Response In Chronic Myeloid Leukemia Research Articles

Generic Imatinib Mesylate is as Effective as Original Glivec in the Clinical Management of CML.

Unsustainable drug prices in chronic myeloid leukemia (CML) and cancer may be causing harm to patients. The aim of this multicenter study is to assess the efficacy of generic imatinib mesylate (IM) over Glivec in terms of hematological, cytogenetic, and molecular responses in CML. The data of 120 CML patients, who were treated with generic or original form of IM, were obtained from six different hematology clinics in Turkey between the years of 2009-2014 and analyzed retrospectively. Initial evaluation revealed that only one patient who was using original molecule switched to second generation tyrosine kinase inhibitor (TKI). In this period, hematological response(HR) was observed in 99.2% of the patients, cytogenetic response (CR) was observed in 88.7% of the patients (47 of 53), and molecular response (MR) was observed in 75% of the patients. Clinicians had a tendency to prefer generic molecules in each sequent visit, and this switch rate was statistically significant (p< 0.001). 11 patients, who were using original molecules during all cohorts, switched to second generation TKI. On the other hand, only one patient, who was using generic molecules, switched to second generation TKI. Our paper may help to clarify the doubts about the efficacy of generic IM compared to original molecule. In our study we did not find any significant difference in HR, CR, and MR for original and generic drugs in each visit. Herein, we find low rates of need to switch to second generation TKIs with generic IM and no difference in treatment responses between generic and original molecules that confirms the non-inferiority of generic TKIs over original molecules.

Cellular Mechanisms Underlying Complete Hematological Response of Chronic Myeloid Leukemia to BRAF and MEK1/2 Inhibition in a Patient with Concomitant Metastatic Melanoma

Targeted MEK inhibition is an emerging therapy in a number of solid tumors. It holds particular promise in BRAF V600E mutation-positive malignant melanoma, where constitutive activation and cell growth through the MAP kinase (MAPK) pathway is well established. In vitro and preclinical research indicates that MAPK pathway activation is important in chronic myeloid leukemia (CML) leukemogenesis; however, the potential of MEK inhibition has not yet been investigated clinically in the setting of such hematologic malignancies. We report a case of complete hematologic response of CML to MEK inhibition in a patient with synchronous metastatic melanoma, who received treatment with combination BRAF and MEK1/2 inhibitors. We studied the effects of these agents on proliferation and outgrowth of myeloid precursors, and longitudinal shifts in peripheral blood phenotyping during the course of treatment. A model cell line system was used to examine the effects of dabrafenib and trametinib on MAPK and BCR-ABL1 signaling. After 35 weeks on treatment with BRAF and MEK inhibitors, complete hematologic response was observed without recourse to BCR-ABL1-targeted therapy. MEK inhibition was principally responsible for impaired proliferation of both mature and primitive myeloid precursors, as well as growth and hemoglobinization of erythroid precursors. Paradoxical activation of the MAPK pathway was seen in response to BRAF inhibitor therapy but this was easily overcome by clinically relevant doses of concurrent MEK inhibitor. These studies suggest that further evaluation of the optimal MAPK targeting approach is warranted to extend therapeutic options in CML.

Genetic variations of hOCT1 gene and CYP3A4/A5 genes and their association with imatinib response in Chronic Myeloid Leukemia

There is an increasing body of evidence demonstrating that mechanisms independent of BCR/ABL gene also contribute to imatinib resistance in Chronic Myeloid Leukemia (CML). It has been extensively reported that polymorphisms of the genes associated with imatinib metabolization and imatinib influx/efflux play an important role in the disease resistance. We investigated the impact of 12 genetic variants of the two genes, CYP3A4/A5 and the human cation transporter 1 gene (hOCT1) on the clinical outcome, in a cohort of 106 newly diagnosed CML patients. In the patient cohort investigated, only 6 variant alleles could be detected. The others were not present and could not be investigated. Two polymorphisms, CYP3A5*3 (rs776746)and hOCT1 M408V (rs628031), were significantly associated with the Complete Cytogenetic Response (CCyR) at 6 months and Major Molecular Response (MMR) at 12 months. The presence of favourable alleles at M408V and M420del in combination was associated with a MMR at 12 months. Functional polymorphisms of the genes associated with imatinib influx and metabolization may play a role in predicting primary response to imatinib and treatment outcome.

Factors Affecting Early Molecular Response in Chronic Myeloid Leukemia.

