Index to Predict MMR at 12 Months in Chronic Phase Chronic Myeloid Leukemia Patients Based on the Area Under the Lymphocyte Curve

Abstract BACKGROUND: Dasatinib is a second-generation BCR-ABL inhibitor that has a 325-fold higher potency than imatinib and a 16-fold higher potency than nilotinib in vitro. Recent reports suggested that absolute lymphocytosis in response to dasatinib for chronic phase (CP) –chronic myeloid leukemia (CML) might be associated with favorable response. However, as the fluctuation of lymphocytosis was often observed, it is sometimes difficult to define lymphocytosis. To evaluate how much increase and how long continuation of lymphocytosis affects the better clinical efficacy, we developed an index (DL index; Dasatinib induced Lymphocytosis index) that combines duration and increase of lymphocytosis. The aim of this study was to test the DL index as a predictor of Major Molecular Response (MMR) at 12 month. PATIENTS and METHODS: The DL area was based on a graph plotting the absolute lymphocyte counts and was the area under the lymphocyte curve using trapezoidal method. DL index was DL area divided by weeks. For example, DL index12W was defined as (DL area from 4 to 12 weeks) divided by (12-4) weeks. We tested the DL index12W in 30 patients who developed MMR at 12 months (MMR group) and 9 patients without MMR (non-MMR group). RESULTS and DISCUSSION: DL score12w in MMR group and non-MMR group were 2714.0 (95% CI; 2286.0-3142.2, n=30) and 1559.9 (95% CI; 1006.9- 2113.0, n=9) respectively. There was a significant difference between MMR group and non-MMR group in DL index12W by t-test(Figure 1, p=0.0016). A significant linear relationship was obtained between DL index12w and the peaked lymphocyte counts within 12 weeks by Spearman's correlation coefficient rank test (Figure 2, p=1.97E-07, correlation coefficient=0.91). The DL index12w, 2,113, which was the upper limit of non-MMR group 95% CI, is equivalent to 2,909/µl in lymphocyte count, and the DL index12w, 2,286, which is the lower limit of MMR group 95% CI, equivalent to 3,123/µl in lymphocyte count. Therefore, we divided all patients (n=39) into two groups, equal or more than 3,123/µl and less than 3,123/µl in the peaked lymphocyte counts. The patients with the peaked lymphocyte counts ≥ 3,123/µl reached MMR at 12 months (19/20=95.0%) to compare those less than 3,123/µl (11/19=57.9%) (p=0.0075). CONCLUSION: The peaked lymphocyte number, induced by the DL index12w, which calculation was extremely easy, was associated with molecular response. These data suggests that this tool can be useful in interpreting the results of molecular response at 12 months. Figure 1 Figure 1. Figure 2 Figure 2. Disclosures No relevant conflicts of interest to declare.

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Multidrug Resistance Gene (MDR1) Polymorphism and Response to Nilotinib in Egyptian Patients with Chronic Myeloid Leukemia (CML)

Blood ◽

10.1182/blood.v124.21.5220.5220 ◽

2014 ◽

Vol 124 (21) ◽

pp. 5220-5220

Author(s):

Mervat Mattar ◽

Hend Ellithy ◽

Yasser Elnahas ◽

Mohamed osman Azzazi

Keyword(s):

Multidrug Resistance ◽

Chronic Myeloid Leukemia ◽

Myeloid Leukemia ◽

Conflicts Of Interest ◽

Chronic Phase ◽

Response To Treatment ◽

Mdr1 Gene ◽

Molecular Response ◽

Multidrug Resistance Gene ◽

Significant Difference

Abstract Introduction: Inappropriate expression of the multidrug resistance (MDR1) gene I in chronic phase chronic myeloid leukemia cases (CML-CP) encodes P glycoprotein (Pgp)that may cause resistance to second generation tyrosine kinase inhibitors (TKIs) Patients and methods: Thirty-one upfront CML-CP patients, planned to receive nilotinib, were included. Detection of MDR1 gene polymorphism C3435T, using PCR Restriction Fragment Length Polymorphisms (PCR-RFLP) was done initially for every patient. We prospectively followed up the patients between February 2012 and February 2014 with PCR for BCR-ABL1 transcripts every 3 months. The molecular response to nilotinib, according to the level of BCR-ABL1 by PCR, was compared to the different MDR1 3435 genotypes. Results: The majority of the patients carried the MDR1 3435CC genotype of Molecular response was optimal in 56%, 60% and 80% of the patients at month 3, 6 and 12 respectively.There was no statistically significant difference between MDR- C3435T genotypes and the molecular response to treatment with nilotinib. Disclosures No relevant conflicts of interest to declare.

