acute graft-versus-host disease; none had extensive chronic graft-versus-host disease. Seventeen of the 20 children were alive a median of 905 days after transplantation, with complete donor chimerism and normal peripheral-blood alpha-L-iduronidase activity (event-free survival rate, 85 percent). Transplantation improved neurocognitive performance and decreased somatic features of Hurler's syndrome.

CONCLUSIONS

Cord blood from unrelated donors appears to be an excellent source of stem cells for transplantation in patients with Hurler's syndrome. Sustained engraftment can be achieved without total-body irradiation. Cord-blood transplantation favorably altered the natural history of Hurler's syndrome and thus may be important to consider in young children with this form of the disease.

Real-world evidence of tisagenlecleucel for pediatric acute lymphoblastic leukemia and non-Hodgkin lymphoma

Tisagenlecleucel is a CD19 chimeric antigen receptor (CAR) T-cell therapy approved for treatment of pediatric and young adult patients with relapsed/refractory acute lymphoblastic leukemia (ALL) and adults with non-Hodgkin lymphoma (NHL). The initial experience with tisagenlecleucel in a real-world setting from a cellular therapy registry is presented here. As of January 2020, 511 patients were enrolled from 73 centers, and 410 patients had follow-up data reported (ALL, n = 255; NHL, n = 155), with a median follow-up of 13.4 and 11.9 months for ALL and NHL, respectively. Among patients with ALL, the initial complete remission (CR) rate was 85.5%. Twelve-month duration of response (DOR), event-free survival, and overall survival (OS) rates were 60.9%, 52.4%, and 77.2%, respectively. Among adults with NHL, the best overall response rate was 61.8%, including an initial CR rate of 39.5%. Six-month DOR, progression-free survival, and OS rates were 55.3%, 38.7%, and 70.7%, respectively. Grade ≥3 cytokine release syndrome and neurotoxicity were reported in 11.6% and 7.5% of all patients, respectively. Similar outcomes were observed in patients with in-specification and out-of-specification products as a result of viability <80% (range, 61% to 79%). This first report of tisagenlecleucel in the real-world setting demonstrates outcomes with similar efficacy and improved safety compared with those seen in the pivotal trials.

Multi-institutional use of defibrotide in 88 patients after stem cell transplantation with severe veno-occlusive disease and multisystem organ failure: response without significant toxicity in a high-risk population and factors predictive of outcome

Veno-occlusive disease (VOD) is the most common regimen-related toxicity accompanying stem cell transplantation (SCT). Severe VOD complicated by multisystem organ failure (MOF) remains almost uniformly fatal. Preliminary experience with defibrotide (DF), a single-stranded polydeoxyribonucleotide with fibrinolytic, antithrombotic, and anti-ischemic properties, in the treatment for severe VOD has suggested safety and activity. Eighty-eight patients who developed severe VOD after SCT were treated with DF under a defined treatment plan. At diagnosis, median bilirubin was 76.95 microM (4.5 mg/dL), median weight gain was 7%, ascites was present in 84%, and abnormal hepatic portal venous flow was present in 35%. At DF initiation, median bilirubin had increased to 215.46 microM (12.6 mg/dL), and MOF was present in 97%. DF was administered intravenously in doses ranging from 5 to 60 mg/kg per day for a median of 15 days. No severe hemorrhage or other serious toxicity related to DF was reported. Complete resolution of VOD was seen in 36%, with 35% survival at day +100. Predictors of survival included younger age, autologous SCT, and abnormal portal flow, whereas busulfan-based conditioning and encephalopathy predicted worse outcome. Decreases in mean creatinine and plasminogen activator inhibitor 1(PAI-1) levels during DF therapy predicted better survival. The complete response rate, survival to day +100, and absence of significant DF-associated toxicity in this largest patient cohort reported to date confirm the results of earlier studies. Certain features associated with successful outcome may correlate with DF-related treatment effects, and prospective evaluation of DF therapy for severe VOD should allow better definition of predictors of response or failure.

