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Introduction: Tyrosine kinase inhibitors (TKIs) have greatly improved the treatment outcome for most patients with chronic myeloid leukemia (CML). Ponatinib is a new pan-inhibitor of TK active in resistant CML. This study aimed to evaluate the efficacy and safety of ponatinib in patients suffering from CML. Patients and methods: This multicenter, non-randomized, observational, retrospective study evaluated the efficacy and safety of ponatinib administered in adult CML patients in any disease phase, including those with a detected ABL T315I mutation, which were resistant or intolerant to previous-generation TKIs. The study comprised 43 patients benefiting from the ponatinib donation program who were treated in 16 Polish centers. Results: For patients who started treatment with ponatinib in chronic phase (CP) (n=23) and in accelerated phase (AP) (n=3) the median time on ponatinib was 19.5 months (range: 1.0-35.4), and 31.7 months (range: 31.0-34.1), respectively. All these patients were in CP after 1 month of treatment and at the end of observation – none of them progressed to AP or blastic phase (BP) during the study, meaning that progression-free survival was 100% at the end of observation (35.4 months). The estimated 2-year survival in this group of patients was 84%. For all 43 patients, median survival was not reached (lower quartile 6.3 months), and estimated 2-year survival was 60%. Conclusion: Our analysis confirmed ponatinib efficacy in a significant proportion of patients heavily pre-treated with TKIs achieving durable responses in both CP and AP/BP CML groups. Microabstract: Ponatinib is a new pan-inhibitor of tyrosine kinase active in resistant chronic myeloid leukemia (CML). Evaluation of outcomes in 43 patients confirmed ponatinib efficacy in a significant proportion of subjects heavily pre-treated with tyrosine kinase inhibitors achieving durable responses in both chronic phase and accelerated/blastic phase CML groups.

Background: Chronic myeloid leukaemia (CML) is a rare disease in children. The frequency and outcome of children evolving to accelerated phase (AP) or blastic phase (BP) under treatment with imatinib is unknown. The aim of the current study is to assess the inci-dence of progression from CML in chronic phase with imatinib frontline in a paediatric setting and describe the management and outcome of these patients.Patients and methods: In the I-CML-Ped Study database (www.clinicaltrials.gov, #NCT01281735), 19 of 339 paediatric patients in chronic phase treated with imatinib in the frontline evolved to CML-AP or CML-BP.Results: With a median follow-up of 38 months (range: 2-190 months), the cumulative inci-dence of progression at 1 and 3 years was 3% (confidence interval [CI] 95%: 1-5%) and 7% (CI 95%: 4-11%), respectively. We observed a large predominance of lymphoid-BP (70%) over myeloid-BP (30%) with imatinib in frontline therapy. Sixteen patients underwent haemato-poietic stem cell transplantation, and eight were treated with a tyrosine kinase inhibitor after transplant. Only the transplanted patients are alive. The 5-year overall survival rate of children with CML-AP/BP is 44%, with no statistical difference between the lymphoid-BP and myeloid-BP outcome.Conclusion: Children evolving to AP or BP under treatment with imatinib have a very poor prognosis with an overall survival under 50%, much worse than children with advanced phase at diagnosis. (c) 2020 Elsevier Ltd. All rights reserved.

Although the prognosis of chronic myeloid leukemia (CML) in blastic crisis remains poor, some patients achieve long-term remission after allogeneic hematopoietic stem cell transplantation (allo-HSCT). This may be attributable to graft-versus-leukemia (GVL) effects by donor lymphocytes, but their regulating mechanisms are unclear. Antitumor natural killer (NK) cell immunity is assumed to be important in CML, and we have previously shown that allelic polymorphisms of killer immunoglobulin-like receptors (KIRs) and histocompatibility leukocyte antigens (HLAs) are associated with the response of CML to tyrosine kinase inhibitors. Here, we report a case of CML in blastic phase who received HLA-matched but KIR3DL1 allelic-mismatched allo-HSCT. After transplant, decreased BCR-ABL transcript levels and enhanced NK cell activity were transiently observed. However, reconstitution of KIR3DL1-expressing NK cells occurred, which was associated with diminished NK cell activity and increased BCR-ABL. This case indicates the potential significance of KIR3DL1 in NK cell-mediated GVL activity following allo-HSCT. To the best of our knowledge, this is the first report to analyze the association between sequential KIR3DL1 expression and activity of NK cells after allo-HSCT. Selecting donors with KIR3DL1-null alleles may maintain competent GVL effects and provide improved outcomes in allo-HSCT for CML.