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Results of Imatinib Dose Escalation After 36 Months of Follow-up in Chronic Myeloid Leukemia Patients with Failure or Sub-Optimal Response According to 2006 EuropeanLeukemia Net (ELN) Criteria.

Blood ◽

10.1182/blood.v114.22.3302.3302 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3302-3302

Author(s):

Massimo Breccia ◽

Fabio Stagno ◽

Roberto Latagliata ◽

Paolo Vigneri ◽

Laura Cannella ◽

...

Keyword(s):

Chronic Myeloid Leukemia ◽

Dose Escalation ◽

Myeloid Leukemia ◽

Conflicts Of Interest ◽

Standard Dose ◽

Acquired Resistance ◽

Chronic Phase ◽

Cytogenetic Response ◽

Molecular Response

Abstract Abstract 3302 Poster Board III-190 Introduction Imatinib mesylate (IM) given at a daily dose of 400 mg currently represents the gold standard of care for patients with chronic myeloid leukemia (CML) in chronic phase (CP). European LeukemiaNet (ELN) guidelines propose IM dose escalation to rescue those CML patients with either suboptimal response or drug resistance. We report on the long-term efficacy of IM dose escalation in 74 patients with CP-CML after suboptimal response or failure to IM conventional dose. Patients and methods Median age was 50 years (range 19-85), there were 52 males and 22 females. Thirteen patients were classified as hematologic failure (10 primary and 3 secondary), 57 patients as cytogenetic resistance (24 primary and 33 acquired). Three patients escalated the dose for cytogenetic suboptimal response and one patient for molecular suboptimal response at 18 months. Fifty-four received IM dose escalation from 400 to 600 mg and 20 patients from 400 to 800 mg. Results Overall, after a median follow-up of 36 months, 68/74 (91.8%) patients maintained or achieved a complete haematologic response (CHR); this was maintained in all patients who escalated the dose for cytogenetic failure or suboptimal response. A major cytogenetic response (MCyR) was achieved in 41 patients (72%) who escalated the dose for cytogenetic failure and in 6/13 (46%) patients who escalated imatinib for hematologic failure (p=0.002). Overall, complete cytogenetic responses (CCR) were achieved in 27 (37%) out of 74 CML patients: of the 13 hematologic failure patients, only 5 achieved CCyR: all patients had prior acquired resistance to imatinib. Of the 57 cytogenetic failure, 22 reached CCR: this response was obtained in 27% of the primary cytogenetic resistant, and in 50% of the acquired cytogenetic resistant patients (p=0.02). Three patients who escalated the dose for cytogenetic suboptimal response obtained CCR and complete molecular response (CMR), whereas one patient who escalated the dose for molecular suboptimal response at 18 months did not obtain CMR. Median time to cytogenetic response was 3.5 months. Cytogenetic responses occurred in 37/50 patients who escalated the dose to 600 mg and in 10/20 patients who escalated to 800 mg daily (p=0.234). CMR was obtained in 10 patients: in 7 patients who escalated the dose for cytogenetic failure and in 3 patients who escalated imatinib for suboptimal cytogenetic response. Estimated 2 year-progression free survival (PFS) and overall survival (OS) is 87% and 85% respectively. Sixteen patients (21.6%) experienced toxicities and had temporarily IM interruption. Conclusions Imatinib dose escalation can induce sustained responses in a subset of patients with cytogenetic resistance and a prior suboptimal cytogenetic response to standard-dose imatinib, whereas it appears less effective in haematologic failure patients or in molecular sub-optimal responders. The availability of second generation TKI should be taken into account in these letter categories of patients. Disclosures No relevant conflicts of interest to declare.

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Long Term Outcomes Of Imatinib In Chronic Myeloid Leukemia In Saudi Population, Single Center Study

Blood ◽

10.1182/blood.v122.21.5180.5180 ◽

2013 ◽

Vol 122 (21) ◽

pp. 5180-5180

Author(s):

Enaam Mohammed Alsobhi ◽

Mohammed m Abrar ◽

Mohammed A Abdelaal ◽

Ahmad S. Alsaeed ◽

Ahmed Al-Absi ◽

...

