Acute Myeloid Leukemia Protocols Research Articles

Development of treatment and clinical results in childhood acute myeloid leukemia in Slovenia in the period from 1991 to 2010

A review of treatment and survival of children with acute myeloid leukemia (AML) in Slovenia from 1991 to 2010. We collected demographic data, information on the time, and course of treatment of patients with AML, which were classified in three risk groups and treated according to standard arm of BFM AML protocols 83, 93, 98, and 04. We assessed the rate of remission, event-free survival and overall survival, the incidence of relapse, the secondary neoplasms, secondary AML, the proportion of patients treated with hematopoietic stem cell transplantation (HSCT) and causes of death. The 2- and 5-year overall survival (5yOS) was estimated according to age group, risk group, the presence of remission, and the time of the treatment. There were 50 patients, 18 males (36 %) and 32 females (64 %) included in this study. Secondary AML was presented in four patients. Patients treated with HSCT were 18 (36 %), 9 of them in first remission. The 2-year overall survival (2yOS) was 63.7 ± 6.8 % and 5-year survival was 55.0 ± 7.2 %. Differences in survival between age groups (0–5 years, 6–10 years and more than 10 years) was not significant. All patients in standard risk group lived for more than 2 years, in high-risk group 2yOS was 56.7 ± 7.7 % (p = 0.05). Patients who were in remission before second treatment block had 2yOS 77.8 ± 7.4 % and 5yOS 63.8 ± 8.8 %, compared to the patients who were not in remission (2yOSand 5yOS 37.5 ± 12.1 %, p = 0.001). The 2yOS in patients treated with HSCT in first remission was 62 %. There were 17 patients (34 %) who had relapse of the disease, 23 (64 %) patients died, 14 (61 %) due to progression of the disease. The results of treatment of AML in our center are comparable with other European centers. Survival was better in the standard risk group and in patients who were in remission before second treatment block. We observed a trend of improvement in survival in the time observed.

Acute leukemias of ambiguous lineage in adults: molecular and clinical characterization

Acute leukemias of ambiguous lineage represent a heterogeneous group of rare, poorly characterized leukemias with adverse outcome. No larger studies have yet performed a combined approach of molecular and clinical characterization of acute undifferentiated leukemia (AUL) and biphenotypic acute leukemia (BAL) in adults. Here we describe 16 adults with AUL and 26 with BAL and performed mutational as well as expression studies of genes with prognostic impact in acute leukemia (BAALC, ERG, MN1, WT1, and IGFBP7). AUL showed overexpression of these genes compared to T-lymphoblastic leukemia (T-ALL), B-precursor ALL, and to acute myeloid leukemia (AML). Genotype alterations were not detectable in AUL. BAL samples were characterized by frequent WT1 mutations (18 %) and BCR-ABL translocations (30 %). ALL-based treatment protocols induced complete remissions in 40 % and AML-like therapies in 22 % of AUL/BAL patients. The outcome in both groups was very poor; a long-term survival was only observed in patients undergoing allogeneic stem cell transplantation (SCT). Our findings indicate that AUL and BAL share important molecular and high-risk features of both myeloid and lymphoid leukemias. BAL patients exhibited genetic alterations, which can be targeted therapeutically. Importantly, ALL therapy might be more effective than AML protocols and AUL/BAL patients should be considered for allogeneic SCT.

Evidence That Activated Hedgehog Signaling Predicts for Poor Clinical Outcome in Acute Myeloid Leukemia

AbstractAbstract 1441▪▪This icon denotes a clinically relevant abstract Introduction:Hedgehog (Hh) signaling is essential in many developmental pathways and a growing body of evidence supports a role for aberrant activation of the Hh pathway in a variety of hematological malignancies including Acute Myeloid Leukemia (AML). Primary CD34+ myeloid blasts and cell lines preferentially demonstrate active Hh signaling suggesting that the Hh pathway may be involved in leukemic stem cell maintenance and survival (Bai et al. Leukemia. 2008;22(1):226-8). In addition, disruption of Hh signaling by targeted agents in this setting results in cell death and confers sensitivity to Ara-C in chemoresistant CD34+ leukemic cell lines (Kobune et al. Cancer Science. 2009;100(5):948-55). These findings provide a rationale for targeted disruption of the Hh pathway in AML and imply that the identification of Hh signaling in AML could correlate with disease that is refractory to standard induction therapy. Methods:To extend these previous findings, the presence of Hh signaling was assessed by the identification of nuclear GLI1 by immunofluorescence in tissue microarrays (TMA) prepared from a large cohort of primary human AMLs and the data correlated with clinical outcome. Presentation bone marrow trephine samples from patients diagnosed with AML between 1994 and 2005 were retrieved from the histopathology archives at Manchester Royal Infirmary. These biopsy samples were routinely processed, formalin-fixed, paraffin-embedded, and EDTA-decalcified. All material used for preparation of the TMA was residual diagnostic tissue, anonymized and consented for its use in research. Each TMA core contained at least 20% leukemic blasts and was representative of the whole biopsy sample. A specific and highly sensitive human GLI1 immunofluorescence assay was developed to visualize nuclear GLI1in four micron thick TMA sections. Human embryonic palatal mesenchymal (HEPM) cells stimulated with SHH and treated with the Hh antagonist saridegib (IPI-926) were used as staining controls to demonstrate assay specificity. To determine the cellular context of GLI1 staining in AML, a GLI1/CD34 double immunoflourescence assay was also developed. All samples were scanned in using the TissueGnostics TissueFAXS 2.0 system. The Cy5 channel was used to detect nuclear GLI1 and the Texas Red channel was used to detect CD34 when double staining was employed. A nuclear algorithm was developed to analyze the GLI1 staining using the TissueQuest version 2.0 software. Results:Of the 160 patient samples stained, 71 samples were evaluable after filtering on the basis of the presence of adequate tissue cores on the TMA and a full set of clinical follow-up data. All patients (36 male, 34 female, 1 unknown; age range 17 to 83 years at diagnosis with a median age of 53 years) received intensive chemotherapy according to standard UK MRC AML protocols and had follow-up data for up to 5124 days. Nuclear GLI1 as a function of total marrow cells showed a wide range of expression (0.0–32.0%) with a mean of 4.8% and a median of 3.1%. In a subset of cases with CD34 positive blasts, nuclear GLI1 co-expression could be readily identified as coexpressed in the CD34 positive cells. The degree of GLI1 expression did not correlate with AML subtype or cytogenetics. Correlation of GLI1 positivity with clinical features was performed and while no association with overall survival was observed in the total population, there was a significant decrease in overall survival in patients with secondary AML that had GLI1 levels above the median (HR = 0.18; p value = 0.0112). In addition, there was a significant correlation between GLI1 either above or below the median and remission status (i.e. complete remission, partial remission or refractory disease) with higher GLI1 levels observed in patients with refractory disease (p value = 0.045) and a more significant correlation with GLI1 values as a continuous variable and remission status (p value = 0.026). Conclusions:These data suggest that high levels of GLI1 predict for poor remission status in patients with AML and poor overall survival in patients with secondary AML. The presence of high levels of nuclear GLI1 in AMLs that are refractory to chemotherapy supports a role for Hh signaling in chemoresistance, particularly in patients with secondary AML, and provides a rationale for targeted inhibition of the Hh pathway in selected AML patients. Disclosures:Campbell:Infinity Pharmaceuticals, Inc.: Employment. Quigley:Infinity Pharmaceuticals, Inc.: Employment. Keilty:Infinity Pharmaceuticals, Inc.: Employment. Kelly:Infinity Pharmaceuticals, Inc.: Employment. McGovern:Infinity Pharmaceuticals, Inc.: Employment. Read:Infinity Pharmaceuticals, Inc.: Employment. Kutok:Infinity Pharmaceuticals, Inc.: Employment.