Augmentation of umbilical cord blood (UCB) transplantation with ex vivo-expanded UCB cells: results of a phase 1 trial using the AastromReplicell System

Allogeneic stem cell transplantation with umbilical cord blood (UCB) cells is limited by the cell dose a single unit provides recipients. Ex vivo expansion is one strategy to increase the number of cells available for transplantation. Aastrom Biosciences developed an automated continuous perfusion culture device for expansion of hematopoietic stem cells (HSCs). Cells are expanded in media supplemented with fetal bovine serum, horse serum, PIXY321, flt-3 ligand, and erythropoietin. We performed a phase 1 trial augmenting conventional UCB transplants with ex vivo-expanded cells. The 28 patients were enrolled on the trial between October 8, 1997 and September 30, 1998. UCB cells were expanded in the device, then administered as a boost to the conventional graft on posttransplantation day 12. While expansion of total cells and colony-forming units (CFUs) occurred in all cases, the magnitude of expansion varied considerably. The median fold increase was 2.4 (range, 1.0-8.5) in nucleated cells, 82 (range, 4.6-266.4) in CFU granulocyte-macrophages, and 0.5 (range, 0.09-2.45) in CD34+ lineage negative (lin-) cells. CD3+ cells did not expand under these conditions. Clinical-scale ex vivo expansion of UCB is feasible, and the administration of ex vivo-expanded cells is well tolerated. Augmentation of UCB transplants with ex vivo-expanded cells did not alter the time to myeloid, erythroid, or platelet engraftment in 21 evaluable patients. Recipients of ex vivo-expanded cells continue to have durable engraftment with a median follow-up of 47 months (range, 41-51 months). A randomized phase 2 study will determine whether augmenting UCB transplants with ex vivo-expanded UCB cells is beneficial.

Phase 3 trial of defibrotide for the treatment of severe veno-occlusive disease and multi-organ failure

Hepatic veno-occlusive disease (VOD), also called sinusoidal obstruction syndrome (SOS), is a potentially life-threatening complication of hematopoietic stem cell transplantation (HSCT). Untreated hepatic VOD/SOS with multi-organ failure (MOF) is associated with >80% mortality. Defibrotide has shown promising efficacy treating hepatic VOD/SOS with MOF in phase 2 studies. This phase 3 study investigated safety and efficacy of defibrotide in patients with established hepatic VOD/SOS and advanced MOF. Patients (n = 102) given defibrotide 25 mg/kg per day were compared with 32 historical controls identified out of 6867 medical charts of HSCT patients by blinded independent reviewers. Baseline characteristics between groups were well balanced. The primary endpoint was survival at day +100 post-HSCT; observed rates equaled 38.2% in the defibrotide group and 25% in the controls (23% estimated difference; 95.1% confidence interval [CI], 5.2-40.8;P= .0109, using a propensity-adjusted analysis). Observed day +100 complete response (CR) rates equaled 25.5% for defibrotide and 12.5% for controls (19% difference using similar methodology; 95.1% CI, 3.5-34.6;P= .0160). Defibrotide was generally well tolerated with manageable toxicity. Related adverse events (AEs) included hemorrhage or hypotension; incidence of common hemorrhagic AEs (including pulmonary alveolar [11.8% and 15.6%] and gastrointestinal bleeding [7.8% and 9.4%]) was similar between the defibrotide and control groups, respectively. Defibrotide was associated with significant improvement in day +100 survival and CR rate. The historical-control methodology offers a novel, meaningful approach for phase 3 evaluation of orphan diseases associated with high mortality. This trial was registered at www.clinicaltrials.gov as #.