Background Dasatinib, a potent Bcr-Abl tyrosine kinase inhibitor, is approved for the treatment of chronic-phase chronic myeloid leukemia (CML-CP) in the frontline and salvage settings. Notable side effects include pleural effusions and myelosuppression. Dasatinib at 50 mg daily has previously been reported to be active and better tolerated than the approved 100-mg daily dose. The aim of this study was to update the long-term follow-up results of dasatinib at 50 mg daily as frontline therapy for CML-CP. Methods Eighty-three patients with newly diagnosed CML-CP received dasatinib at 50 mg daily. Eligibility and response criteria were standards used in previous protocols. Results After a minimum follow-up of 12 months, 81 patients were evaluable. Two patients came off the study in less than 3 months. The rates of BCR-ABL1 transcript levels (International Standard) at ≤10% and ≤1% at 3 months were 96% and 77%, respectively. The cumulative rates for a complete cytogenetic response by 6 and 12 months were 77% and 95%, respectively. The cumulative rates for a major molecular response, a molecular response with a 4.0-log reduction, and a molecular response with a 4.5-log reduction by 12 months were 81%, 55%, and 49%, respectively. Twenty-one patients (25%) had treatment interruptions for a median of 13 days (range, 4-64 days). Five patients (6%) developed pleural effusions; 4 of these patients (80%) required a dose reduction. Two patients (2%) failed to achieve any cytogenetic or molecular response and were taken off the study. At a median follow-up of 24 months, none of the patients had disease transformation to an accelerated or blastic phase. The 2-year event-free and overall survival rates were 100%. Conclusions These updated results continue to support 50 mg of dasatinib daily as an effective and safe dose for early CML-CP.

Chronic myeloid leukemia (CML) is commonly associated with major BCR-ABL transcript. We present a child with blastic phase CML associated with minor BCR-ABL transcript without prior CML diagnosis. Diagnosis was achieved by fluorescence in situ hybridization of peripheral blood neutrophils, which identified 90% as BCR-ABL positive. The patient received chemotherapy with imatinib followed by dasatinib and underwent reduced-intensity hematopoietic allogeneic stem cell transplantation with prophylactic posttransplant dasatinib for 2 years and has remained in complete molecular remission. Our intensified treatment regimen was effective compared with previous studies on minor BCR-ABL CML describing inferior outcomes with tyrosine kinase inhibitor therapy.

Highlights • MS are extremely rare tumors with an aggressive clinical course. • Morphologically, they can mimic small round cell tumors. This problem is further complicated by the lack of clinical suspicion in patients without any hematological disorder. • Accurate diagnosis of isolated MS requires a multifactorial approach including histopathology, immunophenotyping, immunohistochemistry and cytogenic abnormalities. • A high level of suspicion is necessary, because early, accurate diagnosis is important to avoid delaying appropriate chemotherapy. A delay in the diagnosis may result in unwarranted fatality particularly so in pediatric patients. • Here, we report an unusual case of MS initially presenting as a tumor of the temporal bone and first manifestation of AML, in a pediatric patient suffering from Down’s syndrome. This case illustrates the challenges associated with offering a rapid diagnosis with an early initiation of treatment., Introduction Leukemia is the most common malignancy of childhood but myeloid sarcoma is a rare presentation of underlying leukemic disorder. Myeloid sarcoma (MS) is a rare tumor composed of proliferation of myeloid precursors at extramedullary sites. Presentation of case We report an unusual case of myeloid sarcoma involving the temporal bone in a young male child who presented with a large mass involving the left temporal region. This lesion was the initial presentation which led to further diagnosis of acute myeloid leukemia in our case. This case report brings awareness to the diverse extramedullary manifestations of isolated myeloid sarcoma, as well as the importance and difficulties that are associated with establishing a rapid diagnosis and initiating treatment. Discussion They can arise de novo or in association with hematological malignancies, most commonly acute myeloid leukemia (AML-M2). Clinically, it can masquerade as an abscess, cutaneous ulcer, or as a mass lesion. Morphologically, MS can mimic a variety of small round cell tumors including lymphomas, neuroblatoma and rhabdomyosarcoma. The occurrence of this tumor usually heralds AML or the onset of the blastic phase of chronic myeloid leukemia. Early recognition of this rare entity is important, because early aggressive chemotherapy and focal irradiation can cause regression of the tumor and thus improve patient longevity. Conclusion The possibility of MS should be considered when dealing with unusual lymphoma like neoplasms that cannot be categorized as any of the Non-Hodgkin lymphoma subtypes and small blue round cell tumors.

