ALBERT

Description: Guiding antileukemic treatment in patients with acute myeloid leukemia (AML) is increasingly based on levels of minimal residual disease (MRD) which can be quantified with high sensitivity by multiparameter flow cytometry (MFC). The optimum checkpoint for determination of MRD during the course of therapy, however, has not yet been determined. We applied MFC using a comprehensive panel of antibodies to identify leukemia-associated aberrant immunophenotypes (LAIPs) at diagnosis and to quantify MRD by individually selected antibody combinations. The prognostic impact of MRD levels was assessed in comparison to cytogenetics and age. Patients received double induction, consolidation, and maintenance therapies and underwent allogeneic stem cell transplantation if they were younger than 60 years and had a matched related donor. In 286 patients with newly diagnosed and untreated AML MFC-based assessment for the presence of LAIP has been performed. The median percentage of LAIP-positive bone marrow cells at diagnosis was 16.04% (range, 2.54%–76.14%). All individual LAIPs were applied to 26 normal bone marrow samples to estimate sensitivity based on the median percentages of LAIP-positive normal bone marrow cells which ranged from 0.00% to 1.01% (median, 0.02%). A total of 550 follow-up samples has been analyzed in these patients at different checkpoints (CP1, up to day 21 after start of therapy, n=85; CP2, day 22–60, n=122; CP3, day 61–120, n=158; CP4, day 121–365, n=137; CP5, after day 365, n=48). In order to adjust for differences in the percentages of LAIP-positive bone marrow cells at diagnosis the logarithmic difference (LD) between diagnosis and follow-up was calculated for each follow-up sample. The median LDs at the respective checkpoints were: CP1, 2.02; CP2, 2.29; CP3, 2.39; CP4, 2.53; and CP5, 2.81. Separation of patients according to the respective median LDs resulted in differences in event-free survival (EFS; CP1: 21.1 vs. 9.1 months, p=0.0711; CP2: 14.2 vs. 9.3 months, p=0.0095; CP3: 30.9 vs. 13.5 months, p=0.0055; CP4: median not reached vs. 14.1 months, p

Description: Management of patients with refractory and relapsed AML needs optimization. We performed a prospective study in these patients aiming at 1) the definition of the anti-leukemic efficacy of the S-HAI regimen; and 2) the evaluation of the prognostic impact of cytogenetic aberrations at relapse in the context of other prognostic parameters. Treatment consisted of AraC 1 g/sqm q 12 h days 1, 2, 8, and 9 and idarubicin 10 mg/sqm days 3, 4, 10, and 11. AraC was given at 3 g/sqm in patients under age 60 with refractory AML or relapse after CR1

