Phase Chronic Myeloid Leukemia Patients Research Articles

Dosing Patterns of Dasatinib Use in Simplicity, an Observational Study in Chronic Phase Chronic Myeloid Leukemia (CP-CML) Patients (pts) in Routine Clinical Practice

Introduction: Treatment dosing patterns have not been well documented among dasatinib-treated CP-CML pts outside of clinical trials. SIMPLICITY (NCT01244750) is an ongoing observational study of CP-CML adult pts in routine clinical practice receiving tyrosine kinase inhibitors (TKI) since 2010 in the US and Europe, exploring TKI use and management patterns in clinical practice. This analysis reports on dosing patterns of dasatinib and explores potential predictors of dose reductions.Methods: Only pts enrolled in the SIMPLICITY observational study who received first-line (1L) and second-line (2L) dasatinib once daily (n=417) were reviewed to determine dosing patterns. Eleven pts were excluded from the analysis because they were not on a dasatinib once-daily regimen. Longitudinal data were used to determine dose changes. Results are presented according to the first change in dose. No restrictions or instructions regarding dosing were required per enrollment. Results are presented descriptively. Statistical comparisons were made using t-tests and the Mann-Whitney U test for continuous variables and chi-square for categorical variables. Logistic regression models were used to identify factors associated with dose reduction.Results: Of the 406 pts treated with 1L dasatinib (QD), 374 (92.1%) started at 100 mg (Table 1); 318 (78%) remained on dasatinib at Year 1 and 259 (63.8%) at Year 2. The majority (64.4%) remaining on100 mg. Median follow-up was 59 months (IQR: 49, 61). Of the 25 (6.2%) pts who started on <100 mg, 12 started on 50 mg and 8 on 70 mg. Of the 7 (1.7%) who started at >100 mg, 6 started on 140 mg. Median age at start of 1L TKI differed between pts who started on 100 mg (55.2 yrs), <100 mg (73.7 yrs), and >100 mg (49.2 yrs; p<0.0001; Table 1). EU pts were more likely to start with a lower dose vs US pts (p<0.001): with 84.4% vs 95.0% starting on 100 mg; 13.8% vs 3.4% on <100 mg and 1.8% vs 1.7% on >100 mg, respectively. Of the 374 pts who started 1L dasatinib at 100 mg, 133 (35.6%) changed dose; 124 (33.2%) pts received a dose reduction and nine (2.4%) a dose increase (Table 1). Median time to dose reduction was 4.7 months (IQR: 1.5, 19.5): 51.6% pts (n=64) experienced a dose reduction in the first 6 months; 12.9% (n=16) between 6-12 months; 15.3% (n=19) between 12-24 months and 20.2% (n=25) after 24 months. Pts remained on a reduced dose for a median of 47.6 months (Table 2). Among the 33% that experienced dose reductions, the primary reasons for dose reduction were adverse events (63.7%; n=79), side effect/clinical complication (9.7%; n=12) and other clinical decisions, including stable MR4.5 (11.3%; n=9.7%; Table 1). Age (mean, p=0.003; median p=0.001) and male gender (p=0.02) at baseline were associated with dose reduction. Multivariate logistic regression analysis of the 1L dasatinib population, adjusted for covariates revealed that older age at start of 1L TKI (p=0.004) and fatigue at baseline (poorer performance status; p=0.02), were strong predictors for dose reduction (Table 1). Gender was a weak predictor for dose reduction (p=0.06; Table 1). Of the 202 pts receiving 2L dasatinib (QD), 25 (12.4%) started at <100 mg. Median follow-up was 57.4 months (IQR: 46.5, 60.8). Of these, 12 (48%) pts started on 50 mg and 10 (40%) on 70 mg. Of the 166 pts who started 2L dasatinib at 100 mg, 41 (24.7%) changed dose. Thirty-nine pts received a dose reduction (50 mg, n=18 [46.2%]; 70 mg, n=6 [15.4%]) and two a dose increase. Among the 23% receiving a dose reduction, intolerance (n=27; 69.2%) and other clinical decisions, including stable MR4.5 (n=6; 15.4%) were the primary reasons for dose reduction. There was a non-significant difference in median age between pts who started 2L dasatinib at 100 mg, <100 mg, and >100 mg, but otherwise they were similar in terms of other baseline characteristics.Conclusions: Now that long-term survival has been achieved in pts with CML, the focus of clinical practice is shifting to dose optimization, with the goal of maintaining response while improving quality of life. Among the majority of pts who started dasatinib at 100 mg (QD) in 1L, 64.4% received only 100 mg; 33.1% received a dose reduction, and 2.4% received a dose increase; similar patterns were observed for 2L pts. Within the population experiencing a dose reduction, intolerance was the principal reason. Age at start of 1L TKI and fatigue in baseline (poorer performance status) were strong predictors of dose reduction, while gender was a weak predictor. [Display omitted] DisclosuresCortes:Pfizer: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Astellas Pharma: Consultancy, Research Funding; Arog: Research Funding; Daiichi Sankyo: Consultancy, Research Funding. Chen:Bristol-Myers Squibb: Employment. Mauro:Pfizer: Consultancy; Bristol-Myers Squibb: Consultancy; Novartis: Consultancy, Research Funding; Takeda: Consultancy. Sen:ICON PLC: Employment. Gajavelli:Bristol-Myers Squibb: Employment. Davis:Bristol-Myers Squibb: Employment. Goldberg:COTA Inc.: Employment, Equity Ownership.

RUNX1 Mutations Identify an Entity of Blast Phase Chronic Myeloid Leukemia (BP-CML) Patients with Distinct Phenotype, Transcriptional Profile and Drug Vulnerabilities

Introduction: Genetic alterations of RUNX1 gene (mutations and fusion genes) are common in hematological malignancies including AML, ALL, MDS, and MPN. Mutations of RUNX1 occur in 10% of newly diagnosed AML patients and associate with inferior prognosis. Similarly, point mutations in RUNX1 are frequent in BP-CML, but little is known about their role in BP patients.Methods: Bone marrow samples from four BP patients with RUNX1 mutations were collected from Helsinki University Hospital, and samples from four other BP patients without RUNX1 mutations were used as controls. Samples were analyzed by exome and RNA sequencing. For drug sensitivity and resistance testing (DSRT), a high-throughput platform comprising 195 approved and investigational oncology drugs was used. To further study the role of RUNX1 mutations in BP-CML, Baf3/BCR-ABL1+ RUNX1-/- knock-out and RUNX1-/mut heterozygous deletion mutant models were created using CRISPR-CAS9 technology. The effects of the mutations in the cell line models were characterized by flow cytometry, RNA sequencing, and DSRT analyses.Results: The median age of RUNX1-mutated BP patients was 47 years (range 36-56 years) and included 3 patients with myeloid-BP and 1 with lymphoid-BP phenotype. RUNX1-mutated patients tended to have higher mutational load and co-occurrence with mutations to the BCOR, EZH2 and PHF6 genes in agreement with the mutational profile of RUNX1-mutated AML. Signature analysis of RUNX1-mutated BP patients showed dominance of signature 1 (age-related), signature 6, and 15 (DNA mismatch repair) correlating with the control group signature profiles. In addition, the RUNX1 mutated group showed specific enrichment of signature 9, related to somatic hypermutation and AID/RAG axis activity, that was not observed in the control group. RNA sequencing revealed that 388 genes were significantly differentially expressed between RUNX1-mutated and control BP patients (139 upregulated, 249 downregulated). Interestingly, the antigen processing and presentation pathway was among the top upregulated pathways in RUNX1 mutated patients with overexpression of CIITA and HLA-DR genes. Stem cell differentiation, complement, and hemostasis pathways were enriched in the downregulated gene set. Lymphoid-specific transcription factors (DNTT, PAX5 and VPERB1) in addition to CD19 and CD25 were significantly upregulated in the RUNX1-mutated group. DSRT data showed greater sensitivity to glucocorticoids, MEK-, mTOR- and VEGFR-inhibitors in RUNX1-mutated patients compared to the control group. Data from RUNX1-/- and RUNX1-/mut cell line models confirmed the induced expression of CD19 surface marker with RUNX1 mutation. DSRT results showed increased activity of MEK inhibitor and mTOR inhibitors in RUNX1-/- knock-out and RUNX1-/mut cell lines.Conclusions:RUNX1 mutations in BP-CML patients associate with distinct phenotypic and transcriptional features. DSRT results together with transcriptional data support the potential benefits of glucocorticoids and MEK and mTOR inhibitors as well as immunotherapy targeting CD19 and CD25 in this group of BP-CML patients. DisclosuresKankainen:Medix Biochemica: Consultancy. Heckman:Celgene: Research Funding; Orion Pharma: Research Funding; Novartis: Research Funding. Porkka:Novartis: Honoraria, Research Funding; Celgene: Honoraria, Research Funding. Mustjoki:Bristol-Myers Squibb: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Ariad: Research Funding; Celgene: Honoraria.