There is controversy about whether 3- or 6-month molecular assessment predicts progression-free and overall survival in those with chronic myeloid leukemia (CML). The factors predicting molecular response at 3, 6, and 12 months have not been studied extensively. The study objective was to study the factors affecting molecular response at 3 and 6 months in patients with CML who are receiving imatinib mesylate. We prospectively enrolled patients with newly diagnosed CML who were receiving imatinib mesylate as the initial therapy for CML. The diagnosis of CML was based on clinical examination, bone marrow, and demonstration of BCR ABL(IS) transcripts by polymerase chain reaction. The molecular response(IS) was assessed at 3, 6, and 12 months by GeneXpert (Cepheid, Sunnyvale, CA) and co-related with various baseline characteristics of patients. We also looked at whether early achievement of a complete hematologic response within 6 weeks predicts molecular response at 3 or 6 months. The study took place at a tertiary care hospital in Northwest India catering to patients belonging to low-middle socioeconomic status. We enrolled 131 patients with CML in the chronic phase from July 1, 2013, to August 31, 2014. The median age of the patients was 40 years (range, 13-67) with a male preponderance (61% were male). Most patients presented with symptoms of low-grade fever (52.7%) and abdominal fullness (26.7%). Spleen was palpable in 84.7% of patients. The median hemoglobin at presentation was 10.8 g/dL (range, 4.8-18.4 g/dL), white cell count was 138.3 × 10(9)/L (4.1-697 × 10(9)/L), and platelet count was 326 × 10(9)/L (85-1819 × 10(9)/L). The median number of peripheral blood basophils was 3% (range, 0%-20%), and blasts were 3% (range, 0%-10%). Myelofibrosis of more than grade 1 was present in 30% of patients. Most patients belonged to intermediate Sokal (45.8%) and Hasford (55%) scores and low EUropean Treatment Outcome Study (78.6%) score. Of 128 evaluable patients at 3 months, 96.9% achieved complete hematologic remission (CHR) and 82.3% achieved BCR ABL(IS) of less than 10%. None of the patients who had BCR ABL(IS) > 10% at 3 months achieved BCR ABL(IS) < 1% at 6 months or < 0.1% at 12 months. Early achievement of CHR (< 6 weeks), peripheral blood blast count of < 5%, and lactate dehydrogenase < 851 U/L were significantly associated with achievement of BCR ABL(IS) < 10% at 3 months and BCR ABL(IS) < 1% at 6 months. We found that BCR ABL(IS) assessment at 3 months is superior to assessment at 6 months. Patients with CML in the chronic phase who achieve CHR within 6 weeks are more likely to achieve BCR ABL(IS) < 10% at 3 months and < 1% at 6 months than patients who achieve CHR between 7 and 12 weeks.

New tool for monitoring molecular response in chronic myeloid leukemia.

e22136 Background: CML monitoring by PCR methodology has improved test sensitivity over cytology but suffers from inadequate standardization in most labs due to variations inherent in the existing method. Standardized nucleic acid quantification (SNAQ)test is anovel competitive template based peripheral blood b2a2/b3a2 transcript abundance method. It uses mixtures of b2a2 or b3a2 and GusB competitive templates and melting curve analysis to provide desired quality controls. A pilot study was conducted to evaluate the imprecision and linearity of real-time qPCR laboratory developed test (LDT) and SNAQ for monitoring BCR-ABL. Methods: Thirty six CML patients treated at our institution were enrolled in this pilot study. Their peripheral blood samples were analyzed for BCR-ABL by LDT and SNAQ method at MD Anderson Molecular Diagnostic Laboratory (L1 and S1) and Cancer Genetics Institute (L2 and S2). Results: Each test result (n = 36) was ranked against all the other samples tested by the same method. The Pears...

G417(P) Droplet digital polymerase chain reaction (ddpcr) assessment of deep molecular response in chronic myeloid leukaemia (cml)

