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Background Limited information is available regarding the rate of long-term cardiovascular (CV) mortality in chronic myeloid leukaemia (CML) patients treated with second- and third-generation tyrosine kinase inhibitors (2ndG/3rdG TKIs) in the real-life practice. Methods We identified 656 consecutive CML patients treated with nilotinib, dasatinib, bosutinib and ponatinib. Results The 15-year CV-mortality free survival was 93 ± 2.8%. Age ≥65 years (p = 0.005) and a positive history of CV disease (p = 0.04) were significantly associated with a lower CV-mortality free survival. CV disease accounted for 16.5% and 5% of potential years of life lost (PYLL) in male and female patients, respectively. The standard mortality ratio (SMR) following ischemic heart disease (IHD) was 3.9 in males and 3.8 in female patients, meaning an excess of IHD deaths observed, in comparison with the population of control. Conclusion. Prevention strategies based on CV risk factors, in particular in those patients with a previous history of CV disease, should be considered.

Myeloid neoplasms with eosinophilia and abnormalities of the PDGFRA gene can benefit from therapy with tyrosine kinase inhibitors, therefore revealing the PDGFRA rearrangement is essential to ensure the best choice of treatment. The most common PDGFRA partner is the FIP1L1 gene, generating the oncoprotein FIP1L1/PDGFRA (F/P). In the majority of cases the F/P fusion gene originates from intrachromosomal rearrangement at band 4q12, and occasionally from chromosomal translocations. In both cases, the interstitial chromosomal deletion of a region involving the CHIC2 gene has been reported, which is cryptic by conventional karyotyping but detectable by Fluorescence In Situ Hybridization (FISH) analyses. Herein, we report an acute myeloid leukemia (AML) case presenting with eosinophilia; the F/P fusion gene originated from a new, cryptic and complex intrachromosomal rearrangement of 4q12. Classical FISH assay revealed abnormal hybridization signals, but the presence of the F/P chimaeric gene was demonstrated by molecular analysis. We performed molecular characterization of the chromosomal rearrangement and targeted Next-Generation Sequencing (NGS) analysis with a myeloid gene panel, revealing the presence of pathogenic genomic variants affecting the TET2 and ETV6 genes. These mutations were present as subclones at the disease onset and their clone size increased at relapse.

The antigen-mediated triggering of B cell receptor (BCR) activates the transcription factor NF-κB that regulates the expression of genes involved in B cell differentiation, proliferation, and survival. The tyrosine kinase Btk is essentially required for the activation of NF-κB in BCR signaling through the canonical pathway of IKK-dependent phosphorylation and proteasomal degradation of IκB-α, the main repressor of NF-κB. Here, we provide the evidence of an additional mechanism of NF-κB activation in BCR signaling that is Btk-dependent and IKK-independent. In DeFew B lymphoma cells, the anti-IgM stimulation of BCR activated Btk and NF-κB p50/p65 within 0.5 min in absence of IKK activation and IκB-α degradation. IKK silencing did not affect the rapid activation of NF-κB. Within this short time, Btk associated and phosphorylated IκB-α at Y289 and Y305, and, concomitantly, p65 translocated from cytosol to nucleus. The mutant IκB-α Y289/305A inhibited the NF-κB activation after BCR triggering, suggesting that the phosphorylation of IκB-α at tyrosines 289 and 305 was required for NF-κB activation. In primary chronic lymphocytic leukemia cells, Btk was constitutively active and associated with IκB-α, which correlated with Y305-phosphorylation of IκB-α and increased NF-κB activity compared with healthy B cells. Altogether, these results describe a novel mechanism of NF-κB activation in BCR signaling that could be relevant for Btk-targeted therapy in B-lymphoproliferative disorders. KEY MESSAGES: Anti-IgM stimulation of BCR activates NF-κB p50/p65 within 30 s by a Btk-dependent and IKK-independent mechanism. Btk associates and phosphorylates IκB-α at Y289 and Y305, promoting NF-κB activation. In primary CLLs, the binding of Btk to IκB-α correlates with tyrosine phosphorylation of IκB-α and increased NF-κB activity.

Increasing evidence supports the involvement of IBTK in cell survival and tumor growth. Previously, we have shown that IBTK RNA interference affects the wide genome expression and RNA splicing in cell-type specific manner. Further, the expression of IBTK gene progressively increases from indolent to aggressive stage of chronic lymphocytic leukemia and decreases in disease remission after therapy. However, the role of IBTK in tumorigenesis has not been elucidated. Here, we report that loss of the murine Ibtk gene raises survival and delays tumor onset in Eμ-myc transgenic mice, a preclinical model of Myc-driven lymphoma. In particular, we found that the number of pre-cancerous B cells of bone marrow and spleen is reduced in Ibtk−/−Eμ-myc mice owing to impaired viability and increased apoptosis, as measured by Annexin V binding, Caspase 3/7 cleavage assays and cell cycle profile analysis. Instead, the proliferation rate of pre-cancerous B cells is unaffected by the loss of Ibtk. We observed a direct correlation between Ibtk and myc expression and demonstrated a Myc-dependent regulation of Ibtk expression in murine B cells, human hematopoietic and nonhematopoietic cell lines by analysis of ChIP-seq data. By tet-repressible Myc system, we confirmed a Myc-dependent expression of IBTK in human B cells. Further, we showed that Ibtk loss affected the main apoptotic pathways dependent on Myc overexpression in pre-cancerous Eμ-myc mice, in particular, MCL-1 and p53. Of note, we found that loss of IBTK impaired cell cycle and increased apoptosis also in a human epithelial cell line, HeLa cells, in Myc-independent manner. Taken together, these results suggest that Ibtk sustains the oncogenic activity of Myc by inhibiting apoptosis of murine pre-cancerous B cells, as a cell-specific mechanism. Our findings could be relevant for the development of IBTK inhibitors sensitizing tumor cells to apoptosis.

Background Risk of death is particularly high in patients with a previous history of arterial occlusive events (AOEs) and the probability for a recurrent event is around 20%. Little is known about recurrent AOE and the role of secondary prevention in patients with Chronic Myeloid Leukemia (CML) with previous AOE, treated with second- and third-generation tyrosine kinase inhibitors (2ndG/3rdG TKIs), nilotinib, dasatinib, bosutinib and ponatinib. Methods We identified a real-life cohort of 57 consecutive adult CML patients treated with 2ndG/3rdG TKI. All patients had a previous history of AOE. Ongoing use of secondary prevention of AOE (including antiplatelet agents, anticoagulant therapy, and statins) before starting a 2ndG/3rdG TKI was recorded, as well as CV risk factors. Results The 60-month cumulative incidence rate of recurrent AOEs was 47.8 ± 10.9%. Despite a history of AOE, 10 patients (16%) were not receiving secondary preventative measures. Patients treated with nilotinib and ponatinib showed a higher incidence of recurrent AOEs (76.7 ± 14.3% and 64 ± 20.1%, respectively) than those treated with dasatinib and bosutinib (44 ± 24.2% and 30.5 ± 15.5%, respectively) (p = 0.01). Only treatment with a 2ndG/3rdG TKI given as second or subsequent line therapy showed a significant association with an increased incidence of recurrent AOE (p = 0.039). Overall, 17 recurrent AOEs were observed; 3 CV-related deaths were reported. Conclusion CML patients with a previous history of AOE treated with 2ndG/3rdG TKI represent a particular patient population with a higher probability of experiencing a recurrent AOE; individualized treatment is needed to optimize secondary prevention.

Several papers authored by international experts have proposed recommendations on the management of BCR-ABL1+ chronic myeloid leukemia (CML). Following these recommendations, survival of CML patients has become very close to normal. The next, ambitious, step is to bring as many patients as possible into a condition of treatment-free remission (TFR). The Gruppo Italiano Malattie EMatologiche dell’Adulto (GIMEMA; Italian Group for Hematologic Diseases of the Adult) CML Working Party (WP) has developed a project aimed at selecting the treatment policies that may increase the probability of TFR, taking into account 4 variables: the need for TFR, the tyrosine kinase inhibitors (TKIs), the characteristics of leukemia, and the patient. A Delphi-like method was used to reach a consensus among the representatives of 50 centers of the CML WP. A consensus was reached on the assessment of disease risk (EUTOS Long Term Survival [ELTS] score), on the definition of the most appropriate age boundaries for the choice of first-line treatment, on the choice of the TKI for first-line treatment, and on the definition of the responses that do not require a change of the TKI (BCR-ABL1 ≤10% at 3 months, ≤1% at 6 months, ≤0.1% at 12 months, ≤0.01% at 24 months), and of the responses that require a change of the TKI, when the goal is TFR (BCR-ABL1 >10% at 3 and 6 months, >1% at 12 months, and >0.1% at 24 months). These suggestions may help optimize the treatment strategy for TFR.