Safety and Efficacy of HQP1351, a 3rd Generation Oral BCR-ABL Inhibitor in Patients with Tyrosine Kinase Inhibitor—Resistant Chronic Myelogenous Leukemia: Preliminary Results of Phase I Study

Background: HQP1351, a novel, potent 3rd generation TKI, was designed to treat patients with chronic myeloid leukemia (CML) resistant to current TKI-therapies including those with T315I mutation.Aims: A single-agent, open-label dose escalation and dose expansion Phase I study to assess the safety, preliminary efficacy, pharmacokinetic (PK) and pharmacodynamic (PD) properties of orally administered HQP1351 in the TKI-resistant patients with chronic phase (CP) or accelerated phase (AP) CML.Methods: HQP1351 was administered once every other day (QOD) in 28-days cycles at 11 dose cohorts ranging from 1mg to 60 mg. The eligible patients received treatments until disease progression or intolerable toxicities. The primary efficacy endpoint in the CML AP and CP patients, was complete hematological response (CHR) and major cytogenetic response (MCyR) respectively, MCyR includes partial cytogenetic response (PCyR) and complete cytogenetic response (CCyR).Blood samples were collected at various time points on Day 1-2 and Day 27-28 during cycle 1 for PK analyses. BCR-ABL inhibition was evaluated using tyrosine phosphorylation of CRKL and STAT5 in peripheral blood mononuclear cell (PBMCs) collected from the patients before and 4, 8, 24 and 48 hours post HQP1351 treatments on Day 1, 15 and 27 during cycle 1.Results:From November 2016 to July 2018, 70 patients (CP n=58 and AP n=12) enrolled received ≥1 cycle of HQP1351-treatment, only 1 patient withdrew from the study due to disease progression. Median age was 39 (range: 23-59) years. Median interval from CML diagnosis to starting HQP1351-treatment was 6.1 (1.1-14.7) years. Sixty-one (87%) patients received ≥2 prior lines of TKI-therapy. Fifty-three (76%) patients had BCR-ABL mutations and 45 (64%) had T315I mutation at baseline.With a median follow-up of 4.1 (1.0-21.2) cycles, HQP1351 was well-tolerated in all dose cohorts other than the 60mg cohort. In all patients, 67 (96%) patients experienced ≥1 treatment related adverse events (TRAEs) and 44 (63%) experienced TRAE(s) of grade 3-4 (Table 1). There was no patient withdrawal from the study because of TRAEs. Two out of 3 patients in the 60mg cohort experienced dose-limiting toxicity(DLT) and HQP1351 at 50mg QOD was considered as MTD.The anti-leukemic activities of HQP1351 were observed in this study. Sixty-five (93%) patients including 58 (100%) CP and 7 (58%) AP patients achieved CHR at the dose of 2mg to 60mg within 3 cycles. In 47 evaluable patients receiving HQP1351-treatment ≥3 cycles, 24 (51%) achieved MCyR including 21 (54%) CP and 3 (38%) AP patients at the dose of 12mg to 50mg, and 14 (30%) patients achieved CCyR including 12 (31%) CP and 2 (25%) AP patients. Total 6 (15%) CP patients achieved MMR. More than 65% of the patients achieved MCyR or MMR at the end of cycle 3. HQP1351 was highly active in patients with or without T315I mutation at baseline (Table 2).Following oral administration of HQP1351 at doses ranging from 1mg to 60 mg, the peak concentration was reached at 2-8 hrs. The elimination appeared to be linear with a mean terminal T1/2 of 15.3-36.5 hrs on Day 1, 18.8-42.5 hrs on Day 27, respectively. The ratios for AUC0-t and Cmax of HQP1351 on Day 27 versus Day 1 ranged from 1.03 to 2.12 and from 0.78 to 1.93, respectively. Thus, HQP1351 exhibited an approximately dose proportional increase in Cmax and AUC0-t following single or multiple oral administration dose ranging from 1 to 60 mg. PD study results demonstrated that reduction of CRKL phosphorylation was schedule and dose-dependent, ≥50% reduction was observed at doses ranging 12mg-60mg.Conclusions: The preliminary results of the phase 1 study showed that HQP1351, a novel 3rd-generation TKI, is safe and highly active in treatment of the TKI-resistant patients with CP-CML and AP-CML,with or without T315I mutation. DisclosuresChen:HealthQuest Pharma Inc.: Employment. Men:HealthQuest Pharma Inc.: Employment. Liu:HealthQuest Pharma Inc.: Employment. Sun:HealthQuest Pharma Inc.: Employment. JI:HealthQuest Pharma Inc.: Employment. Wang:HealthQuest Pharma Inc.: Employment. Hu:HealthQuest Pharma Inc.: Employment. Zou:HealthQuest Pharma Inc.: Employment. Yan:HealthQuest Pharma Inc.: Employment. Huang:Ascentage Pharma Group Inc.: Employment; HealthQuest Pharma Inc.: Employment. Yang:Ascentage Pharma Group Inc.: Employment. Zhai:Ascentage Pharma Group Inc.: Employment.

Cardiovascular Hospitalization in Patients Treated with Dasatinib or Nilotinib in Simplicity, an Observational Study of Chronic-Phase Chronic Myeloid Leukemia (CP-CML) Patients in Routine Clinical Practice

Introduction: The combined effect of cardiovascular (CV) risk and tyrosine kinase inhibitor (TKI) therapy may contribute to the incidence of CV events in patients (pts) with chronic phase chronic myeloid leukemia (CP-CML). CV events can affect the overall clinical outcomes and survival of CML patients, and hospitalization due to CV events is costly; analyzing the rates and risks of CV hospitalization in pts with CML receiving TKI therapy may help to inform treatment decisions and risk mitigation strategies and to minimize costs. SIMPLICITY (NCT01244750) is an ongoing observational study of CP-CML pts in routine clinical practice receiving first-line (1L) TKIs since 2010 in the US and Europe, exploring TKI use and management patterns in clinical practice. This analysis aims to evaluate rates of CV-related hospitalization and estimate related costs in pts treated with the second-generation TKIs dasatinib (DAS) and nilotinib (NIL).Methods: CV hospitalizations were identified retrospectively from events reported by SIMPLICITY investigators over the course of treatment with DAS or NIL, from the start of treatment (any line of therapy) to 30 days after the end of that line of therapy, or prior to the start of a subsequent line of TKI therapy, whichever was sooner. Pts were followed for a maximum of five years. Owing to the observational nature of SIMPLICITY, patients were not matched between cohorts and adjustments for covariates were not made. Kaplan-Meier methods with the log-rank test were used to estimate time to first CV hospitalization. Statistical comparisons were made using t-tests and the Mann-Whitney U test for continuous variables and chi square for categorical variables.Results: Overall, 825 pts received DAS (n=417) or NIL (n=408) as 1L therapy; 376 pts received DAS (n=214) or NIL (n=162) as second-line (2L) therapy; and 124 pts received DAS (n=63) or NIL (n=61) as third-line (3L) therapy. See table for patient baseline demographics and comorbidities. No significant differences were noted between the DAS and NIL cohorts. Median age was similar between the DAS and NIL groups at 56.2 and 54.1 years. At baseline, both groups had similar CV comorbidities. A significantly greater number of pts were treated in the US vs Europe (p=0.017).Investigators reported that, during 1L DAS and NIL therapy, 43% (n=357) of pts experienced a CV disorder: 45.3% (n=189) of DAS pts and 41.2% (n=168) of NIL pts (DAS vs NIL, p=0.28). Numbers of CV-related hospitalizations occurring during DAS and NIL therapy were 16 and 36, respectively, translating to 12.6 and 27.4 CV-related hospitalizations per 1000 pt years. Across 1L, 2L, and 3L (referred to here as ‘all lines‘) of DAS and NIL therapy, 31 and 51 CV-related hospitalizations occurred, translating to 16.7 and 28.8 CV-related hospitalizations per 1000 pt years, respectively. The three most common CV-related reasons for hospitalization were congestive cardiac failure, atrial fibrillation and myocardial infarction. The figure shows Kaplan-Meier curves of time to first CV-related hospitalization for 1L therapy, for five years of follow-up. CV-related hospitalization at 5 years of follow-up was 5% for pts on 1L DAS, 7.5% for pts on 1L NIL, 5.7% for all lines of DAS and 8.5% for all lines of NIL. Durations of hospital stay related to CV disorders for pts on 1L DAS and 1L NIL were 68 days and 263 days, translating to 53.3 and 199.8 days in hospital per 1000 pt years. Durations of hospital stay related to CV disorders for pts on all lines of DAS and NIL were 107.4 days and 226.1 days, translating to 53.3 and 199.8 days in hospital per 1000 pt years. Incremental cost differences based on mean estimates will be presented.Conclusions: CV disorders and related hospitalizations were frequently seen in patients with CP-CML in SIMPLICITY. In these patients, NIL was associated with a rate of CV hospitalization up to double that associated with DAS and lengthier hospital stay. Owing to the survival benefits conferred by TKIs, it is critical to minimize and manage complications that may arise in treated pts; potential for greater morbidity and healthcare cost should be considered when making decisions about TKIs to use in individual pts, particularly those with preexisting CV comorbidities. [Display omitted] DisclosuresMauro:Pfizer: Consultancy; Bristol-Myers Squibb: Consultancy; Takeda: Consultancy; Novartis: Consultancy, Research Funding. Chen:Bristol-Myers Squibb: Employment. Cortes:Novartis: Consultancy, Research Funding; Arog: Research Funding; Astellas Pharma: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Daiichi Sankyo: Consultancy, Research Funding. Gambacorti-Passerini:Pfizer: Consultancy, Honoraria, Research Funding; BMS: Consultancy. Sen:ICON PLC: Employment. Gajavelli:Bristol-Myers Squibb: Employment. Davis:Bristol-Myers Squibb: Employment. Michallet:Octapharma: Membership on an entity's Board of Directors or advisory committees; Chugai: Consultancy; Novartis: Research Funding.