Formation of a rate-limiting intermediate in 5S RNA gene transcription

We have performed in vitro kinetic analyses of transcription from the 5S gene promoter in order to resolve the rate-limiting events which lead to accurate transcription of the 5S RNA gene. We demonstrate that a rate-limiting intermediate can be formed during an extended incubation prior to initiation of transcription. Formation of such a complex is temperature-dependent, requires magnesium and ATP, consists of stoichiometric amounts of the known class III transcription factors and RNA polymerase III on 5S DNA, and eliminates the normal lag in attainment of a steady-state rate of transcription. This complex is therefore different from the "stable complex" minimally required for template commitment. Further analyses demonstrate that TFIIIB, like TFIIIA and TFIIIC, can be stably sequestered on the 5S gene and also allow us to formulate the following order of factor interactions on the 5S gene: TFIIIA, TFIIIC, TFIIIB, RNA polymerase III.

Defibrotide for the treatment of severe hepatic veno-occlusive disease and multiorgan failure after stem cell transplantation: a multicenter, randomized, dose-finding trial

Therapeutic options for severe hepatic veno-occlusive disease (VOD) are limited and outcomes are dismal, but early phase I/II studies have suggested promising activity and acceptable toxicity using the novel polydisperse oligonucleotide defibrotide. This randomized phase II dose-finding trial determined the efficacy of defibrotide in patients with severe VOD following hematopoietic stem cell transplantation (HSCT) and identified an appropriate dose for future trials. Adult and pediatric patients received either lower-dose (arm A: 25 mg/kg/day; n = 75) or higher-dose (arm B: 40 mg/kg/day; n = 74) i.v. defibrotide administered in divided doses every 6 hours for > or =14 days or until complete response, VOD progression, or any unacceptable toxicity occurred. Overall complete response and day +100 post-HSCT survival rates were 46% and 42%, respectively, with no significant difference between treatment arms. The incidence of treatment-related adverse events was low (8% overall; 7% in arm A, 10% in arm B); there was no significant difference in the overall rate of adverse events between treatment arms. Early stabilization or decreased bilirubin was associated with better response and day +100 survival, and decreased plasminogen activator inhibitor type 1 (PAI-1) during treatment was associated with better outcome; changes were similar in both treatment arms. Defibrotide 25 or 40 mg/kg/day also appears effective in treating severe VOD following HSCT. In the absence of any differences in activity, toxicity or changes in PAI-1 level, defibrotide 25 mg/kg/day was selected for ongoing phase III trials in VOD.

Human herpesvirus 6 limbic encephalitis after stem cell transplantation

Central nervous system complications are common in stem cell transplant recipients, but selective involvement of the medial temporal area is unusual. The 5 patients reported here presented after stem cell transplantation with increased hippocampal T2 signal on magnetic resonance imaging and increased hippocampal glucose uptake on [F-18]fluorodeoxyglucose-positron emission tomography (FDG-PET) associated with short-term memory loss, insomnia, and temporal lobe electrographic seizure activity. The initial scalp electroencephalograms (EEGs) failed to detect seizure activity in these patients, although the memory dysfunction along with the magnetic resonance imaging and FDG-PET findings suggested subcortical seizure activity. However, extended EEG monitoring revealed repetitive temporal lobe electrographic seizure activity. Follow-up MRIs in 2 patients and postmortem findings on 1 patient suggested that hippocampal sclerosis had developed following the clinical syndrome. Cerebrospinal fluid studies revealed the presence of human herpesvirus 6, variant B, DNA in all of 3 patients who had lumbar punctures. Immunohistochemical staining for the P41 and P101 human herpesvirus 6 protein antigens showed numerous immunoreactive astrocytes and neurons in the hippocampus of 1 of the patients who died from other causes. Because of its subtle clinical presentation, this syndrome may be underrecognized, but can be diagnosed with appropriate magnetic resonance imaging techniques, EEG monitoring, and cerebrospinal fluid viral studies.