Arterial occlusive events (AOEs) represent emerging complications in chronic myeloid leukemia (CML) patients treated with ponatinib. We identified 85 consecutive CML adult patients who were treated with ponatinib in 17 Italian centers. Patients were stratified according to the Systematic Coronary Risk Evaluation (SCORE) assessment, based on sex, age, smoking habits, systolic blood pressure, and total cholesterol levels. The 60-month cumulative incidence rate of AOEs excluding hypertension was 25.7%. Hypertension was reported in 14.1% of patients. The median time of exposure to ponatinib was 28months (range, 3-69months). Patients with a high to very high SCORE risk showed a significantly higher incidence rate of AOEs (74.3% vs 15.2%, P&nbsp

We performed a nationwide registry-based analysis to describe the clinical outcome of adult patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) who underwent an allogeneic hematopoietic stem cell transplantation (HSCT) after a tyrosine kinase inhibitor (TKI)-based treatment A total of 441 patients were included in the study. The median age at HSCT was 44 years (range, 18 to 70 years). All 441 patients (100%) received TKI before HSCT (performed between 2005 and 2016). Of these 441 patients, 404 (92%) were in cytologic complete remission (CR), whereas the remaining 37 (8%) had active disease at the time of HSCT. Molecular minimal residual disease (MRD) was negative in 147 patients (36%) at the time of HSCT. The donor was unrelated in 46% of patients. The most prevalent source of stem cells was peripheral blood (70%). The conditioning regimen was myeloablative in 82% of cases (total body irradiation-based in 50%) and included antithymocyte globulin in 51% of patients. With a median follow-up after HSCT of 39.4 months (range, 1 to 145 months), the probability of overall survival (OS) at 1, 2, and 5 years was 69.6%, 61.1% and 50.3%, respectively, with a median OS of 62 months. Progression-free survival (PFS) at 1, 2, and 5 years was 60.2%, 52.1% and 43.7%, respectively. OS and PFS were significantly better in patients who were in CR and MRD-negative at the time of HSCT compared with patients who were in CR but MRD-positive (50% OS not reached versus 36 months; P = .015; 50% PFS not reached versus 26 months, P = .003). The subgroup of MRD-negative patients both at HSCT and at 3 months after HSCT had a better outcome (5-year OS, 70%). Conversely, the 37 patients who underwent a HSCT with active Ph+ ALL had a median OS of 7 months and a median PFS of 5 months. The 5-year cumulative incidence of relapse was significantly lower in MRD-negative patients (19.5% versus 35.4%; P = .001). Nonrelapse mortality (NRM) after 1, 2, and 5 years was 19.1% (95% confidence interval [CI], 15.5% to 22.9%), 20.7% (95% CI, 17% to 24.7%), and 24.1% (95% CI, 20% to 28.5%), respectively. NRM was significantly lower with a modified European Society for Blood and Marrow Transplantation (mEBMT) risk score of 0 to 2 compared with ≥3 (15% versus 25%; P = .016). The median OS for Ph+ ALL patients who underwent a TKI-based treatment followed by an allogeneic HSCT, in recent years at the GITMO centers, was 62 months. Evaluation of the mEBMT risk score can be useful to predict NRM. Our data confirm that HSCT is a potentially curative treatment for Ph+ ALL with an excellent outcome for the subgroup of MRD-negative patients both at HSCT and at 3 months after HSCT (5-year OS, 70%).

We designed a trial in which postremission therapy of young patients with de novo acute myeloid leukemia (AML) was decided combining cytogenetics/genetics and postconsolidation levels of minimal residual disease (MRD). After induction and consolidation, favorable-risk patients (FR) were to receive autologous stem cell transplant (AuSCT) and poor-risk patients (PR) allogeneic stem cell transplant (AlloSCT). Intermediate-risk patients (IR) were to receive AuSCT or AlloSCT depending on the postconsolidation levels of MRD. Three hundred sixty-one of 500 patients (72%) achieved a complete remission, 342/361 completed the consolidation phase and were treatment allocated: 165 (48%) to AlloSCT (122 PR, 43 IR MRD-positive) plus 23 rescued after salvage therapy, for a total of 188 candidates; 150 (44%) to AuSCT (115 FR, 35 IR MRD-negative) plus 27 IR patients (8%) with no leukemia-associated phenotype, for a total of 177 candidates. Overall, 110/177 (62%) and 130/188 (71%) AuSCT or AlloSCT candidates received it, respectively. Two-year overall (OS) and disease-free survival (DFS) of the whole series was 56% and 54%, respectively. Two-year OS and DFS were 74% and 61% in the FR category, 42% and 45% in the PR category, 79% and 61% in the IR MRD-negative category, and 70% and 67% in the IR MRD-positive category. In conclusion, AuSCT may still have a role in FR and IR MRD-negative categories. In the IR MRD-positive category, AlloSCT prolongs OS and DFS to equal those of the FR category. Using all the available sources of stem cells, AlloSCT was delivered to 71% of the candidates.This trial was registered at www.clinicaltrials.gov as #NCT01452646 and EudraCT as #2010-023809-36.

Evidence of shared epitopic reactivity among independent B-cell clones in chronic lymphocytic leukemia patients

The introduction of second-generation tyrosine-kinase inhibitors (TKIs) has generated a lively debate on the choice of first-line TKI in chronic phase, chronic myeloid leukemia (CML). Despite the TKIs have different efficacy and toxicity profiles, the planned use of two TKIs has never been investigated. We report on a phase 2 study that was designed to evaluate efficacy and safety of a treatment alternating nilotinib and imatinib, in newly diagnosed BCR-ABL1 positive, chronic phase, CML patients. One hundred twenty-three patients were enrolled. Median age was 56 years. The probabilities of achieving a complete cytogenetic response, a major molecular response, and a deep molecular response (MR 4.0) by 2 years were 93%, 87%, and 61%, respectively. The 5-year overall survival and progression-free survival were 89%. Response rates and survival are in the range of those reported with nilotinib alone. Moreover, we observed a relatively low rate of cardiovascular adverse events (5%). These data show that the different efficacy and toxicity profiles of TKIs could be favorably exploited by alternating their use. Am. J. Hematol. 91:617-622, 2016. © 2016 Wiley Periodicals, Inc.

In chronic myeloid leukemia (CML) and Philadelphia-positive (Ph+) acute lymphoblastic leukemia (ALL) patients who fail imatinib treatment, BCR-ABL1 mutation profiling by Sanger sequencing (SS) is recommended before changing therapy since detection of specific mutations influences second-generation tyrosine kinase inhibitor (2GTKI) choice. We aimed to assess i) in how many patients who relapse on second-line 2GTKI therapy next generation sequencing (NGS) may track resistant mutations back to the sample collected at the time of imatinib resistance, before 2GTKI start (switchover sample) and ii) whether low level mutations identified by NGS always undergo clonal expansion. To this purpose, we used NGS to retrospectively analyze 60 imatinib-resistant patients (CML, n = 45; Ph+ ALL, n = 15) who had failed second-line 2GTKI therapy and had acquired BCR-ABL1 mutations (Group 1) and 25 imatinib-resistant patients (CML, n = 21; Ph+ ALL, n = 4) who had responded to second-line 2GTKI therapy, for comparison (Group 2). NGS uncovered that in 26 (43%) patients in Group 1, the 2GTKI-resistant mutations that triggered relapse were already detectable at low levels in the switchover sample (median mutation burden, 5%; range 1.1%–18.4%). Importantly, none of the low level mutations detected by NGS in switchover samples failed to expand whenever the patient received the 2GTKI to whom they were insensitive. In contrast, no low level mutation that was resistant to the 2GTKI the patients subsequently received was detected in the switchover samples from Group 2. NGS at the time of imatinib failure reliably identifies clinically relevant mutations, thus enabling a more effective therapeutic tailoring.

The connection between autoimmune disease (AID) and lymphoproliferative disorders is a complex bidirectional relationship that has long been a focus of attention by researchers and physicians. Although advances in pathobiology knowledge have ascertained an AID role in the development of lymphoproliferative diseases developing, results about AID influence on the prognosis of lymphoma are discordant. In this review, we collect the most relevant literature debating a direct or indirect link between immune-mediated diseases and lymphoma prognosis. We also consider the molecular, genetic, and microenvironmental factors involved in the pathobiology of these diseases in order to gain a deeper understanding of the nature of this link.

Simple Summary Immunomodulatory drugs (IMiDs) are a class of molecules composed of thalidomide and its analogs. There is a growing interest in IMiDs on the treatment of acute myeloid leukemia (AML) patients. As AML has a worse prognosis, especially in elderly patients, novel drugs such as IMiDs, as monotherapy or combination with standard induction chemotherapy or hypomethylating agents, are urgently needed. The effect of IMiDs on AML immunosurveillance seems to be the clue to understanding their clinical application in this setting. We describe the several IMiDs currently available and also future directions. Clinical trials have to find the optimal dosing and schedule and combination agents to improve response rates with the use of IMiDs and, finally, survival in patients with AML. Abstract Immunomodulatory drugs (IMiDs) are analogs of thalidomide. They have immunomodulatory, antiangiogenic and proapoptotic properties and exert a role in regulating the tumor microenvironment. Recently IMiDs have been investigated for their pleiotropic properties and their therapeutic applications in both solid tumors (melanoma, prostate carcinoma and differentiated thyroid cancer) and hematological malignancies. Nowadays, they are applied in de novo and relapsed/refractory multiple myeloma, in myelodysplastic syndrome, in del5q syndrome with specific use of lenalidomide and B-cell lymphoma. Several studies have been conducted in the last few years to explore IMiDs possible use in acute myeloid leukemia treatment. Here we report the mechanisms of action of IMiDs in acute myeloid leukemia and their potential future therapeutic application in this disease.

The high mobility group AT-Hook (HMGA) proteins are a family of nonhistone chromatin remodeling proteins known as “architectural transcriptional factors”. By binding the minor groove of AT-rich DNA sequences, they interact with the transcription apparatus, altering the chromatin modeling and regulating gene expression by either enhancing or suppressing the binding of the more usual transcriptional activators and repressors, although they do not themselves have any transcriptional activity. Their involvement in both benign and malignant neoplasias is well-known and supported by a large volume of studies. In this review, we focus on the role of the HMGA proteins in hematological malignancies, exploring the mechanisms through which they enhance neoplastic transformation and how this knowledge could be exploited to devise tailored therapeutic strategies.