Description: The prognostic value of MRD detection in AML has been shown for PML-RARA, AML1-ETO, and CBFB-MYH11positive AML, a group which accounts for only 20–25% of AML. The largest group of AML is represented by cases with normal karyotype or unbalanced intermediate risk group karyotypes. In this group different molecular mutations occur, which are associated with heterogeneous clinical outcome. Thus, different MRD patterns can be anticipated. To expand the spectrum of molecular targets in intermediate risk AML, we used MLL-PTD, FLT3-LM, and NPM1 which are detectable in 45–50% of all intermediate risk group pts for MRD detection. In addition, overexpression of WT1 for MRD detection was used to even include pts. without detectable mutations. In total 996 samples (spl) of 234 patients (pts) were analysed by quantitative real time PCR. For MLL-PTD (321 spl of 78 pt), and WT1 (336 spl of 66 pts) universal assays were used. For NPM1 mutation specific assays (182 spl of 54 pts (42 x type A, 2 x type B, 7 x type D, 3 x rare not yet defined types)) and for FLT3-LM (161 spl of 18 selected pts) patient specific assays were used. All assays were RNA based. Sensitivity of the assays were between 1:100.000 to 1:1.000.000 for the FLT3-LM and NPM1, depending on pts specific assay. Sensitivity was 1:10.000 to 1:100.000 for MLL-PTD due to low background levels detectable in healthy controls. The sensitivity of WT1 was relatively low with 1:100 at most, as there was no high WT1 expressor at diagnosis in this cohort. With all markers the clinical course of the disease was clearly be reflected and all 84 relapses were detectable due to recurring high expression rates. In 17 cases, were samples 2–4 months before clinical relapse were available relapses were predictable based on increasing transcript levels. Five different follow up intervals (int) were defined: up to day 21; days 22–60; days 61–120; day 121–365, later. The log change from diagnosis to defined follow up intervals was analyzed. A rapid decline of median transcript ratios in the NPM1 group (int 1: 2 log; int 2 to 4: 4 log) was observed. Relapses in the NPM1 group occurred earliest after one year. AML with FLT3-LM similarly showed good responses with 1–2 log decreases in int 1 and 2 and 3 log in int 3 and 4. Also this group revealed the first relapses in int 5. The MLL-PTD group was characterized by slow response rates with only 0.2 log reduction in int 1 and 2 and hardly 3 log in int 3. In this group many relapses occurred in int 4 and 5. These data reflect the biological differences of these molecular subgroups: NPM1 as a favourable group, FLT3-LM as a slightly unfavourable group with good response rates but high relapse rates, and MLL-PTD as an entity with bad prognosis due to poor response rates and high relapse rates. Due to low sensitivity WT1 reflected only 0.2 log in interval 1 up to 2 log in interval 3. Seven cases were analyzed in parallel for WT1 and MLL-PTD, 6 for WT1 and FLT3-LM, and one for FLT3-LM and MLL-PTD. Although the correlation of parallel assessment was high (R=0.993) the median differences of log changes of FLT3-LM and NPM1 was one log larger than for MLL-PTD and three log larger than for WT1, depending on the initial sensitivity of the assays. In conclusion: MRD detection is feasible in the karyotypically intermediate risk group. it nicely reflects biological difference in this group NPM1, MLL-PTD and FLT3-LM are better MRD-markers than WT1, which may only be investigated in cases without any other available marker.

Description: Accurate diagnosis and classification of leukemias are the bases for the appropriate management of patients. The diagnostic accuracy and efficiency of present methods may be improved by the use of microarrays for gene expression profiling. We analyzed gene expression profiles in 937 bone marrow and peripheral blood samples from 892 patients with all clinically relevant leukemia subtypes and from 45 nonleukemic controls by U133A and U133B GeneChip arrays. For each subgroup, differentially expressed genes were calculated. Class prediction was performed using support vector machines. Prediction accuracy was estimated by 10-fold cross-validation and was assessed for robustness in a 100-fold resampling approach using randomly chosen test sets consisting of one third of the samples. Applying the top 100 genes of each subgroup, an overall prediction accuracy of 95.1% was achieved that was confirmed by resampling (median, 93.8%; 95% confidence interval, 91.4%-95.8%). In particular, acute myeloid leukemia (AML) with t(15;17), AML with t(8;21), AML with inv(16), chronic lymphatic leukemia (CLL), and pro–B-cell acute lymphoblastic leukemia (pro–B-ALL) with t(11q23) were classified with 100% sensitivity and 100% specificity. Accordingly, cluster analysis completely separated all 13 subgroups analyzed. Gene expression profiling can predict all clinically relevant subentities of leukemia with high accuracy.

