Assessment of imatinib as first-line treatment of chronic myeloid leukemia: 10-year survival results of the randomized CML study IV and impact of non-CML determinants.

Chronic myeloid leukemia (CML)-study IV was designed to explore whether treatment with imatinib (IM) at 400 mg/day (n=400) could be optimized by doubling the dose (n=420), adding interferon (IFN) (n=430) or cytarabine (n=158) or using IM after IFN-failure (n=128). From July 2002 to March 2012, 1551 newly diagnosed patients in chronic phase were randomized into a 5-arm study. The study was powered to detect a survival difference of 5% at 5 years. After a median observation time of 9.5 years, 10-year overall survival was 82%, 10-year progression-free survival was 80% and 10-year relative survival was 92%. Survival between IM400 mg and any experimental arm was not different. In a multivariate analysis, risk group, major-route chromosomal aberrations, comorbidities, smoking and treatment center (academic vs other) influenced survival significantly, but not any form of treatment optimization. Patients reaching the molecular response milestones at 3, 6 and 12 months had a significant survival advantage. For responders, monotherapy with IM400 mg provides a close to normal life expectancy independent of the time to response. Survival is more determined by patients' and disease factors than by initial treatment selection. Although improvements are also needed for refractory disease, more life-time can currently be gained by carefully addressing non-CML determinants of survival.

MATE1 regulates cellular uptake and sensitivity to imatinib in CML patients.

Although imatinib is highly effective in the treatment of chronic myeloid leukemia (CML), 25-30% patients do not respond or relapse after initial response. Imatinib uptake into targeted cells is crucial for its molecular response and clinical effectiveness. The organic cation transporter 1 (OCT1) has been proposed to be responsible for this process, but its relevance has been discussed controversially in recent times. Here we found that the multidrug and toxin extrusion protein 1 (MATE1) transports imatinib with a manifold higher affinity. MATE1 mainly mediates the cellular uptake of imatinib into targeted cells and thereby controls the intracellular effectiveness of imatinib. Importantly, MATE1 but not OCT1 expression is reduced in total bone marrow cells of imatinib-non-responding CML patients compared with imatinib-responding patients, indicating that MATE1 but not OCT1 determines the therapeutic success of imatinib. We thus propose that imatinib non-responders could be identified early before starting therapy by measuring MATE1 expression levels.

Development and evaluation of a secondary reference panel for BCR-ABL1 quantification on the International Scale.

Molecular monitoring of chronic myeloid leukemia patients using robust BCR-ABL1 tests standardized to the International Scale (IS) is key to proper disease management, especially when treatment cessation is considered. Most laboratories currently use a time-consuming sample exchange process with reference laboratories for IS calibration. A World Health Organization (WHO) BCR-ABL1 reference panel was developed (MR(1)-MR(4)), but access to the material is limited. In this study, we describe the development of the first cell-based secondary reference panel that is traceable to and faithfully replicates the WHO panel, with an additional MR(4.5) level. The secondary panel was calibrated to IS using digital PCR with ABL1, BCR and GUSB as reference genes and evaluated by 44 laboratories worldwide. Interestingly, we found that >40% of BCR-ABL1 assays showed signs of inadequate optimization such as poor linearity and suboptimal PCR efficiency. Nonetheless, when optimized sample inputs were used, >60% demonstrated satisfactory IS accuracy, precision and/or MR(4.5) sensitivity, and 58% obtained IS conversion factors from the secondary reference concordant with their current values. Correlation analysis indicated no significant alterations in %BCR-ABL1 results caused by different assay configurations. More assays achieved good precision and/or sensitivity than IS accuracy, indicating the need for better IS calibration mechanisms.

Measurement of compartment elasticity using pressure related ultrasound: a method to identify patients with potential compartment syndrome.