The digital polymerase chain reaction (dPCR) is considered to be the third-generation polymerase chain reaction (PCR), as it yields direct, absolute and precise measures of target sequences. dPCR has proven particularly useful for the accurate detection and quantification of low-abundance nucleic acids, highlighting its advantages in cancer diagnosis and in predicting recurrence and monitoring minimal residual disease, mostly coupled with next generation sequencing. In the last few years, a series of studies have employed dPCR for the analysis of hematologic malignancies. In this review, we will summarize these findings, attempting to focus on the potential future perspectives of the application of this promising technology.

JAK2 V617F mutational status is an essential diagnostic index in myeloproliferative neoplasms (MPNs). Although widely used for detection of JAK2 V617F mutation in peripheral blood (PB), sensitive real-time quantitative PCR (qPCR) presents some methodological limitations. Recently, emerging alternative technologies, like digital droplet PCR (ddPCR), have been reported to overcome some of qPCR&rsquo, s technical drawbacks. The purpose of this study was to compare the diagnostic utility of ddPCR to qPCR for JAK2 V617F detection and quantification in samples from MPNs patients. Sensitivity and specificity of qPCR and ddPCR in the detection of the mutation were assessed by using a calibrator panel of mutated DNA on 195 JAK2 positive MPN samples. Based on our results, ddPCR proved to be a suitable, precise, and sensitive method for detection and quantification of the JAK2 V617F mutation.

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Acute myeloid leukemia (AML) clinical settings cannot do without molecular testing to confirm or rule out predictive biomarkers for prognostic stratification, in order to initiate or withhold targeted therapy. Next generation sequencing offers the advantage of the simultaneous investigation of numerous genes, but these methods remain expensive and time consuming. In this context, we present a nanopore-based assay for rapid (24 h) sequencing of six genes (NPM1, FLT3, CEBPA, TP53, IDH1 and IDH2) that are recurrently mutated in AML. The study included 22 AML patients at diagnosis, all data were compared with the results of S5 sequencing, and discordant variants were validated by Sanger sequencing. Nanopore approach showed substantial advantages in terms of speed and low cost. Furthermore, the ability to generate long reads allows a more accurate detection of longer FLT3 internal tandem duplications and phasing double CEBPA mutations. In conclusion, we propose a cheap, rapid workflow that can potentially enable all basic molecular biology laboratories to perform detailed targeted gene sequencing analysis in AML patients, in order to define their prognosis and the appropriate treatment.

Chronic lymphocytic leukaemia (CLL) is the most common B-cell malignancy with a variable clinical outcome. Biomarkers of CLL progression are required for optimising prognosis and therapy. The Inhibitor of Bruton’s tyrosine kinase—isoform α (IBTKα) gene encodes a substrate receptor of Cullin 3-dependent E3 ubiquitin ligase, and promotes cell survival in response to the reticulum stress. Searching for novel markers of CLL progression, we analysed the expression of IBTKα in the peripheral blood B-cells of CLL patients, before and after first line therapy causing remission. The expression of IBTKα was significantly increased in disease progression, and decreased in remission after chemotherapy. Consistently with a pro-survival action, RNA interference of IBTKα increased the spontaneous and Fludarabine-induced apoptosis of MEC-1 CLL cells, and impaired the cell cycle of DeFew B-lymphoma cells by promoting the arrest in G0/G1 phase and apoptosis. Consistently, RNA interference of IBTKα up regulated the expression of pro-apoptotic genes, including TNF, CRADD, CASP7, BNIP3 and BIRC3. Our results indicate that IBTKα is a novel marker of CLL progression promoting cell growth and resistance to apoptosis. In this view, IBTKα may represent an attractive cancer drug target for counteracting the therapy-resistance of tumour cells.

Protein ubiquitylation plays a central role in eukaryotic cell physiology. It is involved in several regulatory processes, ranging from protein folding or degradation, subcellular localization of proteins, vesicular trafficking and endocytosis to DNA repair, cell cycle, innate immunity, autophagy, and apoptosis. As such, it is reasonable that pathogens have developed a way to exploit such a crucial system to enhance their virulence against the host. Hence, bacteria have evolved a wide range of effectors capable of mimicking the main players of the eukaryotic ubiquitin system, in particular ubiquitin ligases, by interfering with host physiology. Here, we give an overview of this topic and, in particular, we detail and discuss the mechanisms developed by pathogenic bacteria to hijack the host ubiquitination system for their own benefit.

Introduction: Bosutinib is a Src/Abl tyrosine kinase inhibitor (TKI) currently licensed for patients with Ph+ chronic-phase (CP), accelerated-phase (AP), or blast-phase (BP) Chronic Myeloid Leukemia after failure or intolerance to at least 2 other TKIs. It can also be prescribed, in accordance with label if, after failure of the first TKI therapy, another option does not seem feasible. Previous studies demonstrated a potent activity of second-line bosutinib across a spectrum of BCR-ABL1 mutations and a distinct toxicity profile compared to other TKIs. Aim: We retrospectively assessed the efficacy and safety of real life Bosutinib administration in 85 patients resistant/refractory or intolerant to other TKIs, referred to 22 Italian Hematological Institutions. The main features at Bosutinib start are reported in the Table. Results: At Bosutinib start, all patients were in CP. 60 patients (71%) were resistant/refractory, 25 (29%) were intolerant to previous TKIs. BCR-ABL1 kinase mutations were reported in 5/35 evaluable patients (14%); no T315I was reported. The number of previous TKIs was less than 3 in 24/85 patients (28%) and 3 or more in 61 (72%). Comorbidities were present in 63 patients (74%), the most common being arterial hypertension (40), diabetes (14), cardiac disease (10) and chronic obstructive pulmonary disease (6). The most frequent concomitant medications were: antihypertensive in 55% patients, antiplatelets in 26%, antidiabetic in 19%. The initial dose was 100 mg in 4/85 patients (5%), 200 mg in 24 (28%), 300 mg in 18 (22%), 400 in 8 (9%); 31 patients (36%) started at the full standard dose of 500 mg. Major Molecular Response (MMR)/Deep Molecular Response (DMR) were achieved by 37/80 (46%) evaluable patients; 43/80 patients (54%) never reached a MMR/DMR at any time. Best responses in these cases were: Complete Hematologic Response (CHR) in 4 patients (9%), Partial Cytogenetic Response (PCyR) in 6 (14%), Complete Cytogenetic Response (CCyR) in 10 (23%). Dose reductions were necessary in 4 patients (5%) due to adverse events (2 cases of diarrhea, 1 transaminase elevation, 1 skin rash). After a median follow-up of 26 months (range 3-49), 75/85 patients (88%) are alive and 54/75 patients (72%) are still in treatment. Discontinuations were due to: intolerance in 8/75 patients (11%), loss of response in 3/75 (4%), resistance to therapy in 10/75 (13%). Hematological toxicity was observed in 14 patients (16%), any grade, and grade 3-4 in 3 (3%). Extra-hematological toxicity was reported in 41/85 patients (48%), any grade, and grade 3-4 in 14 patients (16%). Causes of death were: acute myocardial infarction (3), cardiac failure (2), acute respiratory distress (2), allogeneic transplant complications (1), cerebral hemorrhage (2). Conclusions: In our "real life experience" with Bosutinib, we confirm a stable long-term efficacy in heavily pre-treated, mainly elderly patients with intolerance/resistance to other TKIs, who show an initial response to treatment, as reported in clinical trials. Patients show a fast response to the drug (mainly at three months). Hematological and extrahematological toxicities are manageable. Disclosures Breccia: BMS: Honoraria; Incyte: Honoraria; Pfizer: Honoraria; Novartis: Honoraria. Abruzzese:Novartis: Consultancy; Ariad: Consultancy; BMS: Consultancy; Pfizer: Consultancy. Castagnetti:Bristol Meyers Squibb: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Incyte: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Bonifacio:Novartis: Research Funding; Amgen: Consultancy; Pfizer: Consultancy; Incyte: Consultancy; Bristol Myers Squibb: Consultancy.

The molecular basis of advanced systemic mastocytosis (SM) is not fully understood and despite novel therapies the prognosis remains dismal. Exome sequencing of an index-patient with mast cell leukemia (MCL) uncovered biallelic loss-of-function mutations in the SETD2 histone methyltransferase gene. Copy-neutral loss-of-heterozygosity at 3p21.3 (where SETD2 maps) was subsequently found in SM patients and prompted us to undertake an in-depth analysis of SETD2 copy number, mutation status, transcript expression and methylation levels, as well as functional studies in the HMC-1 cell line and in a validation cohort of 57 additional cases with SM, including MCL, aggressive SM and indolent SM. Reduced or no SETD2 protein expression-and consequently, H3K36 trimethylation-was found in all cases and inversely correlated with disease aggressiveness. Proteasome inhibition rescued SETD2 expression and H3K36 trimethylation and resulted in marked accumulation of ubiquitinated SETD2 in SETD2-deficient patients but not in patients with near-normal SETD2 expression. Bortezomib and, to a lesser extent, AZD1775 alone or in combination with midostaurin induced apoptosis and reduced clonogenic growth of HMC-1 cells and of neoplastic mast cells from advanced SM patients. Our findings may have implications for prognostication of SM patients and for the development of improved treatment approaches in advanced SM.Leukemia advance online publication, 30 June 2017; doi:10.1038/leu.2017.183.