Description: Acute myeloid leukemia (AML) is a heterogeneous group of diseases with varying clinical outcome. So far the karyotype of the leukemic blasts as well as molecular genetic abnormalities - both abnormalities on the genomic level - have been proven to be strong prognostic markers. However, even in genetically well defined subgroups clinical outcome is not uniform and a large proportion of AML shows genetic abnormalities of yet unknown prognostic significance. Here we addressed the question whether gene expression profiles are associated with clinical outcome independent of the known genomic abnormalities. Therefore, gene expression analyses were performed using Affymetrix U133A+B oligonucleotide microarrays in a total of 403 AML treated uniformly in the AMLCG studies. This cohort was divided randomly into a training set (n=269) and a test set (n=134). The training set included 18 cases with t(15;17), 22 cases with t(8;21), 29 cases with inv(16), 14 cases with 11q23/MLL-rearrangement, 19 with complex aberrant karyotype and 167 cases with normal karyotype or “other” chromosome aberrations. The respective data for the test set were: 10 t(15;17), 8 t(8;21), 11 inv(16), 8 11q23/MLL, 19 cases with complex aberrant karyotype and 78 with normal karyotype or “other” chromosome aberrations. Based on the clinical outcome the training cohort was divided into 4 equally large subgroups. We trained support vector machines (SVM) with the training set and classified the cases of the test set with the respective most discriminating genes. Next a Kaplan-Meier analysis was performed with the test set cases assigned to prognostic groups 1 to 4 according to SVM classification. Based on the expression level of 100 genes group 1 showed an overall survival rate of 57% at 3 years. 31 of 134 (23%) patients were assigned to this favorable subgroup. They belonged to the following cytogenetic subgroups: t(15;17) n=6, t(8;21) n=4, inv(16) n=3, 11q23/MLL n=4, complex aberrant karyotype n=1 and normal karyotype or “other” chromosome aberration n=13. The overall survival rate of groups 2, 3, and 4 did not differ significantly (17%, 21%, and 19% at 3 years). Among the genes highly expressed in the favorable group were MPO and the transcription factor ATBF1, which regulates CCND1. The unfavorable groups were characterized by a higher expression of the transcription factors ETS2, RUNX1, TCF4, and FOXC1. Interestingly, 10 of the top 40 differentially expressed genes are involved in the TP53-CMYC-pathway with a higher expression of 9 of these in the unfavorable groups (SFRS1, TPD52, NRIP1, TFPI, UBL1, REC8L1, HSF2, ETS2 and RUNX1). In conclusion, gene expression profiling leads to the identification of prognostically important alterations of molecular pathways which have not yet been accounted for by use of cytogenetics. This approach is anticipated to help optimizing therapy for patients with AML.

Description: Acute myeloid leukemia (AML) cases with 11q23 abnormalities involving the MLL gene comprise one category of recurring genetic abnormalities in the WHO classification. In an unselected series of 1897 AML cases, 54 patients with an 11q23/MLL rearrangement were identified, resulting in an incidence of 2.8%. The incidence of AML with MLL rearrangement was significantly higher in therapy-related AML (t-AML) than in de novo AML (9.4% vs 2.6%, P 〈 .0001). The frequency of MLL rearrangements was significantly higher in patients younger than 60 years (5.3% vs 0.8%, P 〈 .0001). While the incidence of MLL rearrangements in AML M4, M5a, and M5b was 4.7%, 33.3%, and 15.9%, respectively, it was found in only 0.9% of all other French-American-British (FAB) subtypes (P 〈 .0001). Compared with AML with intermediate karyotype, AML with 11q23/MLL rearrangement had a worse outcome, which was rather comparable with AML with unfavorable karyotype. Compared with t-AML, the median overall survival (OS) of de novo AML with MLL rearrangement was significantly better (2.5 vs 10 months, P = .0143). No significant differences in median OS were observed between cases with t(9;11) compared with all other MLL rearrangements (10.0 vs 8.9 months, P = .36). In conclusion, the category AML with 11q23/MLL abnormalities accounts for 2.8% of unselected AML, is closely associated with monocytic differentiation, and has a dismal prognosis. (Blood. 2003;102:2395-2402)

Description: The advent of imatinib has considerably changed treatment in chronic myeloid leukemia (CML). Although response rate and duration of response with imatinib monotherapy continue to be impressive, the majority of patients (pts) in complete cytogenetic remission (CCR) retain BCR-ABL transcripts as markers of residual disease and potential cause of relapse. In addition rapid evolvement of blast crises from CCR has been reported. Therefore, we designed an investigator-initiated phase IV prospective trial aiming to address the role of imatinib in combination with interferon alpha (IFN) or Ara-C and treatment intensification with high dose imatinib. In July 2002, the German CML-Study Group has activated the four-armed randomized controlled trial comparing imatinib 400 mg/d with imatinib+IFN, imatinib+Ara-C and imatinib after IFN failure in newly diagnosed pts with chronic phase CML. Randomization is stratified according to prognostic risk groups and not biased by consecutive allogeneic stem cell transplantation (SCT). High risk pts are randomly assigned to primary imatinib-based therapies including a 4th treatment arm with imatinib 800 mg/d. The treatment arm imatinib after IFN failure retains the chance of an IFN-induced CCR with 10 year-survival rates of 70–80%. In case of IFN failure pts are crossed over to imatinib. Allogeneic SCT is recommended for all pts with high risk, imatinib failure and EBMT-score 0–1. By August 2004, 429 pts were randomized: imatinib 400 mg/d (n=103), imatinib+IFN (n=130), imatinib+Ara-C (n=108), imatinib after IFN failure (n=84), and imatinib 800 mg/d (n=4). According to the New CML score, 34% of patients were low risk, 56% intermediate risk, and 10% high risk. At baseline, median WBC count was 63/nl (3.5–513), median platelet count was 385/nl (49–2,799) and median hemoglobin was 12.7 g/dl (6.1–16.6). We sought to evaluate results of the first cohort of pts (n=217) with a 〉12 months follow-up, recruited between 7/2002 and 5/2003 (imatinib 400 mg/d, n=52; imatinib+IFN, n=70; imatinib+Ara-C, n=49; imatinib after IFN failure, n=46). Median age was 56 yrs (16–82), 62% of pts were male. Cytogenetic data are available from 117 pts (68%) randomized to primary imatinib-based therapies. At 12 months, 104 pts (89%) achieved a major cytogenetic remission (Ph+