Keyword(s):

Saudi Arabia ◽

Chronic Myeloid Leukemia ◽

Myeloid Leukemia ◽

Conflicts Of Interest ◽

Randomized Study ◽

Cytogenetic Response ◽

Molecular Response ◽

Newly Diagnosed ◽

First Line ◽

Significant Difference

Abstract Background The introduction of Imatinib therapy has significantly changed the treatment of patients with newly diagnosed chronic myeloid leukemia (CML) and improved survival. Since the International Randomized Study of Interferon (IRIS), a number of studies were conducted involving diverse populations and showed significant variations in the treatment outcome. To date, there has been no published study on the effectiveness of imatinib in adult CML patients in Saudi Arabia. The aim of the present study was to present a single-institution experience in the treatment with imatinib of newly diagnosed patients with CML and compare it with results from international studies. Methods A total of 101 medical records of consecutive adult CML patients treated with imatinib as first line therapy at King Abdulaziz Medical City, Jeddah, Saudi Arabia between 2001 and 2012 were retrospectively reviewed. Survival and response rates were evaluated. Results The estimated overall survival (OS) rates at 5 and 10 years were 95%±2.3% when patients were stratified by cytogenetic type (stander vs.variant Ph positive chromosome) at presentations, significant difference in OS, EFS, and PFS were noted (P=0.001). Complete haematological response was achieved in 94 (93.1%) of our patients, cytogenetic response (CR) in 84 (83.2%) while complete and major cytogenetic response (MCR) were observed in 70 (69.3%) and 6 (5.9%) of the patients respectively. (MR), 62 patients (61.4%) achieved major molecular response (MMR) and 34 (33.7%) complete molecular response. Conclusion compared to other studies among different population, our results confirm the previously noted variation in the response to imatinib. Our study has shown that Ph variant has an impact on the outcome. Further study may be indicated. However second TKI generations as first line in treatment CML with Ph variants should be consider! Disclosures: No relevant conflicts of interest to declare.

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The Comparison of Dasatinib 70 Mg/Day to 100 Mg/Day in Newly Diagnosed Patients with Chronic Myeloid Leukemia in Chronic Phase (CML-CP): A Multicenter, Prospective, Randomized Controlled Study

Blood ◽

10.1182/blood-2021-148349 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 3615-3615

Author(s):

Dan Yu ◽

Zhuangzhi Yang ◽

Hui Cheng ◽

Rui Jiang ◽

Jingming Guo ◽

...

Keyword(s):

Chronic Myeloid Leukemia ◽

Myeloid Leukemia ◽

Standard Dose ◽

Chronic Phase ◽

Controlled Study ◽

Molecular Response ◽

Newly Diagnosed ◽

Efficacy And Safety ◽

Best Response ◽

Significant Difference

Abstract Background: The purpose of this study is to compare efficacy and safety of patients with newly diagnosed chronic myeloid leukemia in chronic phase (CML-CP) treated with frontline dasatinib 70 mg/day with those who received standard-dose dasatinib 100 mg/day. Method: From July 2019 to July 2021, 81 patients with newly diagnosed CML-CP were enrolled across 11 centers. All of the patients were randomly treated with dasatinib 70 mg/day (N=43) or standard-dose dasatinib 100 mg/day (N=38). Results: Among 81 enrolled patients, 16 patients were off study at different times for different reasons.All patients achieved hematological remission after 3 months of treatment, and the best response rates were 84.00% (21/25) and 88.89% (24/27) for 70mg/d and 100mg/d groups (P>0.05).At 6 months, the best response, complete cytogenetic response (CCyR) and major molecular response (MMR) rate were 94.44% vs 92.86% (P > 0.05), 94.44% vs 92.86% (P > 0.05) and 55.56% vs 71.43% (P > 0.05), respectively.At 9 months, the rates of CCyR and MMR were 90.91% vs 88.89% (P > 0.05) and 66.67% vs 72.73% (P > 0.05);CCyR and MMR by 12 months, respectively, were 90.91% vs 100.00% (P > 0.05), 81.82% vs 80.00% (P > 0.05).The adverse events (AEs) of the two groups were mild, and there was no significant difference (P > 0.05).The most common grade ≥3 hematological AEs in 70 mg/d group were leukopenia (1/43), neutropenia (1/43) and anemia (2/43), and In 100mg/d group were leukopenia (4/38), neutropenia (6/38), anemia (3/38) and thrombocytopenia (3/38). Conclusions: Our study suggests that patients with newly diagnosed CML-CP treated with dasatinib 70 mg/day or 100 mg/day, there is no significant difference in efficacy and safety. Decreasing the dose of dasatinib can ensure the efficacy of patients, while reducing the economic burden of patients and increasing patient compliance. Disclosures No relevant conflicts of interest to declare.