Molecular monitoring of BCR-ABL1 transcript levels is central to the effective clinical management of patients with CML. Standardised Real time quantitative PCR (RT-qPCR) is currently used to measure the depth and durability of molecular response and forms the basis of the European Leukaemia Net (ELN) treatment recommendations. Close monitoring of patients who come off treatment using maximum sensitivity techniques, is vital in order to ensure early therapeutic intervention, should a BCR-ABL1 clone re-emerge. However, RT-qPCR is susceptible to fluctuations at the limits of its sensitivity, thus limiting its accuracy in assessing complete molecular response. Droplet Digital PCR technology is a new digital PCR technique where the test sample into many individual real-time PCR reactions, where some reactions contain the target molecule (positive) while others (negative) do not. The proportion of negative reactions is used to calculate an absolute count of the number of target molecules in the sample, without reference to external standards. This method should therefore enable increased accuracy and absolute quantification of target molecules, in comparison to the RT-qPCR technique. The aim of this study was to assess the potential of Droplet digital PCR (ddPCR) to improve the sensitivity and precision of the assessment of deep molecular response in patients with CML. A series of 21 patients previously determined to have achieved major molecular response (MMR) using RT-qPCR, were retrospectively monitored for BCR-ABL1 transcripts using ddPCR. A comparison of BCR-ABL1 to ABL1 ratios obtained by ddPCR and RT-qPCR suggested that in 63% of patients ddPCR was more sensitive than RT-qPCR, while in 28% of patients BCR-ABL1 transcript levels were better detected by RT-qPCR. This study demonstrates that ddPCR has the potential to precisely measure changes in minimal residual disease at the limits of detection of current RT-qPCR assays. Assessment of deep molecular response using ddPCR will help to accurately discriminate patients achieving a sustainable response and could therefore be considered for treatment cessation studies from those patients in whom BCR-ABL1 transcripts are likely to re emerge.

Real-life comparison of severe vascular events and other non-hematological complications in patients with chronic myeloid leukemia undergoing second-line nilotinib or dasatinib treatment

We retrospectively analyzed the rates of significant non-hematological adverse events (AEs) in 105 patients with chronic myeloid leukemia (CML) treated with second-generation tyrosine kinase inhibitor (TKIs) dasatinib or nilotinib used as second-line therapy in Polish tertiary care centers. Our analysis revealed that in a “real life setting,” nearly half of patients with CML on second-generation TKIs suffer from therapy complications. Grade 2–5 non-hematological AEs were observed in 40% of patients treated with nilotinib and in 42% treated with dasatinib (p = 0.83). Severe vascular events including peripheral artery occlusive disease (PAOD) occurred in 11% of patients on nilotinib and 4% on dasatinib (p = 0.16). Pleural effusion occurred more often in the dasatinib group (26%) than in the nilotinib group (2%) (p = 0.003). Importantly, most AEs occurred late, after more than 1 year of treatment. Since AEs are most often the reason for poor therapy compliance, careful monitoring of tolerability is crucial for an optimal treatment response in CML.

Evaluation of Electrolytes Disturbances in Iraqi Chronic Myeloid Leukemia Patients treated with Nilotinib with Monitoring of Response by FISH Study

Chronic myeloid leukemia (CML) is a myeloproliferative disorder characterized by the presence Philadelphia chromosome (Ph) which was created by a reciprocal translocation between chromosomes 9 and 22 (t [9;22] [q34;q11]. The approval of the 2nd generation TKI ( Nilotinib) takes the treatment of CML patients into new erea with more efficiency and mild to moderate adverse effects. This study was aimed at evaluation of molecular cytogenetic response by (FISH) for Nilotinib in Iraqi patients with assessment for electrolytes disturbances of Nilotinb by measuring a panel of electrolyte (Na+, K+, Ca++, PO4--- and Mg++) , where thirty Iraqi patients with CML who have resistance or no response to Imatinib treatment, attending to Baghdad Teaching Hospital/Hematology Department, have been submitted to this study. Blood samples have been taken pre and post starting treatment with Nilotinib, FISH study was done only for CML patients, while 30 normal healthy control volunteers submitted to the same panel of electrolytes measurements (Na+, K+, Ca++, PO4--- and Mg++) in addition to pre and post treatment Nilotinib patients. The results show out of 30 patients (17) males and (13) females with male to female ratio 1.3:1, FISH results for patients (pre and post) treatment mean±SD were(58.7%±26.2 % and 45.7%±29.9%) obviously significant with good cytogenetic response in resistance CML for Imatinib. Sodium levels in mmol/L pre, post treatment and control mean±SD were (139.2±6.9 , 142.4±9.2 and 140.4±2.52) respectively, with no significant difference between each other with P value &gt; 0.05 in all comparisons. Potassium levels mean±SD in mmol/L results for patients (pre, post) and control were (4.6±0.69, 4.3±0.68 and 4.46±0.76) respectively, with no significant difference between each other with P value &gt; 0.05 in all comparisons. Calcium levels in mg/dL results for patients (pre, post) and control as mean±SD were (8.68 ±1.68, 8.1±1.72 and 9.12±0.38) respectively with no significant differences except between post treatment and control group with P value &gt; 0.05 in all comparisons. Phosphate levels in mg/dL results for patients (pre, post) and control as mean±SD were (2.5±0.84, 2.95±1.04 and 3.4±0.49) respectively with significant difference with P value &lt; 0.05 in all comparisons. Magnesium levels in mg/dL results for patients pre, post and control as mean±SD were (1.93±0.34, 2.06±0.44 and 2.1±0.34) respectively with no significant difference between each other with P value &gt; 0.05 in all comparisons. This study sheds a light on the molecular cytogenetic response for CML patients who have already resistance to Imatinib and Nilotinib that has much more potent effect as approved by studies and this study has used FISH technique. This study emphasizes on the importance of evaluation of electrolyte panel for CML patients before starting Nilotinib study taking in to consideration if these patients are already receiving Imatinib which can also affect bone metabolism and calcium and phosphate levels.