Molecular Profiling of Blastic Transformation in Chronic Myeloid Leukemia

BackgroundChronic myeloid leukemia (CML) is characterized by the BCR-ABL1 fusion gene. Despite the dramatic improvement of its prognosis in recent years by the development of tyrosine kinase inhibitors (TKIs), a minority of chronic phase (CP) CML patients fail to respond to TKI therapies and progress to blast crisis (BC), showing dismal clinical outcomes. While acquired mutations in ABL1 kinase have been identified as a common mechanism for TKI resistance, recent genetic studies have revealed that patients with BC frequently harbor one or more genetic alterations implicated in myeloid malignancies, suggesting additional mutations other than ABL1 mutations might drive disease progression. However, our knowledge about the mechanism of TKI resistance and progression to BC is largely limited by the scarcity of matched CP and BC samples, which were investigated for genetic alterations in relatively small number of genes. Here, we performed comprehensive genomic studies of CML-BC using paired CP and BC samples to investigate the mutation profiles associated with BC.MethodWe performed whole-exome sequencing of 53 patients with CML-BC, including 40 myeloid and 13 lymphoid crisis cases, as well as corresponding CP controls to investigate acquired mutations during disease progression from CP to BC. We also performed targeted-capture sequencing of known and putative driver genes in an additional 15 CML-BC samples. Combined, a total of 68 CML-BC samples were analyzed for somatic mutations, copy number abnormalities, and structural variations.ResultsCommonly affecting ASXL1, GATA2, and IKZF1, mutations were found only in a minority of CP cases (10/53 [19%]). However, most cases acquired somatic mutations during disease evolution from CP to BC; in whole-exome sequencing, an average of 17 additional non-synonymous mutations were newly acquired per case during evolution from CP to BC. Mutations in CML-BC frequently involved known driver genes, such as ASXL1, RUNX1, ABL1, TP53, BCOR/BCORL1, and WT1. In addition, we identified novel targets of recurrent mutations, including UBE2A, NBEAL2 and KLC2. Of note, most these driver mutations were not detected in corresponding CP samples and newly acquired, whereas ASXL1 mutations were often found in corresponding CP samples in a minor population, suggesting that ASXL1 mutations at CP might play an important role in the disease progression to BC. Mutational profiles were similar between cases with and without a history of TKI therapy before BC, except for frequent ABL1 mutations among TKI-treated cases, mostly affecting the kinase domain. Compared with lymphoid BC, myeloid BC showed a higher number of somatic mutations, which was more prominent for ASXL1, TP53, and WT1 mutations. Copy number abnormalities were rarely found in CML-CP cases (8/53), but were common and newly acquired in 29 (55%) cases with CML-BC, 18 of which showed complex karyotype-like (≥3) abnormalities. Amplification of chromosome 6 and/or 8 were characteristics of myeloid BC, while deletion of chromosome 7 was more characteristic of lymphoid BC. In some cases, structural variations other than BCR-ABL1 translocation were newly acquired in CML-BC, which frequently involved genes implicated in myeloid malignancies such as RUNX1, CBFB, and MECOM. When mutations, copy number abnormalities, and structural variants were combined, most BC cases had at least one driver alterations, which might be involved in CML-BC.ConclusionThrough a comprehensive sequencing analysis using paired samples of CP and BC, we demonstrate a role of additional driver events during the clonal evolution to BC. Additional mutations were common even in CML-CP, some of which might contribute to the progression to BC. DisclosuresTakaori-Kondo:Celgene: Honoraria, Research Funding; Novartis: Honoraria; Janssen Pharmaceuticals: Honoraria; Bristol-Myers Squibb: Honoraria; Pfizer: Honoraria.

Integration of Multiple Bioassays Using Machine Learning to Identify High-Risk CP-CML Patients Treated with Frontline Imatinib

Introduction. Imatinib has revolutionised the treatment of chronic phase-chronic myeloid leukemia (CP-CML), with up to 70% of patients (pts) achieving major molecular response (MMR, BCR-ABL1 < 0.1% IS). Achievement of MMR by 2 years (yrs) is associated with an excellent prospect of long term survival. Currently, three baseline prognostic scoring systems - the Sokal, Hasford (Euro) and EUTOS risk scores - have all been used to identify pts with a poor response and/or an adverse prognosis in CP-CML. Recently, the EUTOS long-term survival (ELTS) score is shown to have strong predictive power for overall survival in CML pts. We have previously reported bioassays that have significant value for predicting MMR. Combinations of these biomarkers, together with clinical risk score, may provide a better indicator of high risk pts at the time of diagnosis.Aim. To identify high-risk pts by combining selected predictive bioassay, determine whether the ELTS score is more discriminating, and determine whether it provides additional predictive value when combined with the biomarker score.Methods. Bioassays including CRKL IC50 imatinib (White, Blood, 2005), OCT-1 Activity (OA)(White, JCO, 2010), leves of 39 plasma cytokines (Nievergall, Leukemia, 2016), expression of 20 most prognostic gene by qPCR TLDA (Kok, ASH abstract, 2015), ABCB1 gene expression (Eadie, Leukemia, 2016), KIR2DL5B genotype (Yeung, Blood, 2015), BIM and ASXL1 polymorphisms (Marum, Blood advances, 2017) were used in this study. High-risk by biomarker score (HR) was defined as pts who did not achieve MMR by 2 yrs. 210 TIDEL-II pts (frontline imatinib with early switch to nilotinib for failure to meet optimal time-dependent molecular targets) were used in this study (Yeung, Blood, 2015). Only 201 pts had ELTS scores. The Recursive Partitioning and Regression Trees (rpart) algorithm was used to identify important bioassays in predicting high-risk pts. Fisher's-exact test was used for statistical analysis.Results. In the TIDEL-II cohort, there were 21 high ELTS and 180 low/intermediate ELTS pts. Pts with high ELTS had significantly lower rates of MMR by 2 yrs compared to those pts with low/intermediate ELTS (57% vs 81%, p=0.02). We constructed a predictive model using multiple different bioassays as variables to predict high-risk pts. The rpart based model used in this analysis yielded four variables (IGFBP2 gene expression, KIR2DL5B genotype, OA, and MCP-1 cytokine plasma level) as most important for predicting high-risk pts. The accuracy of the model was 84%. Pts predicted as high-risk (HR, n=27) had significantly lower MMR achievement rate compared to those predicted as low-risk (LR), (26% vs 86%, n=183, p<0.0001, OR:17.3). Importantly, pts with HR had significantly higher rate of blast-crisis progression (15%, n=4/27) compared to those with LR (1.6%, n=3/183, p=0.006, OR:10.4) and pts with high ELTS (5%, n=1/21). Interestingly, there were two categories of HR patient groups based on the model: 1) Patient with high IGFBP2 gene expression and low OA, and 2) pts with low IGFBP2, KIR2DL5B positive genotype and high MCP-1 cytokine level. When combined with ELTS, the bioassays model improved ELTS performance in predicting HR pts. For instance, within the low/intermediate ELTS pts group, our assays could futher distinguish HR pts with inferior MMR (n=20, 2 yrs MMR of 30%) versus LR pts (n=160, 2 yrs MMR 87%). Similarly, pts with high ELTS in combination with HR also had lower MMR rate (n=1/5, 20%) compared to pts with high ELTS in combination with LR (n=11/16, 69%, p=0.11, OR:8.8).Conclusion. We developed a combined bioassays model that is predictive of MMR failure and adverse clinical outcomes for pts who receive optimised frontline imatinib therapy. This model performs well even without adding clinical parameters. Our model has additional predictive value when used together with the ELTS score, and can distinuguish HR pts within the low/intermediate ELTS group, as well as LR patients within the high ELTS category. Further confirmation of the predictive performance of this model, using a large independent patient cohort is now indicated. We postulate that this bioassay-based model could be used, in combination with ELTS, for identifying HR pts who would benefit from intensified therapeutic approaches to obtain optimal clinical outcome. [Display omitted] DisclosuresYeung:Amgen: Honoraria; Pfizer: Honoraria; BMS: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Specialised Therapeutics Australia: Honoraria. Yong:Celgene: Research Funding; Novartis: Honoraria, Research Funding; BMS: Honoraria, Research Funding. White:BMS: Research Funding; Novartis: Honoraria, Research Funding. Hughes:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees.