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Clinical Relevance of Failure to Achieve Early Molecular Response in Chronic Myeloid Leukemia in Chronic Phase

Blood ◽

10.1182/blood.v126.23.5160.5160 ◽

2015 ◽

Vol 126 (23) ◽

pp. 5160-5160

Author(s):

Ji Yun Lee ◽

Sung Hee Lim ◽

Hae Su Kim ◽

Kwai Han Yoo ◽

Haa-Na Song ◽

...

Keyword(s):

Chronic Myeloid Leukemia ◽

Clinical Outcomes ◽

Myeloid Leukemia ◽

Chronic Phase ◽

Molecular Response ◽

Line Treatment ◽

First Line ◽

Transcript Levels ◽

Significant Difference ◽

First Line Treatment

Abstract Purpose The early molecular response (EMR, ≤ 10% BCR-ABL1 at 3 months) of tyrosine kinase inhibitor (TKI) treatment for patients with chronic myeloid leukemia (CML) in chronic phase (CP) has been reported to have strong correlation with long-term outcome. We aim to investigate the prognostic interaction of the EMR and major molecular response (MMR). Methods We retrospectively reviewed data for a total of 165 patients with newly diagnosed CML-CP who received TKIs (imatinib, nilotinib, or dasatinib) as first-line treatment between January 2003 and April 2013. Of the total 128 patients who were regularly monitored by peripheral blood molecular analysis, 85 had a BCR-ABL1 assessment at 3 months and were finally included in the analysis. Results The median age of all patients was 49 years and 87.1% received imatinib as first line treatment. High risk group by Sokal and EUTOS were 29.4% and 14.1%, respectively. Patients with EMR (n = 56, 65.9%) had a tendency to have low risk disease and to be treated with 2nd generation of TKIs. With a median follow-up duration of 53.6 months (range, 5.4-131.3), the 5-year OS, 5-year FFS, and 5-year EFS were 92.5%, 74.8%, and 68.0%, respectively. Median time to achieve MMR was 11.1 months (95%CI, 8.4 - 13.8). The outcomes at 5 year comparing patients whose BCR-ABL1 transcript levels ≤ 10% vs >10% at 3 months were as follows: OS, 92.2% (95% CI 84.9-99.1) vs 92.8% (95% CI 83.7-102.3), p = 0.819; FFS, 84.7% (95% CI, 75.6-94.4) vs 57.4% (95% CI, 39.0-75.0), p < 0.001; and EFS, 73.6% (95% CI 62.5-85.5) vs 57.8% (95% CI 40.0-76.0), p = 0.050. Six (10.7%) of 56 patients with BCR-ABL1 transcript levels ≤ 10% at 3 months failed to achieved an MMR and 18 (62.1%) of 29 patients with > 10% at 3 months achieved an MMR. Based on these heterogeneous clinical outcomes, we further explored subgroup analysis according to the achievement of MMR for refined discrimination of survival outcomes. There was no significant difference of clinical outcomes between ≤ 10% vs > 10% at 3 months among the patients who achieved MMR (OS, p = 0.376; FFS, p = 0.793; and EFS, p = 0.266). In patients who did not achieved MMR, only FFS was significantly difference between ≤ 10% vs > 10% at 3 months (OS, p = 0.489; FFS, p = 0.014; and EFS, p = 0.199). Conclusion Patients who failed to achieve EMR but finally reached MMR have excellent prognosis that whether we have to change TKI for EMR failure is to be addressed by ongoing prospective clinical trials. Disclosures Jang: Alexion Pharmaceuticals: Research Funding.

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Mutations of TET2, IDH1, IDH2 and ASXL1 In Chronic Myeloid Leukemia.

Blood ◽

10.1182/blood.v116.21.3377.3377 ◽

2010 ◽

Vol 116 (21) ◽

pp. 3377-3377

Author(s):

Catherine Roche-Lestienne ◽

Marceau Alice ◽

Elise Labis ◽

Olivier Nibourel ◽

Valérie Coiteux ◽

...

