Germline Genetic NBN Variation and Predisposition to B-cell Acute Lymphoblastic Leukemia in Children

Biallelic mutation in the DNA-damage repair gene NBN is the genetic cause of Nijmegen Breakage Syndrome, which is associated with predisposition to lymphoid malignancies. Heterozygous carriers of germline NBN variants may also be at risk for leukemia development, although this is much less characterized. We systematically examined the frequency of germline NBN variants in pediatric B-ALL and identified 25 putatively damaging NBN coding variants in 50 of 4,183 B-ALL patients. Compared with the frequency of NBN variants in 118,479 gnomAD non-cancer controls we found significant overrepresentation in pediatric B-ALL (p=0.004, OR=1.77). Most B-ALL-risk variants were missense and cluster within the NBN N-terminal domains. Using two functional assays, we verified 14 of 25 variants with severe loss-of-function phenotypes and thus classified these as pathogenic or likely pathogenic. Finally, we found that heterozygous germline NBN variant carriers showed similar survival outcomes relative to those with WT status. Taken together, our findings provide novel insights into the genetic predisposition to B-ALL, the impact of NBN variants on protein function and suggest that heterozygous NBN variant carriers may safely receive B-ALL therapy.

It Takes a Village

OBJECTIVES

Partnerships between low- to middle-income countries (LMICs) and high-income countries (HICs) is one strategy to mitigate observed health disparities. Cambodia's Angkor Hospital for Children (AHC), an LMIC institution, faces shortages in health care resources, including pathology services. A partnership was created with Children's Wisconsin (CW), an HIC hospital, including provision of pathology services. We describe our established pathology workflow, examine cases seen in AHC patients, and evaluate the impact of CW's interpretations.

METHODS

AHC provides clinical history and impression and ships samples to CW, which processes the samples, and pathologists provide interpretations, sending reports electronically to AHC. For analysis, final diagnoses were considered "concordant," "refined," or "discordant" based on agreement with the clinical impression. Cases were also classified as "did not change management" or "changed management" based on how CW interpretation affected clinical management.

RESULTS

We included 347 specimens (177 malignant, 146 benign, 24 insufficient for diagnosis). Of these cases, 31% were discordant and 44% of cases with clinical follow-up had a change in management with CW interpretation.

CONCLUSIONS

Inclusion of pathology services in LMIC-HIC partnerships is crucial for resolving health disparities between the institutions involved. The described partnership and established pathology workflow can be adapted to the needs and resources of many institutions.

Randomized assessment of delayed intensification and two methods for parenteral methotrexate delivery in childhood B-ALL: Children's Oncology Group Studies P9904 and P9905

The delayed intensification (DI) enhanced outcome for patients with acute lymphoblastic leukemia (ALL) treated on BFM 76/79 and CCG 105 after a prednisone-based induction. Childrens Oncology Group protocols P9904/9905 evaluated DI via a post-induction randomization for eligible National Cancer Institute (NCI) standard (SR) and high-risk (HR) patients. A second randomization compared intravenous methotrexate (IV MTX) as a 24- (1 g/m²) vs. 4-h (2 g/m²) infusion. NCI SR patients received a dexamethasone-based three-drug and NCI HR/CNS 3 SR patients a prednisone-based four-drug induction. End induction MRD (minimal residual disease) was obtained but did not impact treatment. DI improved the 10-year continuous complete remission (CCR) rate; 75.5 ± 2.5% vs. 81.8 ± 2.2% p = 0.002, whereas MTX administration did not; 4-h 80.8 ± 1.9%; 24-h 81.4 ± 1.9% (p = 0.7780). Overall survival (OS) at 10 years did not differ with DI: 91.4 ± 1.6% vs. 90.9 ± 1.7% (p = 0.25) without but was higher with the 24-h MTX infusion; 4-h 91.1 ± 1.4%; 24-h 93.9 ± 1.2% (p = 0.0209). MRD predicted outcome; 10-year CCR 87.7 ± 2.2 and 82.1 ± 2.5% when MRD was <0.01% with/without DI (p = 0.007) and 54.3 ± 8% and 44 ± 8% for patients with MRD ≥ 0.01% with/without DI (p = 0.11). DI improved CCR for patients with B-ALL with and without end induction MRD.

Hematopoietic Stem Cell Transplantation Activity in Pediatric Cancer between 2008 and 2014 in the United States: A Center for International Blood and Marrow Transplant Research Report

This Center for International Blood and Marrow Transplant Research report describes the use of hematopoietic stem cell transplantation (HSCT) in pediatric patients with cancer, 4408 undergoing allogeneic (allo) and3076 undergoing autologous (auto) HSCT in the United States between 2008 and 2014. In both settings, there was a greater proportion of boys (n = 4327; 57%), children < 10 years of age (n = 4412; 59%), whites (n = 5787; 77%), and children with a performance score ≥ 90% at HSCT (n = 6187; 83%). Leukemia was the most common indication for an allo-transplant (n = 4170; 94%), and among these, acute lymphoblastic leukemia in second complete remission (n = 829; 20%) and acute myeloid leukemia in first complete remission (n = 800; 19%) werethe most common. The most frequently used donor relation, stem cell sources, and HLA match were unrelated donor (n = 2933; 67%), bone marrow (n = 2378; 54%), and matched at 8/8 HLA antigens (n = 1098; 37%) respectively. Most allo-transplants used myeloablative conditioning (n = 4070; 92%) and calcineurin inhibitors and methotrexate (n = 2245; 51%) for acute graft-versus-host disease prophylaxis. Neuroblastoma was the most common primary neoplasm for an auto-transplant (n = 1338; 44%). Tandem auto-transplants for neuroblastoma declined after 2012 (40% in 2011, 25% in 2012, and 8% in 2014), whereas tandem auto-transplants increased for brain tumors (57% in 2008 and 77% in 2014). Allo-transplants from relatives other than HLA-identical siblings doubled between 2008 and 2014 (3% in 2008 and 6% in 2014). These trends will be monitored in future reports of transplant practices in the United States.

Cardioprotection and Safety of Dexrazoxane in Patients Treated for Newly Diagnosed T-Cell Acute Lymphoblastic Leukemia or Advanced-Stage Lymphoblastic Non-Hodgkin Lymphoma: A Report of the Children's Oncology Group Randomized Trial Pediatric Oncology Group 9404

PURPOSE

To determine the oncologic efficacy, cardioprotective effectiveness, and safety of dexrazoxane added to chemotherapy that included a cumulative doxorubicin dose of 360 mg/m(2) to treat children and adolescents with newly diagnosed T-cell acute lymphoblastic leukemia (T-ALL) or lymphoblastic non-Hodgkin lymphoma (L-NHL).

PATIENTS AND METHODS

Patients were treated on Pediatric Oncology Group Protocol POG 9404, which included random assignment to treatment with or without dexrazoxane given as a bolus infusion immediately before every dose of doxorubicin. Cardiac effects were assessed by echocardiographic measurements of left ventricular function and structure.

RESULTS

Of 573 enrolled patients, 537 were eligible, evaluable, and randomly assigned to an arm with or without dexrazoxane. The 5-year event-free survival (with standard error) did not differ between groups: 77.2% (2.7%) for the dexrazoxane group versus 76.0% (2.7%) for the doxorubicin-only group (P = .9). The frequencies of severe grade 3 or 4 hematologic toxicity, infection, CNS events, and toxic deaths were similar in both groups (P ranged from .26 to .64). Of 11 second malignancies, eight occurred in patients who received dexrazoxane (P = .17). The mean left ventricular fractional shortening, wall thickness, and thickness-to-dimension ratio z scores measured 3 years after diagnosis were worse in the doxorubicin-alone group (n = 55 per group; P ≤ .01 for all comparisons). Mean fractional shortening z scores measured 3.5 to 6.4 years after diagnosis remained diminished and were lower in the 21 patients who received doxorubicin alone than in the 31 patients who received dexrazoxane (-2.03 v -0.24; P ≤ .001).