Background Dasatinib monotherapy has demonstrated modest clinical activity in chronic myeloid leukemia in lymphoid blastic phase (CML-LBP). The outcome of Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL) has dramatically improved with hyperfractionated cyclophosphamide, vincristine sulfate, doxorubicin hydrochloride, and dexamethasone (hyper-CVAD) in combination with tyrosine kinase inhibitors (TKIs). Methods The authors reviewed 85 patients (23 with CML-LBP and 62 with newly diagnosed Ph-positive ALL) who received hyper-CVAD plus dasatinib. Results In the CML-LBP cohort, 19 had prior chronic myeloid leukemia as chronic phase (n = 17; 74%), accelerated phase (n = 1; 4%), or myeloid blastic phase (n = 1; 4%); 4 (17%) presented with de novo CML-LBP. The BCR-ABL1 transcript was p210 in 22 patients (96%) and p190 in 1 patient (4%). In the Ph-positive ALL cohort, p210 and p190 transcripts were detected in 13 patients (21%) and 48 patients (77%), respectively. Patients with CML-LBP were less likely to achieve deep molecular remission than patients with Ph-positive ALL: the major molecular response (MMR) rates were 70% and 95%, respectively (P = .007), and the complete molecular response (CMR) rates were 55% and 74%, respectively (P = .16). Survival outcomes were similar for CML-LBP and Ph-positive ALL: the 5-year overall survival (OS) rates were 59% and 48%, respectively (P = .97). Allogeneic stem cell transplantation was associated with a better outcome in CML-LBP (5-year OS rate, 88% vs 57%; P = .04). In Ph-positive ALL, the outcome was driven by deeper molecular remission: the 5-year OS rates were 63% and 25% with CMR and MMR, respectively (P = .002). Conclusions The outcome of CML-LBP has improved with hyper-CVAD plus dasatinib therapy with survival comparable to that of Ph-positive ALL. Further improvement may be achieved with the use of novel TKIs and targeted agents.

Myeloproliferative Neoplasm (MPN), unclassifiable (MPN-U) is a heterogeneous disease with regards to both clinical phenotype and disease course. Patients may initially be asymptomatic or present with leucocytosis or thrombocytosis, anaemia, progressive splenomegaly, constitutional symptom, thromboses or accelerated/blastic phase disease. Treatment strategies are variable and there are no widely accepted consensus management guidelines for MNU-U. Allogeneic Haematopoietic Cell Transplantation (allo-HCT) remains the only curative strategy yet outcomes, to date, are not well defined. We hereby report on the largest retrospective study of patients with MPN-U undergoing allo-HCT, highlighting the potentially curative role and providing clinicians with robust engraftment, GvHD and outcome data to facilitate patient discussion.

Background: MicroRNAs (miRNAs) have been observed to exhibit altered expression patterns in chronic myeloid leukemia (CML). Therefore, this study was aimed to evaluate the clinical importance of miR-126 and miR-122 expression in concert to imatinib response in CML patients. Methods: The present study included 100 CML and 100 healthy subjects. The expression of the 2 miRNAs was performed using TaqMan probe chemistry, and snU6 was used as internal control. Results: The expression of miR-126 and miR-122 was downregulated in CML patients, with a mean fold change ± SD 0.20 ± 0.33 and 0.22 ± 0.37, respectively. While the expression of both miRNAs was analysed before and after imatinib treatment, it was observed that the expression levels of both were increased after imatinib treatment by 26.25-fold (5.33 against 0.20) and 13.95-fold (3.07 against 0.22) and the increase was statistically significant (p < 0.0001 and p < 0.0001, respectively). The expression of miR-126 was not conclusive when compared in different clinical stages of the CML disease as it showed a decreased expression in patients with accelerated phase compared to chronic phase (mean fold change = 0.03 and 0.27, respectively), but patients with chronic phase and blastic phase had comparable expression (mean fold change = 0.27 and 0.24, respectively). We also observed an increased expression of both miRNAs after imatinib therapy in each clinical phase. Conclusion: The study concludes that expression of miR-126 and miR-122 increases after imatinib treatment in CML patients and that miR-126 defines the good responders of imatinib therapy.