Residual disease detected by multidimensional flow cytometry signifies high relapse risk in patients with de novo acute myeloid leukemia: a report from Children's Oncology Group

AbstractEarly response to induction chemotherapy is a predictor of outcome in acute myeloid leukemia (AML). We determined the prevalence and significance of postinduction residual disease (RD) by multidimensional flow cytometry (MDF) in children treated on Children's Oncology Group AML protocol AAML03P1. Postinduction marrow specimens at the end of induction (EOI) 1 or 2 or at the end of therapy from 249 patients were prospectively evaluated by MDF for RD, and presence of RD was correlated with disease characteristics and clinical outcome. Of the 188 patients in morphologic complete remission at EOI1, 46 (24%) had MDF-detectable disease. Those with and without RD at the EOI1 had a 3-year relapse risk of 60% and 29%, respectively (P < .001); the corresponding relapse-free survival was 30% and 65% (P < .001). Presence of RD at the EOI2 and end of therapy was similarly predictive of poor outcome. RD was detected in 28% of standard-risk patients in complete remission and was highly associated with poor relapse-free survival (P = .008). In a multivariate analysis, including cytogenetic and molecular risk factors, RD was an independent predictor of relapse (P < .001). MDF identifies patients at risk of relapse and poor outcome and can be incorporated into clinical trials for risk-based therapy allocation. This study was registered at www.clinicaltrials.gov as NCT00070174.

Improved Survival Outcome of Childhood Acute Myeloid Leukemia with Intensified Chemotherapy in Chinese Children

With the use of intensive chemotherapy and hematopoietic stem cell transplantation (HSCT), the prognosis of childhood acute myeloid leukemia (AML) improved over the last 2 decades. Survival data of Chinese pediatric patients were seldom reported. The authors adopted modified UK Medical Research Council (MRC) AML protocols for treatment of childhood AML since 1994. From 1994 to 2008, the outcomes of Chinese AML patients were studied. Sixty-eight patients were studied. The median age at diagnosis was 9.9 years. Twenty-five patients (36.8%) had favorable cytogenetic karyotypes, including t(15;17), t(8;21) and inv(16). Complete remission (CR) rate was 91.2%. The relapse rate was 29.4%. For non-M3 patients, the 5-year overall survival (pOS) was 64% ± 7% and event-free survival (pEFS) was 53% ± 7%. For those non–good-risk patients who achieved CR, there were no significant differences in outcomes between patients who received HSCT in CR1 and those received chemotherapy alone (5-year pOS 80% ± 13% and 69% ± 9%, P = .52), 5-year pEFS 69% ± 15% and 55% ± 10%, P = .40). The pOS of the 20 relapsed patients was 29% ± 11%. Sixteen patients with t(8;21) and inv(16) had similar outcome with those without favorable cytogenetics (pOS 66% ± 12% versus 65% ± 7%, P = .39; pEFS 60% ± 11% versus 54% ± 8%, P = .45). Patients who achieved CR after 2 or more courses of chemotherapy and presenting white blood cell count (WBC) ≥ 100 × 109/L had poorer outcome (pOS 40% versus 80%P < .01; 43% versus 70%, P = .02, respectively). Intensified chemotherapy improved outcome of Chinese AML children. CR after first course of chemotherapy and WBC at diagnosis were important prognostic factors.