CONCLUSION

Dexrazoxane was cardioprotective and did not compromise antitumor efficacy, did not increase the frequencies of toxicities, and was not associated with a significant increase in second malignancies with this doxorubicin-containing chemotherapy regimen. We recommend dexrazoxane as a cardioprotectant for children and adolescents who have malignancies treated with anthracyclines.

Second Allogeneic Hematopoietic Cell Transplantation for Patients with Fanconi Anemia and Bone Marrow Failure

A second allogeneic hematopoietic cell transplantation (HCT) is the sole salvage option for individuals who develop graft failure after their first HCT. Data on outcomes after second HCT in patients with Fanconi anemia (FA) are scarce. Here we report outcomes after second allogeneic HCT for FA (n = 81). The indication for second HCT was graft failure after the first HCT. Transplantations were performed between 1990 and 2012. The timing of the second HCT predicted subsequent graft failure and survival. Graft failure was high when the second HCT was performed less than 3 months from the first. The 3-month probability of graft failure was 69% when the interval between the first HCT and second HCT was less than 3 months, compared with 23% when the interval was longer (P < .001). Consequently, the 1-year survival rate was substantially lower when the interval between the first and second HCTs was less than 3 months compared with longer (23% vs 58%; P = .001). The corresponding 5-year probability of survival was 16% and 45%, respectively (P = .006). Taken together, these data suggest that fewer than one-half of patients with FA undergoing a second HCT for graft failure are long-term survivors. There is an urgent need to develop strategies to reduce the rate of graft failure after first HCT.

Transplantation Outcomes for Children with Hypodiploid Acute Lymphoblastic Leukemia

Children with hypodiploid acute lymphoblastic leukemia (ALL) have inferior outcomes despite intensive risk-adapted chemotherapy regimens. We describe 78 children with hypodiploid ALL who underwent hematopoietic stem cell transplantation between 1990 and 2010. Thirty-nine (50%) patients had ≤ 43 chromosomes, 12 (15%) had 44 chromosomes, and 27 (35%) had 45 chromosomes. Forty-three (55%) patients underwent transplantation in first remission (CR1) and 35 (45%) underwent transplantation in ≥ second remission (CR2). Twenty-nine patients (37%) received a graft from a related donor and 49 (63%) from an unrelated donor. All patients received a myeloablative conditioning regimen. The 5-year probabilities of leukemia-free survival, overall survival, relapse, and treatment-related mortality for the entire cohort were 51%, 56%, 27%, and 22%, respectively. Multivariate analysis confirmed that mortality risks were higher for patients who underwent transplantation in CR2 (hazard ratio, 2.16; P = .05), with number of chromosomes ≤ 43 (hazard ratio, 2.15; P = .05), and for those who underwent transplantation in the first decade of the study period (hazard ratio, 2.60; P = .01). Similarly, treatment failure risks were higher with number of chromosomes ≤ 43 (hazard ratio, 2.28; P = .04) and the earlier transplantation period (hazard ratio, 2.51; P = .01). Although survival is better with advances in donor selection and supportive care, disease-related risk factors significantly influence transplantation outcomes.

Intensified chemotherapy without SCT in infant ALL: results from COG P9407 (Cohort 3)

BACKGROUND

Infants with acute lymphoblastic leukemia (ALL) present with aggressive disease and a poor prognosis. Early relapse within 6-9 months of diagnosis is common. Approximately 75% of infants have MLL-rearranged (MLL-R) ALL with event free survival (EFS) ranging from 20% to 30%. Children's Oncology Group (COG) P9407 used shortened (46 weeks), intensified therapy to address early relapse and poor EFS.

PROCEDURE

P9407 therapy was modified three times for induction toxicity resulting in three cohorts of therapy. One hundred forty-seven infants were enrolled in the third cohort.

RESULTS

We report an overall 5-year EFS and OS of 42.3 ± 6% and 52.9 ± 6.5% respectively. Poor prognostic factors included age ≤90 days at diagnosis, MLL-R ALL and white cell count ≥50,000/μl. For infants ≤90 days of age, the 5-year EFS was 15.5 ± 10.1% and 48.5 ± 6.7% for those >90 days (P < 0.0001). Among infants >90 days of age, 5-year EFS rates were 43.8 ± 8% for MLL-R versus 69.1 ± 13.6% for MLL-germline ALL (P < 0.0001).

CONCLUSIONS

Age ≤90 days at diagnosis was the most important prognostic factor. Despite shortened therapy with early intensification, EFS remained less than 50% overall in MLL-R ALL.

Outcome of transplantation for acute lymphoblastic leukemia in children with Down syndrome

We report on 27 patients with Down syndrome (DS) and acute lymphoblastic leukemia (ALL) who received allogeneic hematopoietic cell transplantation (HCT) between 2000 and 2009. Seventy-eight percent of patients received myeloablative conditioning and 52% underwent transplantation in second remission. Disease-free survival (DFS) was 24% at a median of 3 years. Post-transplant leukemic relapse was more frequent than expected for children with DS-ALL (54%) than for non-DS ALL. These data suggest leukemic relapse rather than transplant toxicity is the most important cause of treatment failure. Advancements in leukemia control are especially needed for improvement in HCT outcomes for DS-ALL.

Effect of postremission therapy before reduced-intensity conditioning allogeneic transplantation for acute myeloid leukemia in first complete remission

The impact of pretransplant (hematopoietic cell transplantation [HCT]) cytarabine consolidation therapy on post-HCT outcomes has yet to be evaluated after reduced-intensity or nonmyeloablative conditioning. We analyzed 604 adults with acute myeloid leukemia in first complete remission (CR1) reported to the Center for International Blood and Marrow Transplant Research who received a reduced-intensity or nonmyeloablative conditioning HCT from an HLA-identical sibling, HLA-matched unrelated donor, or umbilical cord blood donor from 2000 to 2010. We compared transplant outcomes based on exposure to cytarabine postremission consolidation. Three-year survival rates were 36% (95% confidence interval [CI], 29% to 43%) in the no consolidation arm and 42% (95% CI, 37% to 47%) in the cytarabine consolidation arm (P = .16). Disease-free survival was 34% (95% CI, 27% to 41%) and 41% (95% CI, 35% to 46%; P = .15), respectively. Three-year cumulative incidences of relapse were 37% (95% CI, 30% to 44%) and 38% (95% CI, 33% to 43%), respectively (P = .80). Multivariate regression confirmed no effect of consolidation on relapse, disease-free survival, and survival. Before reduced-intensity or nonmyeloablative conditioning HCT, these data suggest pre-HCT consolidation cytarabine does not significantly alter outcomes and support prompt transition to transplant as soon as morphologic CR1 is attained. If HCT is delayed while identifying a donor, our data suggest that consolidation does not increase transplant treatment-related mortality and is reasonable if required.

Providing personalized prognostic information for adult leukemia survivors

Prediction of subsequent leukemia-free survival (LFS) and chronic graft-versus-host disease (GVHD) in adults with acute leukemia who survived at least 1 year after allogeneic hematopoietic cell transplantation is difficult. We analyzed 3339 patients with acute myeloid leukemia and 1434 patients with acute lymphoblastic leukemia who received myeloablative conditioning and related or unrelated stem cells from 1990 to 2005. Most clinical factors predictive of LFS in 1-year survivors were no longer significant after 2 or more years. For acute myeloid leukemia, only disease status (beyond first complete remission) remained a significant adverse risk factor for LFS 2 or more years after transplantation. For lymphoblastic leukemia, only extensive chronic GVHD remained a significant adverse predictor of LFS in the second and subsequent years. For patients surviving for 1 year without disease relapse or extensive chronic GVHD, the risk of developing extensive chronic GVHD in the next year was 4% if no risk factors were present and higher if noncyclosporine-based GVHD prophylaxis, an HLA-mismatched donor, or peripheral blood stem cells were used. Estimates for subsequent LFS and extensive chronic GVHD can be derived for individual patients or populations using an online calculator (http://www.cibmtr.org/LeukemiaCalculators). This prognostic information is more relevant for survivors than estimates provided before transplantation.