Evaluation of Electrolytes Disturbances in Iraqi Chronic Myeloid Leukemia Patients treated with Nilotinib with Monitoring of Response by FISH Study

Chronic myeloid leukemia (CML) is a myeloproliferative disorder characterized by the presence Philadelphia chromosome (Ph) which was created by a reciprocal translocation between chromosomes 9 and 22 (t [9;22] [q34;q11]. The approval of the 2nd generation TKI ( Nilotinib) takes the treatment of CML patients into new erea with more efficiency and mild to moderate adverse effects. This study was aimed at evaluation of molecular cytogenetic response by (FISH) for Nilotinib in Iraqi patients with assessment for electrolytes disturbances of Nilotinb by measuring a panel of electrolyte (Na+, K+, Ca++, PO4--- and Mg++) , where thirty Iraqi patients with CML who have resistance or no response to Imatinib treatment, attending to Baghdad Teaching Hospital/Hematology Department, have been submitted to this study. Blood samples have been taken pre and post starting treatment with Nilotinib, FISH study was done only for CML patients, while 30 normal healthy control volunteers submitted to the same panel of electrolytes measurements (Na+, K+, Ca++, PO4--- and Mg++) in addition to pre and post treatment Nilotinib patients. The results show out of 30 patients (17) males and (13) females with male to female ratio 1.3:1, FISH results for patients (pre and post) treatment mean±SD were(58.7%±26.2 % and 45.7%±29.9%) obviously significant with good cytogenetic response in resistance CML for Imatinib. Sodium levels in mmol/L pre, post treatment and control mean±SD were (139.2±6.9 , 142.4±9.2 and 140.4±2.52) respectively, with no significant difference between each other with P value &gt; 0.05 in all comparisons. Potassium levels mean±SD in mmol/L results for patients (pre, post) and control were (4.6±0.69, 4.3±0.68 and 4.46±0.76) respectively, with no significant difference between each other with P value &gt; 0.05 in all comparisons. Calcium levels in mg/dL results for patients (pre, post) and control as mean±SD were (8.68 ±1.68, 8.1±1.72 and 9.12±0.38) respectively with no significant differences except between post treatment and control group with P value &gt; 0.05 in all comparisons. Phosphate levels in mg/dL results for patients (pre, post) and control as mean±SD were (2.5±0.84, 2.95±1.04 and 3.4±0.49) respectively with significant difference with P value &lt; 0.05 in all comparisons. Magnesium levels in mg/dL results for patients pre, post and control as mean±SD were (1.93±0.34, 2.06±0.44 and 2.1±0.34) respectively with no significant difference between each other with P value &gt; 0.05 in all comparisons. This study sheds a light on the molecular cytogenetic response for CML patients who have already resistance to Imatinib and Nilotinib that has much more potent effect as approved by studies and this study has used FISH technique. This study emphasizes on the importance of evaluation of electrolyte panel for CML patients before starting Nilotinib study taking in to consideration if these patients are already receiving Imatinib which can also affect bone metabolism and calcium and phosphate levels.

Monitoring of Disease Activity in Chronic Myeloid Leukemia-chronic Phase Patients Treated with Indian Generic Veenat (NATCO) Imatinib Mesylate: A Tertiary Care Experience

Aim: Real-time quantitative polymerase chain reaction (RT-PCR) is a sensitive technique to monitor treatment response in chronic myeloid leukemia (CML). Standardization of RT-PCR protocols and interpretation of results are important to maintain the reliability of this molecular test. Methods: We present the analysis of treatment monitoring after administration of Indian generic imatinib mesylate (IM) (Veenat) in 73 patients with CML-chronic phase using RT-PCR. Results: A consistent decrease in the median breakpoint cluster region-abelson1 (BCR-ABL1) percentage denoting a continued time-bound response to IM is observed. At 6 months, 87.5% patients showing ≥ 1-log reduction in BCR-ABL1 levels subsequently developed ≥ 3-log reduction as compared to 42.8% patients showing < 1-log reduction. All patients with ≥ 3-log reduction in BCR-ABL1 at 12 months maintained treatment response at 18 months. Conclusion: The efficacy of Veenat (NATCO) is comparable to Gleevac (Novartis). Patients who attain ≥ 1-log reduction at 6 months and ≥ 2-log reduction at 12 months are more likely to subsequently attain a major molecular response.