Childhood Acute Myeloid Leukemia: An Indian Perspective

Cure rates of childhood malignancies are inferior in India as compared to developed nations. There is paucity of data addressing outcome of childhood acute myeloid leukemia (AML) from India. Hence, this study was designed to assess the outcome of childhood AML in India over the last 2 decades, identify shortcomings and suggest remedial measures. A comprehensive search to identify studies addressing outcome of childhood AML from India was carried out. International Society of Paediatric Oncology annual meeting abstracts were searched to identify unpublished data. Clinicodemographic and outcome data were extracted from these abstracts. Outcomes of <500 patients have been published to date, with predominantly small single-center series from 5 cities. Several AML protocols with modifications to suit the logistics in India have been used. Administration of chemotherapy (standard as well as oral and outpatient based) with manageable toxicity has been deemed feasible. Survival outcomes are modest (23% to 53.8%) except for AML M3 (over 80%), with high early-death rates, relapse, along with abandonment. Few series have identified prognostic parameters and disease burden at diagnosis, and used cytogenetics (for risk stratification) or bone marrow transplant (BMT). There is a need for assessment of risk factors in Indian patients; administration of adequate and appropriate therapy, both upfront and after relapse; improvement in supportive care; and national data management infrastructure with updating/monitoring of registries along with better financial and social support initiatives. These multimodal and additive remedial measures could significantly improve outcome of childhood AML in India by reducing mortality, relapse, and abandonment.

Conventional Cytogenetics, Molecular Profiling, and Flow Cytometric Response Data Allow the Creation of a Two-Tiered Risk-Group System for Risk-Based Therapy Allocation In Childhood AML- a Report From the Children's Oncology Group

AbstractAbstract 761Conventional cytogenetics and morphologic response to induction chemotherapy have historically provided the tools for predicting outcome in patients with acute myeloid leukemia (AML). Several mutations are predictive of clinical outcome and have provided additional tools to help predict outcome in patients with AML without other risk features. Despite these recent advances, our ability to identify specific risk groups has been limited to a subset of patients, and nearly half of the patients with AML are regarded as having standard-risk (SR) disease. We inquired whether adding response by multidimensional flow cytometry (MDF) to data from conventional cytogenetics analysis and presence/absence of genomic alterations of FLT3 (FLT3-ITD), CEBPA, and NPM would provide a more robust risk-stratification system for risk-based therapy allocation. COG AML protocol AAML03P1 collected comprehensive cytogenetics characteristics, mutation profile (FLT3/ITD, CEBPA, and NPM mutation status), and MDF data on most of the 340 eligible patients enrolled on the study. Molecular and cytogenetic data were available for 275 of the 293 (94%) patients with responsive disease at the end of induction I. Disease-free survival (DFS) from the end of induction I was determined based on a combined molecular and cytogenetic risk profile. Risk status was defined based on the presence of t(8;21), inv(16), NPMc, and CEBPA mutations (favorable risk, FR) or the presence of monosomy 7, monosomy 5/del5q, and high allelic ratio FLT3-ITD (high risk, HR). On the basis of this allocation, 88 (32%) patients had FR AML, and 26 (10%) had HR AML. The remaining 161 (59%) patients without specific risk features were considered to have SR AML. DFS at 2 years from the end of induction I was 70%±12% for the FR cohort, 55% ±9% for the SR cohort, and 17%±20% for the HR cohort (p<0.001). The prevalence and prognostic significance of minimal residual disease (MRD) were assessed in the 103 patients with SR disease; 31 (30%) had evidence of MRD by MDF. DFS at 3 years from the end of induction I was significantly worse for those with MRD than for those without it (26%±21% vs. 67%±13%, p=0.01). Corresponding relapse risk in patients with or without MRD was 69%±21% and 30%±13%, respectively (p=0.011). We assessed the clinical impact of MRD in patients with HR or FR disease. Of the 18 patients with HR AML who had MRD data, 8 (44%) had MRD. DFS at 2 years for patients with HR disease with or without MRD was not significantly different (13%±23% vs. 36%±40%; p=0.127). Of the 73 patients with FR AML, MRD was detected in 12 (16%); MRD did not significantly influence DFS at 3 years from the end of induction I in those patients (45%±33% vs. 72%±17%, p=0.138). Thus, although the presence of MRD was significantly associated with worse outcome in patients with SR AML, similar significance could not be demonstrated in the FR or HR cohorts. Clinical outcomes of risk groups were reassessed after combining the MRD data with specific cytogenetic and molecular risk groups, i.e., patients with SR AML and MRD were added to the HR cohort, and those without MRD were added to the FR cohort. In the new risk-stratification system, 57 of 217 (26%) patients were in the HR cohort, and the remaining 160 (74%) patients were in the FR cohort. DFS at 3 years from induction I was 68%±9% for the FR cohort and 20%±16% (p<0.001) for the HR cohort. Cumulative incidence of relapse at 3 years from the end of induction I for those with FR or HR disease was 27%±9% and 71%±17%, respectively (p<0.001). Cytogenetics, molecular genotyping, and post-induction MDF analysis provide a robust means of stratifying all pediatric patients with AML into 2 risk groups with significantly different outcomes. This novel risk-allocation schema will be implemented in the upcoming COG Phase III AML trial. Disclosures:No relevant conflicts of interest to declare.