The use of novel Therakos™ Cellex® for extracorporeal photopheresis in treatment of graft-versus-host disease in paediatric patients

Extracorporeal photopheresis (ECP) is an established second line treatment option for graft-versus-host disease (GVHD) post-haematopoietic progenitor cell transplant. At our centre, the Therakos™ Cellex(®) has replaced the Therakos™ UVAR-XTS™ machine for ECP since 2009. We reviewed the records of 385 procedures using the Therakos™ Cellex(®) for safety and tolerability. Nine patients underwent ECP for GVHD. The median age was 13·5 years (range 3·7-24) and weight was 49·2 kg (range 18·5-86·3). The mean duration per procedure was 106 min (range 60-205). Fifteen (3·9%) procedures were cancelled and 10 (2·6%) were delayed, with central venous line (CVL) issues being the most frequent problem. With the use of prophylactic tissue plasminogen activator, fewer CVL-related occlusions were observed (4·7% vs. 2·3%). There was one episode of a CVL-associated thrombosis and one episode of delayed bleeding. There were four episodes of viral reactivation, four CVL-associated infections (1142 catheter days) and one episode of systemic inflammatory response syndrome. No patient experienced symptomatic hypotension. This is the first report outlining the safety and tolerability of the Therakos™ Cellex(®) device for ECP in children and young adults.

Allogeneic hematopoietic cell transplantation for fanconi anemia in patients with pretransplantation cytogenetic abnormalities, myelodysplastic syndrome, or acute leukemia

PURPOSE

Allogeneic hematopoietic cell transplantation (HCT) can cure bone marrow failure in patients with Fanconi anemia (FA). Data on outcomes in patients with pretransplantation cytogenetic abnormalities, myelodysplastic syndrome (MDS), or acute leukemia have not been separately analyzed.

PATIENTS AND METHODS

We analyzed data on 113 patients with FA with cytogenetic abnormalities (n = 54), MDS (n = 45), or acute leukemia (n = 14) who were reported to the Center for International Blood and Marrow Transplant Research from 1985 to 2007.

RESULTS

Neutrophil recovery occurred in 78% and 85% of patients at days 28 and 100, respectively. Day 100 cumulative incidences of acute graft-versus-host disease grades B to D and C to D were 26% (95% CI, 19% to 35%) and 12% (95% CI, 7% to 19%), respectively. Survival probabilities at 1, 3, and 5 years were 64% (95% CI, 55% to 73%), 58% (95% CI, 48% to 67%), and 55% (95% CI, 45% to 64%), respectively. In univariate analysis, younger age was associated with superior 5-year survival (≤ v > 14 years: 69% [95% CI, 57% to 80%] v 39% [95% CI, 26% to 53%], respectively; P = .001). In transplantations from HLA-matched related donors (n = 82), younger patients (≤ v > 14 years: 78% [95% CI, 64% to 90%] v 34% [95% CI, 20% to 50%], respectively; P < .001) and patients with cytogenetic abnormalities only versus MDS/acute leukemia (67% [95% CI, 52% to 81%] v 43% [95% CI, 27% to 59%], respectively; P = .03) had superior 5-year survival.

CONCLUSION

Our analysis indicates that long-term survival for patients with FA with cytogenetic abnormalities, MDS, or acute leukemia is achievable. Younger patients and recipients of HLA-matched related donor transplantations who have cytogenetic abnormalities only have the best survival.

Unrelated donor allogeneic transplantation after failure of autologous transplantation for acute myelogenous leukemia: a study from the center for international blood and marrow transplantation research

The survival of patients with relapsed acute myelogenous leukemia (AML) after autologous hematopoietic stem cell transplantation (auto-HCT) is very poor. We studied the outcomes of 302 patients who underwent secondary allogeneic hematopoietic cell transplantation (allo-HCT) from an unrelated donor (URD) using either myeloablative (n = 242) or reduced-intensity conditioning (RIC; n = 60) regimens reported to the Center for International Blood and Marrow Transplantation Research. After a median follow-up of 58 months (range, 2 to 160 months), the probability of treatment-related mortality was 44% (95% confidence interval [CI], 38%-50%) at 1-year. The 5-year incidence of relapse was 32% (95% CI, 27%-38%), and that of overall survival was 22% (95% CI, 18%-27%). Multivariate analysis revealed a significantly better overal survival with RIC regimens (hazard ratio [HR], 0.51; 95% CI, 0.35-0.75; P <.001), with Karnofsky Performance Status score ≥90% (HR, 0.62; 95% CI, 0.47-0.82: P = .001) and in cytomegalovirus-negative recipients (HR, 0.64; 95% CI, 0.44-0.94; P = .022). A longer interval (>18 months) from auto-HCT to URD allo-HCT was associated with significantly lower riak of relapse (HR, 0.19; 95% CI, 0.09-0.38; P <.001) and improved leukemia-free survival (HR, 0.53; 95% CI, 0.34-0.84; P = .006). URD allo-HCT after auto-HCT relapse resulted in 20% long-term leukemia-free survival, with the best results seen in patients with a longer interval to secondary URD transplantation, with a Karnofsky Performance Status score ≥90%, in complete remission, and using an RIC regimen. Further efforts to reduce treatment-related mortaility and relapse are still needed.

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.

Outcome of transplantation for acute myelogenous leukemia in children with Down syndrome

Data on outcomes of allogeneic transplantation in children with Down syndrome and acute myelogenous leukemia (DS-AML) are scarce and conflicting. Early reports stress treatment-related mortality as the main barrier; a recent case series points to posttransplantation relapse. We reviewed outcome data for 28 patients with DS-AML reported to the Center for International Blood and Marrow Transplant Research between 2000 and 2009 and performed a first matched-pair analysis of 21 patients with DS-AML and 80 non-DS AML controls. The median age at transplantation for DS-AML was 3 years, and almost half of the cohort was in second remission. The 3-year probability of overall survival was only 19%. In multivariate analysis, adjusting for interval from diagnosis to transplantation, risks of relapse (hazard ratio [HR], 2.84; P < .001; 62% versus 37%) and transplant-related mortality (HR, 2.52; P = .04; 24% versus 15%) were significantly higher for DS-AML compared to non-DS AML. Overall mortality risk (HR, 2.86; P < .001; 21% versus 52%) was significantly higher for DS-AML. Both transplant-related mortality and relapse contribute to higher mortality. Excess mortality in DS-AML patients can only effectively be addressed through an international multicenter effort to pilot strategies aimed at lowering both transplant-related mortality and relapse risks.

Autologous blood cell transplantation versus HLA-identical sibling transplantation for acute myeloid leukemia in first complete remission: a registry study from the Center for International Blood and Marrow Transplantation Research

The optimal post-remission treatment for acute myeloid leukemia in first complete remission remains uncertain. Previous comparisons of autologous versus allogeneic hematopoietic cell transplantation noted higher relapse, but lower treatment-related mortality though using bone marrow grafts, with treatment-related mortality of 12-20%. Recognizing lower treatment-related mortality using autologous peripheral blood grafts, in an analysis of registry data from the Center for International Blood and Transplant Research, we compared treatment-related mortality, relapse, leukemia-free survival, and overall survival for patients with acute myeloid leukemia in first complete remission (median ages 36-44, range 19-60) receiving myeloablative HLA-matched sibling donor grafts (bone marrow, n=475 or peripheral blood, n=428) versus autologous peripheral blood (n=230). The 5-year cumulative incidence of treatment-related mortality was 19% (95% confidence interval, 16-23%), 20% (17-24%) and 8% (5-12%) for allogeneic bone marrow, allogeneic peripheral blood and autologous peripheral blood stem cell transplant recipients, respectively. The corresponding figures for 5-year cumulative incidence of relapse were 20% (17-24%), 26% (21-30%) and 45% (38-52%), respectively. At 5 years, leukemia-free survival and overall survival rates were similar: allogeneic bone marrow 61% (56-65%) and 64% (59-68%); allogeneic peripheral blood 54% (49-59%) and 59% (54-64%); autologous peripheral blood 47% (40-54%) and 54% (47-60%); P=0.13 and P=0.19, respectively. In multivariate analysis the incidence of treatment-related mortality was lower after autologous peripheral blood transplantation than after allogeneic bone marrow/peripheral blood transplants [relative risk 0.37 (0.20-0.69); P=0.001], but treatment failure (death or relapse) after autologous peripheral blood was significantly more likely [relative risk 1.32 (1.06-1.64); P=0.011]. The 5-year overall survival, however, was similar in patients who received autologous peripheral blood (n=230) [relative risk 1.23 (0.98-1.55); P=0.071] or allogeneic bone marrow/peripheral blood (n=903). In the absence of an HLA-matched sibling donor, autologous peripheral blood may provide acceptable alternative post-remission therapy for patients with acute myeloid leukemia in first complete remission.

