The survival of relapsed acute myeloid leukemia (AML) after autologous hematopoietic stem cell transplantation (Autologous 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 regimens (RIC, n=60) reported to CIBMTR. After a median follow-up of 58 months (range 2–160), the probability of treatment-related mortality (TRM) was 44% (95%CI 38–50) at 1-year. The 5-year incidence of relapse and overall survival (OS) was 32% (95%CI 27–38) and 22% (95%CI 18–27), respectively. In multivariate analysis significantly better OS was observed with RIC regimens (Hazard Ratio (HR) 0.51, 95%CI 0.35–0.75, p<0.001), with Karnofsky performance status (KPS) ≥90% (HR 0.62, 95%CI 0.47–0.82, p=0.001) and in CMV-negative recipients (HR 0.64, 95%CI 0.44–0.94, p=0.022). Longer interval (>18 months) from Autologous HCT to URD Allo-HCT was associated with significantly lower Relapse risk (HR 0.19, 95%CI 0.09–0.38, p<0.001) and improved LFS (HR 0.53, 95%CI 0.34–0.84, p=0.006). URD Allo-HCT after Autologous HCT relapse results in 20% long-term leukemia-free survival, with best results with longer interval to secondary URD transplantation, KPS ≥90%, in complete remission, and using RIC regimens. Further efforts to reduce TRM and relapse are still needed.
AML; Unrelated Donor; Transplantation; Allogeneic; Autologous
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 post-transplant relapse.
Design and methods
We reviewed outcome data for 28 patients with DS-AML reported to the Center for International Blood and Marrow Transplant Research (CIBMTR) 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 (HR 2.84, p<0.001; 62% vs. 37%) and transplant-related mortality (HR 2.52, p=0.04; 24% vs. 15%) were significantly higher for DS-AML compared to non-DS AML. Overall mortality risk (HR 2.86, p<0.001; 21% vs. 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 multi-center effort to pilot strategies aimed at lowering both transplant-related mortality and relapse risks.
hematopoietic stem cell transplantation; Down syndrome; trisomy 21; AML; ALL; relapse; pediatric
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.
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.
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.
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.
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.
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.
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.
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 aged 1–15 years with acute lymphoblastic leukemia (ALL) in second complete remission (CR). All patients had their first bone marrow relapse within 3 years from diagnosis. Cox regression models were constructed to examine for differences in transplant-outcome by donor source. Risks of grade 2–4 acute GVHD and chronic GVHD, when compared to HLA-matched sibling transplants, were higher after matched unrelated donor BM (RR 2.42, p=0.001; RR 5.12, p<0.001, respectively), mismatched BM (RR 3.24, p<0.001; 5.19, p<0.001, respectively) and cord blood (RR 2.67, p<0.001; 2.54, p=0.024, respectively) transplants. Though non-relapse 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, 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.
acute lymphoblastic leukemia; unrelated donor transplant; early relapse
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/m2 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/m2 once per day (10 SER patients [one by MRD, nine by PPR]) or 400 mg/m2 once per day (38 RER patients; 12 SER patients [three by MRD, nine by PPR]).
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).
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.
Administration of L-asparaginase is limited by hypersensitivity reactions mediated by anti-asparaginase antibodies. To overcome this problem, native E. coli L-asparaginase was conjugated to polyethylene glycol 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. Between 1988-1992, the Pediatric Oncology Group (POG) conducted a Phase II, randomized trial to compare the efficacy and toxicity of PEG-L-asparaginase compared to native E. coli asparaginase in a standard reinduction regimen for children with acute lymphoblastic leukemia in second bone marrow relapse.
All patients (n=76) received standard doses of vincristine and prednisone. Non-hypersensitive patients (n = 34) were randomized to receive either PEG-L-asparaginase 2,500 IU/m2/dose intramuscularly on days 1 and 15 (Treatment I) or native E. coli asparaginase 10,000 IU/m2/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.