We sought to evaluate the outcomes of chronic phase (CP) chronic myeloid leukemia (CML) in an era where five tyrosine kinase inhibitors (TKIs) are commercially available for the treatment of CML. Records of patients diagnosed with CP CML, treated with TKIs and referred to our center were reviewed. Between January 2005 and April 2016, 206 patients were followed for a median of 48.8 (1.4&ndash, 190.1) months. A total of 76 (37%) patients received one TKI, 73 (35%) received two TKIs and 57 (28%) were exposed to &gt, 3 TKIs (3 TKIs, n = 33, 4 TKIs, n = 17, 5 TKIs, n = 7). Nineteen (9.2%) patients progressed to advanced phases of CML (accelerated phase, n = 6, myeloid blastic phase, n = 4, lymphoid blastic phase, n = 9). One third (n = 69) achieved complete molecular response (CMR) at first-line treatment. An additional 55 patients achieved CMR after second-line treatment. Twenty-five patients (12.1%) attempted TKI discontinuation and 14 (6.8%) stopped TKIs for a median of 6.3 months (range 1&ndash, 53.4). The 10-year progression-free survival and overall survival (OS) rates were 81% and 87%, respectively. OS after 10-years, based on TKI exposure, was 100% (1 TKI), 82% (2 TKIs), 87% (3 TKIs), 75% (4 TKIs) and 55% (5 TKIs). The best OS was observed in patients tolerating and responding to first line TKI, but multiple TKIs led patients to gain treatment-free remission.

Ph+ chronic myeloid leukemia (CML) is a clonal myeloproliferative disease whose clinical course is characterized by progression disease from the early chronic phase (CP) to the fatal blastic phase (BP). This programmed course is closely related to the translocation t(9;22)(q22;q11) and the resulting BCR-ABL1 fusion protein (p210) that drives the leukemic transformation of hematopoietic stem cells. Therefore, the cure of CML can only pass through the abrogation of the Ph+ clone. Allogeneic stem cell transplantation (allo-SCT) and interferon-alpha (IFNα) have been proven to reduce the Ph+ clone in a limited proportion of CML population and this translated in a lower rate of progression to BP and in a significant prolongation of survival. Tyrosine-kinase inhibitors (TKIs), lastly introduced in 2000, by preventing the disease blastic transformation and significantly prolonging the survival in up to 90% of the patient population, radically changed the fate of CML. The current therapy with TKIs induces a chronicization of the disease but several criticisms still persist, and the most relevant one is the sustainability of long-term therapy with TKIs in terms of compliance, toxicity and costs. The perspectives concern the optimization of therapy according to the age, the risk of disease, the potency and the safety profiles of the TKIs. The prolongation of survival is the most important end point which should be guaranteed to all patients. The treatment free remission (TFR) is the new goal that we would like to give to an increasing number of patients. The cure remains the main objective of CML therapy.

Chronic myeloid leukemia (CML) is a hematological malignancy caused by an abnormal tyrosine kinase, BCR-ABL1. Leukemic stem cells (LSCs) in this disease proliferate indefinitely. Also, the LSCs normally differentiate into mature neutrophils. Although tyrosine kinase inhibitors (TKIs) that target the kinase activity of BCR-ABL1 improved prognosis of CML patients, many patients still have residual diseases and need life-long treatment with the TKIs. This is due to a small number of CML LSCs that cannot be completely eradicated by the TKIs. It has been hypothesized that not only chemotherapy alone, but also immune surveillance systems of patients are needed to completely eradicate cancerous cells from their body. We hypothesized that residual CML cells might escape from the immune surveillance. Surfaces molecules associated with immune surveillance are examined on CML cells. At first, we confirmed expression levels of CD80 and PD-L1 by flowcytometry using CML cell lines. Our data showed that CD80 was expressed on surfaces of CML derived cell, K562, not PD-L1. Moreover, an engineered K562 subline is generated with the constitutive active JAK2V617F gene and became dependent on JAK-STAT signaling, but not BCR-ABL. This subline did not show CD80 on the surface. The TKIs inhibited expression of CD80 on the parental K562. Meanwhile, an ERK inhibitor decreased CD80 expression in K562. These results suggested that CD80 was downstream of BCR-ABL-ERK signaling pathway, not JAK-STAT pathway. When K562 cells were differentiated into mature neutrophils by ATRA, levels of CD80 decreased. Cytotoxicity assays using K562 and NK cells from normal individuals showed that the parental K562 cells and K562 cells with decreased levels of CD80 were similarly killed. These data suggested that CD80 on K562 played a minimum role in NK cell immune surveillance. We also found that only a small fraction of CD11b positive monocytes in normal peripheral blood showed expression of CD80. Also, blastic cells of CML blastic phase showed CD80 expression. These results suggested that only blastic cells of CML and a fraction of monocytes expressed CD80. These cells were distinguished by expression of CD11b as a marker. Although it is currently impossible to distinguish normal stem cells from CML LSCs, our study suggested that CD80/CD11b might be helpful to distinguish the CML LSCs in patients' bone marrow. It may be possible to collect a very small number of CML LSCs in CML patients under the TKI treatment using these antibodies and characterize the residual LSCs. Citation Format: Huixin Li, Shunichiro Yasuda, Satoru Aoyama, Chenyang Zhang, Yohei Kawano, Miyuki Azuma, Norihiko Kawamata. CD80 can be the marker of chronic myeloid leukemia stem cells and regulated by BCR-ABL signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 3117.