Achieving early molecular response in chronic myeloid leukemia in chronic phase to reduce the risk of progression: clinical relevance of the 3- and 6-month time points.

Patients with chronic myeloid leukemia in chronic phase who achieve early molecular response (EMR; generally defined as BCR-ABL ≤ 10% on the International Scale at 3 or 6 months) have improved outcomes. However, there is no consensus on whether EMR failure at 3 months requires a change in therapy, and the value of the 6-month time point remains under debate. Some patients who do not achieve EMR at 3 months achieve significant decreases in BCR-ABL levels by 6 months, whereas others have progressive disease. For patients who do not achieve EMR at either time point, the risk of disease progression is higher both between 3 and 6 months and over the longer term, underlining the therapeutic relevance of the 3- to 6-month time period. For patients with EMR failure at 3 months, although there is currently no consensus on whether to switch therapy or wait until the 6-month assessment, some patients may benefit from an early change in treatment. This review synthesizes key clinical data demonstrating improved outcomes associated with the achievement of EMR and discusses the relevance of the 3- and 6-month time points on survival and the risk of disease progression. Several potential clinical situations are also presented to explore when a change in therapy may be considered.

Relationship between SLCO1B3 and ABCA3 polymorphisms and imatinib response in chronic myeloid leukemia patients

BackgroundGenetic variations in membrane transporters may contribute to imatinib mesylate (IM) resistance in chronic myeloid leukemia (CML).ObjectiveTo investigate the relationship between SLCO1B3, SLCO1A2, and ABCA3 polymorphisms and IM response in CML patients.MethodsPatients in chronic phase CML (N = 118) were studied. All patients were treated with a standard dose of IM (400 mg/day) and classified into one of the two groups according to their responses. Major molecular response (MMR) and complete molecular response (CMR) were evaluated. Criteria for response failure were established according to European LeukemiaNet (2009). Analysis of the SLCO1B3 c.334T > G (rs4149117) and c.699G > A (rs7311358), SLCO1A2 c.516A > C (rs11568563) and c.-62-361G > A (rs3764043), and ABCA3 c.1755C > G (rs323043) and c.4548-191C > A (rs150929) polymorphisms was carried out by real-time polymerase chain reaction.ResultsSLCO1A2 and ABCA3 polymorphisms have similar frequencies between responders and non-responders. SLCO1B3 699GG and 344TT genotypes were more frequent in the responder group (63.8%) than in the non-responder group (44.7%, P = 0.042). Furthermore, carriers of 699GA/AA and 334TG/GG genotypes presented a higher probability of not responding to the standard dose of IM (odds ratio: 2.17; 95% confidence interval: 1.02–4.64, P = 0.04). Poor CMR for ABCA3 4548-91C > A was observed in patients with the CC/CA genotype when compared to AA carriers in the responder group (P = 0.014).ConclusionsSLCO1B3 699GG and 344TT genotypes are associated with non-response to IM, while ABCA3 4548-91 CC/CA genotypes are related to poor CMR in CML patients treated with standard-dose imatinib.

MDR1 gene polymorphisms and imatinib response in chronic myeloid leukemia: a meta-analysis.

MDR1 gene polymorphisms were demonstrated to be associated with interindividual variability of imatinib response for chronic myeloid leukemia (CML) patients in several studies; however, the results have been inconclusive. To clarify the effect of common MDR1 variants on clinical response to imatinib, we performed a meta-analysis to quantify the accumulated information from genetic association studies. After a thorough search of the published literature, we undertook a meta-analysis to evaluate the effect of MDR1 C1236T, G2677T and C3435T polymorphisms on imatinib response. Our pooled data showed a significant association between MDR1 C1236T polymorphism and the increasing risk of imatinib resistance in Asian CML patients. However, no significant association was found for the MDR1 G2677T or C3435T polymorphisms in an Asian CML population as well as a Caucasian CML population. The synonymous MDR1 C1236T polymorphism might be a risk factor for nonoptimal clinical response to imatinib in Asian CML patients.