The Predictive Value of Intracellular Imatinib Levels in Chronic Myeloid Leukemia

Background: Plasma levels of imatinib have been shown to be predictive of disease response in chronic phase chronic myeloid leukemia (CML). However, the ultimate site of action of imatinib is intracellular. While intracellular imatinib has been reported to be correlated with plasma imatinib, the use of intracellular imatinib for the prediction of clinical outcomes is unclear. The concentration of intracellular imatinib depends on many factors including the level of alpha-1-acid glycoprotein, which binds to imatinib and prevents intracellular uptake, and the OCT-1 transporter, which mediates the influx of imatinib across the plasma membrane of leukemic cells. We conducted the present study of newly diagnosed CML patients with the primary objective of determining if intracellular levels of imatinib two weeks after treatment initiation predicted major molecular response. The secondary objectives were to elucidate the relationships between the levels of OCT-1 and plasma imatinib with intracellular imatinib.Methods: We prospectively studied newly diagnosed chronic phase CML patients in Canada who were treated with standard dose imatinib (400 mg). We measured both intracellular and extracellular (plasma) levels of imatinib by tandem mass spectrometry at two weeks, four weeks, and twelve months after enrollment. Additionally, we measured transcript levels of OCT-1 and BCR-Abl by q-rt-PCR before treatment, at six months, and at twelve months to determine therapeutic response.Results: Eighty-one patients were screened. A total of 76 patients entered the study, and 55 completed the study per protocol. Patient information is shown in Table 1. There was a significant correlation between intracellular imatinib levels at two weeks and a 2-log reduction of BCR-Abl transcript at six months (r=0.390; 95% CI = 0.136 - 0.595; p = 0.004) (Figure 1), but not at twelve months (r=0.183; 95% CI = -0.094 - 0.434; p = 0.194). Notably, intracellular imatinib levels and plasma levels of imatinib were highly correlated at two weeks (r=0.698; 95% CI = 0.559-0.799; p <0.001) and four weeks (0.699; 95% CI = 0.555 - 0.802; p < 0.001) but not between four weeks and twelve months (r= 0.230; 95% CI = -0.040 - 0.469; p = 0.094). There was no correlation between intracellular imatinib levels at two weeks and the pre-treatment OCT-1 transcript level (r=0.072; 95% CI = -0.166 to 0.301; p =0.556).Conclusions: Intracellular imatinib levels at two weeks was moderately predictive of a disease response at six months as indicated by a 2-log reduction in BCR-Abl transcript. OCT-1 transcript levels did not have utility for predicting intracellular imatinib levels. Measurement of intracellular Imatinib levels may prove to have utility in identifying patients who would benefit from adjustments to therapy. [Display omitted] DisclosuresHillis:Bristol-Myers Squibb: Honoraria; Novartis: Honoraria. Busque:Novartis: Consultancy; Pfizer: Consultancy; Paladin: Consultancy; BMS: Consultancy. Lipton:Bristol-Myers Squibb: Consultancy, Research Funding; ARIAD: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding. Savoie:Pfizer: Consultancy; Novartis: Consultancy, Honoraria; BMS: Consultancy, Honoraria. Leber:Novartis Canada: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis Canada: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Clinical Intervention Using NGS-Based Kinase Domain Mutation Testing in CML Patients

Kinase domain (KD) mutations in the BCR-ABL1 gene are associated with resistance to tyrosine kinase inhibitors (TKI) in chronic myeloid leukemia (CML). Next-generation Sequencing (NGS) allows detection of low-level KD mutations (<20% VAF), although the detection of true low level KD mutation can be challenging. We have previously reported an improved single round PCR based NGS method to ensure higher accuracy for clinical use (Kizilors et al. ASH 2015). To implement this improved assay in our routine clinical setting, we obtained ISO 15189 accreditation for NGS based BCR-ABL1 KD mutation detection.We have previously shown the clinical significance of low-level KD mutation by NGS. However our study, along with previous studies, was retrospective. Since August 2014, we have been using NGS-based assay (in replacement of Sanger sequencing) for clinical intervention, allowing us to study the clinical relevance of low level mutations and monitor the kinetics of mutated clones.We herein report the outcome of patients in whom clinical intervention was made based on NGS KD mutation screening and monitoring.We analyzed the outcome of 340 consecutive Chronic Phase CML patients treated with first-line TKI at our institution and within our network (imatinib 235, nilotinib 49, dasatinib 10, unknown 46), of whom 70.42% achieved CCyR with first-line TKI. NGS-based KD mutation testing was done retrospectively until January 2014, and prospectively from that date.Overall, a mutation was found in 41(12.05%) patients at a median time of 14 months (range, diagnosis to 156 months). Twenty five different mutations were identified, including T315I (n=9), M244V (n=8), F317L (n=8) and E255K (n=6). Of 41 patients with mutated clone, 27 were found to have a mutation conferring resistance to the ongoing TKI treatment (defined as ‘clinically relevant’ mutation). In 8 patients, the mutation was sensitive to the TKI treatment received (M244V in 6 patients, M351T in one patient on imatinib and an E255V in one patient on dasatinib), two patients with intermediate resistance to the treatment received (H396R and E355G) and four patients with mutations of unknown clinical significance (Q252R, E450K and E450G). Of the 27 patients with clinically relevant mutations, 8 patients were part of our initial retrospective NGS screening study, of whom 3 had clinical intervention based on Sanger Sequencing results.From August 2014, clinical intervention was made based on KD mutations found by NGS. Eighteen patients had their TKI treatment changed because of mutations found to confer resistance to their ongoing TKI (including 2 with unknown clinical significance), of whom 14 had single mutation (F317L, n=3; T315I, n=2; Y253H, n=1; F359V, n=1; L248V, n=1; G250E, n=1; F311L, n=1; E459G, n=1; E450K, n=1; F359I, n=1; E450G, n=1). Four patients had multiple mutations, including two patients who developed mutations sequentially.Of the 18 patients who had clinical intervention, the first detection of the KD mutation was at a low-level in 13 patients.Response to change of TKI was seen in 12 patients, of whom 11 achieved a stable MR3, and one patient with a 2.2 log reduction in BCR-ABL transcript levels. One patient proceeded to allogeneic HSCT and four patients did not show significant response at last follow up. Finally, one patient had a low level Y253H mutation detected while on nilotinib which initially reduced after TKI change and then subsequently increased while gaining an additional T315I at the time of Blastic Phase transformation. Response to combining chemotherapy and ponatinib was seen with the achievement of sustained MR3 until allogeneic HSCT.Kinetics of mutated clone(s) was monitored post TKI change and all patients who responded experienced a reduction in their clone size. Among 12 patients who responded to TKI change, 3 had multiple mutations. One patient had a low level E255K mutation at 4% at 3 months despite achieving CCyR on nilotinib and subsequently developed an additional T315I mutation after 15 months upon loss of CCyR. This patient achieved a sustained MR3 upon switch to ponatinib with concomitant drop in the T315I clone size.To our knowledge, this is the first report of clinical intervention using NGS based KD mutation detection in the management of CML patients. Our findings suggest that NGS may improve clinical decision-making in these patients. A prospective clinical study using NGS (acronym CALLS) is currently ongoing in the UK. DisclosuresKizilors:Incyte: Honoraria, Research Funding. Harrington:BMS: Research Funding. Pagliuca:Jazz Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gentium: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Mufti:Celgene: Research Funding. De Lavallade:Incyte: Honoraria, Research Funding; BMS: Honoraria, Research Funding.