Background Secondary acute myelogenous leukemia (sAML) is highly aggressive and molecularly heterogenous. Previous reports have demonstrated differential serum lipid expression among hemopoietic malignancies (i.e AML, myelodysplastic syndrome (MDS) and acute lymphoblastic leukemia (ALL). Such a distinct serum lipidome among hemopoietic disorders suggest "unique oncogenic metabolic addiction" of leukemia initiating cells (LICs). MDS to AML transition is characterized by clonal evolution [i.e severe aneuploidy, high P53 frequency etc.] and chemorefractoriness. However, mechanism(s) for transformation are not entirely understood. In this study, we investigate serum lipidome and "proxy" of glucose [HbA1C] metabolism among: (1) low risk, (2) high risk MDS and (3) sAML patients (pts) to identify features that may suggest disease specific vulnerabilities. Methods After IRB approval, 214 pts were selected for analysis. ANOVA was used to detect differential expression of total cholesterol (TC), low density lipoprotein (LDL), high-density lipoprotein (HDL), and triglycerides (TAG) among low risk, high risk and sAML pts. Multivariate linear regression model was performed to evaluate the independent effect of confounders on relevant lipid modifications observed among subtypes of MDS and sAML pts. SAS software was used for data processing. Results 69/214 (32.2%), 26/214 (12.1%), 35/214 (16.3%), 35/214 (16.3%), 28/214 (13.08%), 21/214 (9.8%) were sAML, very low (VLR), low (LR), intermediate (I), high (H) and very high risk (VHR) MDS. Median age (range) was 68 y (42-91), 68 y (22-87), 70 y (55-91), 76 (53-88), 72 y (60-85) and 74 y (54-84), for sAML, VLR, LR, I, H and VHR, p=0.0001. In sAML, VLR, LR, I, HR and VHR MDS TC was 177 mg/dL, 150 mg/dL, 126 mg/dL, 134 mg/dL, 125 mg/dL and 122 mg/dL, p=0.0001; LDL was 113.4 mg/dL, 81.3 mg/dL, 67.8 mg/dL, 72 mg/dL, 63.2 mg/dL and 70.8 mg/dL, p=0.0001; HDL 35.8 mg/dL, 39.2 mg/dL, 36.1 mg/dL, 40 mg/dL, 33.7 mg/dL, 32.05 mg/dL, p=0.40; TAG 134 mg/dL, 140 mg/dL, 109 mg/dL, 120 , mg/dL 134 mg/dL, 98 mg/dL, p=0.1. Given "similarities" among MDS subgroups, "MDS lipid data" was compared vs sAML. Median TC, LDL, HDL and TAG among sAML vs MDS pts was 179.1 mg/dL vs 130.4 mg/dL, p=0.0001; 113 mg/dL vs 70.1 mg/dL, p=0.0001; 38.6 mg/dL vs 36.7 mg/dL, p=0.5; 142 mg/dL vs 116.6 mg/dL, p=0.056, respectively. 20/89 (22.7%) vs 69/89 (77.53%) sAML vs MDS pts, respectively were diabetic, p=0.002, OR =2.62; 95% CI 1.40-4.90. However, data extracted from 82 pts (16 sAML and 66 MDS, each) demonstrated that hemoglobin A1C (HbA1C) was 7.84% vs 6.34%, in sAML vs MDS, respectively, p=0.009. Multivariate linear regression accounting for age, blast count, BMI, DM status and HbA1C showed that higher TC, LDL and HbA1C were independent predictors of sAML. Conclusions While this study is restricted to demonstrate distinct lipid and metabolic profile between sAML and MDS, our results suggest blastic phase dependency on higher serum cholesterol and possibly higher advanced glycosylation. As compared to MDS, our data highlights the possibility that sAML induces serum Lipidome modifications that may "hijack endogenous lipogenesis" to favor TC, LDL and possibly TAG production. Additionally, despite larger number of patients is needed to confirm our results, higher HbA1C potentially initiates advanced glycosylation facilitating blastic conversion in MDS pts. Disclosures Rivero: Incyte: Membership on an entity's Board of Directors or advisory committees; agios: Membership on an entity's Board of Directors or advisory committees; celgene: Membership on an entity's Board of Directors or advisory committees.