Most acute promyelocytic leukemia (APL) patients express PML-RARA fusion; in rare cases, RARA is rearranged with partner genes other than PML. To date, only 2 patients presenting features similar to APL showing the RARG gene rearrangement have been described. We report an acute myeloid leukemia patient with morphology resembling APL without involvement of the RARA gene. Molecular and fluorescent in situ hybridization analyses excluded PML-RARA fusion and variant rearrangements involving RARA and RARG loci. Targeted next-generation sequencing showed EZH2- D185H mutation. As this mutation involved the region of interaction with DNA methyltransferases, we speculate an epigenetic alteration of genes involved in the APL-like phenotype. Expression analysis by droplet digital polymerase chain reaction revealed downregulation of the RARA and RARG genes. We hypothesize a novel mechanism of EZH2 function alteration, which may be responsible for an acute myeloid leukemia with APL-like phenotype featuring dysregulation of the RARA and RARG genes.

// Alessandra Capasso 1, * , Carmen Cerchia 2, * , Carmen Di Giovanni 2 , Giuseppina Granato 1 , Francesco Albano 1 , Simona Romano 1 , Emmanuele De Vendittis 1 , Maria Rosaria Ruocco 1 , Antonio Lavecchia 2 1 Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, 80131 Naples, Italy 2 Department of Pharmacy, “Drug Discovery” Laboratory, University of Naples Federico II, 80131 Naples, Italy * These authors have contributed equally to this work Correspondence to: Maria Rosaria Ruocco, e-mail: mariarosaria.ruocco2@unina.it Antonio Lavecchia, e-mail: antonio.lavecchia@unina.it Keywords: cancer, CDC25 phosphatases, drug discovery, cell cycle, melanoma cells Received: April 26, 2015 Accepted: October 02, 2015 Published: October 13, 2015 ABSTRACT CDC25 phosphatases are important regulators of the cell cycle and represent promising targets for anticancer drug discovery. We recently identified NSC 119915 as a new quinonoid CDC25 inhibitor with potent anticancer activity. In order to discover more active analogs of NSC 119915, we performed a range of ligand-based chemoinformatic methods against the full ZINC drug-like subset and the NCI lead-like set. Nine compounds (3, 5–9, 21, 24, and 25) were identified with K i values for CDC25A, -B and -C ranging from 0.01 to 4.4 μM. One of these analogs, 7, showed a high antiproliferative effect on human melanoma cell lines, A2058 and SAN. Compound 7 arrested melanoma cells in G2/M, causing a reduction of the protein levels of CDC25A and, more consistently, of CDC25C. Furthermore, an intrinsic apoptotic pathway was induced, which was mediated by ROS, because it was reverted in the presence of antioxidant N-acetyl-cysteine (NAC). Finally, 7 decreased the protein levels of phosphorylated Akt and increased those of p53, thus contributing to the regulation of chemosensitivity through the control of downstream Akt pathways in melanoma cells. Taken together, our data emphasize that CDC25 could be considered as a possible oncotarget in melanoma cells and that compound 7 is a small molecule CDC25 inhibitor that merits to be further evaluated as a chemotherapeutic agent for melanoma, likely in combination with other therapeutic compounds.

The BCR-ABL1 fusion on the Philadelphia (Ph) chromosome is a hallmark of chronic myeloid leukemia (CML). More than 95 % of BCR-ABL1 transcripts in CML are either e13a2 or e14a2 (major breakpoint cluster region or M-bcr), whereas rare BCR-ABL1 transcripts are occasionally observed, accounting for less than 1 % of CML cases. Among these, a very rare fusion transcript joining the first 6 exons of BCR to exon 2 of ABL1 (e6a2) has been reported in various hematological malignancies characterized by an aggressive clinical course. We report a new case of blast crisis (BC) CML with an e6a2 fusion transcript characterized by many eosinophil precursors with abnormal granules. Moreover, fluorescence in situ hybridization analysis revealed genomic deletions of 1.3 megabases and 342 kilobases on der(9) of chromosome 9 and 22 sequences, respectively. The fusion transcript was quantified at diagnosis and during follow-up using digital droplet polymerase chain reaction (ddPCR) technology. The patient was treated with Dasatinib (140 mg/day), resulting in a 3-log reduction of the e6a2 transcript molecular burden from the third month after treatment. In this twentieth e6a2 case, characterized by marked eosinophilic dysplasia, deletions on der(9), and responsive to tyrosine kinase inhibitors therapy, we demonstrate that for molecular response monitoring of rare fusion transcripts associated with CML, ddPCR is a very useful technology.

Introduction Some retrospective studies in tyrosine kinase inhibitor (TKI)-resistant Philadephia-positive (Ph+) leukemia patients (pts) have suggested that deep sequencing (DS) may provide a more accurate picture of BCR-ABL1 kinase domain (KD) mutation status as compared to conventional sequencing (CS). However, the frequency and clinical relevance of low burden mutations remains to be explored prospectively in large series of unselected pts. In addition, the implementation of routine BCR-ABL1 DS in multiple molecular diagnostic laboratories has never been attempted. These open issues led us to design a multi-center, multi-laboratory prospective study ('NEXT-IN-CML') aimed to assess the feasibility, performance and informativity of DS for BCR-ABL1 KD mutation screening. Aims The first phase of the study was aimed to establish a network of 5 reference labs sharing a standardized DS workflow, a joint database for clinical and mutational data storage and a common pipeline of data analysis, interpretation and clinical reporting. The second phase of the study, involving 54 Italian Hematology Units, is aimed to assess the frequency and clinical significance of low burden mutations detectable by DS by prospective collection and analysis of samples from chronic myeloid leukemia (CML) pts who exhibit failure (F) or warning (W) responses and relapsed Ph+ acute lymphoblastic leukemia (ALL) pts. Methods A PCR and an amplicon DS protocol already set up and optimized for the Roche GS Junior in the framework of the IRON II international consortium was adopted. In the first phase, 5 batches of blinded cDNA samples were prepared and shipped to evaluate individual lab performances. The batches included archival samples with known BCR-ABL1 mutation status as assessed by CS and serial dilutions of BaF3 T315I+ cells in BaF3 unmutated cells, simulating mutation loads of 20% down to 1%. In the ongoing second phase prospectively, consecutively collected CML and Ph+ ALL samples are being analyzed in parallel by CS and DS. Clinical history and follow-up data are used for correlations. Results In the first phase of the study, 312/320 amplicons were successfully generated and sequenced. A median of 124,686 (range, 48,181-170,687) high quality reads were obtained across the 5 labs. Median number of forward and reverse reads was 1,757 (range 884-7,838), with no coverage dropouts for any amplicon or index. Comparison of observed vs expected mutations showed that 76/78 evaluable samples were accurately scored. In the remaining two, the analysis software failed to detect the 35bp insertion ('35INS') commonly detectable between exons 8 and 9. Quantitation of point mutation burden was highly reproducible across the entire range of frequencies, from 100% to 1%. The second phase of the study has started in Jan 2016. As of Jul 31st, a total of 106 consecutive pts (CML, n=96; Ph+ ALL, n=10) have been enrolled. The present analysis focuses on the first 75 CML pts (60 F and 15 W), for whom sequencing results are currently available (analysis of the entire population of patients enrolled up to Nov 2016 will be presented at the meeting). Clinically actionable mutations have been detected in 10/75 (14%) pts by CS and in 20/75 pts (27%) by DS. Notably, among the 10 pts positive for clinically actionable mutations by DS but not by CS, 3 had a low burden T315I (2 F [dasatinib, imatinib] and 1 W [dasatinib]). In 5 additional pts negative for mutations by CS (3 F and 2 W), DS identified multiple low burden mutations with unknown IC50, suggesting that the cooperation of individually 'weak' mutants may be a new mechanism underlying reduced TKI efficacy. Longitudinal analysis and follow-up of pts are shaping the clinical significance of different types of low burden mutations and will be presented. Conclusions The 'NEXT-in-CML' study is demonstrating that DS of BCR-ABL1 can successfully be implemented in national lab networks and is an important step forward towards routine use of this technology. We have now adapted the protocol for both the Ion Torrent PGM and the Illumina Miseq platforms. For a minimum of 15 samples per sequencing run, DS costs are estimated to equal those of CS (cost per sample, reagents only: ≈100€ for PGM (314 chip) and Miseq (nano kit v2) vs ≈95€ for CS) with comparable turnaround times for delivery of results. Our study is also contributing useful data for the clinical interpretation of DS findings. Disclosures Soverini: Bristol-Myers Squibb: Consultancy; Ariad: Consultancy; Novartis: Consultancy. Castagnetti:ARIAD Pharmaceuticals: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria. Ciceri:MolMed SpA: Consultancy. Breccia:Novartis: Consultancy, Honoraria; Bristol Myers Squibb: Honoraria; Celgene: Honoraria; Ariad: Honoraria; Pfizer: Honoraria. Di Raimondo:Janssen-Cilag: Honoraria. Bassan:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria; Ariad: Honoraria, Membership on an entity's Board of Directors or advisory committees. Cavo:Millennium: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Janssen-Cilag: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Rosti:Novartis: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Ariad: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria. Baccarani:Novartis: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria. Saglio:Roche: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; ARIAD: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Martinelli:Ariad: Consultancy, Speakers Bureau; Pfizer: Consultancy, Speakers Bureau; Roche: Consultancy, Speakers Bureau; Novartis: Speakers Bureau; BMS: Speakers Bureau; Celgene: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; MSD: Consultancy; Genentech: Consultancy.