Impact of Myelofibrosis at Presentation on Outcomes in Chronic Myeloid Leukemia in Chronic Phase

Background:Presence of myelofibrosis on bone marrow examination is considered as poor prognostic factor in patients with chronic myelogenous leukemia (CML). Scant data is available on myelofibrosis, especially in the era of tyrosine kinase therapy. The present study was designed to analyze impact of myelofibrosis on outcomes in newly diagnosed patients with chronic myeloid leukemia in chronic phase (CML-CP).Aims and objectives:The primary objective of this analysis was to study event free survival (EFS) and major molecular response rates (MMR) at one year in patients with CML-CP with myelofibrosis.Secondary objectives were to study the parameters impacting outcomes in patients with CML-CP with myelofibrosisMaterials and methods:Study period: 2010 to 2016Type of study: retrospective analysis.The diagnosis of CML-CP was done by demonstration of BCR-ABL translocation by polymerase chain reaction or fluorescence in situ hybridization. Event free survival was defined as the time from start of therapy to death, transformation to accelerated or blast phase, hematologic resistance or toxicity intolerance. Statistical analysis was done using SPSS software, version 25. Overall survival curves were plotted using the Kaplan-Meier method. Grade of myelofibrosis, EUTOS risk, age and compliance were analyzed on multivariate analyses.Results:Data of 147 patients with CML-CP with myelofibrosis at presentation was retrospectively collected, of which 79(53.7%) were males and 68(46.3%) were females. The baseline characters were tabulated in Table 1. Abdominal fullness (60.5%) was the most common symptom at presentation followed by fatigue (48.9%), weight loss (36.7%), fever (25.1%) and bleeding manifestations (12.9%). EUTOS risk was low in 94(64%) patients and high in 53 (36%) patients. Myelofibrosis grade 1, 2, 3 and 4 were seen in 20(13.6%), 36(24.5%), 38(25.9%) and 27(18.3%) patients respectively. Grade of myelofibrosis was not available in 26(17.7%) patients.Of 147 patients, outcome parameters were available in 92 patients. Of 92 patients, 34(37%) attained MMR at 1 year. At a median follow up of 46 months, event free survival was 60.9%. Of 92 patients, MMR at one year differed significantly in patients with grade 1 and 2 myelofibrosis (48.8%) compared to patients with grade 3 and 4 myelofibrosis (26.5%) (p=0.02). Event free survival was higher in patients with grade 1 and 2 myelofibrosis (76.7%) compared to patients with grade 3 and 4 myelofibrosis (46.9%) (p=0.005). Drug induced myelosuppression was seen in 27(29.3%) patients, of which 7(26%) patients received dose reduction. Phase transformation was seen in 6 patients, of which 1(16.7%) and 5(83.3%) patients were transformed to accelerated phase and blastic phase respectively. On multivariate analysis, only grade of myelofibrosis had significant impact on event free survival(p=0.013).Conclusion:In patients with newly diagnosed CML-CP, major molecular response was significantly lower for those with higher grade of myelofibrosis. Grade of myelofibrosis at presentation had significant impact on outcomes in CML-CP. Hence, bone marrow examination for presence and grade of myelofibrosis helps in prognosticating CML-CP patients. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

The e13a2 BCR-ABL1 Transcript Is Associated with Higher Rates of Molecular Recurrence after Treatment-Free Remission Attempts: Retrospective Analysis of the Adelaide Cohort

The e13a2 BCR-ABL1 Transcript Is Associated with Higher Rates of Molecular Recurrence after Treatment-Free Remission Attempts: Retrospective Analysis of the Adelaide Cohort

Deep Molecular Response in Imatinib First-Line 418 Newly Diagnosed CP CML Patients.

IntroductionDeep molecular response (DMR) are now highly desirable goals in the treatment of CP-CML, especially in the front-line setting, because it can lead to a definitive treatment-free remission (TFR). However, such a goal is difficult to attain and does not concern the majority of patients (pts), but currently the precise number of pts able to access to TFR is unknown.AimsWe aim to determine the number or newly diagnosed CP-CML pts reaching DMR, stable DMR, and access to TFR, on Imatinib (IM, Glivec®) first-line.MethodsWe retrospectively analyzed in an observational study, a cohort of newly diagnosed CP-CML pts treated with IM first-line 400 mg daily alone in our 3 reference centers between 2000→2018. All pts were followed according to the ELN recommendations 2006, 2010 and 2013. Clinical data were extracted from medical files, and responses (hematologic, cytogenetic, molecular) were analysed according to standard methods. Molecular results were standardised according to the ELN/Eutos programs since 2003, and were all expressed as BCR-ABLIS in %. DMR have been defined according to the ELN (NCP. Cross et al., Leukemia 2015). Stability of DMR has been defined as a stable if ≥2 years at least on 4 datapoints. TFR has been proposed to pts presenting the only current recommended criteria: MR4.5 ≥2 years at least on 4 datapoints [(Rea et al., Cancer 2018)], in the 3 centers involved, within clinical trials, pioneered in our country, or now as a clinical routine recommendation. Loss of MMR was the trigger for TKI resumption after IM cessation for TFR. Overall survival (OS), progression-free survival (PFS), failure-free survival (FFS, defined as progression to advanced phases death, loss of CHR, CCyR, or MMR, discontinuation of IM for toxicity, primary cytogenetic resistance) were analysed since IM initiation in intention-to-treat.ResultsFour hundred and eighteen pts have been included in this study, with a median age of 60.7 (48-70) years at diagnosis, with 57% males and 43% females. Sokal score (n=401) was low in 32%, intermediate in 51% and high in 17%. ACA were present at diagnosis in 5.5% of the pts (NA in 1.44%). Major BCR transcripts were found in 98% of pts, and atypical transcripts in 1.9%. CHR was reached in a median of 1 (0.85 to 1.64) month of IM, <10% BCR-ABL transcript (IS) level at 3 months was found in 81% of the pts, and only 9.5% of pts were in MMR at 3 months. The median follow-up after IM initiation is 77.4 (0.9-231.5) months, 125 (30%) pts have switched to TKI2 for IM resistance or intolerance. Overall, 252 (60%) pts reached MR4, 127 (30%) stable MR4, 170 (41%) MR4.5, and 82 (20%) stable MR4.5. The median time on TKI necessary for obtaining stable MR4.5 is 15.6 (5.9-28) months. The cumulative incidence of MR4.5 at 12, 24, 36, 48, 60, 72, 84, 96, 108 and 120 months were 12.5%, 23.4%, 31.6%, 36.72%, 43.55%, 48.7%, 48.3%, 52.98%, 54.03%, 59.18% respectively (Figure 1A.). The cumulative incidence of stable MR4.5 at 12, 24, 36, 48, 60, 72, 84, 96, 108 and 120 months were 5.76%, 11.5%, 17.83%, 21.82%, 26.35%, 28.13%, 28.13%, 29.13%, 29.13%, 29.13% respectively (See figure 1B.).Seventeen (13%) and 10 (12%) pts have switched IM→TKI2 before obtaining a stable MR4 and a stable MR4.5 respectively.Overall, 41 (10%) pts have reached the TFR criteria and stopped their TKI and 23 (56%) never lost their MMR after cessation, with a median follow-up of 41.7 (9.4-121.8) months.In an univariate analysis, only gender (female vs male, 39% vs 61% for no MR4.5 and 53.66% vs 46.34% for stable MR4.5, p=0.028, Pearson's CHI2 test), and MMR at 3 months (yes vs no, 3.74% vs 96.26% for no MR4.5 and 17.46% vs 82.54% for stable MR4.5, p<0.001, Pearson's CHI2 test) were identified variables impacting on stable MR4.5. A multivariate analysis could not be performed on so few discriminant factors identified in the univariate analysis.ConclusionsOnly 42 out 418 (10%) of the newly diagnosed CP-CML pts on IM first-line in our study reach the TFR criteria we recommended, and only 22 over 418 pts (5%) will finally definitively stop any TKI durably within the limits of this retrospective observational study. Urgent strategies in order to increase the access to definitive TFR are needed. [Display omitted] DisclosuresNicolini:Sun Pharma Ltd: Consultancy; Incyte Biosciences: Consultancy, Speakers Bureau; BMS: Consultancy, Speakers Bureau. Cony-Makhoul:BMS: Consultancy, Speakers Bureau; Pfizer: Consultancy; Incyte: Other: Travels for attending to Congress; Novartis: Consultancy, Other: Writing support, Travels for attending to Congress. Dulucq:BMS: Consultancy; Incyte: Consultancy. Hayette:Incyte: Consultancy. Mahon:BMS: Speakers Bureau; Novartis: Speakers Bureau; Pfizer: Speakers Bureau; Incyte: Speakers Bureau. Etienne:Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Other: Travel, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Other: Travel, Speakers Bureau; Incyte: Honoraria, Patents & Royalties, Speakers Bureau.