Comparison of simultaneous bone marrow cytogenetic and peripheral blood molecular responses in chronic myeloid leukemia

Compare the correlation and the concordance of simultaneous bone marrow cytogenetic and peripheral blood molecular responses in patients with chronic myeloid leukemia (CML) during tyrosine kinase inhibitor (TKI) treatment. A total of 1 030 pairs of simultaneous bone marrow and peripheral blood samples from 419 patients with CML during TKI treatment were analyzed with standard G-banding techniques and real-time quantitative reverse transcriptase PCR (Q-PCR). The Spearman correlation coefficient for the paired analysis of the percentage of Ph- positive metaphases versus Q-PCR (BCR-ABL/ABL) values was 0.655 (n=1 030, P<0.01). There was a significant difference in terms of BCR-ABL values among all three cytogenetic response groups of no partial cytogenetic (no PCyR), partial cytogenetic (PCyR) and complete cytogenetic responses(CCyR) (P<0.01). 93.8% of the patients in CCyR had BCR-ABL≤1% [International Scale (IS)], and 97.5% of those with BCR-ABL≤0.1% (IS) were in CCyR. There was good concordance of 86.2% (888 of 1 030 samples) when BCR-ABL values according to cutoffs of BCR-ABL>10%(IS), ≤10%->1%(IS)and ≤1%(IS) were coupled with cytogenetic responses including no PCyR, PCyR and CCyR. Furthermore, 497 pairs of samples from 279 patients with newly diagnosed CML in chronic phase during the first year on TKI as first-line therapy were analyzed. Concordances between major cytogenetic response and BCR-ABL≤10%(IS) at 3 months, CCyR and BCR-ABL≤1%(IS) at 6 months and 12 months were 89%, 83.5% and 92.1%, respectively. There were significant correlation and concordance between cytogenetic and molecular responses, and some differences in assessment of early responses between using cytogenetic and molecular analyses in CML patients during TKI treatment.

Reduced ABCG2 and increased SLC22A1 mRNA expression are associated with imatinib response in chronic myeloid leukemia

Imatinib mesylate (IM) has become a standard of care in chronic myeloid leukemia (CML) therapy. Single nucleotide polymorphisms (SNPs) and altered expression in drug transporter genes may influence IM response. In order to investigate whether mRNA expression and SNPs in drug transporters are associated with IM resistance, we studied 118 chronic-phase CML patients receiving the standard dose of IM (400 mg/day). They were assigned as responders and non-responders according to European LeukemiaNet criteria (2009). mRNA expression in samples at diagnosis (without IM therapy) and outcomes after IM failure were also evaluated in subgroups of patients. Major molecular response (MMR), complete molecular response and primary and secondary resistance were all assessed. BCR-ABL1, ABCB1, ABCG2, SLC22A1 and SLCO1A2 mRNA expression and SNPs in ABCG2 and SLC22A1 genes were analyzed. ABCG2 mRNA expression in the non-responders was higher before and during IM therapy. Furthermore, ABCG2 was overexpressed in those who did not achieve MMR (P=0.027). In a subgroup of patients who switched to second-generation tyrosine kinase inhibitors, high mRNA expression of ABCG2 was associated with a risk of 24 times that of not achieving complete cytogenetic response (OR 24.00, 95% CI 1.74-330.80; P=0.018). In the responder group, patients who achieved MMR (P=0.009) presented higher mRNA levels of SLC22A1. The SNPs were not associated with mRNA expression of ABCG2 and SLC22A1. Our data suggest that elevated ABCG2 expression (an efflux transporter) could be associated with IM resistance and could impact on second-generation TKI response, whereas high SLC22A1 expression (an influx transporter) may be associated with a successful IM therapy in CML patients.

Deep Molecular Response in Chronic Myeloid Leukemia: The New Goal of Therapy?