Background Patients with primary refractory or first relapse acute myeloid leukemia (AML) are considered to have worse clinical outcomes after treatment. For these patients, the achievement of complete remission appears crucial for them to be able to undergo allotransplantation, which might be the only possible treatment. Patients and Methods We used the FLAG-Ida (fludarabine, cytarabine [cytosine arabinoside], granulocyte colony-stimulating factor, idarubicin) regimen in patients with primary refractory/first relapse AML as a bridge to transplantation. We studied its efficacy in terms of overall response and overall survival to assess which variables (age, lactate dehydrogenase, bone marrow blast count, peripheral blood blast count, platelet count, white blood cell count, de novo or secondary AML, molecular-cytogenetic risk, duration of response, and relapsed or refractory disease) might have an effect on outcome. Results We analyzed the data from 108 consecutive adult patients (52 males, 66 females; median age, 49 years; range, 17-72 years) with newly diagnosed AML refractory to standard induction regimens or relapse after first complete remission, who had received the FLAG-Ida protocol as salvage therapy from January 2005 to December 2015. An overall response was achieved in 48 patients (44%). On multivariate analysis, the variables with a positive effect on the response rate were molecular-cytogenetic risk ( P = .009), duration of first response in relapsed AML ( P = .003), AML status (relapsed or refractory; P = .047), and peripheral blood blast count ( P = .016). On multivariate analysis, overall survival was significantly associated with FLAG-Ida response (hazard ratio, 0.343; P = .001) and receipt of allotransplantation (hazard ratio, 0.277; P Conclusion Our data seem to confirm the value of FLAG-Ida in this setting and might suggest its best usage as bridge therapy for patients awaiting allotransplantation.

Polycythemia vera (PV) and essential thrombocythemia (ET) are myeloproliferative neoplasms with variable risk of evolution into post-PV and post-ET myelofibrosis, from now on referred to as secondary myelofibrosis (SMF). No specific tools have been defined for risk stratification in SMF. To develop a prognostic model for predicting survival, we studied 685 JAK2, CALR, and MPL annotated patients with SMF. Median survival of the whole cohort was 9.3 years (95% CI: 8-not reached-NR-). Through penalized Cox regressions we identified negative predictors of survival and according to beta risk coefficients we assigned 2 points to hemoglobin level

Driver mutations’ effect in secondary myelofibrosis: an international multicenter study based on 781 patients

The majority of patients with chronic myeloid leukemia are successfully managed with life-long treatment with tyrosine kinase inhibitors. In patients in chronic phase, other malignancies are among the most common causes of death, raising concerns on the relationship between these deaths and the off-target effects of tyrosine kinase inhibitors. We analyzed the incidence of second primary malignancies, and related mortality, in 514 chronic myeloid leukemia patients enrolled in clinical trials in which imatinib was given as first-line treatment. We then compared the observed incidence and mortality with those expected in the age- and sex-matched Italian general population, calculating standardized incidence and standardized mortality ratios. After a median follow-up of 74 months, 5.8% patients developed second primary malignancies. The median time from chronic myeloid leukemia to diagnosis of the second primary malignancies was 34 months. We did not find a higher incidence of second primary malignancies compared to that in the age- and sex-matched Italian general population, with standardized incidence ratios of 1.06 (95% CI: 0.57–1.54) and 1.61 (95% CI: 0.92–2.31) in males and females, respectively. Overall, 3.1% patients died of second primary malignancies. The death rate in patients with second primary malignancies was 53% (median overall survival: 18 months). Among females, the observed cancer-related mortality was superior to that expected in the age- and sex-matched Italian population, with a standardized mortality ratio of 2.41 (95% CI: 1.26 – 3.56). In conclusion, our analysis of patients with imatinib-treated chronic myeloid leukemia did not reveal a higher incidence of second primary malignancies; however, the outcome of second primary malignancies in such patients was worse than expected. Clinicaltrials.gov: NCT00514488, NCT00510926.

Bcl-6 translocation is a genetic alteration that is commonly detected in Primary Central Nervous System Lymphoma. The role of this protein in cerebral tumors is unclear. In this study we investigated Bcl-6 translocation and its transcriptional and translational levels in formalin-fixed, paraffin-embedded cerebral tissue sections from glioblastoma (GBM), low-grade glioma (Astrocytoma grade II and III), and meningioma patients, and correlated them with apoptotic processes and p53 and caspase-3 expression. The results showed a frequency of 36.6% of Bcl-6 translocation in GBM patients and a decreased expression in low-grade glioma patients, correlated with the severity of the disease. Bcl-6 translocation induced an overexpression of both Bcl-6 protein and messenger in GBM, inhibiting apoptotic processes and caspases 3 expression. On the contrary, in low-grade gliomas and meningiomas Bcl-6 expression was reduced, resulting in an increase of apoptotic processes. Finally, p53 expression levels in brain tumors were comparable to Bcl-6 levels. Overall, these data demonstrate, for the first time, that the Bcl-6 gene translocates in GBM patients and that its translocation and expression are correlated with apoptosis inhibition, indicating a key role for this gene in the control of cellular proliferation. This study offers further insights into glioblastoma biology, and supports Bcl-6 as a new diagnostic marker to evaluate the disease severity.

Introduction IBtk acts as substrate receptor of a Cullin 3-dependent E3 ligase, and promotes proteasomal degradation of Pdcd4, a translation inhibitor. There are evidences that IBtk is involved in cell survival. RNA interference of IBtk reduced viability of Ras-positive colorectal cancer cells and mouse embryonic fibroblasts under reticulum stress. Differential methylation of the IBtk genomic region was reported for U-CLL (Unmutated-Chronic Lymphocytic Leukaemia) and M-CLL (Mutated-Chronic Lymphocytic Leukaemia),suggesting a possible correlation between the IBtk expression levels and aggressiveness of disease. Recently, we provided the evidence of IBtk as a prognostic marker of CLL progression. Material and methods Ibtk-/- mice were bred with congenic Em-myc transgenic mice, a pre-clinical mouse model of Non-Hodgkin’s Lymphoma, to generate Ibtk-/-Em-myc mice, which were monitored for survival and tumour development. We used flow-cytometry for B cells immunophenotyping. Primary murine B cells were compared using different approaches: proliferation, cell viability and cell death assays. Results and discussions Our data provide the evidence that Ibtk gene increases survival and delays tumour onset in Eμ-myc mice.Ibtk-/-Em-myc mice mostly developed pre-B lymphoma and to a lesser extent mature B lymphoma, which was consistent with the tumour phenotype of Em-myc mice.Loss of Ibtk substantially reduced the number of premalignant B-lymphoid cells without affecting their proliferation rate. In particular, pre-cancerous immature B cells were reduced in bone marrow and spleen of Ibtk-/-Em-myc compared to Ibtk+/+Em myc mice.In Em-myc mice, the pre-cancerous state is characterised by aberrant proliferation of B-lymphoid cells, which is initially offset by pro-apoptotic action of c-Myc.We have previously shown that the enhanced expression of IBtk in CLL cells down regulate the expression of pro-apoptotic genes, thus counteracting apoptosis.According to this hypothesis, we found an increased spontaneous apoptosis of pre-cancerous Ibtk-/-Em-myc B cells ex vivo and in vitro without added cytokines. Conclusion c-Myc is abnormally expressed in a great majority of human cancers. The evidence that IBtk promotes the survival of c-Myc–driven premalignant B cells could have general implications for oncogenesis. Our findings support a synergistic role of IBtk in Myc-driven B-lymphomagenesis conferring resistance to apoptosis.In summary, this study provides the rationale for novel therapeutic approaches of B-lymphoma.