Unrelated donor umbilical cord blood transplantation for inherited metabolic disorders in 159 pediatric patients from a single center: influence of cellular composition of the graft on transplantation outcomes

Outcomes of 159 young patients with inherited metabolic disorders (IMDs) undergoing transplantation with partially HLA-mismatched unrelated donor umbilical cord blood were studied to investigate the impact of graft and patient characteristics on engraftment, overall survival (OS), and graft-versus-host disease (GVHD). Patients received myeloablative chemotherapy (busulfan, cyclophosphamide, ATG) and cyclosporine-based GVHD prophylaxis. Infused cell doses were high (7.57 x 10(7)/kg) because of the patients' young age (median, 1.5 years) and small size (median, 12 kg). Median follow-up was 4.2 years (range, 1-11 years). The cumulative incidences of neutrophil and platelet engraftment were 87.1% (95% confidence interval [CI], 81.8%-92.4%) and 71.0% (95% CI, 63.7%-78.3%). A total of 97% achieved high (> 90%) donor chimerism. Serum enzyme normalized in 97% of patients with diseases for which testings exist. Grade III/IV acute GVHD occurred in 10.3% (95% CI, 5.4%-15.2%) of patients. Extensive chronic GVHD occurred in 10.8% (95% CI, 5.7%-15.9%) of patients by 1 year. OS at 1 and 5 years was 71.8% (95% CI, 64.7%-78.9%) and 58.2% (95% CI, 49.7%-66.6%) in all patients and 84.5% (95% CI, 77.0%-92.0%) and 75.7% (95% CI, 66.1%-85.3%) in patients with high (80-100) performance score. In multivariate analysis, favorable factors for OS were high pretransplantation performance status, matched donor/recipient ethnicity, and higher infused colony forming units.

Novel susceptibility variants at 10p12.31-12.2 for childhood acute lymphoblastic leukemia in ethnically diverse populations

BACKGROUND

Acute lymphoblastic leukemia (ALL) is the most common cancer in children and the incidence of ALL varies by ethnicity. Although accumulating evidence indicates inherited predisposition to ALL, the genetic basis of ALL susceptibility in diverse ancestry has not been comprehensively examined.

METHODS

We performed a multiethnic genome-wide association study in 1605 children with ALL and 6661 control subjects after adjusting for population structure, with validation in three replication series of 845 case subjects and 4316 control subjects. Association was tested by two-sided logistic regression.

RESULTS

A novel ALL susceptibility locus at 10p12.31-12.2 (BMI1-PIP4K2A, rs7088318, P = 1.1 × 10(-11)) was identified in the genome-wide association study, with independent replication in European Americans, African Americans, and Hispanic Americans (P = .001, .009, and .04, respectively). Association was also validated at four known ALL susceptibility loci: ARID5B, IKZF1, CEBPE, and CDKN2A/2B. Associations at ARID5B, IKZF1, and BMI1-PIP4K2A variants were consistent across ethnicity, with multiple independent signals at IKZF1 and BMI1-PIP4K2A loci. The frequency of ARID5B and BMI1-PIP4K2A variants differed by ethnicity, in parallel with ethnic differences in ALL incidence. Suggestive evidence for modifying effects of age on genetic predisposition to ALL was also observed. ARID5B, IKZF1, CEBPE, and BMI1-PIP4K2A variants cumulatively conferred strong predisposition to ALL, with children carrying six to eight copies of risk alleles at a ninefold (95% confidence interval = 6.9 to 11.8) higher ALL risk relative to those carrying zero to one risk allele at these four single nucleotide polymorphisms.

CONCLUSIONS

These findings indicate strong associations between inherited genetic variation and ALL susceptibility in children and shed new light on ALL molecular etiology in diverse ancestry.

Estrogen therapy arrests bone loss in elderly women

Although osteoporosis is an age-related disorder, the accelerated bone loss observed in postmenopausal women may be preventable with early diagnosis and adequate estrogen replacement. In a prospective study, we investigated the effect of oral estrogen replacement using conjugated estrogens (Premarin, 0.625 mg) or micronized 17 beta-estradiol (Estrace, 1 mg) versus no estrogen in sequential single-photon bone density measurements over 3-year intervals in 397 postmenopausal women. Estradiol, 1 mg, and conjugated estrogens, 0.625 mg, were equally effective in regarding bone loss. The rate of bone loss was about the same for estrogen users regardless of age (51 to 80 years) and was approximately one third that of nonusers. Among nonusers a uniform accelerated rate of bone loss of 2.5% per year was noted between 56 and 70 years old, whereas between the ages of 51 and 55 years and after age 70 years, the rate of bone loss was significantly less. Ever users over age 65 years showed continued protection from bone loss as long as estrogen therapy was continued. Previous estrogen users who stopped estrogen after age 65 years lost bone more rapidly than women of similar age who had never taken estrogen. Thus to prevent accelerated bone loss in postmenopausal women, we recommend early and continued hormone replacement for life. Estrogen nonusers should be monitored at regular intervals to minimize accelerated bone loss.