B3a2 Transcript Is an Independent Factor for the Achievement of a Deep Molecular Response in Chronic Phase - Chronic Myeloid Leukemia Patients Treated with Imatinib in First-Line

Introduction: The achievement of a deep and sustained molecular response after treatment with tyrosine kinase inhibitors (TKI) is one of the requirements for therapy discontinuation in chronic myeloid leukemia (CML) patients.Objectives: This study aimed to evaluate the proportion of CML patients treated with imatinib in first-line that achieve MR4.5 (BCR-ABL transcripts ≤ 0.0032% in the international scale) after imatinib treatment and the predictive factors for this response. The secondary objectives were to evaluate the rate of MMR (PCR ≤0.1%), MR4.0 (PCR ≤ 0.01%), time to molecular responses, event-free survival, progression-free and overall survival.Patients and methods: This is a retrospective analysis of CP-CML patients treated in first-line with imatinib in a single center. Patients diagnosed after 2006 were managed according to the European Leukemia Net recommendations. All patients started CML imatinib within six months from diagnosis. The type of BCR-ABL1 transcript was determined by multiplex RT-PCR from cDNA synthesized from total leukocytes RNA at diagnosis. BCR-ABL transcripts by quantitative real-time polymerase chain reaction were assessed at baseline, and then every three months for the first year until reaching a stable major molecular response, then every 3-6 months. The SPSS software was used for the Cox Regression model for univariate and multivariate analysis, using backward Wald. The cumulative incidence was calculated with the R Program, with Gray test for curve comparisons. Event-free, progression-free and overall survivals were calculated with the Kaplan-Meier method, and the curves were compared with the log-rank test.Results: From January 2005 to December 2015 172 patients were treated with imatinib, median age 48 years (18-93), 55.8% male. Sokal score: 31% low-risk, 40% intermediate-risk and 29% high-risk. The median follow-up was 56 months (0-157). The Cumulative Incidence (CI) of MMR was 48% in 24 months and 84% in 5 years, while the CI of MR4.0 and MR4.5 was 63% and 51%, respectively, in 5 years. The median time to MMR, MR4.0 and MR4.5 was 16.7 (2-102), 31 (5-150) and 36 months (7-153), respectively. The univariate regression factors related to MR4.5 achievement were: age >48 years (HR 1.79; 95%CI: 1.08-2.98; P=0.023); days between diagnosis and imatinib start (HR=0.99; 95%CI: 0.98-0.99, P=0.020); e14a2 (b3a2) transcript (HR= 3.37; 95%CI: 1.67-6.81; P=0.001), which was the only factor in the multivariate analysis. Imatinib was discontinued in 96/172 (55.8%) patients due to resistance (36.5%), intolerance (20.8%), clinical trials (25%), death (15.6%) and adherence (2.1%). Eighteen out of 67 (26.8%) patients that achieved MR4.5 are currently participating in a discontinuation trial. Overall survival, PFS and EFS were 92%, 87% and 61% in 5 years.Conclusion: Approximately half of the patients that start imatinib in first-line obtain deep molecular responses within five years and could be candidates for treatment discontinuation. B3a2 transcript was an independent factor for MR4.5 achievement in the multivariate analysis, confirming the results of other studies that have reported earlier and deeper molecular responses in patients with b3a2 transcripts. DisclosuresDe Paula:Hematology and Transfusion Medicine Center, University of Campinas: Employment. Pagnano:Abbvie: Consultancy; EMS: Other: Financial support for participation in congress; Shire: Other: Lecture; Novartis: Consultancy.

Proteomics Analysis Reveals Protein Panels That Are Associated with Prediction to Tyrosine Kinase Inhibitors Response, Bone Marrow Transplant, Survival and Disease Outcome of Chronic Myeloid Leukemia Patients

Clinical and molecular diagnosis of most hematological malignancies including Chronic Myeloid Leukemia (CML) can be accurately made. However, prediction of treatment response and estimation of disease survival period eludes the currently available tools for patient care. Quantitative expression proteomics can potentially be developed as effective tool to monitor therapy response towards achieving personalized medicine for CML patients.We have over 10 years follow up period for some of the CML patients, and the majorities of them are alive and doing well on Imatinib. On the other hand, a small fraction of the patients were switched to alternative Tyrosine Kinase Inhibitors (TKI) and some underwent bone marrow transplants (BMT).Our follow up results stratified all 37 analyzed newly diagnosed CP-CML patients into 5 distinct cohorts including 52% on Imatinib, 12% on Nilotinib, 9% on Dasatinib, and 15% BMT, while 12% of the patients had disease-related mortality. Kaplan-Meier survival curve showed no significant difference between all patients on TKI and BMT that were alive under a follow up period of 4-11 years compared. On the other hand 3 of 4 patients had disease related deaths less than 2 years of diagnosis. Only one patient survived for almost 10 years (Figure 1). Besides survival analysis, peripheral blood samples obtained from the patients at time of diagnosis were subjected to expression proteome analysis using label-free quantitative liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). A subset of significantly differentially expressed proteins was able to distinctively discriminate samples into their respective treatment response and disease outcome groups based on unique protein expression signatures (P<0.05 and > 2- ∞- fold change, (Figure 2). Some of the identified proteins were implicated in hematological diseases including CML as potential biomarkers using Ingenuity Pathway Analysis.These protein signatures once validated in larger sample cohorts might be capable of prediction of molecular response, choice of therapy and disease outcome for CML patients. Therefore; allowing for identification of would be high risk patients that might potentially benefit from aggressive treatment at point of diagnosis pre initiation of conventional therapy. Altogether our findings indicate that analysis of panel of protein markers have the potential of clinical utility for prediction of response to therapy, disease survival and objective prognostication of disease outcome, thus bringing personalized medicine closer to CML patients. DisclosuresNo relevant conflicts of interest to declare.

One Size Does Not Fit to All: Intolerant or Resistant CML Patients Could Benefit from Different Ponatinib Starting Dose Strategies. Multicenter Italian Experience