H3K36 tri-methylation by SETD2 has been linked to a plethora of pathways critical for the regulation of a multitude of cellular processes, including transcription, DNA replication and DNA repair after damage, yet the functional implications of perturbed H3K36 tri-methylation by SETD2 mutations or non-genomic loss of function in leukemia are still unclear. We have previously reported that the HMC-1.1 and -1.2 mast cell leukemia (MCL) cell lines and many patients (pts) with advanced systemic mastocytosis (advSM) display H3K36Me3 deficiency as a result of non-genomic loss of function of SETD2. Proteasome inhibition restored SETD2 protein expression and H3K36me3, suggesting that a functional protein is produced but rapidly degraded. To understand the mechanisms underlying this phenomenon, we used an in silico approach to identify candidate SETD2-interacting proteins, followed by experimental confirmation by co-immunoprecipitation. We found that, after proteasomal inhibition, SETD2 co-immunoprecipitates with Aurora Kinase A (AKA). We also found that AKA was overexpressed and hyper-activated in pts with advSM compared to ISM pts and to a pool of healthy donors, and that AKA can phosphorylate SETD2. Both pharmacological inhibition by Danusertib and siRNA-mediated knock-down of AKA rescued SETD2 expression and activity, raising the hypothesis that phosphorylation by AKA might be implicated in proteasome-mediated degradation of SETD2. The new standard of therapy in advSM is midostaurin, that inhibits the activity of both wild‐type and D816V mutant KIT, as well as of various other kinases including AKA. Therefore we investigated if midostaurin effects may be addressed to AKA inhibition and consequent SETD2/H3K36me3 rescue. To this purpose, HMC-1 cells were treated with 5 µM midostaurin for 24 h and AKA, SETD2 and H3K36me3 expression were evaluated by western blotting. Treatment with midostaurin was able to inhibit AKA activity by about 60%, partially restoring SETD2 expression and H3K36Me3. Moreover, midostaurin treatment of HMC-1 cells at micromolar doses induced cytostatic but not cytotoxic effects as shown by cell growth curves performed in liquid medium and as confirmed by annexin V/PI staining and subsequent cytofluorimetric analysis of apoptotic cell death. Our observations in cell lines were confirmed in neoplastic mast cells collected from six patients with advSM before and after three months of midostaurin treatment. Western blotting showed that midostaurin treatment in vivo indeed results in a rescue of SEDT2 expression and activity, associated with a partial de-phosphorylation of AKA. Our subsequent experimental step was therefore to hypothesize and test the possibility of a combined treatment between midostaurin and second generation TKIs to induce not only a cytostatic but also a cytotoxic effect both in our in vitro models and in primary cells obtained from bone marrow samples of advSM patients. We performed growth curves in liquid medium and clonogenic assays to evaluate the therapeutic potential of pharmacological combination of midostaurin with Nilotinib and Dasatinib in HMC-1 cells and in neoplastic mast cells from 3 patients with advSM and we observed in all cases synergistic effects at nanomolar doses. Moreover, cytofluorimetric analysis of apoptotic cell death in HMC-1 cells showed an important advantage in using the combination of the two drugs, compared to single agents, underlined by the significant reduction of drug doses used to obtain cytotoxic effects (Figure 1). Our results suggest that AKA-mediated post-translational modifications contribute to SETD2 non-genomic loss of function in advSM. Inhibiting AKA and c-Kit activity by midostaurin in combination with a second generation TKI is a promising therapeutic strategy in patients with SETD2/H3K36Me3 deficiency. Acknowledgments: study supported by AIRC (project code 16996) and AIL (Associazione Italiana contro le Leucemia, Linfomi e Mieloma). Disclosures Papayannidis: Incyte: Honoraria; Shire: Honoraria; Novartis: Honoraria; Teva: Honoraria; Amgen: Honoraria; Pfizer: Honoraria. Bonifacio:Pfizer: Honoraria; Amgen: Honoraria; Novartis: Honoraria; Incyte: Honoraria; BMS: Honoraria. Albano:Incyte: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Elena:Novartis: Consultancy; Pfizer: Consultancy. Valent:Deciphera: Honoraria, Research Funding; Blueprint: Research Funding; Pfizer: Honoraria; Celgene: Honoraria; Novartis: Consultancy, Honoraria, Research Funding. Cavo:celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel accommodations, Speakers Bureau; janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel accommodations, Speakers Bureau; bms: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; novartis: Honoraria; takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Soverini:Incyte: Consultancy.

Background: Polycythemia vera (PV) and essential thrombocythemia (ET) are myeloproliferative neoplasms that can progress to post-PV (PPV) myelofibrosis (MF) and post-ET (PET) MF, also known as secondary myelofibrosis (SMF). The 2009 International Working Group for Myelofibrosis Research and Treatment group (IWG-MRT) diagnostic criteria for SMF require the presence of grade 2 or 3 bone marrow fibrosis (BMF) according to the European classification. The prognostic value of BMF in primary MF has been recently explored. Aim of this study is to describe the relevance of BMF grading in terms of presentation and outcome in SMF. Methods: The MYSEC (Myelofibrosis Secondary to PV and ET Collaboration) project is an international retrospective collaboration that collected 805 SMF cases. BMF grade at time of SMF evolution was defined as grade 2 (BMF2) in case of a diffuse increase in reticulin with extensive intersections, occasional bundles of collagen and/or osteosclerosis, or as grade 3 (BMF3) if presenting with coarse bundles of collagen, often associated with osteosclerosis. Chi-square or Fisher exact test for categorical variables, Wilcoxon rank-sum test for continuous ones and multiple logistic regression analysis were applied in order to explore pattern of association between BMF grading and patients' characteristics. A Poisson regression model was applied to estimate incidence rate of events, together with 95% Confidence Interval (CI). Survival was estimated using the Kaplan-Meier method. Differences between BMF groups were compared by a Log-rank test. The MYSEC study was approved by the Review Board of each Institution and conducted in accordance with the Declaration of Helsinki. Results: Detailed information about BMF grade was available in 675 patients: BMF2 was reported in 443 (65.6%) and BMF3 in 232 (34.4%). We did not find any correlation between BMF grade and advanced age, marrow blasts percentage, spleen and liver size, presence of constitutional symptoms, abnormal karyotype at the time of SMF diagnosis. No imbalance was evident for gender and for time to progression from PV/ET to SMF. Looking at genotype, BMF grading was not differently distributed among the 3 phenotypic driver mutations as well as the "triple negative" cases. On the contrary, in univariate analysis we found a significant association between BMF3 and previous diagnosis of ET vs. PV, decreased hemoglobin levels, reduced platelet and leukocyte counts, higher percentage of circulating blast cells and higher LDH value (Table 1). In a multivariate analysis that took into consideration SMF subtypes, complete blood count and circulating blast cells in 437 SMF patients, PET-MF, lower hemoglobin levels and reduced platelet count maintained their association with BMF3 (Table 2). The cumulative incidence of thrombosis after SMF was 3.2% (CI 95%: 2.4-4.2) person-year of follow up (PYFU) in BMF2, equivalent to BMF3 (2.7% PYFU, CI 95%: 1.2-5.7) (P = 0.44). Besides, BMF grade did not impact on the cumulative incidence of post-SMF blast phase, which resulted 2.4% (CI 95%: 1.8-3.3) PYFU in case of BMF2 and 3% (CI 95%: 1.3-6.9) PYFU in the BMF3 cohort (P = 0.68). Overall, MYSEC-PM (MYSEC-Prognostic Model) risk categories were differently distributed between BMF grades: patients with BMF2 were more frequently included in lower risk groups, while those with BMF3 were enriched in the higher categories (Table 1). Finally, we found a significantly higher mortality in patients with BMF3 vs. BMF2, mainly due to SMF progression (Table 1). Figure 1 shows the Kaplan-Meier estimate of survival in the 2 populations, resulting significantly different. Nevertheless, when considering the MYSEC-PM score in a multivariate analysis, BMF grade lost its prognostic impact on survival. Conclusions: This study provides evidence that BMF grade does correlate with specific clinical phenotype in SMF. BMF3 was associated with a more "cytopenic" phenotype (lower hemoglobin levels and reduced platelet count) and clustered with higher MYSEC-PM scores. Survival is significantly reduced in patients with BMF3. In conclusion, irrespectively of the PV/ET duration, progressive anemia and thrombocytopenia imply more frequently BMF3, finally resulting in a worse survival. This highlights the need of performing bone marrow biopsy earlier in disease evolution. Disclosures Rumi: novartis: Honoraria, Research Funding. Rambaldi:Omeros: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau, travel support; Celgene: Membership on an entity's Board of Directors or advisory committees, Other: travel support, Speakers Bureau; Amgen: Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Other: travel support, Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees, Other: travel support, Speakers Bureau; Italfarmaco: Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding, Speakers Bureau. Komrokji:Incyte: Consultancy; pfizer: Consultancy; JAZZ: Speakers Bureau; celgene: Consultancy; JAZZ: Consultancy; Novartis: Speakers Bureau; Agios: Consultancy; DSI: Consultancy. Gotlib:Deceiphera: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Seattle Genetics: Research Funding; Promedior: Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Research Funding; Blueprint Medicines: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Allakos: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Kiladjian:Novartis: Honoraria, Research Funding; AOP Orphan: Honoraria, Research Funding; Celgene: Consultancy. Cervantes:Novartis: Honoraria, Speakers Bureau; Celgene: Consultancy, Speakers Bureau. Palandri:Novartis: Consultancy, Honoraria. Silver:PharmEssentia: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Benevolo:Novartis Pharmaceuticals: Consultancy. Albano:Incyte: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Iurlo:Novartis: Other: Speaker Honoraria; Incyte: Other: Speaker Honoraria; Pfizer: Other: Speaker Honoraria. Vannucchi:Incyte: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees; Italfarmaco: Membership on an entity's Board of Directors or advisory committees; CTI BioPharma: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Passamonti:Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Consultancy, Speakers Bureau; Celgene Corporation: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau.