Prevalence and prognostic significance of KIT mutations in pediatric patients with core binding factor AML enrolled on serial pediatric cooperative trials for de novo AML

KIT receptor tyrosine kinase mutations are implicated as a prognostic factor in adults with core binding factor (CBF) acute myeloid leukemia (AML). However, their prevalence and prognostic significance in pediatric CBF AML is not well established. We performed KIT mutational analysis (exon 8 and exon 17) on diagnostic specimens from 203 pediatric patients with CBF AML enrolled on 4 pediatric AML protocols. KIT mutations were detected in 38 (19%) of 203 (95% CI, 14%-25%) patient samples of which 20 (52.5%) of 38 (95% CI, 36%-69%) involved exon 8, 17 (45%) of 38 (95% CI, 29%-62%) involved exon 17, and 1 (2.5%; 95% CI, 0%-14%) involved both locations. Patients with KIT mutations had a 5-year event-free survival of 55% (+/- 17%) compared with 59% (+/- 9%) for patients with wild-type KIT (P = .86). Rates of complete remission, overall survival, disease-free survival, or relapse were not significantly different for patients with or without KIT mutations. Location of the KIT mutation and analysis by cytogenetic subtype [t(8;21) vs inv(16)] also lacked prognostic significance. Our study shows that KIT mutations lack prognostic significance in a large series of pediatric patients with CBF AML. This finding, which differs from adult series and a previously published pediatric study, may reflect variations in therapeutic approaches and/or biologic heterogeneity within CBF AML. Two of 4 studies included in this analysis are registered at http://clinicaltrials.gov as NCT00002798 (CCG-2961) and NCT00070174 (COG AAML03P1).

Infantile mixed phenotype acute leukemia (bilineal and biphenotypic) with t(10;11)(p12;q23); MLL-MLLT10

We report a case of a 6-month-old boy with a mixed phenotype acute leukemia (MPAL), bilineal and biphenotypic immunophenotype (B-lymphoid lineage and combined B-lymphoid and monocytic lineage) with t(10;11)(p12;q23); MLL-MLLT10. He was treated with acute myeloid leukemia protocol and in complete remission at 7-month follow-up. To the best of our knowledge, this is the first reported MLL-MLLT10 rearranged case presenting as MPAL in an infant. From a clinical practice standpoint, this case illustrates the importance of detection of MLL rearrangement due to its prognostic implication and the effectiveness of flow cytometry immunophenotyping in diagnosing MPAL and monitoring minimal residual disease.

Acute Megakaryoblastic Leukemia (AMKL) in Children without Down Syndrome.

Abstract 482 Background:Acute megakaryoblastic leukemia (AMKL) in children without Down syndrome represents approximately 10% of pediatric acute myeloid leukemia (AML). Published reports regarding prognosis of non-Down syndrome children with AMKL vary; hence, some groups treat these patients as high-risk while others as standard-risk. As a result, the optimal treatment strategy, including the role of hematopoeitic stem cell transplant (HSCT), remains unclear. Methods:We reviewed the treatment and outcomes of patients with AMKL treated on two pediatric AML protocols. Pediatric Oncology Group (POG) 9421 (1995-99) included two cycles of induction chemotherapy with randomization to standard or high-dose DAT (daunorubicin, cytarabine, 6-thioguanine) followed by HSCT for children in remission with matched sibling donors or three cycles of consolidation chemotherapy with or without cyclosporine for those without suitable donors. St. Jude protocol AML02 (2002-2008) randomized patients during induction to receive high- or low-dose cytarabine with daunorubicin and etoposide (ADE). Patients without complete remission (CR) received gemtuzumab ozogamicin (GO) with induction 2 chemotherapy (ADE). After induction, AMKL patients with availabel donor proceeded to HSCT while those without donors received three cycles of consolidation chemotherapy including mitoxantrone and cytarabine. Comparisons of event-free survival (EFS) and overall survival (OS) were performed by Mantel-Haenszel log-rank test. Independent effect of HSCT on EFS or OS were analyzed by Cox proportional hazard model, with HSCT as time-dependent variable. Results:The 49 patients with AMKL treated on POG 9421 had a median age at diagnosis of 1.8 years (range 0.13-16.2 years), and a median leukocyte count of 13.5 × 109/L (range 0.3-98.4). The patient with the t(1;22) translocation remains in CR. 39 patients had CR after induction, 5 partial response and 4 no response with no difference between standard- and high-dose DAT. The 5-year EFS for all AMKL patients was 34.7% ± 7.5%. Of the 39 patients in CR, 6 underwent matched sibling HSCT, of whom 4 remain in CR, and the other 33 patients received consolidation chemotherapy, of whom 15 remain in continuous remission. The 5-year OS for patients undergoing HSCT was 66.7% ± 19.3% compared to 36.1% ± 8.4% for those receiving consolidation chemotherapy (p = 0.2). The 26 patients with AMKL treated on SJCRH AML02 had a median age at diagnosis of 1.2 years (range 0.21-11.2 years), and a median leukocyte count of 11.8 × 109/L (range 2.3-72.9). All 5 patients with the t(1;22) translocation achieved CR after one induction cycle, with negative minimal residual disease, and remain in CR after treatment with chemotherapy only. The 3-year EFS was 35.9% ± 12.9% for the other AMKL patients, significantly lower than the 61.5% ± 4.8% for non-AMKL patients (p = 0.026). The 3-years OS estimates are 100% for patients with t(1;22), 48% ± 14.1% for other AMKL patients, and 71.8% ± 4.4% for non-AMKL patients (p = 0.03). Of the 21 patients without t(1;22), 14 received HSCT with 7 survivors (3-year EFS 46.3 ± 17%) while 7 received chemotherapy with only one long-term survivor (3-year EFS 14.3 ± 9.4%) (p=0.55). Conclusions:AMKL patients with the t(1;22) translocation have excellent treatment outcome with chemotherapy alone. In contrast, AMKL patients without t(1;22) fared poorly, especially when they were treated with only chemotherapy. Additional studies of larger number of patients are needed to determine if they would benefit from HSCT. Disclosures:No relevant conflicts of interest to declare.