Keyword(s):

Chronic Myeloid Leukemia ◽

Candidate Genes ◽

Myeloid Leukemia ◽

Conflicts Of Interest ◽

Chronic Phase ◽

Cytogenetic Response ◽

Haematopoietic Stem Cell ◽

Molecular Response ◽

Genetic Event ◽

Myeloid Malignancies

Abstract Abstract 3377 It is generally accepted that the BCR-ABL oncoprotein transformes haematopoietic stem cell and initiates chronic myeloid leukemia (CML). However, leukemogenesis is a complex process, and genomic heterogeneity of the chronic phase (CP) of the disease has been reported. At the molecular level, this intrinsic heterogeneity could support a causative link with the varying response to treatment and disease progression. Genetic analysis of candidate genes in myeloid malignancies reported mutations of the ten-eleven translocation 2 (TET2), the isocitrate deshydrogenase (IDH) 1 and IDH2, and the additional sex combs like 1 (ASXL1) genes in myeloproliferative, acute myeloid and myelodysplasic neoplasms. Similarly, we can stipulate that these candidate genes may contribute to phenotypic heterogeneity of CML. To investigate whether TET2, IDH1, IDH2 and ASXL1 defect could represent a significant event in CML, we selected 91 CML patients (pts) treated with imatinib (IM) at first line and presenting five profiles of IM response at time of the analysis: 1) 25 pts in major molecular response (MMR) at 12 months of IM; 2) 11 pts in CCR but presenting additional Philadelphia (Ph) negative clonal evolution; 3) 20 pts in partial cytogenetic response at 18 months of IM, referred as primary resistant (R1); 4) 20 pts in acute transformation 4 to 72 months after onset IM; and 5) 15 pts relapsing in CP of the disease, referred as secondary resistant (R2). The search for mutation was performed by sequencing the entire TET2 coding region (11 exons), the IDH1 and IDH2 exon 4 and the ASXL1 exon 12. Analysis of paired samples from CML diagnosis, time of IM response and, when available, CCR revealed: 1) 2 pts (2.2%) in acute transformation presenting 3 TET2 stop mutations not located within conserved region (del at A2079, substitution T4893A - both also been detected at diagnosis -, and del at C4851 which has not been detected at diagnosis, even by mutation-specific ASO-PCR); 2) no IDH1 and IDH2 mutation; and 3) 8 pts (8.7%) presenting ASXl1 stop mutations at diagnosis. Among them, 3 pts (two ins at G646 and one ins at V751) have reached MMR without detected mutations at this time; one R1 pt presenting ins at G646 had major cytogenetic response with 5% Ph+ cells but the mutation was not found at this time and the pt have progressed to MMR 9 months later; one pt with 23 bp del at R634 has evolved in acute transformation with detected mutation at this time; and 3 R2 pts presenting either 4 bp del at S895, del at R860 or 2 pb ins at A752 have lost CCR associated with lost of hematologic response in one case. In this later group of 3 pts, except for del at R860, all ASXL1 mutations were found in samples at time of relapse. We therefore conclude that, contrary to what has been reported in other myeloid malignancies, TET2, IDH1 and IDH2 are not commonly acquired in CML and may not represent a major genetic event in CML transformation. However, ASXL1 alteration seems to be an early event in CML leukemogenesis but does not seem to participate in the disease transformation. Disclosures: No relevant conflicts of interest to declare.

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hOCT1 Gene Expression Might Predict Molecular Response In Patients with Chronic Myeloid Leukemia

Blood ◽

10.1182/blood.v116.21.4838.4838 ◽

2010 ◽

Vol 116 (21) ◽

pp. 4838-4838

Author(s):

Lurdes Zamora ◽

Marta Cabezon ◽

Concha Boqué ◽

Silvia Marce ◽

Jordi Ribera ◽

...

Keyword(s):