BACKGROUND: In chronic phase (CP) chronic myeloid leukemia (CML) nilotinib (NIL) showed better efficacy compared to imatinib. The higher rates of deep molecular response with NIL may translate into more patients (pts) eligible for treatment discontinuation. On the other hand, cardiovascular toxicity may limit NIL use in selected groups of pts (e.g. elderly pts). Long follow-up is required for a proper evaluation of the benefit-risk ratio between efficacy (including treatment-free remission [TFR] rates) and toxicity. However, only few data are currently available on the very long-term outcome of NIL treated pts. AIM: To describe the very-long term outcome of patients treated with nilotinib first-line. METHODS: The GIMEMA CML WP initiated in 2007 a phase II study (NCT 00481052) with NIL first-line (400 mg BID). Seventy-three adult (≥18 years old) pts with newly diagnosed, CP-CML were enrolled at 18 GIMEMA Centers in Italy. Median age was 51 (18-83) years. ELTS risk score was low in 64.4% of pts, intermediate in 30.1% of pts, and high in 5.5% of pts. Early and mid-term results have been previously published. Here, we report the very long-term outcome of this study, focusing on survival measures, TFR rates and adverse events. The updated, final results (with 10-year follow-up) of the trial will be available for presentation at the meeting. RESULTS: After a median follow-up of 92 months, 70 (95.9%) pts are alive and progression-free. Three pts (4.1%) died (progression to blast phase, n=1; CML-unrelated death, n=2). Failures according to ELN 2013 recommendation occurred in 5 (6.8%) pts (progression to BP, n=1; BCR-ABL transcript level > 1% at 12 months, n=2; confirmed loss of major molecular response, n=2). At last contact, 45 (61.6%) pts were still on NIL (dose ≥ 600 mg/day in 29 pts; 400 or 450 mg/day in 12 pts; ≤ 300 mg in 4 pts). Reasons for permanent NIL discontinuation in the remaining 28 (38.4%) pts were: adverse events (n=17, 23.3%; two of these pts maintained a deep molecular response without treatment - TFR); successful TFR attempts (n=9, 12.3%); failures (n=2 pts, 2.7%). The median age at CML diagnosis of pts obtaining the TFR was 47 (21-70) years. Fifteen athero-thrombotic events (ATEs) occurred in 13 (17.8%) pts (peripheral arterial occlusive disease, n=5; acute myocardial infarction, n=5; others ATEs, n=5), after a total NIL exposure of 478 years (3.1 events/100 pt-years). The median age at CML diagnosis of these pts was 66 (43 - 83) years; 8/13 (61.5%) pts had at least a baseline cardiovascular risk factor (hypertension, diabetes, hypercholesterolemia, or BMI ≥ 30). SUMMARY: These data highlight the efficacy of first-line NIL in the long-term, with excellent overall survival. TFR was obtained in 15% of pts, and particularly in younger ones. Some safety concerns remain, with ATEs occurring in 17.8% of pts (mainly in elderly ones), although none of these events was fatal. Disclosures Gugliotta: Incyte: Honoraria; Pfizer: Honoraria; Novartis: Honoraria. Castagnetti:Incyte: Honoraria; Pfizer: Honoraria; Bristol Myers Squiib: Consultancy, Honoraria; Novartis: Honoraria. Breccia:Novartis: Honoraria; Incyte: Honoraria; BMS: Honoraria; Pfizer: Honoraria; Celgene: Honoraria. Levato:BMS: Honoraria; Incyte: Honoraria; Pfizer: Honoraria; Novartis: Honoraria. Stagno:Pfizer: Honoraria; Novartis: Honoraria; BMS: Honoraria; Incyte: Honoraria. Tiribelli:Incyte: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees. Bocchia:Incyte: Honoraria; BMS: Honoraria; Novartis: Honoraria. Cavazzini:Novartis: Honoraria; Incyte: Honoraria; Pfize: Honoraria. Caocci:Novartis: Honoraria; Celgene: Honoraria. Albano:Incyte: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Martinelli:Ariad: Consultancy, Other: trial grant; Amgen: Consultancy, Other: trial grant; Novartis: Consultancy, Other: trial grant; Pfizer: Consultancy, Other: trial grant; Janssen: Consultancy, Other: trial grant; Abbvie: Consultancy, Honoraria, Other: trial grant; Incyte: Consultancy, Other: trial grant; Daiichi Sankyo: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Other: trial grant; Roche: Consultancy, Other: trial grant. Soverini:Incyte: Consultancy. Foà:Abbvie: Consultancy, Speakers Bureau; Celltrion: Membership on an entity's Board of Directors or advisory committees; Amgen Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Consultancy, Speakers Bureau; Shire: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Consultancy, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celltrion: Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Speakers Bureau; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Shire: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Pane:GSK: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Other: research founding; BMS: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees. Cavo:amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel accommodations, Speakers Bureau; janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel accommodations, Speakers Bureau; bms: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; novartis: Honoraria; takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Saglio:Celgene: Consultancy; BMS: Consultancy; Novartis: Consultancy; Ariad: Consultancy; Incyte: Consultancy; Pfizer: Consultancy; Jansen: Consultancy. Baccarani:Novartis: Consultancy, Speakers Bureau; Incyte: Consultancy, Speakers Bureau; Takeda: Consultancy. Rosti:BMS: Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Incyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

One of the hallmarks of chronic myeloid leukemia (CML) is genomic instability, that fosters the acquisition of tyrosine kinase inhibitor (TKI)-resistant BCR-ABL1 mutations and/or of additional chromosomal aberrations leading to progression to blast crisis (BC). Inactivating mutations in the SETD2 tumor suppressor occur in solid tumors and acute leukemias. SETD2 trimethylates histone H3 Lysine 36 (H3K36Me3) playing a key role in maintaining DNA integrity. We have recently demonstrated that, in CML, SETD2 loss of function may occur at the post-translational level. Reduced or null SETD2 and H3K36Me3 was detected in 83/96 (86%) patients (pts) with BC CML as compared to a pool of healthy donors and to chronic phase (CP) pts at diagnosis. Proteasome inhibition in primary cells from pts with undetectable SETD2 restored H3K36Me3 and led to accumulation of hyper-ubiquitinated SETD2. In K562 cells (SETD2/H3K36Me3low), we observed that after proteasome inhibition hyper-ubiquitinated SETD2 co-immunoprecipitates with MDM2. MDM2 inhibition rescued SETD2 expression and activity, suggesting that MDM2 is implicated in SETD2 reduced stability. Co-IP also showed that SETD2 interacts with Aurora Kinase A (AKA) a S/T kinase frequently overexpressed in CML. We found that AKA phosphorylates SETD2, and its inhibition rescued SETD2 expression and activity. To investigate whether SETD2/H3K36Me3 loss may be a druggable lesion, we performed clonogenic assays in LAMA84 (SETD2/H3K36Me3high) cells before and after SETD2 silencing, in imatinib-sensitive K562 (SETD2/H3K36Me3low) cells and in IM-resistant K562 cells, that are characterized by complete SETD2 loss. The extent of reduction of clonogenic growth after proteasomal, AKA or MDM2 inhibition was found to be inversely correlated to SETD2 residual expression. These observations were confirmed in cells from both CP (n=2) and BC (n=4) CML pts showing different levels of SETD2 expression and activity. Further experiments were performed in the aforementioned cell lines to verify if reduced clonogenic potential was due to cytostatic or cytotoxic effects. Apoptotic cell death was quantified by annexin V/propidium iodide staining and flow cytometry. Proteasomal inhibition by bortezomib, carfilzomib and ixazomib and AKA de-phosphorylation by Danusertib caused a time-dependent increase of annexin-V-positive cells by activating the mitochondrial apoptotic pathway as reflected by an increase in Bax expression and induction of the cleavage of caspase-3,-9 and PARP. Moreover, all drug treatments as single agent, at nanomolar doses (Bortezomib: 10 nM, Carfilzomib: 5 nM, Ixazomib: 10 nM and Danusertib: 500 nM) induced a significant increase of the DNA double-strand break marker γH2AX, suggesting that in a SETD2 knock-down context, proteasomal and AKA inhibition propagates genomic instability by forcing the cells through successive replication cycles, ultimately resulting in apoptosis from mitotic catastrophe. Reduced SETD2/H3K36Me3 levels, in association with MDM2 and AKA hyper-activation, were also detected when the CD34+ cell fraction of 10 CML-CP pts, was compared to the total mononuclear cell fraction or to the CD34+ compartment obtained from a pool of healthy donors. We thus hypothesized that leukemia progenitor cells, showing higher MDM2 and AKA activity and consequent SETD2 loss, accumulate genetic aberrations despite inhibition of BCR-ABL1 kinase. Studies are ongoing to verify if MDM2 or AKA inhibition may restore SETD2 expression and function and induce cell death. Finally, it has already been shown that alterations of epigenetic regulators such as the KDM4 family members control tumor cell proliferation in a variety of cancers including acute myeloid leukemia. Recent findings have identified KDM4 demethylases as putative therapeutic targets in a SETD2 mutated context and illustrated the efficacy of KDM4 inhibitors in AML therapy. Starting from these evidences, we will test the same approach in BC CML models. In conclusion, phosphorylation by AKA and ubiquitination by MDM2 contribute to SETD2 non-genomic loss of function in BC CML and in CD34+ leukemic progenitors. Restoring physiological H3K36Me3 may help to improve the outcome of this critical subset of pts. Acknowledgments: Study supported by AIRC (project code 16996), AIL (Associazione Italiana contro le Leucemia, Linfomi e Mieloma), Italian Ministry of Health, project GR-2016-02364880. Disclosures Gugliotta: Pfizer: Honoraria; Novartis: Honoraria; Incyte: Honoraria. Castagnetti:Novartis: Honoraria; Incyte: Honoraria; Pfizer: Honoraria; Bristol Myers Squiib: Consultancy, Honoraria. Rosti:BMS: Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Incyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Iurlo:Incyte: Other: Speaker Honoraria; Novartis: Other: Speaker Honoraria; Pfizer: Other: Speaker Honoraria. Abruzzese:Incyte: Consultancy; Novartis: Consultancy; Pfizer: Consultancy; BMS: Consultancy. Pregno:Incyte: Consultancy, Honoraria; Pfizer: Honoraria; Novartis: Honoraria; Bristol Myers Squibb: Honoraria. Crugnola:Novartis: Honoraria; Incyte: Honoraria. Albano:Novartis: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees. Bonifacio:Novartis: Honoraria; Amgen: Honoraria; Pfizer: Honoraria; Incyte: Honoraria; BMS: Honoraria. Tiribelli:Pfizer: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees. Baccarani:Novartis: Consultancy, Speakers Bureau; Incyte: Consultancy, Speakers Bureau; Takeda: Consultancy. Martinelli:Roche: Consultancy; Pfizer: Consultancy; BMS: Consultancy; Novartis: Consultancy; ARIAD: Consultancy. Cavo:amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel accommodations, Speakers Bureau; novartis: Honoraria; takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; bms: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel accommodations, Speakers Bureau. Soverini:Incyte: Consultancy.