Successful Treatment of Congenital Acute Myeloid Leukemia (AML-M6) in a Premature Infant

Congenital acute myeloid leukemia (AML), and especially AML-M6 is a rare disease with a poor prognosis. Moreover, reports of treatment outcome of congenital AML-M6 in premature infants are not available. We report the first treated case of congenital AML-M6 in a premature girl, who received a full AML protocol. She presented with blueberry-muffin spots, anemia, high white blood cell count, and serious cardiopulmonary distress. Peripheral blood smears showed AML-M6 blasts. After treatment with a sequential low-dose cytarabine after birth and full-dose AML treatment according to the MRC-12 protocol at the age of 2 months, she now is in continuous complete remission for 4 years.

Prevalence and Prognostic Significance of c-KIT Mutations in Pediatric CBF AML Patients Enrolled on Serial CCG/COG Protocols.

Pediatric patients with core binding factor (CBF) acute myeloid leukemia (AML) [t(8;21) and inv(16)] typically have favorable outcome, yet 20–40% of patients will relapse, suggesting that additional events may impact disease response. Recently, mutations of the c-KIT receptor tyrosine kinase gene were implicated as a prognostic factor in adults with CBF AML. The prevalence and prognostic significance of c-KIT mutations in pediatric CBF AML has not been well established. We analyzed diagnostic specimens from 156 pediatric patients with CBF AML enrolled on serial AML protocols CCG 2891, 2961 and COG AAML03P1 with 3 different methodologies (direct sequencing, HPLC, and micro capillary electrophoresis) to identify mutations in c-KIT exons 8 and 17. Mutations were detected in 27 samples (17%); 13 (48%) involved exon 8, 13 (48%) involved exon 17, and 1 (4%) involved both regions. Of 15 inv(16) specimens with c-KIT mutations, 9 (60%) involved exon 8, 5 (33%) involved exon 17, and 1 (7%) affected both exons. In contrast, of 12 t(8;21) specimens with c-KIT mutations, 4 (33%) involved exon 8 whereas 8 (67%) affected exon 17. Clinical outcome data from 98 CBF AML patients enrolled on CCG 2961 was analyzed to determine the prognostic significance of c-KIT mutations in this patient population. CBF AML patients with c-KIT mutations had similar clinical characteristics (age, sex, race, presenting white blood cell count and blast percentage) to those CBF AML patients without c-KIT mutations. There was no difference in the rate of complete remission (CR) (c-KIT mutations, 88% vs. no mutation 92%; p=0.645), overall survival (OS) at 5 years from study entry (c-KIT mutation, 68% vs. no mutation 71%; p=0.733), or corresponding relapse risk (RR) from the time of CR (c-KIT mutations, 33% vs. no mutation 31%; p=0.92). The relative prognostic significance of the location of c-KIT mutation (i.e. exon 8 or exon 17) was also evaluated. No differences were found in CR rates (exon 8 mutation, 100% vs. exon 17 mutation, 75%; p= 0.467), OS from CR (exon 8 mutation, 86% vs. exon 17 mutation, 47%; p=0.088), or corresponding RR at 5 years from CR (exon 8 mutation, 29% vs. exon 17 mutation, 50%; p=0.517). This study demonstrates that the prevalence of c-KIT mutations in pediatric CBF AML patients enrolled on serial CCG/COG AML protocols is lower than that observed in adult studies. We found that c-KIT mutations lacked prognostic significance in pediatric CBF AML patients treated with intensive chemotherapy on CCG 2961, though there was a suggestion that patients with exon 17 mutations may have worse outcome. Outcome data from the entire cohort (CCG 2891, 2961 and COG AAML03P1) will be analyzed to determine whether this finding is significant with larger scale analysis.

The Presence of Central Nervous System Disease at Diagnosis in Pediatric Acute Myeloid Leukemia Does Not Affect Outcome.

Introduction: The presence of disease in the central nervous system (CNS) in pediatric acute myeloid leukemia (AML) is often thought to confer a worse prognosis. This study examined the outcome of children with AML who had CNS disease at diagnosis.Methods: Patients enrolled on Children's Oncology Group protocols 2891 (N=836)and 2961 (N=901) being treated for de novo AML were classified for the presence of CNS disease at diagnosis as: CNS1 (less than 5 WBC in the CSF with no blasts), CNS2 (less than 5 WBC in the CSF with blasts) or CNS3 (5 or more WBC in the CSF with blasts). CNS disease at diagnosis was then analysed for survival, patient characteristics and outcome using univariate analysis. Patients on these protocols were treated with intrathecal chemotherapy and not radiation therapy for their CNS disease.Results: For both AML protocols, the overall survival and event free survival were highest in patients with CNS2 disease but this was not significantly different from the survival of the CNS1 and CNS3 patients. [Display omitted] [Display omitted] Patients with CNS 2 and 3 disease were of significantly lower median age than CNS1 patients (p=0.001 in 2891 and p=0.005 in 2961). There was a significantly higher WBC count at diagnosis (p=0.001 in both studies), presence of hepatomegaly (p=0.001 in both studies), presence of splenomegaly (p=0.003 in 2891 and p=0.001 in 2961), FAB M2 morphology (p=0.001 in both studies) and FAB M4 morphology (p=0.001 in both studies) in patients with CNS2 and 3 disease compared to CNS 1 patients. Also, CNS2 and 3 patients had a significantly higher incidence of abnormal chromosome 16 (p=0.002 in 2891 and p=0.001 in 2961). In protocol 2891 significantly more CNS2 and 3 patients had hyperdiploid cytogenetics compared to CNS1 patients (p=0.016), and in protocol 2961 there were significantly more patients with t(8;21) in the CNS1 group (p=0.007). In terms of overall outcome, there was a significantly higher incidence of isolated CNS relapse in patients with CNS3 disease at diagnosis in the 2891 protocol (p=0.001), and in patients with both CNS2 and 3 disease at diagnosis in the 2961 protocol (p=0.001).Conclusion: Patients with CNS disease at diagnosis have similar survival to those without CNS disease, although they have an increased incidence of isolated CNS relapse. More aggressive CNS directed therapy may be warranted in this patient population.