Introduction Tyrosine kinase inhibitors (TKIs) have transformed outcomes in chronic myeloid leukemia (CML). Patients who respond to imatinib, have a life expectancy comparable with that of the global population, however, up to 40% of patients discontinue imatinib due to resistance or intolerance. Ponatinib is a third-generation highly-potent-pan-inhibitor of tyrosine kinases, active in all single resistance ABL kinase mutations, including the T315l mutation. This report presents the results of a prospective analysis of 3-year ponatinib therapy available in Poland by Angelini's donation program for patients in all phases of CML resistant or intolerant to previous TKI therapy. Methods 43 CML patients (20 women, 24 men, aged 19 to 76 years, mean age 49 ± 15 years) were treated in 20 Polish Hematology Centers with ponatinib initiated between March 2016 and December 2019. 23 pts (53%) were in the chronic phase (CP), 3 pts (7%) in accelerated phase (AP), and 17 pts (40%) in blastic phase (BP) (9 myeloblastic and 8 lymphoblastic). The majority of patients received three lines of TKI therapy. The T315I mutation was detected in 30% of patients (the initial characteristics of the 43 analyzed patients are shown in Table 1). The indication for ponatinib and its dose schedule was made according to the discretion of the attending physician. The initial dose of ponatinib was 45 mg/d in 60% of all patients (without statistically significant differences in the initial dose between patients starting treatment in CP, AP, and BP). Molecular biology tests were performed according to ELN guidelines and BCR-ABL/ABL ratios were expressed as % [IS] in all patients. Treatment responses were calculated at each specific time points recommended by ELN. Statistica 12 software (StatSoft, Tulsa, OK, USA) was used for calculations. Results The follow-up ranged from one week to 35.4 months (median 11.4 months) (one male patient died on infection one week after ponatinib introduction and was excluded from further analysis, he did not achieve CHR and he transformed to blast phase-BP). The responses to ponatinib are shown in Table 2. Among 23 CP patients, 18 achieved CHR (78%), 6 (26%) MCyR, 5 (22%) CCyR, and 1 (4%) MMR at 1 month of treatment. There were only 2 patients in this group (9%) who did not achieve CHR. Eleven CP patients (48%) achieved stable MMR. In all 3 AP patients, the best responses (CHR, CCyR, and MMR) were maintained until the end of observation (Table 2). Among 17 BP patients, 8 (47%) achieved CHR. The overall survival was significantly better in those patients who achieved CHR at 1 month of therapy (Figure 1). 19 patients (44%) experienced toxicity of ponatinib including: increase in blood pressure overall 9 patients (21%), hematological toxicity grade 3-4- 12 patients (28%).A total of 19 patients (44%) remained on ponatinib at the end of the observation. Ponatinib dose was reduced during the study in 18 patients (42%): in 11 (61% of those requiring dose reduction) because of toxicity, in 6 (33%) because of good response to treatment, and in 1 patient (6%) because of both reasons. The need for dose reduction was not significantly associated with comorbidities (p=0.4). Eight patients (19%) underwent allo-SCT during the observation. Ponatinib was discontinued in eight patients (19%), in six CP and two BP-patients. In five patients (12%), ponatinib was discontinued because of toxicity (hematological in one, non-hematological in two, and both in one patient); all were CP patients. In two patients (one CP, one BP patient), ponatinib was discontinued as they underwent allo-SCT. Overall, 16 patients (37%) died during the study: 12 of them (28%) due to CML progression. In all 43 patients, median survival was not reached. The estimated 2-year survival was 60% (95% confidence interval 44-76%) (Figure 2A) 84% in CP patients, 100% in AP patients (Figure 2B), and 20% in BP patients. None of the CP patients progressed to AP or BP during the study, i.e. progression-free survival was 100% at the end of observation (35.4 months). The presence of T315I mutation (p=0.2) or the initial dose of ponatinib (p=0.4) was not significantly associated with the overall survival. Conclusion Our study confirmes that ponatinib could induce durable responses with acceptable toxicity profiles in highly pretreated patients with CML resistant or intolerant to previous TKIs treated in standard clinical practice. Disclosures Sacha: Adamed:Consultancy, Honoraria;Bristol-Myers Squibb Company:Consultancy, Honoraria, Speakers Bureau;Pfizer:Consultancy, Honoraria, Speakers Bureau;Novartis:Consultancy, Honoraria, Speakers Bureau;Incyte:Consultancy, Honoraria, Speakers Bureau.Niesiobedzka-Krezel:Angelini Pharma:Other: lecture fee and meeting partcipation.Ciepluch:Copernicus Wojewodzkie centrum Onkologii:Current Employment.