Gene Expression ◽

Chronic Myeloid Leukemia ◽

Myeloid Leukemia ◽

Conflicts Of Interest ◽

Fusion Gene ◽

Chronic Phase ◽

Organic Cation Transporter ◽

Initial Response ◽

Molecular Response ◽

Hematopoietic Malignancy

Abstract Abstract 4838 Introduction: Chronic myeloid leukemia (CML) is a clonal hematopoietic malignancy characterized by the presence of BCR/ABL fusion gene. The resulting protein has a high tyrosine kinase (TK) activity. The first-line treatment for CML is Imatinib, which allow the achievement of cytogenetic and molecular response in most of patients with CML in chronic phase. However, some patients do not respond to this treatment or lose their initial response. Imatinib has been reported to be incorporated into the cell through hOCT1 transporter (human organic cation transporter). The aim of this study was to determine whether the expression of hOCT1 at diagnosis of CML influenced the achievement of molecular response. Patients and Methods: We analyzed hOCT1 gene expression by quantitative PCR in 42 patients at diagnosis and 18 months after treatment with Imatinib. We compared the expression with the presence of compleat molecular response (CMR) at 18 months. We consider CMR when the Ratio (BCR-ABL/ABL)×100 was <0.1% (after International Scale correction). For statistical analysis methods we have used Kolmogorov-Smirnov and Mann-Whitney nonparametric methods. Results: Of the 42 patients, 2 were in hematological response, 22 were in cytogenetic response and 18 in CMR at 18 months. We found a higher hOCT1 gene expression at 18 month than at diagnosis (53.3 versus 29.6, p<0.001) in all patients (Figure 1). We have found some tendency of higher hOCT1 expression at diagnosis in patients with CMR at 18 months than in those who did not had (25.5 versus 18.8, p = 0.07) (Figure 2). Conclusions: Partially funded by FICJ-P-EF-09, RD06/0020/1056 de RTICC and Novartis. We want to thank Dr. David Marin for providing us plasmid for quantitative analysis. Disclosures: No relevant conflicts of interest to declare.

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Significant Discrepancy In Peripheral Blood Compared to Bone Marrow BCR-ABL Transcript Levels In Chronic Phase Chronic Myeloid Leukemia (CML)

Blood ◽

10.1182/blood.v116.21.4471.4471 ◽

2010 ◽

Vol 116 (21) ◽

pp. 4471-4471

Author(s):

Jason N Berman ◽

Wenda Greer ◽

Ridas Juskevicius ◽

Conrad V Fernandez ◽

Mark Bernstein ◽

...

Keyword(s):

Bone Marrow ◽

Chronic Myeloid Leukemia ◽

Peripheral Blood ◽

Myeloid Leukemia ◽

Conflicts Of Interest ◽

Health Centre ◽

Chronic Phase ◽

Transcript Level ◽

Transcript Levels ◽

Significant Difference

Abstract Abstract 4471 Chronic myeloid leukemia (CML) is associated with the reciprocal t(9;22)(q34;q11) translocation, which generates the BCR-ABL fusion oncogene and is the most common myeloproliferative disease affecting adults. The clinical outcome in this disease has been revolutionized with the use of imatinib mesylate (Gleevec), a targeted tyrosine kinase inhibitor, and molecular surveillance, with the development of quantitative PCR (qPCR) approaches to measure BCR-ABL transcript levels. A number of guidelines outlining follow-up strategies for patients with chronic phase CML on imatinib therapy have been established. Once a patient is stable, a typical recommendation includes peripheral blood (PB) monitoring by qPCR of BCR-ABL levels every 3–6 months to determine response or relapse, with consideration of annual bone marrow (BM) examinations to assess for cytogenetic evolution. At the Queen Elizabeth II Health Sciences Centre and IWK Health Centre in Halifax, Nova Scotia, 34 patients with chronic phase CML on imatinib were identified from 2006 to 2008, with 36 paired samples, where transcript levels were assessed in both PB and BM within one week of each other. In 24 of the cases, the BCR-ABL transcript levels in PB and BM were within 0.5 log values of each other. In the remaining 12 cases, BCR-ABL transcript levels differed by greater than 0.5 log. Three cases had higher BM levels, but surprisingly, 9 patients had a higher BCR-ABL transcript level in the PB. In all cases, BCR-ABL levels were assessed by Q-RT-PCR using the ABI7500 instrument and primers and probe designed to detect p210 and p190 breakpoints. Results were recorded as a ratio of %BCR-ABL to GAPDH that was amplified as an internal control. There was no significant difference in clinical, morphological or laboratory parameters between these patients and others who had comparable PB and BM BCR-ABL levels. These findings highlight the need to compare BCR-ABL transcript levels derived from the same tissue during longitudinal monitoring. Moreover, while potentially due to stochastic factors, the striking observation of higher PB BCR-ABL transcript levels raises the question of which tissue represents the most accurate source for monitoring of BCR-ABL transcript levels and whether there is value in confirming a significant change in PB transcript level with BM evaluation. The discrepant levels in PB and BM could not be attributed to technical issues; the timing of sample processing from collection and quality of mRNA were comparable and no variability was observed in GAPDH levels to account for the difference. Without a technical explanation, the mechanism underlying this phenomenon remains uncertain. We speculate that it may reflect CML stem cell geography with one possibility being that the CML niche may be located external to the BM. Further studies are needed to confirm these observations. If corroborated, then revision of surveillance approaches for chronic phase patients may be indicated. Disclosures: No relevant conflicts of interest to declare.