Pharmacogenetics, Pharmacogenomics and Personalized Medicine: Are We There Yet?

The genetic basis of a differential response to drugs has been understood for a limited number of agents for over 30 years. This knowledge has generated hope that the individual basis for response to a wide range of drugs would be quickly known, and individualized drug selection and dosing would be possible for many or all disorders. Understanding the variable response to drugs seems particularly pressing in the field of oncology, in which the stakes are high (failure to cure cancer usually leads to death), drugs commonly have a narrow therapeutic index, and toxicities can be severe (a significant frequency of toxic death is a feature of most acute myeloid leukemia protocols, for example). However, in common with many new technologies, the generalizability and clinical application of pharmacogenetics has proved more challenging than expected. Difficulties include, in many examples, a modest clinical effect relative to genotype, therapy-specific, not broad, applicability and the very major challenge of unraveling the complexity of gene-gene interactions. In addition, ethical and economic challenges to the application of pharmacogenetics have moved to the fore in recent years, particularly in the context of racial differences in outcome of therapy. Genomic, rather than candidate gene approaches to identification of relevant loci are increasingly being explored, and significant progress is being made. However, greater understanding of the complexities of multiple gene modifiers of outcome, and the statistical challenge of understanding such data, will be needed before individualized therapy can be applied on a routine basis.

Results of the Japanese Childhood Acute Myeloid Leukemia 99 Protocol for Down Syndrome and Acute Myeloid Leukemia.

Purpose: Recent multi-institutional studies have reported that children with Down syndrome (DS) and acute myeloid leukemia (AML) have a favorable outcome with less intensive chemotherapy. Based on our previous trial (Kojima, et al: Leukemia ; 14:786, 2000), the Japanese Childhood AML Cooperative Study Group conducted the AML-Down protocol study designed for children with DS and AML.Patients and Method: Between February 2000 and June 2004, 72 children (44 boys, 28 girls; median age, 1 year; range, 7 months to 7 years) were enrolled in this study. The median white blood cell count was 5,800/10−9 L. The median follow-up period was 3 years (range, 9 months to 5 years). Acute megakaryocytic leukemia (M7) was diagnosed most often (90%). The treatment regimen consisted of 5 cycles of Ara C 100mg/m2 (1-hour infusion) x 7 days, THP-ADR 25mg/m2 x 2 days, and etoposide 150mg/m2 x 3days. No prophylaxis against CNS leukemia was included.Results: Among the 72 children, 69 achieved complete remission (CR) after 1 to 2 cycles of induction therapy, with no deaths occurring during the induction period. One of 3 patients with induction failure achieved CR after another intensified chemotherapy. Eight patients relapsed during chemotherapy. One relapsed while off therapy and successfully entered a second remission after an intensified chemotherapy, followed by an allogeneic bone marrow transplant. There was no CNS relapse alone, although 1 patient relapsed in the bone marrow and CNS simultaneously. Eight relapsed patients and 2 refractory patients died without achieving a remission. The cause of death was pneumonia in 4 patients and disease progression in 7 patients. One patient died from pneumonia during the first CR. The CR rate, 3-year survival rate, and event-free survival (EFS) rate were 97.2%, 84.4%, and 83.0%, respectively. In a univariate analysis of factors that predict EFS, we found that the presence of monosomy 7 cytogenetic abnormality at diagnosis, and response to induction therapy were predictive factors for EFS. Neither age older than 2 years nor higher white blood cell count at diagnosis were statistically significant risk factors. Children with monosomy 7 had more adverse outcomes than those without monosomy 7 (41.7% vs 86.4%, p=0.02).Discussion: Our AML protocol specified for children with DS and AML does not include high-dose Arac and is much less intensive than other protocols used for treatment of these children. However, this less intensive regimen leads to an excellent outcome. In contrast to a previous study reported from CCG (Children's Cancer Group) in the United States, age was not a significant risk factor. However, monosomy 7 is a poor prognostic factor in children with AML, whether or not they have DS. Our study strongly suggests that children with DS and AML can be treated successfully with a less intensive chemotherapy regimen that does not include high-dose Arac.

No evidence that FLT3 status should be considered as an indicator for transplantation in acute myeloid leukemia (AML): an analysis of 1135 patients, excluding acute promyelocytic leukemia, from the UK MRC AML10 and 12 trials

AbstractFetal liver tyrosine kinase 3 (FLT3) internal tandem duplications (ITDs) are powerful adverse prognostic indicators for relapse in acute myeloid leukemia (AML) but the most efficacious therapy for FLT3/ITD+ patients is currently unknown. We evaluated outcome according to FLT3/ITD status in 1135 adult patients treated according to United Kingdom Medical Research Council (UK MRC) AML protocols: 141 received an autograft, and 170 received a matched sibling allograft in first complete remission (CR). An FLT3/ITD was detected in 25% of patients and was an independent predictor for relapse (P < .001). It remained prognostic for increased relapse in patients who received a transplant (odds ratio [OR] = 1.91; 95% confidence intervals [CIs] = 1.13-3.21; P = .02), with no evidence of a difference in effect between patients who received an autograft (OR = 2.39; CIs = 1.24-4.62) and patients who received an allograft (OR = 1.31; CIs = 0.56-3.06) (test for interaction, P = .3) or between patients who did or did not receive a transplant (P = .4). These results were confirmed in an analysis of 186 patients randomized to receive or not receive an autograft in first CR and in a donor-versus–no donor analysis of 683 patients to assess the role of allograft (for latter, FLT3/ITD- OR = 0.70, CIs = 0.53-0.92; FLT3/ITD+ OR = 0.59, CIs = 0.40-0.87; test for interaction, P = .5). These results suggest that at present there is no strong evidence that FLT3 status should influence the decision to proceed to transplantation.