Treatment of recurrent CNS disease post-bone marrow transplant in familial HLH

CNS involvement in Hemophagocytic Lymphohistiocytosis (HLH) has been reported in 63-73% of children at diagnosis [Haddad et al. (1997); Blood 89: 794-800; Horne et al. (2008); Br J Haematol 140: 327-335]. Patients can present with neurologic symptoms, abnormal CSF cytology, abnormal neuro-imaging, or a combination of these findings. CNS involvement is usually associated with a poor prognosis and increased mortality. The 3 year overall survival is 44% in patients with CNS involvement compared to 67% in patients without CNS involvement at diagnosis [Horne et al. (2008); Br J Haematol 140: 327-335]. We describe a treatment strategy employing systemic dexamethasone to control CNS disease in a patient with familial HLH and persistent CNS disease post Bone Marrow Transplant.

Pilot study of nelarabine in combination with intensive chemotherapy in high-risk T-cell acute lymphoblastic leukemia: a report from the Children's Oncology Group

PURPOSE

Children's Oncology Group study AALL00P2 was designed to assess the feasibility and safety of adding nelarabine to a BFM 86-based chemotherapy regimen in children with newly diagnosed T-cell acute lymphoblastic leukemia (T-ALL).

PATIENTS AND METHODS

In stage one of the study, eight patients with a slow early response (SER) by prednisone poor response (PPR; ≥ 1,000 peripheral blood blasts on day 8 of prednisone prephase) received chemotherapy plus six courses of nelarabine 400 mg/m(2) once per day; four patients with SER by high minimal residual disease (MRD; ≥ 1% at day 36 of induction) received chemotherapy plus five courses of nelarabine; 16 patients with a rapid early response (RER) received chemotherapy without nelarabine. In stage two, all patients received six 5-day courses of nelarabine at 650 mg/m(2) once per day (10 SER patients [one by MRD, nine by PPR]) or 400 mg/m(2) once per day (38 RER patients; 12 SER patients [three by MRD, nine by PPR]).

RESULTS

The only significant difference in toxicities was decreased neutropenic infections in patients treated with nelarabine (42% with v 81% without nelarabine). Five-year event-free survival (EFS) rates were 73% for 11 stage one SER patients and 67% for 22 stage two SER patients treated with nelarabine versus 69% for 16 stage one RER patients treated without nelarabine and 74% for 38 stage two RER patients treated with nelarabine. Five-year EFS for all patients receiving nelarabine (n = 70) was 73% versus 69% for those treated without nelarabine (n = 16).

CONCLUSION

Addition of nelarabine to a BFM 86-based chemotherapy regimen was well tolerated and produced encouraging results in pediatric patients with T-ALL, particularly those with a SER, who have historically fared poorly.

Cardioprotection and safety of dexrazoxane (DRZ) in children treated for newly diagnosed T-cell acute lymphoblastic leukemia (T-ALL) or advanced stage lymphoblastic leukemia (T-LL)

9504

Background: POG 9404 evaluated the efficacy of DRZ as a cardioprotectant and its side effects in children receiving doxorubicin (DOX) as part of chemotherapy for T-ALL/T-LL. Methods: Between 6/1996 and 9/2001, 537 T-ALL/T-LL patients were treated with multi-agent chemotherapy that included 12 DOX doses of 30 mg/m2. Patients were randomized at diagnosis to treatment with or without DRZ (300 mg/m2 IV immediately prior to each DOX dose). Cardiac effects were assessed by serial echocardiograph measurements of left ventricular (LV) function (fractional shortening) and structure (end-diastolic dimension, wall thickness, and mass). Adverse events, grades 3-5 were recorded using CTCAE version 2.0. Results: Five-year EFS was similar for the DRZ (0.77±0.03%) and no-DRZ (0.76±0.03%) groups (p=0.9). Acute cardiac toxicity occurred in 1 patient (arrhythmia) on DRZ and 4 patients treated without DRZ (1-arrhythmia, 3-decreased LV fractional shortening). At each of the three time-points post-baseline (end-induction, after the last DOX dose and two years post study entry) LV dimensions were larger from baseline for patients who did not receive DRZ. In univariate analyses, change in LV end-diastolic dimension from baseline was the only variable that was significantly different between DRZ and no-DRZ arms. This was true at each of the three time points (p=0.005-0.02). The frequencies of grade 3 or 4 toxicity (hematologic, infection, CNS events, mucositis) or death were similar in groups with or without DRZ (p<0.24). There were 13 second malignancies, 10 patients had received DRZ and 3 had not (p=0.07). Conclusions: Our LV dimension measurements suggest that DRZ may protect against the early LV remodeling and enlargement that is seen with DOX cardiotoxicity. Addition of DRZ did not interfere with the anti-tumor efficacy of this DOX-containing, multi-agent regimen, and there was no significant increase in toxicities. An increased rate of second malignancies with DRZ did not reach conventional levels of statistical significance. The study was not powered to assess second malignancy rates and this trend is of unknown clinical significance.

Outcomes after induction failure in childhood acute lymphoblastic leukemia

BACKGROUND

Failure of remission-induction therapy is a rare but highly adverse event in children and adolescents with acute lymphoblastic leukemia (ALL).

METHODS

We identified induction failure, defined by the persistence of leukemic blasts in blood, bone marrow, or any extramedullary site after 4 to 6 weeks of remission-induction therapy, in 1041 of 44,017 patients (2.4%) 0 to 18 years of age with newly diagnosed ALL who were treated by a total of 14 cooperative study groups between 1985 and 2000. We analyzed the relationships among disease characteristics, treatments administered, and outcomes in these patients.

RESULTS

Patients with induction failure frequently presented with high-risk features, including older age, high leukocyte count, leukemia with a T-cell phenotype, the Philadelphia chromosome, and 11q23 rearrangement. With a median follow-up period of 8.3 years (range, 1.5 to 22.1), the 10-year survival rate (±SE) was estimated at only 32±1%. An age of 10 years or older, T-cell leukemia, the presence of an 11q23 rearrangement, and 25% or more blasts in the bone marrow at the end of induction therapy were associated with a particularly poor outcome. High hyperdiploidy (a modal chromosome number >50) and an age of 1 to 5 years were associated with a favorable outcome in patients with precursor B-cell leukemia. Allogeneic stem-cell transplantation from matched, related donors was associated with improved outcomes in T-cell leukemia. Children younger than 6 years of age with precursor B-cell leukemia and no adverse genetic features had a 10-year survival rate of 72±5% when treated with chemotherapy only.

CONCLUSIONS

Pediatric ALL with induction failure is highly heterogeneous. Patients who have T-cell leukemia appear to have a better outcome with allogeneic stem-cell transplantation than with chemotherapy, whereas patients who have precursor B-cell leukemia without other adverse features appear to have a better outcome with chemotherapy. (Funded by Deutsche Krebshilfe and others.).

Improved survival for children and adolescents with acute lymphoblastic leukemia between 1990 and 2005: a report from the children's oncology group

PURPOSE

To examine population-based improvements in survival and the impact of clinical covariates on outcome among children and adolescents with acute lymphoblastic leukemia (ALL) enrolled onto Children's Oncology Group (COG) clinical trials between 1990 and 2005.

