Presence Of BCR-ABL Fusion Gene Research Articles

Efficacy and Safety of Generic Dasatinib As First-Line Treatment in Patients with Chronic Myeloid Leukemia in Chronic Phase: Final Analysis with 2-Year Follow-up

Purpose: Generic dasatinib, a second-generation tyrosine kinase inhibitor (TKI), was approved as a second-line treatment for chronic myeloid leukemia (CML) patients in chronic phase (CP) in china. We initiated a prospective, multi-center and single-arm clinical trial (NCT04925141) from May 2016 to October 2018 to evaluate efficacy and safety of generic dasatinib as first-line treatment in China. The primary endpoint was achieved, here we reported the 2 years follow-up results to see its long-term clinical benefit in Chinese patients.Methods:The study included the newly diagnosed CML-CP patients who was diagnosed by the presence of Philadelphia (Ph) chromosome and/or presence of BCR-ABL fusion gene. Key inclusion criteria were as follows: 1) Age ≥ 18 years; 2) The CML subjects in chronic phase with the Ph+ definitive diagnosis were within 6 months before the onset of administration of the study drug; 3) The ECOG performance grades of 0-2; 4) Sufficient main organ functions. All newly diagnosed patients were given 100mg/d (initial dose) of the generic dasatinib. The primary endpoint was molecular major response (MMR) calculated based on the BCR-ABL1 ≤ 0.1% at the 12th month. Secondary endpoints were proportion of subjects who achieved and maintained MMR at 3, 6, and 18 months; Cumulative MMR rates at 6, 12, and 24 months were determined. All patients were followed up through the hospital outpatient departments at second, fourth and eighth weeks, and third, sixth, ninth, twelfth, eighteenth, and twenty-fourth months. The follow-up ended on December 6, 2019. The SAS 9.2 software was utilized for all statistical analyses in this study, and the two-sided test was performed to see variances.Results: A total of 59 patients were included in this trail, with median age of 44 (19 - 70), and 7% of the subjects were at high risk based on the Sokal index for the disease prognosis. The primary endpoint MMR rate at the 12th month was 80.8% which had been published. At 12 months, the cumulative response rate (CCyR) was 85.5% (47/55) and the cumulative MMR was 76.4% (42/55). Here we are reporting the 2 years follow ups. At 24 months, the complete hematological response (CHR) was 88.4%, the cumulative MMR rate was 73.7%, the cumulative MR4.0 rate was 63.6%, the cumulative MR4.5 rate was 58.2%, and the cumulative complete molecular response (CMR) rate was 58.2%. The most common adverse events (AEs) was thrombocytopenia (42.4%) in hematology and pleural effusion (20.3%) in non-hematology, only 11.9% and 1.7% of whom were grade III~IV respectively.Conclusion: This was the first report on domestic dasatinib as the first-line treatment for CML-CP patients received a clinical benefit with 24 months in China. Safety was similar with that of the original study data. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

A Bio-Integrative Approach Identifies an Inflammatory Signature in Chronic Myeloid Leukemia (CML) Stem Cells That Is Highly Perturbed in CML Blast Crisis and Involves REL transcription Factor