The response rate for the total study population was 51% and there was no difference in response between the randomized groups, (p = 0.73, (exact χ2, two-sided). Toxicity was minimal. No unexpected or previously unreported adverse reactions occurred. Results of pharmacologic studies are reported and recommendations for dosing of PEG-L-asparaginase in hypersensitive patients are made.
Asparaginase; Relapsed Acute Lymphoblastic Leukemia (ALL); Reinduction chemotherapy; Hypersensitivity
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.
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.
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% versus 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.
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.
Acute lymphocytic leukemia; Phase III clinical trial; Prognostic factors; Minimal residual disease
The aim of this study was to identify risk factors associated with progression-free survival in patients with Ewing sarcoma undergoing autologous stem cell transplantation (ASCT); 116 patients underwent ASCT in 1989-2000 and reported to the Center for International Blood and Marrow Transplant Research. Eighty patients (69%) received ASCT as first-line therapy and 36 (31%), for recurrent disease. Risk factors affecting ASCT were analyzed with use of the Cox regression method. Metastatic disease at diagnosis, recurrence prior to ASCT and performance score <90 were associated with higher rates of disease recurrence/progression. Five-year probabilities of progression-free survival in patients with localized and metastatic disease at diagnosis who received ASCT as first-line therapy were 49% (95% CI 30 – 69) and 34% (95% CI 22 – 47) respectively. The 5-year probability of progression-free survival in patients with localized disease at diagnosis, and received ASCT after recurrence was 14% (95% CI 3 – 30). Progression-free survival rates after ASCT are comparable to published rates in patients with similar disease characteristics treated with conventional chemotherapy, surgery and irradiation suggesting a limited role for ASCT in these patients. Therefore, ASCT if considered should be for high-risk patients in the setting of carefully controlled clinical trials.
Autologous transplant; Ewing sarcoma; Progression-free survival
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.
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, ≥ 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 ≥ 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 ≥ 3.
Pretransplantation variables delineate subgroups with different outcomes. HSCT during relapse can achieve long-term survival in selected patients with acute leukemia.
Rhabdomyosarcoma (RMS), the most common soft-tissue sarcoma in children, is cured with conventional therapy in 70%. However, 5 year survival for those who relapse is about 30% and drops to about 15% for those with unfavorable histologies (alveolar/undifferentiated subtypes). We describe outcomes of 62 subjects receiving autologous blood/bone marrow transplants for RMS between 1989 and 2003 and reported to CIBMTR. Histological subtype was confirmed by reviewing pathology reports. Transplant-related mortality (TRM), progression-free survival (PFS) and survival were evaluated. Overall 73% of subjects were < 20 years; 39% had cancer bulk >5cm, 63% had metastasis at diagnosis, 55% had unfavorable histologies, 92% had cancer responsive to chemotherapy pretransplant and 67% were in 1st remission. The 1-year TRM was 5% (95% CI, 1–12%) and the 5 year PFS and survival were 29% (95% CI, 18–41%) and 32% (95% CI, 21–44%) respectively. There was only a 4% relapse rate after the first year. There were no differences in 5 year PFS or survival based on histological subtype, transplant in 1st remission vs. relapse (36% vs. 29%; p=0.5), or transplantation for poor-risk histologies in 1st remission vs. relapse (34% vs. 33%; p=0.9). Our data indicate that autotransplants for RMS disease are typically done in patients with disease responsive to chemotherapy pretransplant, with approximately one-third long-term survivors. Despite high risk factors, we also found a low TRM, perhaps reflecting the migration from marrow to blood stem cells as the graft source. Even when performed after relapse for alveolar/undifferentiated histologies, long-term survivals were seen seemingly better than results with conventional therapies.
Rhabdomyosarcoma; autotransplant; soft-tissue sarcoma
We examined the role of hematopoietic cell transplantation (HSCT) for patients aged ≤18 years with refractory or recurrent Burkitt (n=41), lymphoblastic (n=53), diffuse large B cell (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, marrow 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 diffuse large B cell (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<0.01). 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 histologic sub-types.