PATIENTS AND METHODS

In total, 21,626 persons age 0 to 22 years were enrolled onto COG ALL clinical trials from 1990 to 2005, representing 55.8% of ALL cases estimated to occur among US persons younger than age 20 years during this period. This period was divided into three eras (1990-1994, 1995-1999, and 2000-2005) that included similar patient numbers to examine changes in 5- and 10-year survival over time and the relationship of those changes in survival to clinical covariates, with additional analyses of cause of death.

RESULTS

Five-year survival rates increased from 83.7% in 1990-1994 to 90.4% in 2000-2005 (P < .001). Survival improved significantly in all subgroups (except for infants age ≤ 1 year), including males and females; those age 1 to 9 years, 10+ years, or 15+ years; in whites, blacks, and other races; in Hispanics, non-Hispanics, and patients of unknown ethnicity; in those with B-cell or T-cell immunophenotype; and in those with National Cancer Institute (NCI) standard- or high-risk clinical features. Survival rates for infants changed little, but death following relapse/disease progression decreased and death related to toxicity increased.

CONCLUSION

This study documents ongoing survival improvements for children and adolescents with ALL. Thirty-six percent of deaths occurred among children with NCI standard-risk features emphasizing that efforts to further improve survival must be directed at both high-risk subsets and at those children predicted to have an excellent chance for cure.

Comparison of outcomes after HLA-matched sibling and unrelated donor transplantation for children with high-risk acute lymphoblastic leukemia

We compared outcomes after 94 HLA-matched sibling, 168 unrelated donor bone marrow (BM; n = 81 matched and n = 88 mismatched), and 86 cord blood transplantations in patients age 1 to 15 years with acute lymphoblastic leukemia (ALL) in second complete remission (CR). All patients had their first BM relapse within 3 years from diagnosis. Cox regression models were constructed to examine for differences in transplant outcome by donor source. Risks of grade 2 to 4 acute graft-versus-host disease (aGVHD) and chronic graft-versus-host disease (cGVHD), when compared to HLA-matched sibling transplants, were higher after matched unrelated donor BM (relative risk [RR], 2.42; P = .001; RR, 5.12; P < .001, respectively), mismatched BM (RR, 3.24; P < .001; RR, 5.19; P < .001, respectively), and cord blood (RR, 2.67; P < .001; RR, 2.54; P = .024, respectively) transplants. Although nonrelapse mortality was higher after transplantation of mismatched unrelated donor BM and cord blood, there were no differences in leukemia-free survival (LFS) between HLA-matched sibling and any of the unrelated donor transplantations. The 3-year probabilities of LFS were 50% after HLA-matched sibling and 44% after matched unrelated BM, and 44% after mismatched unrelated BM and 43% after cord blood transplantation. Our observations support transplantation of BM or cord blood from a suitably matched unrelated donor or cord blood for patients without an HLA-matched sibling with ALL in second CR.

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.

Polyethylene Glycol-conjugated L-asparaginase versus native L-asparaginase in combination with standard agents for children with acute lymphoblastic leukemia in second bone marrow relapse: a Children's Oncology Group Study (POG 8866)

BACKGROUND

Administration of L-asparaginase is limited by hypersensitivity reactions mediated by anti-asparaginase antibodies. To overcome this problem, native Escherichia coli L-asparaginase was conjugated to polyethylene glycol (PEG) to formulate PEG-L-asparaginase, a preparation with decreased immunogenicity and increased circulating half-life. In early trials, PEG-L-asparaginase was tolerated by patients known to be hypersensitive to the native E. coli product.

METHODS

The Pediatric Oncology Group conducted a phase II, randomized trial to compare the efficacy and toxicity of PEG-L-asparaginase compared with native E. coli asparaginase in children with acute lymphoblastic leukemia in second bone marrow relapse. All patients (n=76) received standard doses of vincristine and prednisone. Nonhypersensitive patients (n=34) were randomized to receive either PEG-L-asparaginase of 2500 IU/m/dose intramuscularly on days 1 and 15 (treatment I) or native E. coli asparaginase of 10,000 IU/m/dose intramuscularly on days 1, 3, 5, 8, 10, 12, 15, 17, 19, 22, 24, and 26 (treatment II). Patients with a clinical history of an allergic reaction to unmodified asparaginase were directly assigned to treatment with PEG-L-asparaginase (n=42). Asparaginase levels and anti-asparaginase antibody titers were monitored in all patients. Response and toxicity were scored using conventional criteria.

RESULTS

The complete response rate for the total study population was 41%. There was no difference in complete response between patients randomized to PEG (47%) and native asparaginase (41%). PEG was well tolerated even in patients with prior allergic reactions to native asparaginase. PEG half-life was shorter in patients with prior allergy.

CONCLUSIONS

PEG asparaginase is a useful agent in patients with allergic reactions to native asparaginase.

Augmented therapy improves outcome for pediatric high risk acute lymphocytic leukemia: results of Children's Oncology Group trial P9906

BACKGROUND

The augmented BFM regimen improves outcome for children with NCI high acute lymphoblastic leukemia (ALL). Patient age, sex, and presenting white blood cell count (WBC) can be used to identify a subset of approximately 12% of children with B-precursor ALL that had a 5-year continuous complete remission (CCR) rate of only about 50% on earlier Pediatric Oncology Group (POG) trials.

PROCEDURES

Children's Oncology Group trial P9906 evaluated a modified augmented BFM regimen in 267 patients with particularly high risk B-precursor ALL. Minimal residual disease (MRD) was assessed in blood at day 8 and in marrow at day 29 of induction and correlated with outcome.

RESULTS

The 5-year CCR probability for patients in P9906 was significantly better than that observed for similar patients on POG trials 8602/9006 (62.2 ± 3.7% vs. 50.6 ± 2.4%; P = 0.0007) but similar to POG 9406 (63.5 ± 2.4%; P = 0.81). Interim analysis showed poor central nervous system (CNS) control, especially in patients with initial WBC ≥ 100,000/microliter. Day 29 marrow MRD positive (≥ 0.01%) vs. negative patients had 5 year CCR rates of 37.1 ± 7.4% vs. 72.6 ± 4.3%; day 8 blood MRD positive vs. negative patients had 5 year CCR rates of 57.1 ± 4.6% vs.83.6 ± 6.3%. End induction marrow MRD predicted marrow but not CNS relapse. In multivariate analysis, day 29 MRD > 0.01%, initial WBC ≥ 100,000/µl, male gender, and day 8 blood MRD > 0.01% were significant prognostic factors.

CONCLUSIONS

Augmented BFM therapy improved outcome for children with higher risk ALL. Day 8 blood and day 29 marrow MRD were strong prognostic factors in these patients.

Classifying cytogenetics in patients with acute myelogenous leukemia in complete remission undergoing allogeneic transplantation: a Center for International Blood and Marrow Transplant Research study

Cytogenetics play a major role in determining the prognosis of patients with acute myelogenous leukemia (AML). However, existing cytogenetics classifications were developed in chemotherapy-treated patients and might not be optimal for patients undergoing allogeneic hematopoietic cell transplantation (HCT). We studied 821 adult patients reported to the Center for International Blood and Marrow Transplant Research (CIBMTR) who underwent HCT for AML in first or second complete remission between 1999 and 2004. We compared the ability of the 6 existing classifications to stratify patients by overall survival. We then defined a new scheme specifically applicable to patients undergoing HCT using this patient cohort. Under this scheme, inv(16) is favorable, a complex karyotype (4 or more abnormalities) is adverse, and all other classified abnormalities are intermediate in predicting survival after HCT (5-year overall survival, 64%, 18%, and 50%, respectively; P = .0001). This scheme stratifies patients into 3 groups with similar nonrelapse mortality, but significantly different incidences of relapse, overall and leukemia-free survival. It applies to patients regardless of disease status (first or second complete remission), donor type (matched related or unrelated), or conditioning intensity (myeloablative or reduced intensity). This transplantation-specific classification could be adopted for prognostication purposes and to stratify patients with AML and karyotypic abnormalities entering HCT clinical trials.