Results of the Cord Blood Transplantation Study (COBLT): Outcomes of Unrelated Donor Umbilical Cord Blood Transplantation in Pediatric Patients with Lysosomal and Peroxisomal Storage Diseases

The Cord Blood Transplantation Study (COBLT), sponsored by the National Heart, Lung, and Blood Institute, is a phase II multicenter study designed to evaluate the use of cord blood in allogeneic transplantation. In this report, we evaluated the outcomes of cord blood transplantation in 69 patients with lysosomal and peroxisomal storage diseases. Patients with mucopolysaccharidoses I to III, mucolipidoses (ML) II (n = 36), adrenoleukodystrophy (n = 8), metachromatic leukodystrophy (n = 6), Krabbe disease (n = 16), and Tay-Sachs disease (n = 3) were enrolled between August 1999 and June 2004. All patients received the same preparative regimen, graft-versus-host disease (GVHD) prophylaxis, and supportive care. End points included survival, engraftment, GVHD, and toxicity. Sixty-nine patients (64% men; 81% white) with a median age of 1.8 years underwent transplantation with a median cell dose of 8.7 x 10(7)/kg. One-year survival was 72% (95% confidence interval, 61%-83%). The cumulative incidence of neutrophil engraftment by day 42 was 78% (95% confidence interval, 67%-87%) at a median of 25 days. Grade II to IV acute GVHD occurred in 36% of patients. Cord blood donors are readily available for rapid transplantation. Cord blood transplantation should be considered as frontline therapy for young patients with lysosomal and peroxisomal storage diseases.

Management guidelines for paediatric patients receiving chimeric antigen receptor T cell therapy

In 2017, an autologous chimeric antigen receptor (CAR) T cell therapy indicated for children and young adults with relapsed and/or refractory CD19+ acute lymphoblastic leukaemia became the first gene therapy to be approved in the USA. This innovative form of cellular immunotherapy has been associated with remarkable response rates but is also associated with unique and often severe toxicities, which can lead to rapid cardiorespiratory and/or neurological deterioration. Multidisciplinary medical vigilance and the requisite health-care infrastructure are imperative to ensuring optimal patient outcomes, especially as these therapies transition from research protocols to standard care. Herein, authors representing the Pediatric Acute Lung Injury and Sepsis Investigators (PALISI) Network Hematopoietic Stem Cell Transplantation (HSCT) Subgroup and the MD Anderson Cancer Center CAR T Cell Therapy-Associated Toxicity (CARTOX) Program have collaborated to provide comprehensive consensus guidelines on the care of children receiving CAR T cell therapy.

Three-Year Update of Tisagenlecleucel in Pediatric and Young Adult Patients With Relapsed/Refractory Acute Lymphoblastic Leukemia in the ELIANA Trial

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.In the primary analysis of the global phase II ELIANA trial (ClinicalTrials.gov identifier: NCT02435849), tisagenlecleucel provided an overall remission rate of 81% in pediatric and young adult patients with relapsed or refractory B-cell acute lymphoblastic leukemia (R/R B-ALL), with 59% of responders remaining relapse-free at 12 months. Here, we report an update on efficacy, safety, and patient-reported quality of life in 79 pediatric and young adult patients with R/R B-ALL following a median follow-up of 38.8 months. The overall remission rate was 82%. The median event-free survival was 24 months, and the median overall survival was not reached. Event-free survival was 44% (95% CI, 31 to 57) and overall survival was 63% (95% CI, 51 to 73) at 3 years overall (most events occur within the first 2 years). The estimated 3-year relapse-free survival with and without censoring for subsequent therapy was 52% (95% CI, 37 to 66) and 48% (95% CI, 34 to 60), respectively. No new or unexpected long-term adverse events were reported. Grade 3/4 adverse events were reported in 29% of patients > 1 year after infusion; grade 3/4 infection rate did not increase > 1 year after infusion. Patients reported improvements in quality of life up to 36 months after infusion. These findings demonstrate favorable long-term safety and suggest tisagenlecleucel as a curative treatment option for heavily pretreated pediatric and young adult patients with R/R B-ALL.