Chronic myeloid leukemia (CML) is caused by formation of the BCR-ABL1 fusion protein. Tyrosine kinase inhibitors (TKI) that target BCR-ABL1 are now the standard of care for patients with CML. Molecular monitoring of residual BCR-ABL1 mRNA transcripts, typically performed using real-time quantitative PCR, has improved treatment management, particularly for patients with CML in chronic phase. Major molecular response (MMR; i.e., a ≥3-log reduction in BCR-ABL1 transcript levels) is used in current treatment guidelines to assess prognosis. Recent evidence suggests that deeper molecular responses (≥4-log reductions in BCR-ABL1 transcript levels), particularly when attained early during treatment, may have even better correlation with long-term outcomes, including survival and disease progression. Furthermore, achieving deep molecular response is a requirement for entering trials evaluating treatment-free remission (TFR). In this review, we discuss the evolving definition of minimal residual disease and the various levels of molecular response under evaluation in current clinical studies. In addition, the available clinical data on achieving MMR and deeper levels of molecular response with TKI therapy, the prognostic value of deep molecular response, and factors that may predict a patient's ability to achieve and sustain a deep molecular response on TKI therapy are also discussed. Available data from TFR studies are addressed. We discuss current knowledge of the ideal conditions for attempting treatment discontinuation, factors predictive of molecular relapse, when TKI therapy should be restarted, and which therapeutic strategies (when administered in the first-line setting and beyond) are expected to best enable successful TFR.

A comprehensive analysis of breakpoint cluster region-abelson fusion oncogene splice variants in chronic myeloid leukemia and their correlation with disease biology.

BACKGROUND:BCR-ABL fusion oncogene is a hallmark of Chronic Myeloid Leukemia (CML). It results due to translocation between chromosome 22 and chromosome 9 [t (9; 22)(q34; q11)]. It gives rise to translation of a 210 KDa chimeric protein (p210), leading to enhanced tyrosine kinase activity and activation of leukemogenic pathways, ultimately causing onset of CML. In case of CML, the classic fusions are b2a2 or b3a2, fusing exon 13 (b2) or exon 14 (b3) of BCR, respectively, to exon 2 (a2) of ABL. The type of BCR-ABL transcripts are thought to be have different prognosis and hence useful in clinical decision-making. The frequencies of different fusion oncogenes associated with leukemia can vary in different ethnic groups and geographical regions due to interplay of genetic variation in different ethnic populations, diverse environmental factors and living style. Moreover, earlier relevant studies from our region were carried out in small subset of patients. Therefore, objective of this study was to find out frequencies of different BCR-ABL splice variants in larger subset of CML patients.METHODS:A nested reverse transcriptase polymerase chain reaction (RT-PCR) was established to detect BCR-ABL splice variants in 130 CML patients. Sensitivity of RT-PCR and ability to detect BCR-ABL fusion gene in least possible time was studied.RESULTS:BCR-ABL detection using our optimized RT-PCR protocol could be completed in 8 hours, starting from RNA extraction to Gel electrophoresis. Sensitivity of RT-PCR assay was of the order of 10−6. Out of 130 Pakistani patients, 83 (63.84%) expressed b3a2 while 47 (36.15%) expressed b2a2 transcript.CONCLUSION:Our RT-PCR was proved to be very quick to detect BCR-ABL fusion oncogene in CML patients within one working day. Because of its sensitivity, it can be used to monitor complete molecular response in CML. BCR-ABL RT-PCR and BCR-ABL splice variants frequency in our study differs from other ethnic groups. It shows that ethnic and geographical differences exist in BCR-ABL splice variant frequency, which may have a profound effect on disease biology as well as implications in prognosis and clinical management of BCR-ABL positive leukemias.

GSTP1 (Ile105Val) Gene Polymorphism: Risk and Treatment Response in Chronic Myeloid Leukemia

Background: Genetic variation influencing individual susceptibility to chemical carcinogens is one of the main factors leading to cancer development. The glutathione S-transferases (GSTs) are a family of enzymes belonging to phase II enzymes involved in detoxification of xenobiotics. A significant relationship is observed between the risk of developing cancer and genetic polymorphisms within GSTs. Methods: In this study, we investigated the influence of inherited GSTP1 (Ile105Val) gene polymorphism on the susceptibility to CML in Egypt in 40 CML patients (20 children and 20 adults), together with 40 healthy controls using a [PCR-RFLP] assay. Results: We found that the mutant type (IIe/Val, Val/Val) was significantly higher in CML patients (67.5%) compared to controls (35%) (p = 0.004); [odds ratio 3.9; 95% CI: 1.5 - 9.7]. The mutant type was associated with more advanced phases in disease and with both worse hematological and cytogenetic responses when compared to the wild type (p = 0.03, p = 0.05, and p 0.001, respectively). Conclusion: GSTP1 (Ile105Val) gene polymorphism conferred a significant association with increased risk of CML and is associated with worse prognosis. Further studies on the functional consequences of this genetic polymorphism would pave the way to declare its role in the pathogenesis of CML or as a possible predictor for response to therapy.