Hematopoietic stem-cell transplantation for acute leukemia in relapse or primary induction failure

PURPOSE

Patients with acute leukemia refractory to induction or reinduction chemotherapy have poor prognoses if they do not undergo hematopoietic stem-cell transplantation (HSCT). However, HSCT when a patient is not in complete remission (CR) is of uncertain benefit. We hypothesized that pretransplantation variables may define subgroups that have a better prognosis.

PATIENTS AND METHODS

Overall, 2,255 patients who underwent transplantation for acute leukemia in relapse or with primary induction failure after myeloablative conditioning regimen between 1995 and 2004 were reported to the Center for International Blood and Marrow Transplant Research. The median follow-up of survivors was 61 months. We performed multivariate analysis of pretransplantation variables and developed a predictive scoring system for survival.

RESULTS

The 3-year overall survival (OS) rates were 19% for acute myeloid leukemia (AML) and 16% for acute lymphoblastic leukemia (ALL). For AML, five adverse pretransplantation variables significantly influenced survival: first CR duration less than 6 months, circulating blasts, donor other than HLA-identical sibling, Karnofsky or Lansky score less than 90, and poor-risk cytogenetics. For ALL, survival was worse with the following: first refractory or second or greater relapse, > or = 25% marrow blasts, cytomegalovirus-seropositive donor, and age of 10 years or older. Patients with AML who had a predictive score of 0 had 42% OS at 3 years, whereas OS was 6% for a score > or = 3. Patients with ALL who had a score of 0 or 1 had 46% 3-year OS but only 10% OS rate for a score > or = 3.

CONCLUSION

Pretransplantation variables delineate subgroups with different outcomes. HSCT during relapse can achieve long-term survival in selected patients with acute leukemia.

Hematopoietic stem cell transplantation for refractory or recurrent non-Hodgkin lymphoma in children and adolescents

We examined the role of hematopoietic stem cell transplantation (HSCT) for patients aged< or =18 years with refractory or recurrent Burkitt (n=41), lymphoblastic (n=53), diffuse large B cell (DLBCL; n=52), and anaplastic large cell lymphoma (n=36), receiving autologous (n=90) or allogeneic (n=92; 43 matched sibling and 49 unrelated donor) HSCT in 1990-2005. Risk factors affecting event-free survival (EFS) were evaluated using stratified Cox regression. Characteristics of allogeneic and autologous HSCT recipients were similar. Allogeneic donor HSCT was more likely to use irradiation-containing conditioning regimens, bone marrow (BM) stem cells, be performed in more recent years, and for lymphoblastic lymphoma. EFS rates were lower for patients not in complete remission at HSCT, regardless of donor type. After adjusting for disease status, 5-year EFS were similar after allogeneic and autologous HSCT for DLBCL (50% vs 52%), Burkitt (31% vs 27%), and anaplastic large cell lymphoma (46% vs 35%). However, EFS was higher for lymphoblastic lymphoma, after allogeneic HSCT (40% vs 4%; P < .01). Predictors of EFS for progressive or recurrent disease after HSCT included disease status at HSCT and use of allogeneic donor for lymphoblastic lymphoma. These data were unable to demonstrate a difference in outcome by donor type for the other histological subtypes.

Risk factors affecting outcome of second HLA-matched sibling donor transplantations for graft failure in severe acquired aplastic anemia

We examined transplantation outcomes after a second HLA-matched sibling transplantation for primary (16%) or secondary (84%) graft failure in 166 patients with severe acquired aplastic anemia (AA). Two-thirds of these patients has a performance score < 90. In most cases (88%), the same donor was used for both transplants, for both transplantations, and 84% of the second transplantations used bone marrow grafts. We identified 2 prognostic factors: intertransplantation interval (surrogate for primary graft failure and early secondary graft failure) and performance status. Shorter intertransplantation interval (<or= 3 months) and poor performance score (< 90) at second transplantation were associated with high mortality. In patients with a performance score of 90% to 100%, the 8-year probability of overall survival (OS) after second transplantation <or= 3 and > 3 months from first transplantation was 56% and 76%, respectively. The corresponding probabilities in patients with lower performance scores were 33% and 61%. The predominant cause of failure after second transplantation was nonengraftment (in 72 of 166 patients), most commonly in patients with primary or early secondary graft failure (51 of 72; 71%). Our data indicate that novel approaches, including conditioning regimens with greater immunosuppression, should be explored for these patients.

Genome-wide interrogation of germline genetic variation associated with treatment response in childhood acute lymphoblastic leukemia

CONTEXT

Pediatric acute lymphoblastic leukemia (ALL) is the prototype for a drug-responsive malignancy. Although cure rates exceed 80%, considerable unexplained interindividual variability exists in treatment response.

OBJECTIVES

To assess the contribution of inherited genetic variation to therapy response and to identify germline single-nucleotide polymorphisms (SNPs) associated with risk of minimal residual disease (MRD) after remission induction chemotherapy.

DESIGN, SETTING, AND PATIENTS

Genome-wide interrogation of 476,796 germline SNPs to identify genotypes that were associated with MRD in 2 independent cohorts of children with newly diagnosed ALL: 318 patients in St Jude Total Therapy protocols XIIIB and XV and 169 patients in Children's Oncology Group trial P9906. Patients were enrolled between 1994 and 2006 and last follow-up was in 2006.

MAIN OUTCOME MEASURES

Minimal residual disease at the end of induction therapy, measured by flow cytometry.

RESULTS

There were 102 SNPs associated with MRD in both cohorts (median odds ratio, 2.18; P < or = .0125), including 5 SNPs in the interleukin 15 (IL15) gene. Of these 102 SNPs, 21 were also associated with hematologic relapse (P < .05). Of 102 SNPs, 21 were also associated with antileukemic drug disposition, generally linking MRD eradication with greater drug exposure. In total, 63 of 102 SNPs were associated with early response, relapse, or drug disposition.

CONCLUSION

Host genetic variations are associated with treatment response for childhood ALL, with polymorphisms related to leukemia cell biology and host drug disposition associated with lower risk of residual disease.

HLA-matched sibling hematopoietic stem cell transplantation for fanconi anemia: comparison of irradiation and nonirradiation containing conditioning regimens

Related to the underlying DNA repair defect that is the hallmark of Fanconi anemia (FA), preparatory regimen-related toxicities have been obstacles to hematopoietic cell transplantation (HCT). In an attempt to decrease the risk and severity of regimen-related toxicities, nonirradiation regimens have been explored. The aim of this study is to compare outcomes after irradiation and nonirradiation regimens in 148 FA patients and identify risk factors impacting upon HCT outcomes. Hematopoietic recovery, acute and chronic graft-versus-host disease (aGVHD, GVHD), and mortality were similar after irradiation and nonirradiation regimens. In both groups of recipients aged >10 years, prior use of androgens and cytomegalovirus seropositivity in either the donor or recipient were associated with higher mortality. With median follow-ups >5 years, the 5-year probability of overall survival, adjusted for factors impacting overall mortality was 78% and 81% after irradiation and nonirradiation regimens, P = .61. In view of the high risk of cancer and other radiation-related effects on growth and development, these results support the use of nonirradiation preparatory regimens. As the peak time for developing solid tumors after HCT is 8 to 9 years, longer follow-up is required before definitive statements can be made regarding the impact of nonirradiation regimens on cancer risk.

Unrelated donor bone marrow transplantation for children with acute myeloid leukemia beyond first remission or refractory to chemotherapy

PURPOSE

Identify prognostic factors that influence outcome after unrelated donor bone marrow transplantation in children with acute myeloid leukemia (AML).

PATIENTS AND METHODS

Included are 268 patients (age <or= 18 years) with AML in second complete remission (n = 142), relapse (n = 90), or primary induction failure (n = 36) at transplantation. All patients received bone marrow grafts from an unrelated donor and a myeloablative conditioning regimen. Cox regression models were constructed to identify risk factors that influence outcome after transplantation.