Chronic myeloid leukemia is a clonal myeloproliferative neoplasm defined by the presence of BCR-ABL fusion gene. This oncogenic event occurs in a hematopoietic stem cell (HSC) involved in CML initiation, maintenance, relapse and progression. Several evidences suggest that inflammatory pathways may participate to the pathophysiology of CML as well as disease progression to blast crisis. It has been shown that NFKB/REL pathway is constitutively activated both in BCR-ABL positive leukemic cell lines as well as in primary blast cells from CML-BC patients. More recent works identified IL6 as key cytokine acting on CML multipotent progenitors and their normal bystander counterpart to favor their differentiation toward the myeloid lineage. In addition, high levels of autocrine TNFα secretion by quiescent CML stem/progenitor cells activate NFKB pathway and promote their survival. Although all of these observations are linked to inflammatory processes, a focused analysis of inflammatory pathways in primary CML stem cells has not been performed so far. In the present study we undertook a text-mining strategy using pubmed e-querying to generate an exhaustive set of genes linked to inflammation. Then we integrated transcriptome analysis of highly purified CML stem cells to evaluate the contribution of these genes in CML development and progression.Methods : We queried 6 key words (Inflammation, macrophages, inflammatory response, chemokines, leukocytes and interleukins) that returned a total of 332000 hits in Pubmed. A raw gene set of 918 genes was found significantly associated (p<0.05) with these hits. Using R-package, we applied a false discovery rate correction that decreased the set to 588 relevant genes. The expression level of this gene set was then analyzed in previously reported microarray data (GEO accession: GSE47927) of highly purified normal cord blood CD34+CD38-CD90+ HSCs (CB; n=3), chronic phase (CP; n= 6), accelerated phase (AP; n =4) and Blast crisis (BC; n=2) CML cells.Results: Among the 588 genes related to inflammation we found 70 genes differentially expressed between the four groups (normal, CP, AP and BC, p<0.01; ANOVA test). Enrichment analysis confirmed 29 up regulated genes (NES = 2.12; p<0.0001) among which IL-6, PARP1, IL1R2, IRF5, IRF8, IL20. 39 genes such as STAT3, STAT4, CD47, CXCR4 IL-11, IL15, TLR-1, were down-regulated in CML CD34+CD38-CD90+ (all phases) as compared with normal HSCs (NES = -2,58; p<0.0001). Using principal component analysis on the 70 inflammatory deregulated genes we identified 10 genes such as IRAK1, IL1R2, VEGF and ESAM that discriminate "all phase" CML samples from normal HSCs (Dim 2 = 22.7%). Another inflammatory gene subset (n=26 genes) comprising IL6, REL, CXCR4, CXCL2, IL11, TLR1, IL1R2, PPARA highly separated CML stem cells according to the disease phase. The later gene set highly separates CP and AP-CML stem cells from BC-CML stem cell (Dim 1 = 50.3%). We next performed a random forest analysis with machine learning (1000 trees) and found that the inflammatory transcript level that best predicted CML phase was REL transcription factor. The expression of 413 genes were found positively correlated with REL expression in CP, AP and BC-CML CD34+CD38-CD90+ cells (r>0.75 and p-value <0.001). A search using JASPAR and TRANSFAC database identified a significant enrichment of NFKB1 and RELA binding motif in the promoter regions of these 413 genes (p<0.00001) among which several regulatory factors of hematopoietic stem cell biology.Conclusion : Using a bio-integrative approach we identified a specific inflammatory signature in CD34+CD38-CD90+ CML stem cells. This inflammatory network is highly altered in blast crisis suggesting its contribution to disease evolution. We identified REL overexpression as a good predictor for disease progression to blast crisis and found NFKB1and RELA (p=3.2x10-13) as the best REL target candidates. RELA/NFKB1 was previously shown to be constitutively activated in CML and Ph+ ALL and this analysis suggests that this may also take place in the most primitive subset of CML cells although REL may be the main partner of NFKB in CML stem cells. These results which are currently validated using functional assays, could lead to identification of novel therapeutic strategies. DisclosuresTurhan:Bristol Myers Squibb: Consultancy; Novartis: Research Funding.

BCR-ABL Fusion Gene and BCR-ABL Transcript - Correlation with Response to Therapy in Chronic Myeloid Leukaemia.

INTRODUCTION: The quantification of BCR-ABL transcript (RNA) has been consistently associated with the evolution of Chronic Myeloid Leukaemia (CML), frequently determining therapeutic decisions. We did not find in the literature any attempt of measuring tumour burden directly by its genomic marker (DNA).AIMS: To correlate the quantification of BCR-ABL fusion gene with the quantification of BCR-ABL transcript, in the evaluation of response to therapy in patients (pts) with CML.METHODS: Between October/2002 and July/2005, we analysed 393 samples of peripheral blood of 33 pts, M/F:17/16, median age 52 (27–76) years, with chronic phase CML (2 pts developed blast crisis), median time since diagnosis 60,5 (19–170) months, under Imatinib or alpha Interferon (INF) + Cytarabin (Ara-C) therapy. Pts total RNA and genomic DNA were extracted from peripheral blood samples and total RNA was reverse transcribed into cDNA. Real-time PCR absolute quantification with TaqMan® probes was used to measure the fusion transcript's levels and Sybr Green I® dye was used to measure the fusion gene levels. Imatinib was initiated in pts with cytogenetic responses (CyR) inferior to 90%, after more than 1 year of INF+Ara-C therapy. Criteria used in the evaluation of response: molecular response (MR) - reduction of transcript ≥ 3 logs, major MR (MMR) - reduction ≥ 4 logs, complete MR (CMR) - absence of transcript in 2 consecutive analyses.RESULTS: From 33 studied pts, 26 were under Imatinib therapy, after a median of 21 (2–38) months, 6 pts maintain therapy with INF+Ara-C and 1 pt died (lower respiratory tract infection), in therapy with INF+Ara-C. The evaluation of therapy demonstrated MR in 18 pts (55%), 5 of which with IFN+Ara-C. From these 18 pts, 7 achieved CMR and 6 MMR. In the 15 pts without MR, 8 presented reduction of transcript of 1 to 2 logs and 7 pts maintained stable levels of transcript. Two pts developed blast crisis, after 4 and 20 months of therapy with Imatinib, the latter 12 months after MMR. We observed a higher incidence of transcripts b3a2 (23 pts) compared with b2a2 (11 pts), but we did not find any correlation between the type of transcript and response to therapy. In all pts BCR-ABL fusion gene was present, including in those pts in CMR. We did not observe any correlation between the quantification of BCR-ABL fusion gene and the quantification of BCR-ABL transcript.CONCLUSIONS: The present data demonstrates that MR can be achieved in pts with CML by INF+Ara-C therapy. If INF+Ara-C fails to induce CyR, MR can be obtained with Imatinib. In the 33 CML presented pts, the evaluation of response to therapy showed that 55% pts obtained MR. No correlation between the quantification of BCR-ABL fusion gene and the quantification of BCR-ABL transcript was observed. These preliminary results suggest that the absence of BCR-ABL transcripts does not exclude the presence of BCR-ABL fusion gene. However more studies with larger series of pts are needed to confirm these results.