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Evaluation Of hOCT1expression In Patients With Chronic Myeloid Leukemia (CML) Treated With Imatinib In First Line

Blood ◽

10.1182/blood.v122.21.4041.4041 ◽

2013 ◽

Vol 122 (21) ◽

pp. 4041-4041

Author(s):

Cintia Do Couto Mascarenhas ◽

Maria Helena Almeida ◽

Eliana C M Miranda ◽

Bruna Virgilio ◽

Marcia Torresan Delamain ◽

...

Keyword(s):

Chronic Myeloid Leukemia ◽

Peripheral Blood ◽

Myeloid Leukemia ◽

Conflicts Of Interest ◽

Chronic Phase ◽

Taqman Probe ◽

Molecular Response ◽

Imatinib Treatment ◽

First Line ◽

Transcript Levels

Abstract Introduction The majority of chronic myeloid leukemia (CML) patients (pts) in chronic phase (CP), present satisfactory response to imatinib treatment. However, 25-30% of these pts exhibit suboptimal response or treatment failure. The probability of achieving optimal response may be related with several factors. The human organic cation transporter 1 (hOCT1, SLC22A1), an influx transporter, is responsible for the uptake of imatinib into chronic myeloid leukemia (CML) cells The aim of this study was to analyze hOCT-1 levels at diagnosis of CML patients and correlate with cytogenetics and molecular responses. Methods hOCT-1 expression was evaluated in 58 newly diagnosed CML pts. Pts were treated with imatinib 400-600mg in first line. Samples were collected from peripheral blood at diagnosis and RNA was obtained from total leucocytes. For cDNA synthesis, 3 ug of RNA was used. hOCT-1 expression was evaluated by real-time PCR with TaqMan probe SLC22A1 (Applied Biosystems) and endogenous GAPDH control. The results were analyzed using 2-ΔΔCT. Cytogenetic analysis was performed at diagnosis, 3, 6, 12 and 18 months after starting therapy and then every 12-24 months thereafter if CCR was achieved. BCR-ABL transcripts were measured in peripheral blood at 3-month intervals using quantitative RT-PCR (RQ-PCR). Results were expressed as BCR-ABL/ABL ratio, with conversion to the international scale (IS). Major molecular response (MMR) was defined as a transcript level ≤ 0.1%. Results 58 CML pts, 60% male, median age of 46 years (19-87) were evaluated, 71% in chronic phase (CP), 21% in accelerated phase (AP) and 5% in blast crisis (BC). The mean and median of hOCT-1 transcript levels in the total group was 2.03 and 0.961 respectively (0.008–19.039) and CP pts was 1.86 and 1.00 (0.008-10.34).The median duration of imatinib treatment was 27 months (1-109) and 96.6% achieved complete hematological response, 79.3% complete cytogenetic response and 69% major or complete molecular response. The regression analysis showed correlation between higher transcript levels of hOCT-1 and BCR-ABL transcripts<10%) at 3 months analysis (p<0.0001). Albeit, there was no influence of the hOCT-1 transcript levels at diagnosis in the achievement of cytogenetic and molecular response at 24 months of treatment. Conclusions In this report, we found that high hOCT-1 expression was predictive of BCR-ABL transcripts<10% at 3 months, although we did not find correlation between hOCT-1 levels at diagnosis and the achievement of molecular response at 24 months, studies show that there is correlation between BCR-ABL log reduction in the first months of treatment and the achievement of molecular response. Disclosures: No relevant conflicts of interest to declare.

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Mutational Profiles during the Progression of Chronic Myeloid Leukemia

Blood ◽

10.1182/blood-2021-154273 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 3596-3596

Author(s):

Mengxing Xue ◽

Zhao Zeng ◽

Qinrong Wang ◽

Lijun Wen ◽

Yi Xu ◽

...