Imatinib mesylate (IM), a tyrosine kinase inhibitor, is the treatment of choice in patients with chronic myeloid leukemia (CML). It is considered a very safe drug, with mostly mild and reversible side effects. Lately, it has been suggested that adverse events may occur after a long term. We report a case of a 72-year-old woman diagnosed with blastic phase of Philadelphia chromosome positive CML treated with IM for 28 months. The patient presented first with ascites as a side effect of the drug. When the ascites re- occurred, it was caused by neuroendocrine tumor (NET) with peritoneal carcinomatosis. We believe this is the first case of a NET as a secondary malignancy (SM) after IM treatment. SM have been described in patients on IM before. It is unclear whether these tumors are caused by imatinib or found more easily because of close follow-up.

A 35-year-old male was diagnosed with chronic myeloid leukemia in the chronic phase and was prescribed 100 mg daily dasatinib. However, dasatinib was discontinued due to thrombocytopenia, and within six months, the disease progressed to the lymphoid blastic phase. Hyper-cyclophosphamide, vincristine, adriamycin and dexamethasone chemotherapy combined with 140 mg dasatinib or 600 mg imatinib was prescribed. The two inhibitors were soon discontinued due to severe thrombocytopenia and jaundice, respectively. Myelosuppression persisted subsequent to the nadir. Bone marrow (BM) aspiration and biopsy revealed hypercellular marrow filled with blasts. Sequencing of the leukemia cells revealed overlapping peaks for the wild-type sequence and the T315I mutant sequence. The patient was treated with 500 mg bosutinib (which was later reduced to 300 mg) for pretransplant cytoreduction. After 5 months, the patient's spleen exhibited a reduction in volume and the percentage of blasts in the BM decreased from 96.1 to 17.5%. The patient successfully underwent cord blood transplantation. The patient has been disease-free for 5 months subsequent to transplantation. This case suggests that bosutinib may be effective for cytoreduction prior to stem cell transplantation, unless the leukemia cells consistently harbor the T315I mutation.

Of all the cancers, chronic myeloid leukaemia (CML) has witnessed the most rapid evolution of the therapeutic milieu in recent decades. The introduction of tyrosine kinase inhibitors (TKIs) as a therapeutic option has profoundly changed patient experience and outcome. The availability of multiple new highly effective therapies has increasingly underscored the importance of a good understanding of the underlying pathophysiological basis in CML, as well as patient-specific factors in choosing the right treatment for every individual. The treatment of CML has migrated in many jurisdictions from the office of a highly specialized malignant hematologist to the general hematologist or even a general practitioner. The goal of this review is to offer an overview of the modern approach to the treatment of CML, with an emphasis on chronic phase (CP) CML, including both TKI-based therapies such as imatinib, dasatinib, nilotinib, bosutinib and ponatinib, and non-TKI medications, such as omacetaxine. We discuss evidence behind each drug, most common and material adverse reactions and outline how this information can be used in selecting the right drug for the right patient. We also discuss evidence as it relates to other therapies, including stem cell transplant (SCT), and patients in accelerated (AP) and blastic phase (BP).