ABC Expression As Additionally Marker To Monitoring Response In CML - A Preliminary Study

Chronic myeloid leukemia (CML) is a mieloproliferative disorder characterized by the presence of the BCR-ABL gene fusion, which encodes an oncoprotein with a deregulated tyrosine kinase activity. This oncoprotein became the main therapeutic target of the disease with the introduction of specific tyrosine kinase inhibitors (TKIs). Additionally, the fusion gene expression level is used as a monitoring tool to determine the molecular response of each patient. However, several patients show incomplete or loss of response and even in some cases resistance to the TKI therapy. Leukemia stems cells, as normal stem cells, could present ABC transporters to protect them-self against therapeutic agents which could contribute to therapeutic failure. One of the most described ABC transporters is PgP and Imatinib and other TKIs are substrates for these efflux transporters. The precise link between ABC transports and response to therapy in CML is not fully understood.The aims of this work were to evaluate the expression levels of ABC transporters, namely PgP and BCRP, in CML patients and to correlate them with the BCR-ABL levels.We examined in CD34+ cells obtained from peripheral blood of 46 patients with CML, the expression levels of PgP and BCRP by flow cytometry using monoclonal antibodies. The BCR-ABL quantification was determined according to the international guidelines for CML management and at the time point of the study 26 patients (56,5%) present a positive quantification of BCR-ABL while the remain 20 patients (43,5%) were BCR-ABL negative. The median patient age at diagnosis was approximately 48 years (24–88), gender M/F=24/22, and 95% of the patients are under treatment with TKIs.Our preliminary results show that patients with no detectable BCR-ABL mRNA (negative) present a higher percentage of CD34+ cells than patients positive for this fusion gene. Furthermore, 80% of these negative patients (n=16) expressed PgP and/or BCRP in cell membrane and 56,2% of these patients would present a positive quantification of BCR-ABL levels in the first 6 months and 75% at the end of one year.These results suggest that the presence of ABC transporters in CD34+ cells of patients without detectable levels of BCR-ABL could constitute an earlier marker of loss of response and may be an additional tool for monitoring response in CML patients. However, further analysis should be performed, namely an increased number of patients, to confirm our results and the clinical relevance. Disclosures:No relevant conflicts of interest to declare.

Expression Proteomics As Surrogate Biomarkers For Early Treatment Response In Chronic Myeloid Leukemia (CML) Patients

PurposeDespite advancements in diagnosis and treatment modalities for hematological malignancies, presently, there are no reliable blood tests for disease prognosis or prediction of patient's response to particular treatments. Identification of such biomarkers for diagnostic or therapeutic response in clinical monitoring of hematologic diseases such as Chronic Myeloid Leukemia (CML) would be very useful. Experimental DesignThe ability to identify biomarkers in body fluids (i.e., plasma or serum) will not only involve minimally invasive procedures, but also more importantly, the potential for monitoring disease progression and effective response to therapy in relatively early stages. In this study, global proteome analysis of serum, plasma, and bone marrow samples from 28 patients with newly diagnosed chronic–phase CML were analyzed by using expression proteomics technology (label free quantitative liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The goal was to evaluate for early treatment response and discovery disease–specific /disease-associated proteins for prognostic monitoring and patient's response to therapy at protein level. ResultsWe identified a panel of 15 differentially expressed proteins (> 2- °- fold change, p< 0.001) to accurately discriminate between CML patients that achieved Major Molecular Response (MMR) vs. No-Major Molecular Response (NoMMR) at 6 months (Figure 1 & Table 1). Six (6) of the 15 identified proteins were filtered and mapped as potential biomarkers using Ingenuity Pathway Analysis. Among the identified proteins implicated in hematological diseases include Group-specific component (vitamin D binding protein), haptoglobin and vitronectin. Others were inter-alpha-trypsin inhibitor heavy chain 1, leucine-rich alpha-2-glycoprotein 1 and metallophosphoesterase 1. We also observed most of these proteins to be located in extracellular space, acts as transporters and have been implicated as markers of hematological disease and inflammatory response. Our data indicates that multivariate analysis of quantitative proteome data can potentially be useful as a means of unsupervised artificial intelligence algorithm for classification and stratification of clinical CML patients. [Display omitted] [Display omitted] ConclusionOur results highlight the power of proteomics in the discovery of biomarkers for more accurate prediction of prognosis and monitoring treatment response in CML patients. These proteins might be valuable, once validated, to complement the currently existing parameters for reliable and objective prediction of disease progression, monitoring treatment response and clinical outcome of CML patients. Disclosures:No relevant conflicts of interest to declare.