Keyword(s):

Chronic Myeloid Leukemia ◽

Myeloid Leukemia ◽

Kinase Inhibitors ◽

Conflicts Of Interest ◽

Prognostic Significance ◽

Chronic Phase ◽

The Other ◽

Molecular Response ◽

Dismal Prognosis

Abstract Background: Despite significant improvements in the prognosis of chronic myeloid leukemia (CML) achieved by targeted therapy with tyrosine kinase inhibitors (TKIs), a small proportion of cases may not respond to TKIs or may relapse after an initial response, and then progress from chronic phase (CP) to blastic crisis (BC), characterized by a dismal prognosis. It remained uncertain whether the genetic lesions in addition to the BCR-ABL1 fusion could predict clinical outcomes of CML in the TKI era. Aim: To study the mutational profiles at each stage of CML and the prognostic significance of somatic mutations in addition to the BCR-ABL1 fusion in the TKI era. Patients and Methods: We performed targeted sequencing in 81 CML patients chosen retrospectively. 10 patients had optimal response to TKIs by European LeukemiaNet criteria and maintained durable major molecular response more than 5 years. 71 patients had progressed to accelerated phase (AP) or BC, of whom 43 had sequencing performed at paired CP and AP/BC samples, 28 at AP or BC samples. Totally, we analyzed 53 CP, 20 AP, and 61 BC samples. The targeted resequencing gene panel, covering 386 genes which were recurrently mutated in hematologic malignancies, were performed on a HiSeq 4000 NGS platform (Illumina). Results: Among the 53 CP samples, 20 (37.7%) had mutations involving 14 genes, and the number of mutated genes in each patient was 0-3 (median 0). ASXL1 was the most commonly mutated gene, 10/53 (18.9%) patients had this mutation, followed by KMT2D (4/53, 7.5%), PC (2/53, 3.8%), ERBB4 (2/53, 3.8%). ASXL1 mutation mainly existed in 43 patients with progressed disease , while only one case carried this mutation in 10 patients responsive to TKIs (20.9% vs 10%). 17/20 (85%) AP samples (including 10 patients progressed to AP and the other 10 patients who eventually progressed to BC from AP ) carried mutations involving 18 genes, the number of mutated genes in each patient was 0-6 (median 1.5). ABL1 was the most commonly mutated gene, and 8/20 (40%) patients had this mutation. The second was the ASXL1 mutation, 7 (7/20, 35%) patients carried this mutation. The other genes mutated in more than 2 patients included BCORL1 (3/20, 15%), RUNX1 (2/20, 10%), PHF6 (2/20, 10%), KMT2D (2/20, 10%), ATM (2/20, 10%). 54/61 (88.5%) BC samples (44 with myeloid crisis, 14 with lymphoid crisis, 3 with mixed phenotypic crisis) carried mutations, involving 41 genes, and the number of mutated genes in each patient was 0-9 (median 2). Similar to the mutation status in AP, the most commonly mutated gene was also ABL1, 24/61 (39.3%) patients carried this gene mutation, followed by ASXL1 mutation (13/61, 21.3%), and the other genes were in order, RUNX1 (11/61, 18.0%), WT1 (8/61, 13.1%), GATA2 (6/61, 9.8%), MED12 (5/61, 8.2%), IDH1 (5/61, 8.2%), TP53 (4/61 , 6.6%), KMT2D (4/61, 6.6%), etc. (Figure 1A) Among all the samples, 34 nonsynonymous variants in the ASXL1 gene were identified in 31 samples of 21 patients ( 3 samples with two variants). All the variants were frameshift and nonsense mutations, localized at the last exon of the ASXL1 gene. 13/21 patients with ASXL1 mutations had multi-stage samples. The median VAF of the ASXL1 mutations in the advanced stage was 31.4% (0-47.0%), which was significantly higher than that in CP at diagnosis (7.0%, 0-27.2%, P=0.033). Most of the ASXL1 mutations detected in CP expanded at the advanced disease, and were accompanied with other additional gene abnormalities, such as ABL1, RUNX1 and WT1 mutations, with the VAF similar to or lower than that of the ASXL1 mutations. In a few cases, the ASXL1 mutant clones in the CP disappeared, suggesting that some ASXL1 mutations may be clonal hematopoiesis unrelated to disease progression.(Figure 1B) In order to evaluate the effects of ASXL1 mutations on sensitivity to TKIs in vitro. We co-expressed P210-BCR-ABL1 fusion and ASXL1 mutation (G646Wfs*12) in Ba/F3 cells. Compared to Ba/F3 cells co-expressing BCR-ABL1 fusion and ASXL1 mutation (Ba/F3-BA/As), Ba/F3-BCR-ABL1 cells without ASXL1 mutation (Ba/F3-BA/Ve) showed higher sensitivity to TKIs, including imatinib, dasatinib and nilotinib.(Figure 1C) Conclusions: These results demonstrated the genetic lesions accumulated during the progression of CML from CP to BC. ASXL1 mutations were the most common genetic lesion in CP at diagnosis and may confer a poor prognosis, as it reduced the sensitivity to TKIs. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

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