PURPOSE OF THE STUDY Decision-making in treatment of an acute compartment syndrome is based on clinical assessment, supported by invasive monitoring. Thus, evolving compartment syndrome may require repeated pressure measurements. In suspected cases of potential compartment syndromes clinical assessment alone seems to be unreliable. The objective of this study was to investigate the feasibility of a non-invasive application estimating whole compartmental elasticity by ultrasound, which may improve accuracy of diagnostics. MATERIAL AND METHODS In an in-vitro model, using an artificial container simulating dimensions of the human anterior tibial compartment, intracompartmental pressures (p) were raised subsequently up to 80 mm Hg by infusion of saline solution. The compartmental depth (mm) in the cross-section view was measured before and after manual probe compression (100 mm Hg) upon the surface resulting in a linear compartmental displacement (Δd). This was repeated at rising compartmental pressures. The resulting displacements were related to the corresponding intra-compartmental pressures simulated in our model. A hypothesized relationship between pressures related compartmental displacement and the elasticity at elevated compartment pressures was investigated. RESULTS With rising compartmental pressures, a non-linear, reciprocal proportional relation between the displacement (mm) and the intra-compartmental pressure (mm Hg) occurred. The Pearson's coefficient showed a high correlation (r2 = -0.960). The intraobserver reliability value kappa resulted in a statistically high reliability (κ = 0.840). The inter-observer value indicated a fair reliability (κ = 0.640). CONCLUSIONS Our model reveals that a strong correlation between compartmental strain displacements assessed by ultrasound and the intra-compartmental pressure changes occurs. Further studies are required to prove whether this assessment is transferable to human muscle tissue. Determining the complete compartmental elasticity by ultrasound enhancement, this application may improve detection of early signs of potential compartment syndrome. Key words: compartment syndrome, intra-compartmental pressure, non-invasive diagnostic, elasticity measurement, elastography.

Assessment of elevated compartment pressures by pressure-related ultrasound: a cadaveric model.

PURPOSE: There is a risk of misinterpreting the clinical signs of acute compartment syndrome of the lower limb resulting in delayed fasciotomy. Up to date, the diagnosis of compartment syndrome is based on clinical assessment and of invasive needle pressure measurement in uncertain cases. Close monitoring is necessary for early recognition of raising compartment pressures. Clinical assessment of muscle firmness by the physician's palpation alone is unreliable. Thus, a device objectifying this assessment would be beneficial. The purpose of this study was to determine the feasibility of muscle compartment elasticity measurements by a novel and non-invasive device using pressure-related ultrasound. METHODS: In a cadaveric model, the anterior tibial compartment was prepared to simulate raising intra-compartmental pressures (0-80 mmHg) by saline infusion. Standard invasive pressure monitoring was compared with a novel method to determine tissue elasticity. Changing cross-sectional view in B-mode ultrasound was exerted to measure the compartment depth before and after physician's probe compression of 100 mmHg. Compartment displacement (∆d) was measured and related to the corresponding compartmental pressure (Spearman correlation coefficient). Delta (mm) of the control group at 10 mmHg compartment pressure was compared with measured data at rising compartmental pressures of 30, 50, and 70 mmHg using the Wilcoxon rank-sum test. The intra-observer reliability (κ) was additionally calculated. RESULTS: Fresh and never frozen lower human limbs (n = 6) were used. The average displacement measured in the anterior tibial compartment was 2.7 mm (0.3-6.7 mm). A concordant consistent correlation between the compartmental displacement and the intra-compartmental pressure occurred. The Spearman coefficient (r s = 0.979) showed a significant correlation between the rising pressure and the decreasing tissue displacement visualized by ultrasound. The intra-observer value kappa showed reliable values (κ 10 = 0.73, κ 30 = 0.80, and κ 70 = 0.79). CONCLUSIONS: We introduce a new method of ultrasound imaging enhanced with probe pressure measurement to determine changes of the visco-elastic behavior of isolated muscle compartments. Pressure-related ultrasound could be a reliable tool to determine the correlation between the measured compartmental displacement and the increasing intra-compartmental pressure. Its accuracy revealed promising results. This technique may help the physician to objectify the clinical assessment of compartment elasticity, mainly indicated in cases of unconscious patients and imminent pathology. Further clinical studies and improvements of this technique are required to prove its accuracy and reliability in cases of compartment syndrome.

BAALC expression: a suitable marker for prognostic risk stratification and detection of residual disease in cytogenetically normal acute myeloid leukemia.

High brain and acute leukemia, cytoplasmic (BAALC) expression defines an important risk factor in cytogenetically normal acute myeloid leukemia (CN-AML). The prognostic value of BAALC expression in relation to other molecular prognosticators was analyzed in 326 CN-AML patients (<65 years). At diagnosis, high BAALC expression was associated with prognostically adverse mutations: FLT3 internal tandem duplication (FLT3-ITD) with an FLT3-ITD/FLT3 wild-type (wt) ratio of 0.5 (P=0.001), partial tandem duplications within the MLL gene (MLL-PTD) (P=0.002), RUNX1 mutations (mut) (P<0.001) and WT1mut (P=0.001), while it was negatively associated with NPM1mut (P<0.001). However, high BAALC expression was also associated with prognostically favorable biallelic CEBPA (P=0.001). Survival analysis revealed an independent adverse prognostic impact of high BAALC expression on overall survival (OS) and event-free survival (EFS), and also on OS when eliminating the effect of allogeneic stem cell transplantation (SCT) (OS(TXcens)). Furthermore, we analyzed BAALC expression in 416 diagnostic and follow-up samples of 66 patients. During follow-up, BAALC expression correlated with mutational load or expression levels, respectively, of other minimal residual disease markers: FLT3-ITD (r=0.650, P<0.001), MLL-PTD (r=0.728, P<0.001), NPM1mut (r=0.599, P<0.001) and RUNX1mut (r=0.889, P<0.001). Moreover, a reduction in BAALC expression after the second cycle of induction chemotherapy was associated with improved EFS. Thus, our data underline the utility of BAALC expression as a marker for prognostic risk stratification and detection of residual disease in CN-AML.