Non-Hodgkin lymphoma; allogeneic HSCT; autologous HSCT
Recent genomic profiling of childhood acute lymphoblastic leukemia (ALL) identified a novel high-risk subtype with a gene expression signature resembling Philadelphia chromosome-positive ALL and a poor prognosis (Ph-like ALL). However, the role of inherited genetic variation in Ph-like ALL pathogenesis remains unknown. In a genome-wide association study (GWAS) of 511 ALL cases and 6,661 non-ALL controls, we identified a single susceptibility locus for Ph-like ALL (GATA3, rs3824662, P=2.17×10−14, odds ratio [OR]=3.85, for Ph-like ALL vs. non-ALL; P=1.05×10−8, OR=3.25, for Ph-like ALL vs. non-Ph-like ALL) that was independently validated. The rs3824662 risk allele was associated with somatic lesions underlying Ph-like ALL (i.e., CRLF2 rearrangement, JAK mutation, and IKZF1 deletion) and directly influenced GATA3 transcription. Finally, GATA3 SNP genotype was also associated with early treatment response and the risk of ALL relapse. Our results provide insights into interactions between host and tumor genomes and their importance in ALL pathogenesis and prognosis.
We examined transplant outcomes after second HLA-matched sibling transplants for primary (16%) and secondary (84%) graft failure in 166 patients with severe acquired aplastic anemia. Performance scores were < 90 in 67% of patients. Most (88%) transplantations used the same donor for both transplants and 84% of second transplants used bone marrow graft. We identified two prognostic factors: inter-transplant interval (surrogate for primary graft failure and early secondary graft failure) and performance status. Shorter inter-transplant interval (≤3 months) and poor performance score (<90) at second transplantation were associated with high mortality. The 8-year probabilities of overall survival when second transplantation was ≤ 3 and > 3 months from first transplant in patients with performance scores of 90–100% were 56% and 76%, respectively. Corresponding probabilities in patients with lower performance scores were 33% and 61%. The predominant cause of failure after second transplantation was non-engraftment (72 of 166 patients) and frequent in patients with primary or early secondary graft failure (51 of 72; 71%). Therefore, novel approaches including conditioning regimens with greater immunosuppression should be explored for these patients.
severe aplastic anemia; second transplantation; graft failure
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, non-irradiation regimens have been explored. The aim of this study is to compare outcomes after irradiation and non-irradiation regimens in 148 FA patients and identify risk factors impacting upon HCT outcomes. Hematopoietic recovery, acute and chronic graft-versus-host disease and mortality were similar after irradiation and non-irradiation regimens. In both groups recipient 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 non-irradiation regimens, p=0.61. In view of the high risk of cancer and other radiation related effects on growth and development, these results support the use of non-irradiation preparatory regimens. As the peak time for developing solid tumors after HCT is 8–9 years, longer follow up is required before definitive statements can be made regarding the impact of non-irradiation regimens on cancer risk.
Fanconi anemia; matched sibling donor; conditioning regimen; survival; graft versus host disease
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 ≤ 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.
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.
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.
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.
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.
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.
Uridine diphosphate galactose 4-epimerase and phosphomannose isomerase-deficient mutants of Escherichia coli O111:B4 were studied to test the hypothesis that in E. coli a specific relationship exists between O antigenicity, virulence, and capacity to resist phagocytosis. The first mutant, designated J-5, produces a cell wall lipopolysaccharide, the side chains of which do not contain galactose, glucose, N-acetylglucosamine, or colitose. The second mutant produces a cell wall lipopolysaccharide which lacks only colitose. The capacity of these various organisms to kill mice was strikingly different. E. coli O111 was 1000 times as virulent as J-5, and 100 times as virulent as L-2. The capacity of the organisms to kill mice was correlated with their ability to resist phagocytosis and to persist in the peritoneal cavity. The parent strain of O111 resisted phagocytosis by macrophages in vivo and polymorphonuclear leukocytes in vitro. The mutants did not, and the organism most deficient in the saccharide component of its LPS was most susceptible to phagocytosis and least virulent. These results were corroborated by growing the mutants in appropriately supplemented media which permitted the synthesis of complete LPS, reversed the susceptibility to phagocytosis, and restored virulence. Finally, serological reactivity was consistent with previous observations which had demonstrated that the O antigenicity of E. coli is determined by the saccharide composition of its cell wall lipopolysaccharide. Despite the difference in the capacity of the various log-phase organisms to kill mice when injected intraperitoneally, purified lipopolysaccharides extracted from them did not differ significantly in their capacity to kill or produce fever. Thus virulence was shown to be independent of endotoxin activity which in turn seemed to be unrelated to the saccharide composition of the cell wall LPS. Collectively, these data provide at least a partial molecular definition of virulence in E. coli by demonstrating that the presence or absence of specific sugars in its cell wall lipopolysaccharide is a determinant of its antiphagocytic capacity and its virulence.