Description: Balanced chromosomal rearrangements leading to fusion genes on the molecular level define distinct biological subsets in AML. The four balanced rearrangements (t(15;17), t(8;21), inv(16), and 11q23/MLL) show a close correlation to cytomorphology and gene expression patterns. We here focused on seven AML with t(8;16)(p11;p13). This translocation is rare (7/3515 cases in own cohort). It is more frequently found in therapy-related AML than in de novo AML (3/258 t-AML, and 4/3287 de novo, p=0.0003). Cytomorphologically, AML with t(8;16) is characterized by striking features: In all 7 cases the positivity for myeloperoxidase on bone marrow smears was 〉70% and intriguingly, in parallel 〉80% of blast cells stained strongly positive for non-specific esterase (NSE) in all cases. Thus, these cases can not be classified according to FAB categories. These data suggest that AML-t(8;16) arise from a very early stem cell with both myeloid and monoblastic potential. Furthermore, we detected erythrophagocytosis in 6/7 cases that was described as specific feature in AML with t(8;16). Four pts. had chromosomal aberrations in addition to t(8;16), 3 of these were t-AML all showing aberrations of 7q. Survival was poor with 0, 1, 1, 2, 20 and 18+ (after alloBMT) mo., one lost to follow-up, respectively. We then analyzed gene expression patterns in 4 cases (Affymetrix U133A+B). First we compared t(8;16) AML with 46 AML FAB M1, 41 M4, 9 M5a, and 16 M5b, all with normal karyotype. Hierachical clustering and principal component analyses (PCA) revealed that t(8;16) AML were intercalating with FAB M4 and M5b and did not cluster near to M1. Thus, monocytic characteristics influence the gene expression pattern stronger than myeloid. Next we compared the t(8;16) AML with the 4 other balanced subtypes according to the WHO classification (t(15;17): 43; t(8;21): 40; inv(16): 49; 11q23/MLL-rearrangements: 50). Using support vector machines the overall accuracy for correct subgroup assignment was 97.3% (10-fold CV), and 96.8% (2/3 training and 1/3 test set, 100 runs). In PCA and hierarchical cluster analysis the t(8;16) were grouped in the vicinity of the 11q23 cases. However, in a pairwise comparison these two subgroups could be discriminated with an accuracy of 94.4% (10-fold CV). Genes with a specific expression in AML-t(8;16) were further investigated in pathway analyses (Ingenuity). 15 of the top 100 genes associated with AML-t(8;16) were involved in the CMYC-pathway with up regulation of BCOR, COXB5, CDK10, FLI1, HNRPA2B1, NSEP1, PDIP38, RAD50, SUPT5H, TLR2 and USP33, and down regulation of ERG, GATA2, NCOR2 and RPS20. CEBP beta, known to play a role in myelomonocytic differentiation, was also up-regulated in t(8;16)-AML. Ten additional genes out of the 100 top differentially expressed genes were also involved in this pathway with up-regulation of DDB2, HIST1H3D, NSAP1, PTPNS1, RAN, USP4, TRIM8, ZNF278 and down regulation of KIT and MBD2. In conclusion, AML with t(8;16) is a specific subtype of AML with unique characteristics in morphology and gene expression patterns. It is more frequently found in t-AML, outcome is inferior in comparison to other AML with balanced translocations. Due to its unique features, it is a candidate for inclusion into the WHO classification as a specific entity.