SF3B1 mutations correlated to cytogenetics and mutations in NOTCH1, FBXW7, MYD88, XPO1 and TP53 in 1160 untreated CLL patients.

We analyzed a large cohort of 1160 untreated CLL patients for novel genetic markers (SF3B1, NOTCH1, FBXW7, MYD88, XPO1) in the context of molecular, immunophenotypic and cytogenetic data. NOTCH1 mutations (mut) (12.3%), SF3B1mut (9.0%) and TP53mut (7.1%) were more frequent than XPO1mut (3.4%), FBXW7mut (2.5%) and MYD88mut (1.5%). SF3B1mut, NOTCH1mut, TP53mut and XPO1mut were highly correlated to unmutated, whereas MYD88mut were associated with mutated IGHV status. Associations of diverse cytogenetic aberrations and mutations emerged: (1) SF3B1mut with del(11q), (2) NOTCH1mut and FBXW7mut with trisomy 12 and nearly exclusiveness of SF3B1mut, (3) MYD88mut with del(13q) sole and low frequencies of SF3B1mut, NOTCH1mut and FBXW7mut. In patients with normal karyotype only SF3B1mut were frequent, whereas NOTCH1mut rarely occurred. An adverse prognostic impact on time to treatment (TTT) and overall survival (OS) was observed for SF3B1mut, NOTCH1mut and TP53 disruption. In multivariate analyses SF3B1mut, IGHV mutational status and del(11q) were the only independent genetic markers for TTT, whereas for OS SF3B1mut, IGHV mutational status and TP53 disruption presented with significant impact. Finally, our data suggest that analysis of gene mutations refines the risk stratification of cytogenetic prognostic subgroups and confirms data of a recently proposed model integrating molecular and cytogenetic data.

Contrast enhanced ultrasound (CEUS) reliably detects critical perfusion changes in compartmental muscle: a model in healthy volunteers.

PURPOSE: The purpose of this study was to assess the utility of contrast enhanced ultrasound (CEUS) in the differentiation between physiological and simulated pathophysiological lower limb muscle perfusion pressures in healthy volunteers. METHODS: The lower limb muscle perfusion pressures in eight healthy volunteers were assessed in the supine position (as a control) and then subsequently in an elevated position with a thigh tourniquet applied to induce venous stasis. An intravenous bolus injection of 2.5 ml contrast agent was given to create a perfusion signal, which was measured with a multiple-frequency probe. Semiquantitative analysis was performed using specific software to create a perfusion curve which allowed measurement of six parameters: the time to arrival (TTA) starting from bolus application (s); peak of signal intensity (%); time to peak (TTP) maximum (seconds); regional blood volume (RBV), regional blood flow (RBF), and mean transit time (MTT) in seconds. Statistical analysis was performed using the Mann-Whitney U test as a non-parametric test (IBM SPSS statistics, version 21, USA). RESULTS: The group of simulated hypoperfusion showed significant higher values for TTA (39.8 ± 5.1 s) (p = 0.028), TTP (43.8 ± 13.6 s) (p = 0.003), RBV (8,424 ± 5,405) (p = 0.028), and MTT (262 ± 90.6 s) (p = 0.005). In contrast, the parameter of regional blood flow (32.1 ± 10.9) was significantly lower (p = 0.038). The peak signal intensity (25.8 ± 8.2 %) was lower, but this was not significant (p = 0.083). CONCLUSIONS: CEUS provides a reliable non-invasive imaging modality for the assessment of lower limb muscle perfusion pressures. This may be of clinical use in the assessment of a developing compartment syndrome. Further clinical studies are required to further define its accuracy and reproducibility.

The role of different genetic subtypes of CEBPA mutated AML.