Germline Genetic IKZF1 Variation and Predisposition to Childhood Acute Lymphoblastic Leukemia

Somatic genetic alterations of IKZF1, which encodes the lymphoid transcription factor IKAROS, are common in high-risk B-progenitor acute lymphoblastic leukemia (ALL) and are associated with poor prognosis. Such alterations result in the acquisition of stem cell-like features, overexpression of adhesion molecules causing aberrant cell-cell and cell-stroma interaction, and decreased sensitivity to tyrosine kinase inhibitors. Here we report coding germline IKZF1 variation in familial childhood ALL and 0.9% of presumed sporadic B-ALL, identifying 28 unique variants in 45 children. The majority of variants adversely affected IKZF1 function and drug responsiveness of leukemic cells. These results identify IKZF1 as a leukemia predisposition gene, and emphasize the importance of germline genetic variation in the development of both familial and sporadic ALL.

ARID5B genetic polymorphisms contribute to racial disparities in the incidence and treatment outcome of childhood acute lymphoblastic leukemia

PURPOSE

Recent genome-wide screens have identified genetic variations in ARID5B associated with susceptibility to childhood acute lymphoblastic leukemia (ALL). We sought to determine the contribution of ARID5B single nucleotide polymorphisms (SNPs) to racial disparities in ALL susceptibility and treatment outcome.

PATIENTS AND METHODS

We compared the association between ARID5B SNP genotype and ALL susceptibility in whites (> 95% European genetic ancestry; 978 cases and 1,046 controls) versus in Hispanics (> 10% Native American ancestry; 330 cases and 541 controls). We determined the relationships between ARID5B SNP genotype and ALL relapse risk in 1,605 children treated on the Children's Oncology Group (COG) P9904/9905 clinical trials.

RESULTS

Among 49 ARID5B SNPs interrogated, 10 were significantly associated with ALL susceptibility in both whites and Hispanics (P < .05), with risk alleles consistently more frequent in Hispanics than in whites. rs10821936 exhibited the most significant association in both races (P = 8.4 × 10(-20) in whites; P = 1 × 10(-6) in Hispanics), and genotype at this SNP was highly correlated with local Native American genetic ancestry (P = 1.8 × 10(-8)). Multivariate analyses in Hispanics identified an additional SNP associated with ALL susceptibility independent of rs10821936. Eight ARID5B SNPs were associated with both ALL susceptibility and relapse hazard; the alleles related to higher ALL incidence were always linked to poorer treatment outcome and were more frequent in Hispanics.

CONCLUSION

ARID5B polymorphisms are important determinants of childhood ALL susceptibility and treatment outcome, and they contribute to racial disparities in this disease.

Germline genetic variation in ETV6 and risk of childhood acute lymphoblastic leukaemia: a systematic genetic study

BACKGROUND

Hereditary predisposition is rarely suspected for childhood acute lymphoblastic leukaemia (ALL). Recent reports of germline ETV6 variations associated with substantial familial clustering of haematological malignancies indicated that this gene is a potentially important genetic determinant for ALL susceptibility. Our aims in this study were to comprehensively identify ALL predisposition variants in ETV6 and to determine the extent to which they contributed to the overall risk of childhood ALL.