Background: Ponatinib is effective as salvage treatment for chronic phase (CP) Ph+ chronic myeloid leukemia (CML) patients resistant or intolerant to prior TKIs. Based on the concern for an unfavourable cardiovascular toxicity profile, a dose reduction to 15 mg daily is currently recommended in CP patients after the achievement of treatment milestones. As more flexible approaches with TKIs dosage are increasingly adopted in clinical practice, identifying specific profiles of patients eligible for different treatment strategies, in order to improve the benefit/risk ratio, would be of particular interest.Aims: To update previous observations in an extended cohort of CML patients, resistant or intolerant to prior TKIs, describing the efficacy and toxicity of two different ponatinib schedules (de-escalated vs 15 mg starting dose). Secondly, to investigate whether specific subsets of CML patients were managed more successfully with one strategy.Methods: A retrospective analysis of CML-CP patients treated with ponatinib 15 mg, as starting or de-escalated dose has been performed. No pre-specified criteria to switch to ponatinib, to reduce or to start therapy with a lower dose were indicated. Cytogenetic and molecular responses were evaluated according to the ELN2013 recommendations. Toxicities under ponatinib treatment leading to transient or definitive discontinuation were recorded.Results: 68 patients were included in this analysis. Median age at ponatinib start was 57 years (range: 28-87). The median time from CML diagnosis to ponatinib treatment was 4.6 years (range: 0.4-19). Most patients (70.6%) were treated with imatinib as frontline treatment. 30/68 patients (44%) received ponatinib as 4th or subsequent line of therapy. ABL1 mutations were detected in 18 (26.5%) patients (being 44% of them positive for the T315I mutation). 50/68 (73.5%) of cases had less than MR2 at the time of ponatinib initiation, with one third exhibiting primary refractoriness to all prior treatments. Resistance to prior TKIs was the reason for switch in 85% of patients treated with higher doses of ponatinib, while 13/26 patients starting with 15 mg were purely intolerant or intolerant and resistant (p= 0.001). No other significant differences between the two groups were identified.MR2, MR3 and MR4/MR4.5 rates were 78.6%, 59.6% and 28.6% in 42 patients treated with the “de-escalated” approach, respectively. First step of dose reduction was decided after a median time of 3.1 months, with a subsequent decrease to 15 mg after a median of 10 months. Dose modifications were guided mostly by adverse events (73%) and, less frequently, to prevent toxicity and/or following response attainment (27%). Median duration of treatment was 27 months (range: 2-81), with 5/42 patients discontinuing ponatinib (1 cerebrovascular accident, 2 severe hematologic toxicities, two cases of resistance/progression). 4 deaths were registered, three after blast crisis and one for a fatal cardiovascular event.26 patients started ponatinib 15 mg daily, with a median duration of treatment was 15 months (range: 2-58). MR2 was obtained in 77%, MR3 in 69.3% and MR4 in 46.2% of cases, respectively. MR3 or deeper responses were maintained in 80% of patients; 7/26 lost their best acquired response, with subsequent dose escalation to higher than 15 mg in 5/26 patients. Treatment discontinuation was necessary in 3 cases (1 coronary vasospasm-induced acute coronary syndrome, 2 muscle skeletal pain).Of note, patients with ABL mutations gained benefit only from the “de-escalated” approach, with response improvements in 10/14 of cases vs 0/4 in the “low dose” group. Similarly, a higher rate of at least a MR2 was obtained in primary refractory patients treated ab initio with higher doses of ponatinib (57.1 % vs 14.3 %). However, focusing only on pure intolerant patients, 15 mg starting dose was very effective, with all patients achieving at least a MR3 or deeper response.Summary/Conclusion: With the limits of the retrospective nature and small sample size, these data suggest that different dose strategies could be applied to specific subsets of CP-CML patients. While mutations or refractoriness to previous treatments should address towards a “debulking approach” with 45 or 30 mg ponatinib dose, intolerant or “low level resistance” cases could benefit from lower starting dose. Further investigation in larger prospective trials is warranted. DisclosuresCastagnetti:Incyte: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Bristol Meyers Squibb: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Gugliotta:Bristol-Myers Squibb: Honoraria; Incyte: Honoraria; Novartis: Honoraria; Pfizer: Honoraria. Abruzzese:Ariad: Consultancy; BMS: Consultancy; Novartis: Consultancy; Pfizer: Consultancy. Breccia:Pfizer: Honoraria; BMS: Honoraria; Novartis: Honoraria; Incyte: Honoraria. Levato:Novartis: Other: Advisory board. Pane:AMGEN: Speakers Bureau; BMS: Speakers Bureau; Novartis: Research Funding, Speakers Bureau.

International, Prospective Study Comparing Nilotinib Versus Imatinib with Early Switch to Nilotinib to Obtain Sustained Treatment-Free Remission in Patients with Chronic Myeloid Leukemia. a GIMEMA and HOVON Study

BackgroundThe best front-line treatment of CML is not yet defined. Indeed, despite the higher activity of the second-generation TKIs respect to Imatinib and the higher rates of deep molecular remission (DMR), no clear superiority in term of long-term overall survival among the first and second TKIs for the initial treatment of CML has been shown in all the available studies. Furthermore, treatment free remission is emerging as one of the most important goal of the treatment of this disease, but no clinical trial has shown so far the best first line treatment to reach this aim.MethodsSince it is widely accepted that a sustained DMR is the pre-requisite to discontinue the TKI treatment for an extended duration of time, and since in patients who start treatment with imatinib (IM) and fail EMR, it is expected that a switch to NIL may improve the probability of achieving a DMR, we launched in November 2016 an international, prospective, interventional, randomized, two arms, phase IV study to evaluate both the depth of the molecular response and the rate of TFR in newly diagnosed CP-CML patients treated with a second generation TKI (Nilotinib, NIL) or with Imatinib (IM) followed by switch to NIL in absence of optimal response (defined according the ELN 2013 criteria (Clinical Trial number 02602314) The enrolled patients are randomized 1:1 between NIL and IM. Patients are stratified at randomization according to the Sokal risk score (high versus intermediate/low risk) and country (Italy, The Netherlands, Belgium). All the patients who obtain a reduction greater than 4.0 logs of residual disease (MR4.0) within the first three years of treatment, and maintain this level of response in all the subsequent tests up to the end of the fourth years of therapy qualify for the discontinuation phase of the study. The study has two primary end-points: a) the rates of molecular response (MR4.5) at 24 months, and b) the rate of patients who remain in sustained treatment free remission (≥MR3.0) without molecular relapse 12 months after entering the TFR phase. The molecular relapse is defined as loss of MMR, or confirmed loss of MR3.0. Differences in the patient-reported quality of life (QoL) were are investigated by QoL questionnaires (EORTC QLQ-C30 and EORTC CML-24) at baseline (before the randomization) and at 3, 6, 12, 18, 24, 30, 36, 42, 48, 60 months. A total of 165 patients will be enrolled. Enrollment will be concluded in 2019, and final results will be given in 2024.ResultsFrom November 2016 to the 15 July 15 2018, 165 patients with newly diagnosed CP-CML patients (mean age 54.6 years - range 20.0-85.8) were enrolled and randomized into the two arms of the study. Of those, 137 (83%) were classified as low/intermediate-risk Sokal, and the remaining 28 (17%) as high-risk. Additional chromosome abnormalities in the Philadelphia positive clone were detected in 20 (12.1%) patients, 7 (8.5%) in the IM group and 13 (15.9%) in the NIL group.Overall, 12 patients of the IM group switched to NIL; for absence of optimal response at 3 months in two cases, at 6 months in 7 patients and at 12 months in one case. The remaining two patients switched to NIL for IM related toxicity. Among NIL treated patients, two patient stopped treatment, in one case at 1 month due to absence of hematological response and the other due to suboptimal response at 15 months. These patients were treated according to the principal investigator of the participating center and censored for final analysis.At a preliminary evaluation of patient-reported QoL questionnaires completed at baseline, women and elderly had a perception of higher symptom burden.ConclusionThis is the first and the unique prospective study comparing not only the rate of DMR but, more important, also the rate of TFR according to treatment: a second generation TKI frontline vs Imatinib frontline followed by the same second generation in case of non-optimal response to ImatinibAcknowledgmentsThe present study is a non-commercial study sponsored by Fondazione GIMEMA together with the HOVON that are responsible for the database of the study. Novartis Pharma supports the study with an unrestricted grant. DisclosuresPane:AMGEN: Speakers Bureau; Novartis: Research Funding, Speakers Bureau; BMS: Speakers Bureau. Abruzzese:BMS: Consultancy; Ariad: Consultancy; Pfizer: Consultancy; Novartis: Research Funding. Breccia:Incyte: Honoraria; Novartis: Honoraria; BMS: Honoraria; Pfizer: Honoraria. Soverini:Incyte Biosciences: Consultancy; Bristol Myers Squibb: Consultancy; Novartis: Consultancy. Castagnetti:Pfizer: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Incyte: Consultancy, Honoraria. Janssen:Pfizer: Consultancy, Speakers Bureau; Novartis: Research Funding; Incyte: Consultancy, Speakers Bureau; BMS: Research Funding; Abbvie: Consultancy; Jazz pharmaceuticals: Consultancy.