The prognostic impact of mutations in the CCAAT/enhancer binding protein α (CEBPA) gene was evaluated in the context of concomitant molecular mutations and cytogenetic aberrations in acute myeloid leukemia (AML). CEBPA was screened in a cohort of 2296 adult AML cases. Of 244 patients (10.6%) with CEBPA mutations, 140 cases (6.1%) were single-mutated (CEBPAsm) and 104 cases (4.5%) were double-mutated (CEBPAdm). Cytogenetic analysis revealed normal karyotype in 172/244 (70.5%) of CEBPAmut cases, whereas in 72/244 cases (29.5%) at least one cytogenetic aberration was detected. Concurrent molecular mutations were seen less frequently in CEBPAdm than in CEBPAsm AML cases (69.2% vs 88.6% P<0.001). In detail, the spectrum of concurrent mutations was different in both groups with the frequent occurrence of GATA1 and WT1 mutations in CEBPAdm patients. In contrast, FLT3-ITD, NPM1, ASXL1 and RUNX1 mutations were detected more frequently in CEBPAsm cases. Favorable outcome was restricted to CEBPAdm cases and remained an independent prognostic factor for a favorable outcome in multivariate analysis (hazard ratio: 0.438, P=0.020). Outcome in CEBPAsm cases strongly depended on concurrent FLT3-ITD. In conclusion, we propose that only CEBPAdm should be considered as an entity in the WHO classification of AML and should be clearly distinguished from CEBPAsm AML.

Age, JAK2(V617F) and SF3B1 mutations are the main predicting factors for survival in refractory anaemia with ring sideroblasts and marked thrombocytosis.

Refractory anaemia with ring sideroblasts (RARS) and marked thrombocytosis (RARS-T) is a provisional entity in the World Health Organisation 2008 classification and has previously been shown to have a high proportion of JAK2(V617F) (Janus Kinase 2) and SF3B1 (Splicing Factor 3B subunit 1) mutations. The purpose of the present study was to analyse the frequency of SF3B1 mutations in a large cohort of 111 patients with RARS-T and 33 patients with RARS and to explore the prognostic impact of SF3B1 mutational status on RARS-T. The frequency of SF3B1 mutations in RARS-T (96/111, 86.5%) and RARS (28/33, 84.8%) was similar. In RARS-T, median survival was better in SF3B1-mutated patients than in SF3B1-non-mutated patients (6.9 and 3.3 years, respectively, P=0.003). RARS can be differentiated from RARS-T by the frequency of JAK2(V617F) (0% vs 48.6%). In RARS-T patients, SF3B1 (P=0.021) and JAK2 mutations (P=0.016) were independent factors for a better prognosis. Altogether, our results confirm that RARS-T is an independent entity that should be recognised by the next World Health Organisation classification. The assessment of SF3B1 mutations is of prognostic interest in RARS-T patients. Younger age, JAK2(V617F) and SF3B1 mutations are the main predicting factors for survival in RARS-T.

ASXL1 exon 12 mutations are frequent in AML with intermediate risk karyotype and are independently associated with an adverse outcome.

We aimed at evaluating ASXL1mut in 740 AML with intermediate risk karyotype for frequency, association with other mutations and impact on outcome. Five hundred fifty-three cases had a normal karyotype (NK) and 187 had intermediate risk aberrant cytogenetics. Overall, ASXL1mut were detected in 127/740 patients (17.2%). ASXL1mut were more frequent in males than in females (23.5% vs 9.9%, P<0.001). They were associated with higher age (median: 71.8 vs 61.8, P<0.001), a history of preceding myelodysplastic syndromes, and with a more immature immunophenotype compared with patients with wild-type ASXL1 (ASXL1wt). ASXL1mut were more frequent in patients with aberrant karyotype (58/187; 31.0%), especially in cases with trisomy 8 (39/74; 52.7%), than in those with NK (69/553; 12.5%; P<0.001). ASXL1mut were observed more frequent in RUNX1mut (P<0.001), and less frequent in NPM1mut (P<0.001), FLT3-internal tandem duplication (ITD) (P<0.001), FLT3-TKD (P=0.001) and DNMT3Amut (P<0.001). Patients with ASXL1mut had a shorter overall survival (OS) (P<0.001) and event free survival (P=0.012) compared with ASXL1wt. In multivariable analysis, ASXL1mut was an independent adverse factor for OS (P=0.032, relative risk: 1.70). In conclusion, ASXL1mut belong to the most frequent mutations in intermediate risk group AML. Their strong and independent dismal prognostic impact suggests the inclusion into the diagnostic work-up of AML.