METHODS

Whole-exome sequencing of an index family with several cases of ALL was done to identify causal variants for ALL predisposition. Targeted sequencing of ETV6 was done in children from the Children's Oncology Group and St Jude Children's Research Hospital front-line ALL trials. Patients were included in this study on the basis of their enrolment in these clinical trials and the availability of germline DNA. ETV6 variant genotypes were compared with non-ALL controls to define ALL-related germline risk variants. ETV6 variant function was characterised bioinformatically and correlated with clinical and demographic features in children with ALL.

FINDINGS

We identified a novel non-sense ETV6 variant (p.Arg359X) with a high penetrance in an index family. Subsequent targeted sequencing of ETV6 in 4405 childhood ALL cases identified 31 exonic variants (four non-sense, 21 missense, one splice site, and five frameshift variants) that were potentially related to ALL risk in 35 cases (1%). 15 (48%) of 31 ALL-related ETV6 variants clustered in the erythroblast transformation specific domain and were predicted to be highly deleterious. Children with ALL-related ETV6 variants were significantly older at leukaemia diagnosis than those without (10·2 years [IQR 5·3-13·8] vs 4·7 years [3·0-8·7]; p=0·017). The hyperdiploid leukaemia karyotype was highly over-represented in ALL cases harbouring germline ETV6 risk variants compared with the wild-type group (nine [64%] of 14 cases vs 538 [27%] of 2007 cases; p=0·0050).

INTERPRETATION

Our findings indicated germline ETV6 variations as the basis of a novel genetic syndrome associated with predisposition to childhood ALL. The development of recommendations for clinical interventions and surveillance for individuals harbouring ALL-related ETV6 variants are needed.

FUNDING

US National Institutes of Health and American Lebanese Syrian Associated Charities.

Circulating estradiol, estrone and gonadotropin levels following the administration of orally active 17beta-estradiol in postmenopausal women

Ingestion of a single tablet containing 2 mg micronized 17beta-estradiol (E-2) produced marked increases in the serum concentrations of E-2 and estrone (E-1) in 9 postmenopausal women. The rise in circulating E-2 became significant within 2 h, reached a maximum (110 pg/ML; 437% increase) at 5 h, and remained significantly elevated at 8 h posttreatment. By 24 h, the serum E-2 concentration was not significantly different than baseline. In contrast, a more rapid (within 1 h) and pronounced (4-fold) increase in the serum concentration of E-1 was observed. This rise continued until a peak (467 pg/ml; 2000%) was reached 6 h posttreatment. Thereafter, the serum E-1 concentration declined progressively but was still significantly elevated (140 pg/ml; P smaller than 0.01) 24 h after treatment. Serum concentrations of FSH AND LH were significantly decreased within 6 and 3 h, respectively and both gonadotropins remained significantly suppressed 24 h following the ingestion of E-2. The ratios of circulating E-1: E-2 reported herein (ca. 3-6) were much higher than those observed by other investigators following iv E-2 (I.E., smaller than 1). Thus the data indicate that micronized E-2 peros is readily absorbed and that during this process a significant portion of the hormone is converted to E-1 by the gstrointestinal tract. In addition, 2 mg oral E-2 exerts significant biologic activity as assessed by serum gonadotropin suppression.

TP53 Germline Variations Influence the Predisposition and Prognosis of B-Cell Acute Lymphoblastic Leukemia in Children