Pre-Treatment Cytogenetics Predict Complete Remission and Long-Term Outcome in Patients (Pts) ≥60 Years with Acute Myeloid Leukemia (AML): Results from Cancer and Leukemia Group B (CALGB) 8461.

Previous studies have identified broad cytogenetic risk groups in AML, by comparing outcome of pts with different recurring abnormalities, using cytogenetically normal pts as the reference group. Pts with better survival were considered as “favorable”, and those with worse outcome as “unfavorable” risk. To identify prognostic cytogenetic groups for complete remission (CR) and overall survival (OS), without the selection of a reference group, we used classification trees and tree-structured survival analysis (TSSA). We analyzed the outcome of 600 AML pts ≥60 years (yrs), enrolled in the prospective CALGB cytogenetic study 8461 and treated on CALGB front-line AML protocols. Analysis was restricted to cytogenetic aberrations occuring in ≥5 pts. Once prognostic cytogenetic abnormalities for CR and OS were identified, multivariable models were constructed. Median age was 68 (range, 60–86) yrs, and 98% had de novo AML. The most common karyotypes were normal (46%), complex with ≥3 abnormalities (complex ≥3, 19%), and ≥5 abnormalities (complex ≥5, 14%). Core binding factor (CBF) abnormalities, ie, inv(16) and t(8;21), occurred in 5%. Overall, 49.5% of pts achieved CR with only 7% (95%CI: 5%–9%) alive at 5 yrs. Table 1 shows prognostic cytogenetic risk groups identified by classification trees and TSSA for CR and OS, respectively.Table 1: Prognostic Cytogenetic Groups by Tree AnalysisCROSRisk groupCR rateRisk group5-yr OS (95% CI)Complex≥330%*CBF20 (6–20)%Abnormal, non CBF46%*<5 abnormalities without CBF or −78 (5–10)%Normal57%Complex≥50%CBF75%−70%*P<0.05 compared to CBF; CI, confidence intervalTable 2 shows the multivariable analyses adjusting for other baseline clinical variables. Only lower % circulating blasts (P=0.0002) and cytogenetic risk groups (P<0.0001) predicted CR. Compared to CBF pts, the odds of CR were significantly lower for pts with complex ≥3 and abnormal, non-CBF karyotypes, whereas the odds of CR for cytogenetically normal pts was not significantly different from CBF pts. For OS, cytogenetic risk groups (P<0.0001), older age (P=0.03), and higher WBC at diagnosis (P=0.02) predicted shorter survival. Compared to CBF pts, the risk of death was significantly higher for those with complex ≥5 karyotype, −7, and <5 abnormalities without CBF or −7.Table 2: Multivariable AnalysesCROSSignificant VariablesOR (95% CI)Significant VariablesHR (95% CI)% circulating blasts0.90 (0.84–0.95)Age1.28 (1.09–1.50)Cytogenetics group*WBC1.03 (1.01–1.04)Complex≥30.12 (0.05–0.33)Cytogenetics group*Abnormal, non CBF0.26 (0.10–0.65)Complex≥54.53 (2.80–7.32)Normal0.44 (0.18–1.09)−72.57 (1.39–4.76)<5 abnormalities without CBF or −71.62 (1.07–2.46)*CBF is the reference group; OR, odds ratio of achieving CR; HR, hazard ratio of death; CI, confidence intervalWe conclude that pre-treatment cytogenetics are predictive of CR and OS of older AML pts, particularly identifying pts with complex ≥5 karyotype and −7, who benefit minimally if at all from standard chemotherapy. Such pts may be better suited for investigational therapy or only supportive care.

Morphological diagnoses of the Japan adult leukemia study group acute myeloid leukemia protocols: central review.

A morphological review system of the Japan Adult Leukemia Study Group has developed from the AML-87 through the AML-92 experience. We reviewed 1427 (90%) of 1592 cases enrolled in the AML-87, -89, or -92 protocols for morphology; 1408 (88%) were eligible. The rate of diagnostic concordance between each institute and the Committee on Morphological Diagnosis ranged from 76% to 80%. Acute myeloid leukemia (AML) subtypes were as follows: AML M0, 27 (2%); M1, 179 (13%); M2, 472 (34%); M3, 358 (25%); M4, 265 (19%); M5, 57 (4%); M6, 39 (3%); and M7, 11 (1%). The reason for the high number of patients with AML M3 is that many M3 patients were enrolled in the AML-92 protocol, which contained all-trans-retinoic acid. AML M0, M6 and M7 belonged to the poor prognostic groups. Auer bodies were found in 284 (53%) of 538 patients who survived significantly longer than those without Auer bodies in AML-87/-89. In AML-92 except for AML M3, 259 (43%) of 602 cases were Auer+ and also showed better survival rates. The survival of patients with >50% myeloperoxidase (MPO)-positive blast cells was better than those with < or =50% MPO+ blast cells in AML-87/-89. This trend was also seen in AML-92 excluding M3. AML with trilineage dysplasia (AML/TLD) is characterized as a subtype of de novo AML that shows morphological dysplasia of mature hematopoietic cells on a background of leukemic blast cells The number of patients with AML/TLD was 89 (16.5%) of 545 patients reviewed in AML-87/-89. AML-92, except for M3, showed a higher rate of patients with TLD (161 cases; 27.6%) because there were no patients with TLD in the AML M3 group. Survival rates for AML/TLD were worse than those for AML/non-TLD in both the AML-87/-89 and -92 protocols. Eighty percent of all cases (793/986) entered in AML-92 were analyzed cytogenetically. Fifty-one cases were not available for karyotyping because of a lack of mitoses or inappropriate preparations. The most frequent karyotype was normal, which accounted for 34.2%. The t(15;17), t(8;21), and inv(16) karyotypes, which are regarded as good risk factors, were 23.8%, 9.2%, and 1.6%, respectively. Abnormal chromosomes 5, 7, t(9;22), and t(6;9) were considered to be poor or intermediate risk factors As a new system of karyotyping begins in the ongoing AML protocol, useful chromosomal data will be obtained in the near future.