RESULTS

In this analysis, the only risk factor that predicted leukemia recurrence and overall and leukemia-free survival was disease status at transplantation. The 5-year probabilities of leukemia-free survival were 45%, 20%, and 12% for patients who underwent transplantation at second complete remission, relapse, and primary induction failure, respectively. As expected, risk of acute but not chronic graft-versus-host disease (GVHD) was lower with T-cell-depleted bone marrow grafts; T-cell-depleted grafts were not associated with higher risks of leukemia recurrence. We observed similar risks of leukemia relapse in patients with and without acute and chronic GVHD.

CONCLUSION

Children who underwent transplantation in remission had a superior outcome compared with children who underwent transplantation during relapse or persistent disease. Nevertheless, 20% of children who underwent transplantation in relapse are long-term survivors, suggesting that unrelated donor bone marrow transplantation is an effective therapy in a significant proportion of children with recurrent or primary refractory AML.

Reinduction platform for children with first marrow relapse of acute lymphoblastic Leukemia: A Children's Oncology Group Study[corrected]

PURPOSE

Treatment of childhood relapsed acute lymphoblastic leukemia (ALL) remains a significant challenge. The goal of the Children's Oncology Group (COG) AALL01P2 study was to develop a safe and active chemotherapy reinduction platform, which could be used to evaluate novel agents in future trials.

PATIENTS AND METHODS

One hundred twenty-four patients with ALL and first marrow relapse received three, 35-day blocks of reinduction chemotherapy: 69 with early relapse (ER; < 36 months from initial diagnosis) and 55 with late relapse (LR). Minimal residual disease (MRD) was measured by flow cytometry after each treatment block.

RESULTS

Second complete remission (CR2) rates at the end of block 1 in 117 assessable patients were 68% +/- 6% for ER (n = 63) and 96% +/- 3% for LR (n = 54; P < .0001). Five of seven patients with T-cell ALL (T-ALL) failed to achieve CR2. Among patients in CR2, MRD greater than 0.01% was detected at the end of block 1 in 75% +/- 7% of ER (n = 36) versus 51% +/- 8% of LR (n = 43; P = .0375) and 12-month event-free survival was 80% +/- 7% versus 58% +/- 7% in MRD-negative versus positive patients (P < .0005). Blocks 2 and 3 of therapy resulted in reduction of MRD burden in 40 of 56 patients who were MRD positive after block 1. Toxicity was acceptable during all three blocks with five deaths (4%) from infections.

CONCLUSION

The AALL01P2 regimen is a tolerable and active reinduction platform, suitable for testing in combination with novel agents in B-precursor ALL. Alternative strategies are needed for T-ALL. Serial MRD measurements were feasible and prognostic of outcome.

Outcomes after HLA-matched sibling transplantation or chemotherapy in children with acute lymphoblastic leukemia in a second remission after an isolated central nervous system relapse: a collaborative study of the Children's Oncology Group and the Center for International Blood and Marrow Transplant Research

In children with acute lymphoblastic leukemia (ALL) with isolated central nervous system (CNS) relapse and a human leucocyte antigen (HLA)-matched sibling, the optimal treatment after attaining second remission is unknown. We compared outcomes in 149 patients enrolled on chemotherapy trials and 60 HLA-matched sibling transplants, treated in 1990-2000. All patients achieved a second complete remission. Groups were similar, except the chemotherapy recipients were younger at diagnosis, less likely to have T-cell ALL and had longer duration (> or = 18 months) first remission. To adjust for time-to-transplant bias, left-truncated Cox's regression models were constructed. Relapse rates were similar after chemotherapy and transplantation. In both treatment groups, relapse rates were higher in older children (11-17 years; RR 2.81, P=0.002) and shorter first remission (< 18 months; RR 3.89, P<0.001). Treatment-related mortality rates were higher after transplantation (RR 4.28, P=0.001). The 8-year probabilities of leukemia-free survival adjusted for age and duration of first remission were similar after chemotherapy with irradiation and transplantation (66 and 58%, respectively). In the absence of an advantage for one treatment option over another, the data support use of either intensive chemotherapy with irradiation or HLA-matched sibling transplantation with total body irradiation containing conditioning regimen for children with ALL in second remission after an isolated CNS relapse.

Allergic reactions to E. coli L-asparaginase do not affect outcome in childhood B-precursor acute lymphoblastic leukemia: a Children's Oncology Group Study

We describe the outcome of children with B-precursor acute lymphoblastic leukemia registered on Pediatric Oncology Group 8602 who switched to Erwinia asparaginase (ASP) due to an allergy to the Escherichia coli product. Between February 1986 and January 1991, children in complete remission after induction that included intramuscular E. coli ASP (6000 U/m2x6) were randomized for consolidation. One regimen included intensive weekly intramuscular E. coli ASP (25,000 U/m2/wkx24). In case of an allergic reaction to E. coli ASP, Erwinia ASP was substituted at the same dose and schedule. Of the 540 eligible patients, 408 switched to Erwinia ASP due to an allergic reaction. Allergic reactions were significantly associated with younger age, white race, and standard-risk acute lymphoblastic leukemia. Multivariate Cox analysis adjusting for these factors demonstrated no correlation between the switch per se or the timing of the switch and event-free survival.

Specific extra chromosomes occur in a modal number dependent pattern in pediatric acute lymphoblastic leukemia

Children with acute lymphoblastic leukemia (ALL) and high hyperdiploidy (>50 chromosomes) are considered to have a relatively good prognosis. The specific extra chromosomes are not random; extra copies of some chromosomes occur more frequently than those of others. We examined the extra chromosomes present in high hyperdiploid ALL to determine if there were a relation of the specific extra chromosomes and modal number (MN) and if the extra chromosomes present could differentiate high hyperdiploid from near-triploid and near-tetraploid cases. Karyotypes of 2,339 children with ALL and high hyperdiploidy at diagnosis showed a distinct nonrandom sequential pattern of gain for each chromosome as MN increased, with four groups of gain: chromosomes 21, X, 14, 6, 18, 4, 17, and 10 at MN 51-54; chromosomes 8, 5, 11, and 12 at MN 57-60; chromosomes 2, 3, 9,16, and 22 at MN 63-67; chromosomes 1, 7 13, 15, 19, and 20 at MN 68-79, and Y only at MN >or=80. Chromosomes gained at lower MN were retained as the MN increased. High hyperdiploid pediatric ALL results from a single abnormal mitotic division. Our results suggest that the abnormal mitosis involves specific chromosomes dependent on the number of chromosomes aberrantly distributed, raising provocative questions regarding the mitotic mechanism. The patterns of frequencies of tetrasomy of specific chromosomes differs from that of trisomies with the exception of chromosome 21, which is tetrasomic in a high frequency of cases at all MN. These results are consistent with different origins of high hyperdiploidy, near-trisomy, and near-tetrasomy.

Prognostic significance of cytogenetically detected chromosome 21 anomalies in childhood acute lymphoblastic leukemia: a Pediatric Oncology Group study

Chromosome anomalies have been shown to have prognostic significance in children with acute lymphoblastic leukemia (ALL). Chromosome 21 was evaluated for its ability to predict outcome when found in either a single copy (the Mono21 group) or when involved in a structural aberration (the Misc21 group). Both anomalies were associated with an increased risk of failure for patients with standard-risk ALL, rather than higher-risk ALL. Event-free survival was 50.0% at 5 years and 48.4% at 8 years for standard-risk patients with Mono21+Misc21, compared with 77.8 and 75.5%, respectively, for standard-risk patients without these anomalies of chromosome 21. There was no significant difference in outcome between the Mono21 and the Misc21 group (P = 0.10). Mono21 and Misc21 were determined to be independently prognostic whether or not the primary leukemic clone had fewer than 45 chromosomes. The frequency of an adverse outcome was comparable to other poor prognosis subgroups such as hypodiploidy (<45 chromosomes), t(9;22), or t(4;11), all of which have been targeted for aggressive therapy even if the case is otherwise standard risk.