Purpose Germline TP53 variation is the genetic basis of Li-Fraumeni syndrome, a highly penetrant cancer predisposition condition. Recent reports of germline TP53 variants in childhood hypodiploid acute lymphoblastic leukemia (ALL) suggest that this type of leukemia is another manifestation of Li-Fraumeni syndrome; however, the pattern, prevalence, and clinical relevance of TP53 variants in childhood ALL remain unknown. Patients and Methods Targeted sequencing of TP53 coding regions was performed in 3,801 children from the Children's Oncology Group frontline ALL clinical trials, AALL0232 and P9900. TP53 variant pathogenicity was evaluated according to experimentally determined transcriptional activity, in silico prediction of damaging effects, and prevalence in non-ALL control populations. TP53 variants were analyzed for their association with ALL presenting features and treatment outcomes. Results We identified 49 unique nonsilent rare TP53 coding variants in 77 (2.0%) of 3,801 patients sequenced, of which 22 variants were classified as pathogenic. TP53 pathogenic variants were significantly over-represented in ALL compared with non-ALL controls (odds ratio, 5.2; P < .001). Children with TP53 pathogenic variants were significantly older at ALL diagnosis (median age, 15.5 years v 7.3 years; P < .001) and were more likely to have hypodiploid ALL (65.4% v 1.2%; P < .001). Carrying germline TP53 pathogenic variants was associated with inferior event-free survival and overall survival (hazard ratio, 4.2 and 3.9; P < .001 and .001, respectively). In particular, children with TP53 pathogenic variants were at a dramatically higher risk of second cancers than those without pathogenic variants, with 5-year cumulative incidence of 25.1% and 0.7% ( P < .001), respectively. Conclusion Loss-of-function germline TP53 variants predispose children to ALL and to adverse treatment outcomes with ALL therapy, particularly the risk of second malignant neoplasms.

Marrow cell transplantation for infantile hypophosphatasia

An 8-month-old girl who seemed certain to die from the infantile form of hypophosphatasia, an inborn error of metabolism characterized by deficient activity of the tissue-nonspecific isoenzyme of alkaline phosphatase (TNSALP), underwent the first trial of bone marrow cell transplantation for this heritable type of rickets. After cytoreduction, she was given T-cell-depleted, haplo-identical marrow from her healthy sister. Chimerism in peripheral blood and bone marrow became 100% donor. Three months later, she was clinically improved, with considerable healing of rickets and generalized skeletal remineralization. However, 6 months post-transplantation, worsening skeletal disease recurred, with partial return of host hematopoiesis. At the age of 21 months, without additional chemotherapy or immunosuppressive treatment, she received a boost of donor marrow cells expanded ex vivo to enrich for stromal cells. Significant, prolonged clinical and radiographic improvement followed soon after. Nevertheless, biochemical features of hypophosphatasia have remained unchanged to date. Skeletal biopsy specimens were not performed. Now, at 6 years of age, she is intelligent and ambulatory but remains small. Among several hypotheses for our patient's survival and progress, the most plausible seems to be the transient and long-term engraftment of sufficient numbers of donor marrow mesenchymal cells, forming functional osteoblasts and perhaps chondrocytes, to ameliorate her skeletal disease.

Prospective Aspergillus galactomannan antigen testing in pediatric hematopoietic stem cell transplant recipients

BACKGROUND

The galactomannan (GM) assay is an approved noninvasive test for detection of invasive aspergillosis (IA) that has been validated in adult patients with hematologic malignancies who are undergoing bone marrow transplantation. There have been few studies with this assay in pediatric patients, but early reports suggest that there may be differences in the performance such that false-positive GM tests in pediatric patients are more common than in adult patients.

METHODS

We performed a prospective study in pediatric hematopoietic stem cell transplant recipients with twice-weekly sampling for GM detection during the highest risk periods of neutropenia and graft-versus-host disease. We analyzed 826 serum samples from 64 patients, including 15 serum samples from one patient diagnosed with probable IA according to defined criteria.

RESULTS

Twenty of 811 samples tested positive on repeat testing (specificity, 97.5%; 95% CI: 96.2-98.4%) including samples from 8 of 63 patients without clinical evidence of IA according to study criteria (specificity, 87.3%; 95% CI: 76.9-93.4%). Eleven patients received piperacillin/tazobactam therapy, and 4 of the 11 patients had a positive assay result coinciding with the dates of piperacillin/tazobactam administration. When samples from these patients were excluded, specificity increased to 98.4% (95% CI: 97.2-99.1%) by sample and to 91.5% (95% CI: 81.6-96.3%) by patient.

CONCLUSIONS

The GM assay holds promise for early, noninvasive diagnosis of IA in high-risk children and false-positive results were not common or unexplainable. This study supports further validation of this assay in a large-scale, pediatric-dedicated format.