Plasma steady state methotrexate (MTX) level and red blood cell (RBC) MTX and folate concentrations were evaluated in 1124 children with newly diagnosed acute lymphoblastic leukemia (ALL) enrolled on the Pediatric Oncology Group studies 9005 (lower risk; Regimens A and C) and 9006 (higher risk; Regimen A). These regimens included intermediate dose MTX (1 gram/m2) given as a 24 hour infusion every other week for 12 doses during intensification. Plasma MTX level was evaluated at the end of MTX infusions. RBC MTX and folate concentrations were measured at the end of intensification. The five year continuous complete remission (CCR) was 76 ± 1.4% versus 85 ± 3.0% for those patients with steady state MTX levels ≤ and > 14 µM, respectively (p=0.0125). Hispanic children had significantly reduced median steady state MTX levels, 8.7 µM, compared to non-Hispanic children, 9.95 µM (p=0.0015), but this did not correlate with a difference in outcome. Neither RBC MTX, RBC folate, nor the RBC MTX:folate ratio identified children at increased risk of failure.
Red Blood Cell Methotrexate and Folate; Childhood Acute Lymphoblastic Leukemia
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.
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.
ARID5B polymorphisms are important determinants of childhood ALL susceptibility and treatment outcome, and they contribute to racial disparities in this disease.
Cytogenetics play a major role in determining the prognosis of patients with AML. However, the existing cytogenetics classifications were developed on chemotherapy-treated patients and may not be optimal for patients undergoing allogeneic hematopoietic cell transplantation (HCT). We studied 821 adult patients reported to the CIBMTR who underwent HCT for AML in first or second CR between 1999 and 2004. We compared the ability of the 6 existing classifications to stratify patients by overall survival (OS). We then defined a new schema specifically applicable to HCT patients using this patient cohort. Under this CIBMTR schema, inv(16) is favorable, complex karyotype (4+ abnormalities) is adverse, and all other classified abnormalities are intermediate in predicting survival after HCT (5y OS 64%, 18%, and 50%, respectively, p=0.0001). This schema stratified patients into 3 groups with similar non-relapse mortality, but significantly different incidences of relapse, overall and leukemia-free survival. It applied to patients regardless of their disease status (CR1 or CR2), donor type (MRD or URD), 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.
AML; cytogenetics; stem cell transplantation
Failure of remission-induction therapy is a rare but highly adverse event in children and adolescents with acute lymphoblastic leukemia (ALL).
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.
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.
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.)
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.
Using a genome-wide approach, 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
We performed a genome-wide interrogation of 476,796 germline SNPs to identify genotypes that predicted MRD in two independent cohorts of children with newly diagnosed ALL: 318 patients on St. Jude trials Total XIIIB and XV and 169 patients on a Children’s Oncology Group (COG) trial P9906.
Main Outcome Measures
MRD at the end of induction therapy, measured by flow cytometry.
There were 102 SNPs associated with MRD in both cohorts (P≤0.0125), including 5 SNPs in the interleukin 15 (IL15) gene. A high proportion, 21 of these 102 SNPs, also predicted hematologic relapse (P<0.05). 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 also associated with early response, relapse, or with drug disposition.
Host genetic variability affected treatment response for childhood ALL, and germline variants may exert their effects on MRD by effects on leukemic cell biology and on host disposition of antileukemic drugs.