Chronic myeloid leukemia (CML) results from malignant transformation of hematopoietic stem cells induced by the BCR-ABL oncogene. Transformation from chronic to blastic phase is the lethal step in CML. Leukemic stem cells (LSCs) are the basic reason for blastic transformation. It has been shown that Wnt/β-catenin signaling contributes to the self-renewal capacity and proliferation of LSCs in CML. However, the role of Wnt/β-catenin signaling in blastic transformation of CML is still obscure. Here, we explored the relationship between BCR-ABL and β-catenin signaling in vitro and in vivo. We found that BCR-ABL stimulated β-catenin via activation of PI3K/AKT signaling in blastic phase CML cells. Inhibition of the kinase activity of BCR-ABL, PI3K, or AKT decreased the level of β-catenin in both K562 cells and a CML mouse model and suppressed the transcription of downstream target genes (c-myc and cyclin D1). In addition, inhibition of the BCR-ABL/PI3K/AKT pathway delayed the disease progression in the CML mouse model. To further explore the role of β-catenin in the self-renewal and survival of CML LSCs, we established a secondary transplantation CML mouse model. Our data revealed that inhibition of the BCR-ABL/PI3K/AKT pathway reduced the tumor-initiating ability of K562 cells, decreased leukemia cell infiltration into peripheral blood and bone marrow, and prolonged the survival of mice. In conclusion, our data indicate a close relationship between β-catenin and BCR-ABL/PI3K/AKT in blastic phase CML. β-Catenin inhibition may be of therapeutic value by targeting LSCs in combination with a tyrosine kinase inhibitor, which may delay blastic transformation of CML.

Purpose In patients with chronic myelogenous leukemia (CML), point mutations in the BCR-ABL1 kinase domain are the most common cause of treatment failure with a tyrosine kinase inhibitor (TKI). It is not clear whether the splice variant BCR-ABL135INS is also associated with treatment failure. Patients and methods We reviewed all CML patients who had BCR-ABL1 kinase mutation analysis performed between August 1, 2007, and January 15, 2014. Patients who had BCR-ABL135INS detected had their medical records reviewed to determine response to TKI therapy. Results Two hundred and eighty four patients had kinase mutation testing performed; of these, 64 patients (23%) had BCR-ABL135INS detected. Forty-five patients were in chronic phase (70%), 10 were in accelerated phase (16%), 6 were in blastic phase (9%), and 3 were in other settings (5%). Of the 34 chronic phase patients who began therapy with imatinib, 23 patients (68%) failed therapy: 8 patients (24%) had primary refractory disease, 11 patients (32%) progressed, and 4 patients (12%) had disease progression after dose interruption. In contrast to the patients with disease progression or lack of response, none of 23 patients who were responding to imatinib had BCR-ABL135INS detected. DNA sequencing of commonly mutated spliceosomal genes SF3B1, U2AF1, SRSF2, ZRSR2, SFA31, PRPF408, U2A565, and SF1 did not reveal mutations in seven BCR-ABL135INS –positive patients tested. Conclusions The splice variant BCR-ABL135INS is frequently found in patients who are resistant to imatinib. Mutations in the commonly mutated spliceosomal proteins do not contribute to this association.

Very elderly (> 75years) chronic myeloid leukaemia (CML) patients at diagnosis are sometimes treated with different doses of imatinib (IM) based on concomitant diseases and physicians’ judgement. However, data on long-term follow-up of these patients are still lacking. To investigate treatment response and outcome, we retrospectively revised an Italian database of 263 very elderly CML patients receiving IM from the time of diagnosis. Median age at diagnosis was 78.5years and 56% of patients had 2 or 3 comorbidities. A complete haematological and cytogenetic response were achieved in 244 (92.8%) and 184 (69.9%) patients, respectively. In 148 cases (56.2%), a major molecular response was observed, which was deep in 63 cases (24%). A blastic phase occurred in 11 patients (4.2%). After a median follow-up of 45.0months, 93 patients have died (9 from disease progression) and 104 (39.5%) are still in treatment with IM. Incidence of grades 3–4 haematological and non-haematological toxicity was similar to those reported in younger patients. Five-year event-free survival was 54.5% and 45.2% in patients ≤80years and > 80years, respectively (p = 0.098). Five years OS was 75.7% and 61.6% in patients ≤80years and > 80years, respectively (p = 0.003). These findings show that IM plays an important role in frontline treatment of very elderly CML patients without increased toxicity and any effort to treat these patients with standard doses should be made in order to achieve responses as in younger subjects.