The Role of Shelterin Complex and Post-Translational Non-Enzymatic Modification in Telomere Maintenance in Chronic Myeloid Leukemia

The introduction of tyrosine kinase inhibitors (TKI) revolutionized therapy of chronic myeloid leukemia (CML) and gives long-lasting remission in majority of patients. However, a significant proportion of patients develops resistance and are at risk of progression. Genomic instability is one of the key features associated with CML progression and as in majority of human malignancies, reduction in telomere length characterize transition from chronic phase (CML-CP) to the blastic phase (CML-BP). Telomere maintenance depends on telomerase nucleoprotein complex consisting of reverse transcriptase TERT, RNA template TERC and structural proteins, such as dyskerin (DKC1), but also on telomere-associated proteins including but not limited to shelterin complex(TRF1, TRF2, RAP1, TIN2, TPP1, POT1) and other telomeric-associated proteins (such as TEP1 and Tankyrase). The role of shelterin complex and its post-translational non-enzymatic modifications in BCR/ABL1-mediated genomic instability in CML progression and resistance to TKIs is not fully elucidated, thus we decided to examine the possible role of different components of shelterin complex and its glycation and carbonylation in promoting genomic instability and CML progression. We employed CML CD34+ primary cells isolated from peripheral blood leukocytes or bone marrow of CML patients at different stages of disease: CML-CP, CML-BP and CML-TKIres (TKI-resistant cells). Blood samples were taken after informed consent. The length of telomeres was determined by Southern blotting and PNA-FISH technique. Enzymatic activity of telomerase, as well as protein glycation was measured immunoenzymatically, while expression of subunits of telomerase and shelterin complexes was examined by RT-qPCR and by Western Blot.We confirmed that reduction in telomere length was positively correlated with CML progression. However, in samples from CD34+ CML-TKIres patients in comparison to CML-CP patients, an increase in telomere length was observed (Fig 1). In addition, the negative correlation between mean telomere length and expression of BCR-ABL1 in CML samples was observed. This suggests involvement of alternative telomere lengthening mechanisms, since dynamic changes in telomere length were neither associated with enzymatic activity of telomerase nor with gene copy number/expression of TERT/TERC. Therefore we postulate that telomere dynamics in CML may have a bi-phasic scenario. We found that the expression of RAP1, DKC1 and Tankyrase1 was increased in CML-BP as compared to CML-CP. Moreover, RAP1 is involved in increased metabolism, which is associated with elevated glycolytic and oxidative rates leading to post-translational non-enzymatic modification of proteins and damage of cellular proteostasis which may indirectly influence telomere length in CML. We found that telomere shortening was associated with accumulation of post-translational non-enzymatic modification ofselected proteins of shelterin complex, namely glycation and carbonylation.In conclusion, we postulate that aberrant expression of members of the shelterin complex such as RAP1 may be responsible for aberrant telomere maintenance mechanisms in CML cells and may play role in genomic instability associated with CML progression as well as the clonal selection and resistance to TKIs. In addition, the changes in the level of protein glycation may influence telomere length in CML. DisclosuresNo relevant conflicts of interest to declare.

Genomic amplification of BCR-ABL1 fusion gene and its impact on the disease progression mechanism in patients with chronic myelogenous leukemia

Identification of BCR-ABL1 fusion gene amplification status is critically important in the effective management of chronic myelogenous leukemia (CML) patients. Earlier reports suggested that overexpression of BCR-ABL1 either through amplification of BCR-ABL1 fusion gene or by the up regulation of BCR-ABL1 transcript level might be an early phenomenon in the establishment of IM resistance and disease evolution in CML. In the current study, we performed dual color dual fusion locus specific BCR/ABL1 FISH analysis along with karyotype analysis using GTG banding (G-banding using trypsin and Giemsa) technique in 489 patients with different clinical stages of CML at diagnosis or during the course of the disease to unravel the spectrum of BCR-ABL1 fusion gene amplification status. Among the study group analyzed, it was found that prevalence of occurrence of BCR-ABL1 fusion gene amplification was significantly higher in advanced stages of disease and in IM resistant CML-CP patients when compared to initial stage of disease, de novo CML-CP. Cytogenetic and metaphase FISH characterization on our study samples revealed that BCR-ABL1 fusion gene amplification was occurred through the formation of extra copies Ph chromosomes and isoderived Ph chromosomes. Current study suggests that unrestrained activity of BCR-ABL1 played a vital role in resistance to targeted therapy and disease evolution in CML. In our study population, patients in progressive stage CML and in IM resistant CP with multiple copies of BCR-ABL1 fusion gene displayed a poor response to targeted treatment with IM. Hence, the early identification of BCR-ABL1 fusion gene amplification using FISH technique will lead to improved interventions and outcome in future CML patients.

A phase I clinical trial of ruxolitinib in combination with nilotinib in chronic myeloid leukemia patients with molecular evidence of disease

PurposePreclinical evidence indicates that the bone marrow microenvironment provides a protective niche for leukemic stem cells, allowing them to evade the effects of BCR-ABL tyrosine kinase inhibitors (TKIs), but that targeting of the JAK-STAT pathway with the JAK2 inhibitor ruxolitinib increases TKI-induced apoptosis. A phase I clinical trial (NCT01702064) investigated the tolerability and safety of treating chronic-phase chronic myeloid leukemia patients with ruxolitinib in combination with the BCR-ABL TKI nilotinib and explored initial efficacy evidence. Experimental designEleven patients already treated with single-agent nilotinib (300–400 mg twice daily) commenced combination therapy, and molecular responses were evaluated after 6 months. Three ruxolitinib dose cohorts were studied: 5 mg, 10 mg, and 15 mg twice daily. ResultsOne patient experienced a grade 3/4 adverse event (hypophosphatemia) and 36% of patients experienced grade 1/2 anemia. Of 10 patients who were evaluable for responses, 40% had undetectable BCR-ABL transcripts, as measured by quantitative RT-PCR after 6 months. Plasma inhibitory assay results revealed a decrease in phospho-STAT3 levels after treatment with ruxolitinib. The recommended phase 2 dose of ruxolitinib was 15 mg BID. ConclusionsOverall, this combination was safe and well-tolerated, and the molecular responses were encouraging, thereby warranting further investigation in a phase 2 trial.

Safety and efficacy of switching from branded to generic imatinib in chronic phase chronic myeloid leukemia patients treated in Italy

The use of generic drugs after patent expiration of their originators is a relative novelty in the treatment of chronic cancer patients in Western countries. In this observational study we analyzed a cohort of 294 Italian chronic phase chronic myeloid leukemia patients treated frontline with branded imatinib (Glivec®) for at least 6 months and then uniformly switched to generic imatinib upon requirement of health authorities in early 2017.Median age at diagnosis was 57 years (range 19–87). Sokal risk was low/intermediate/high in 55%, 32% and 8% of cases, respectively. Median duration of branded imatinib treatment was 7.4 years (range 0.5–16.7). At a median follow-up of 7.5 months after switch to generic imatinib, 17% of patients reported new or worsening side effects, but grade 3–4 non-hematological adverse events were rare. Six patients switched back to branded imatinib, with improvement in the side effect profile, and 4 pts moved to bosutinib or nilotinib for resistance/intolerance. The majority of patients were in major (26%) or deep molecular response (66%) at the time of switch. Molecular responses remained stable, improved or worsened in 61%, 25% and 14% of patients, respectively.We conclude that switch to generic imatinib for patients who have been receiving branded imatinib appears to be effective and safe. Molecular responses may continue to improve over time. Some patients experienced new or worsened side effects but less than 5% of the whole cohort needed to switch back to branded imatinib or move to other treatments. Savings were around 3 million Euros.

Effect of Additional Chromosomal Abnormalities on the Outcome of CML-CP Patients Receiving TKI Therapy

To explore the effect of additional chromosomal abnormalities on the prognosis and outcome of CML-CP patients receiving imatinib therapy. The clinical and genetic data of 589 CML-CP patients receiving imatinib treatment between May 2009 and October 2014 in the 1st Affiliated Hospital of Soochow University were analyzed, the 589 patients were divided into 5 groups according to the karyotypes at the initial diagnosis. The OS(overall survival), PFS (progression-free survival), EFS (event-free survival), Cumulative MMR (major molecular remission) and Cumulative CCyR (complete cytogenetic remission) were calculated by using the Kaplan-Meier method and compared by using the log-rank text by Graphpad 6.0. The χ2 test was used to compare the frequency of optimal molecular response at 3, 6, 12 months among the 5 groups. There was significant difference about the frequency of optimal molecular response at 3 and 6 months between CML-CP patients with additional chromosomal abnormalities and those with classic t(9;22) ［50%（12/24） vs. 73.94%(261 /353), P<0.05; 50%(10 /20) vs. 72.05%(232 /322) (P<0.05)］, and the same significant difference was found at 6 months between the group with variant translocations and that with classic t(9;22) ［53.3% (16 /30) vs. 72.05%(232 /322) (P<0.05)］. The P values of cumulative CCyR (P<0.05) and EFS (P<0.01) for 4 years were statistically significant between CML-CP patients with additional chromosomal abnormalities and the other 4 groups. Compared one to another, there was the significant difference in cumulative CCyR and EFS for 4 years between CML-CP patients with additional chromosomal.abnormalities and those with classic t(9;22) (47.25% vs. 84.01%)(P<0.05); (75.03% vs. 90.01%)(P<0.01). The additional chromosomal abnormalities influence the outcome of CML-CP patients receiving imatinib treatment, which make poor prognosis.