Immunophenotyping Investigation of Minimal Residual Disease Is a Useful Approach for Predicting Relapse in Acute Myeloid Leukemia Patients

A high complete remission rate is currently achieved in patients with acute myeloid leukemia (AML). However, many patients eventually relapse due to the persistence of low numbers of residual leukemic cells that are undetectable by conventional cytomorphologic criteria (minimal residual disease [MRD]). Using immunophenotypic multiparametric flow cytometry, we have investigated in sequential studies (diagnosis and follow-up) the impact of MRD detection on the outcome of 53 AML patients that had achieved morphologic remission with standard AML protocols and displayed at diagnosis an aberrant phenotype. Patients were studied at diagnosis with a panel of 35 monoclonal antibodies in triple staining combinations for detection of aberrant or uncommon phenotypic features. According to these features, a patient's probe was custom-built at diagnosis for the identification of possible residual leukemic cells during follow-up. The level of MRD at the end of induction and intensification therapy correlated with the number of relapses and relapse-free survival (RFS). Thus, patients with more than 5 × 10−3 residual cells (5 residual cells among 1,000 normal bone marrow [BM] cells) identified as leukemic by immunophenotyping in the first remission BM showed a significant higher rate of relapse (67% v 20% for patients with less than 5 × 10−3 residual cells; P = .002) and a lower median RFS (17 months v not reached; P = .01). At the end of intensification, with a cut-off value of 2 × 10−3 leukemic cells, AML patients also separated into two distinct groups with relapse rates of 69% versus 32% (P = .02), respectively, and median RFS of 16 months versus not reached (P = .04). In addition, overall survival was also significantly related to the level of residual cells in the marrow obtained at the end of induction and particularly after intensification therapy (P = .008). Furthermore, we have explored whether residual disease was related with the functional expression of multidrug resistance (MDR-1) at diagnosis as assessed by the rhodamine-123 assay. Patients with ≥5 × 10−3 residual leukemic cells at the end of induction therapy had a significantly higher rhodamine-123 efflux (mean, 56% ± 24%) than those with less than 5 × 10−3 residual cells (mean, 32% ± 31%; P = .04). Finally, multivariate analysis showed that the number of residual cells at the end of induction or intensification therapy was the most important prognostic factor for prediction of RFS. Overall, our results show that immunophenotypical investigation of MRD strongly predicts outcome in patients with AML and that the number of residual leukemic cells correlates with multidrug resistance.

Immunophenotyping Investigation of Minimal Residual Disease Is a Useful Approach for Predicting Relapse in Acute Myeloid Leukemia Patients

AbstractA high complete remission rate is currently achieved in patients with acute myeloid leukemia (AML). However, many patients eventually relapse due to the persistence of low numbers of residual leukemic cells that are undetectable by conventional cytomorphologic criteria (minimal residual disease [MRD]). Using immunophenotypic multiparametric flow cytometry, we have investigated in sequential studies (diagnosis and follow-up) the impact of MRD detection on the outcome of 53 AML patients that had achieved morphologic remission with standard AML protocols and displayed at diagnosis an aberrant phenotype. Patients were studied at diagnosis with a panel of 35 monoclonal antibodies in triple staining combinations for detection of aberrant or uncommon phenotypic features. According to these features, a patient's probe was custom-built at diagnosis for the identification of possible residual leukemic cells during follow-up. The level of MRD at the end of induction and intensification therapy correlated with the number of relapses and relapse-free survival (RFS). Thus, patients with more than 5 × 10−3 residual cells (5 residual cells among 1,000 normal bone marrow [BM] cells) identified as leukemic by immunophenotyping in the first remission BM showed a significant higher rate of relapse (67% v 20% for patients with less than 5 × 10−3 residual cells; P = .002) and a lower median RFS (17 months v not reached; P = .01). At the end of intensification, with a cut-off value of 2 × 10−3 leukemic cells, AML patients also separated into two distinct groups with relapse rates of 69% versus 32% (P = .02), respectively, and median RFS of 16 months versus not reached (P = .04). In addition, overall survival was also significantly related to the level of residual cells in the marrow obtained at the end of induction and particularly after intensification therapy (P = .008). Furthermore, we have explored whether residual disease was related with the functional expression of multidrug resistance (MDR-1) at diagnosis as assessed by the rhodamine-123 assay. Patients with ≥5 × 10−3 residual leukemic cells at the end of induction therapy had a significantly higher rhodamine-123 efflux (mean, 56% ± 24%) than those with less than 5 × 10−3 residual cells (mean, 32% ± 31%; P = .04). Finally, multivariate analysis showed that the number of residual cells at the end of induction or intensification therapy was the most important prognostic factor for prediction of RFS. Overall, our results show that immunophenotypical investigation of MRD strongly predicts outcome in patients with AML and that the number of residual leukemic cells correlates with multidrug resistance.