Intensified PEG-L-asparaginase and antimetabolite-based therapy for treatment of higher risk precursor-B acute lymphoblastic leukemia: a report from the Children's Oncology Group

The Pediatric Oncology Group 9203 pilot protocol was designed to determine the feasibility of delivering 29 biweekly doses of polyethylene glycol (PEG)-L-asparaginase, on a backbone of intensive multiagent antimetabolite-based consolidation and maintenance in higher risk B-precursor acute lymphoblastic leukemia. Between June 1992 and August 1993, 34 patients were enrolled on this limited institution pilot. The 5-year event-free survival (+/-standard error) and overall survival (+/-standard error) were 68+/-8% and 76+/-7%, respectively. Excessive toxicities attributed to PEG-L-asparaginase and myelosuppression associated with cytosine arabinoside were encountered during consolidation resulting in early study closure and modification of therapy for those already enrolled. Ninety-two percent of methotrexate/cytosine arabinoside cycles were associated with grades 3 to 4 myelosuppression, and 24% resulted in delays in therapy of more than 7 days. Fifteen PEG-L-asparaginase related toxicities occurred in 13 patients (8 allergy, 4 pancreas, 2 central nervous system, and 1 hemorrhage). Intensification of therapy with PEG-L-asparaginase resulted in event-free survival and overall survival comparable to other studies of the same time period without the use of agents associated with long-term complications, such as anthracyclines, epipodophyllotoxins, and alkylating agents. However, excessive toxicity occurred with intensified PEG-L-asparaginase and antimetabolite based therapy delivered on this schedule.

Worse outcome and more chronic GVHD with peripheral blood progenitor cells than bone marrow in HLA-matched sibling donor transplants for young patients with severe acquired aplastic anemia

We analyzed the outcome of 692 patients with severe aplastic anemia (SAA) receiving transplants from HLA-matched siblings. A total of 134 grafts were peripheral blood progenitor cell (PBPC) grafts, and 558 were bone marrow (BM) grafts. Rates of hematopoietic recovery and grades 2 to 4 chronic graft-versus-host disease (GVHD) were similar after PBPC and BM transplantations regardless of age at transplantation. In patients older than 20 years, chronic GVHD and overall mortality rates were similar after PBPC and BM transplantations. In patients younger than 20 years, rates of chronic GVHD (relative risk [RR] 2.82; P = .002) and overall mortality (RR 2.04; P = .024) were higher after transplantation of PBPCs than after transplantation of BM. In younger patients, the 5-year probabilities of overall survival were 73% and 85% after PBPC and BM transplantations, respectively. Corresponding probabilities for older patients were 52% and 64%. These data indicate that BM grafts are preferred to PBPC grafts in young patients undergoing HLA-matched sibling donor transplantation for SAA.

Bone marrow transplantation for severe aplastic anemia: a randomized controlled study of conditioning regimens

The addition of antithymocyte globulin (ATG) to a regimen of high-dose cyclophosphamide has been advocated to enhance engraftment after allogeneic bone marrow transplantation (BMT) for severe aplastic anemia (SAA). In a prospective clinical trial, 134 patients were randomly assigned to receive cyclophosphamide alone or in combination with ATG. All patients received T-cell-replete bone marrow from an HLA-matched sibling. With a median follow-up of 6 years, the 5-year probabilities of survival were 74% for the cyclophosphamide alone group and 80% for the cyclophosphamide plus ATG group (P = .44). Graft failure and graft-versus-host disease (GVHD) rates were similar in both groups. With the survival rates achieved, this study is not adequately powered to detect significant differences between the 2 treatment groups. In conclusion, the results of allogeneic BMT for SAA have improved over time related to advances in supportive care. The addition of ATG to the preparative regimen did not significantly improve the outcome.

Methotrexate pharmacokinetics in infants with acute lymphoblastic leukemia

PURPOSE

We performed a pharmacokinetic evaluation of methotrexate (MTX) in infants with acute lymphoblastic leukemia enrolled on the Pediatric Oncology Group (POG) 9407 Infant Leukemia Study to evaluate the effects of age on MTX pharmacokinetics and pharmacodynamics.

METHODS

A pharmacokinetic database of 61 patients was developed by combining MTX data obtained from 16 patients in a pharmacokinetic sub-study with data obtained for clinical care in other patients enrolled on the POG 9407 protocol. The data were analyzed for the first dose of MTX given to patients in induction/intensification therapy. Patients received MTX (4 g/m2) over 24 h at week 4 of therapy. Toxicity data were also reviewed to evaluate the incidence of common MTX toxicities during the first 6 weeks of therapy (the induction/intensification phase).

RESULTS

Steady-state clearance (mean+/-standard deviation) for infants aged 0-6 months was 89+/-32 ml/min/m2 compared to 111+/-40 for infants aged 7-12 months (P=0.030). In the subgroup of infants aged 0-3 months the mean steady-state clearance was 84+/-30 ml/min/m2 (P=0.026 vs. the 7-12-month group). The incidence of renal toxicity (all grades) during induction/intensification therapy was 23% in the 0-3 months age group compared to 0% (for n=27) in the group 7-12 months of age (P=0.029). There were no significant differences in hepatoxicity or mucous membrane toxicity between age groups.

CONCLUSIONS

A modest difference in steady-state MTX clearance is observed between younger infants (0-6 months) and older infants (7-12 months). Very young infants (0-3 months) also experienced a slightly higher incidence of renal toxicity during induction/intensification therapy. Steady-state clearance for the older infants is similar to values reported for children in other studies.

Risk- and response-based classification of childhood B-precursor acute lymphoblastic leukemia: a combined analysis of prognostic markers from the Pediatric Oncology Group (POG) and Children's Cancer Group (CCG)

The Children's Cancer Group (CCG) and the Pediatric Oncology Group (POG) joined to form the Children's Oncology Group (COG) in 2000. This merger allowed analysis of clinical, biologic, and early response data predictive of event-free survival (EFS) in acute lymphoblastic leukemia (ALL) to develop a new classification system and treatment algorithm. From 11 779 children (age, 1 to 21.99 years) with newly diagnosed B-precursor ALL consecutively enrolled by the CCG (December 1988 to August 1995, n=4986) and POG (January 1986 to November 1999, n=6793), we retrospectively analyzed 6238 patients (CCG, 1182; POG, 5056) with informative cytogenetic data. Four risk groups were defined as very high risk (VHR; 5-year EFS, 45% or below), lower risk (5-year EFS, at least 85%), and standard and high risk (those remaining in the respective National Cancer Institute [NCI] risk groups). VHR criteria included extreme hypodiploidy (fewer than 44 chromosomes), t(9;22) and/or BCR/ABL, and induction failure. Lower-risk patients were NCI standard risk with either t(12;21) (TEL/AML1) or simultaneous trisomies of chromosomes 4, 10, and 17. Even with treatment differences, there was high concordance between the CCG and POG analyses. The COG risk classification scheme is being used for division of B-precursor ALL into lower- (27%), standard- (32%), high- (37%), and very-high- (4%) risk groups based on age, white blood cell (WBC) count, cytogenetics, day-14 marrow response, and end induction minimal residual disease (MRD) by flow cytometry in COG trials.

Bone marrow transplants from mismatched related and unrelated donors for severe aplastic anemia

For patients with acquired severe aplastic anemia without a matched sibling donor and not responding to immunosuppressive treatment, bone marrow transplantation from a suitable alternative donor is often attempted. We examined risks of graft failure, graft-versus-host disease and overall survival after 318 alternative donor transplants between 1988 and 1998. Sixty-six patients received allografts from 1-antigen and 20 from >1-antigen mismatched related donors; 181 from matched and 51 from mismatched unrelated donors. Most patients were young, had had multiple red blood cell transfusions and poor performance score at transplantation. We did not observe differences in risks of graft failure and overall mortality by donor type. The probabilities of graft failure at 100 days after 1-antigen mismatched related donor, >1-antigen mismatched related donor, matched unrelated donor and mismatched unrelated donor transplants were 21, 25, 15 and 18%, respectively. Corresponding probabilities of overall survival at 5 years were 49, 30, 39 and 36%, respectively. Although alternative donor transplantation results in long-term survival, mortality rates are high. Poor performance score and older age adversely affect outcomes after transplantation. Therefore, early referral for transplantation should be encouraged for patients who fail immunosuppressive therapy and have a suitable alternative donor.