Background and Rationale. Bosutinib (BOS), dasatinib (DAS) and nilotinib (NIL) are 2nd generation TKIs with similar second-line efficacy. The use of DAS and NIL may be burdened by pulmonary, infectious, cardiovascular and metabolic complications; these complications are more frequent and more clinically relevant in the elderly. BOS could represent an important therapeutic option in elderly patients intolerant to or failing a first-line TKI, but the dose of 500 mg OAD may be higher than necessary. Aims. All TKIs have been tested at a fixed initial dose, with dose adjustment in case of toxicity or treatment failure. On the contrary, the aim of our study was to evaluate in elderly CML patients if second-line BOS was effective and better tolerated at doses lower than 500 mg OAD, beginning with 200 mg OAD, then increasing the dose to 300 OAD or 400 mg OAD according to the molecular response, to find the minimum effective dose. Methods. A prospective phase 2 single-arm multicenter study has been designed by the GIMEMA CML Working Party (NCT02810990). Study design: all patients started with 200 mg OAD for 2 weeks ("run-in" period), then the dose was increased to 300 mg OAD; after 3 months, patients with BCR-ABLIS transcript ≤ 1% continued 300 mg OAD, while in patients with transcript > 1% the dose is furtherly increased to 400 mg OAD. In responsive patients, BOS dose was maintained, 300 mg or 400 mg OAD. Key inclusion criteria: > 60 yrs old, chronic phase CML, intolerance or failure of any first-line TKI (2013 ELN criteria), absence of T315I or V299L mutation. Sixty-three patients have been enrolled. The primary endpoint was the proportion of patients in MR3 at 1 year. Definitions: MR3, BCR-ABLIS < 0.1%; MR4, BCR-ABLIS < 0.01% with > 10.000 copies; MR4.5, BCR-ABLIS < 0.0032% with > 32.000 copies. Results. Median age: 73 yrs (range 60-90). Age distribution: 60-69 yrs, 18 pts (29%); 70-79 yrs, 31 pts (49%); > 80 yrs, 14 pts (22%). Sokal score at diagnosis: low 19%, intermediate 49%, high 32%. Reasons for switching to BOS: intolerance 63%, resistance 37%. First-line TKI: imatinib 83%, DAS 11%, NIL 6% (same TKI distribution in intolerant and resistant patients). Median follow-up: 9 mos (range 1-30). Overall, 10/63 patients had a dose-increase to 400 mg OAD, 49/63 to 300 mg OAD, while 4/63 continued on BOS 200 mg OAD without any dose increase. At baseline, 13 patients were already in MR3. The MR3 rates by 3 and 6 months were 43% and 56%, respectively. The cumulative rate of patients achieving or maintaining a MR3 by 12 months was 60% (65% in intolerant and 52% in resistant patients, p = 0.31). Interestingly, only 21% of patients > 80 yrs old achieved or maintained a MR3 (p < 0.001, compared to younger patients). Patients achieving MR4 or MR4.5 were 38% and 19%, respectively. Overall, 22%, 27% and 11% of patients had 1 log, 2 logs or > 3 logs reduction from baseline BCR-ABLIS transcript level. Selected adverse events: cardiac ischemia, 2 patients; pericardial effusion, 2 patients; no pleural effusions. Events leading to permanent treatment discontinuation: 2 unrelated deaths, 7 adverse events (3 hypertransaminasemia, 1 nephrotoxicity, 1 diarrhea, 1 skin rash, 1 myalgia/fatigue), 3 unsatisfactory responses (without progressions). Fifty-one out of 63 patients are still on BOS at the last contact: 6 on 400 mg OAD, 34 on 300 mg OAD, 11 on 200 mg OAD. Conclusions. A gradual dose increase, based on prospective molecular monitoring, allowed the great majority of enrolled patients (approximately 70%) to remain on treatment with BOS 300 mg OAD or less, achieving a major molecular response (MR3) in 60% of the cases. These results trial showed that, in elderly patients intolerant to or failing a first-line TKI, BOS may be highly effective and better tolerated at a dose lower than 500 mg OAD, namely at 300 mg OAD. Disclosures Castagnetti: Pfizer: Honoraria; Novartis: Honoraria; Incyte: Honoraria; Bristol Myers Squiib: Consultancy, Honoraria. Gugliotta:Pfizer: Honoraria; Incyte: Honoraria; Novartis: Honoraria. Bocchia:Novartis: Honoraria; Incyte: Honoraria; BMS: Honoraria. Trawinska:Novartis: Consultancy, Honoraria. Bonifacio:Novartis: Honoraria, Research Funding; Amgen: Honoraria; Pfizer: Honoraria; Incyte: Honoraria. Crugnola:Novartis: Honoraria; Incyte: Honoraria. Elena:Novartis: Consultancy; Pfizer: Consultancy. Lucchesi:Novartis: Honoraria; Incyte: Honoraria; Pfizer: Honoraria. Albano:Incyte: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Lunghi:Novartis: Honoraria; Incyte: Honoraria; Pfizer: Honoraria. Stagno:BMS: Honoraria; Incyte: Honoraria; Pfizer: Honoraria; Novartis: Honoraria. Pregno:Pfizer: Honoraria; Novartis: Honoraria; Bristol Myers Squibb: Honoraria; Incyte: Consultancy, Honoraria. Iurlo:Novartis: Honoraria; BMS: Honoraria; Pfizer: Honoraria; Incyte: Honoraria. Ferrero:Novartis: Honoraria. Cavo:janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel accommodations, Speakers Bureau; novartis: Honoraria; takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; bms: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel accommodations, Speakers Bureau. Saglio:BMS: Consultancy; Novartis: Consultancy; Ariad: Consultancy; Pfizer: Consultancy; Celgene: Consultancy; Jansen: Consultancy; Incyte: Consultancy. Pane:Novartis: Membership on an entity's Board of Directors or advisory committees, Other: research founding; Janssen: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees. Baccarani:Novartis: Consultancy, Speakers Bureau; Incyte: Consultancy, Speakers Bureau; Takeda: Consultancy. Rosti:BMS: Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Incyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. OffLabel Disclosure: Bosutinib is a second generation TKI already registered for the treatment of adult patients with chronic phase CML with resistance or intolerance to prior therapy. In the present study the initial dose is 200 mg instead of 500 mg OAD. A dose increase to 300 or 400 mg is scheduled according to molecular response and tolerabiliy

Background. Ponatinib is a third-generation tyrosine kinase inhibitor indicated for adult patients with resistant or intolerant chronic phase (CP), accelerated phase (AP) or blast phase (BP) chronic myeloid leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia, or for those carrying the T315I mutation. In the real-world setting, there is a paucity of data regarding the use of ponatinib. The goal of the Observational study of Iclusig® (ponatinib) Treatment in patients with CML in Italy (OITI) is to evaluate treatment patterns and outcomes, including the safety and efficacy of ponatinib, in patients with CML treated in hematology centers in Italy since January 2015, when ponatinib became commercially available. Methods. This ongoing, non-interventional study includes patients aged ≥18 years with CP, AP or BP CML who initiated ponatinib treatment in routine clinical practice across 40 centers (academic and hospital settings) as of October 2018. The study population consists of a prospective cohort, including patients who started treatment with ponatinib after site activation during the ongoing enrolment period; a retrospective cohort, including patients who started treatment with ponatinib but who died or were lost to follow-up prior to site activation; and a retrospective/prospective cohort, including patients who started treatment with ponatinib prior to site activation and are still on treatment. Demographic, efficacy and safety data are collected from patient medical charts at study entry and at routine care visits. The primary endpoint is complete cytogenetic response (CCyR) rate in patients with CP CML 6 months after starting ponatinib treatment. Here, the first interim analysis after ≥6 months' observation is presented for the retrospective and retrospective/prospective cohorts. Results. At time of data analysis (02 July 2019), 56 patients (53 CP, 1 AP and 2 BP CML) had been enrolled across 21 Italian centers. Twenty-eight (50.0%) patients had received ponatinib as second-line (2L) treatment and 33.9% received ponatinib in third-line (3L). Twenty (35.7%) patients had a history of cardiovascular events and 23 (41.1%) had a history of hypertension. Among patients with CP, AP and BP CML, median age at study entry was 59.1, 33.7 and 48.5 years, respectively; among 37 evaluable patients, 12 (32.4%), 1 (2.7%) and 1 (2.7%) patient(s) had a confirmed BCR-ABL1 mutation. Of evaluable patients, 4 (10.8%) had the T315I mutation. The starting dose of ponatinib for patients with CP CML was 45 mg once daily in 41.5% of patients, 30 mg in 39.6% of patients and 15 mg in 17.0% of patients; 1 (1.9%) patient started ponatinib at another dose. Median treatment duration was 23.9 months (range, 3.3-49.9 months) at the time of analysis. At Month 6, 88.6% of patients with CP CML achieved a CCyR. Additionally, 37.5% and 15.0% of evaluable patients with CP CML achieved a major molecular response (MMR; MR3.0) and a deep molecular response (MR4.5), respectively (Table 1). Estimated progression-free survival rates for patients with CP CML at Months 12 and 24 were 86.6% (95% CI, 77.8-96.4%) and 83.7% (95% CI, 73.8-94.9%), respectively. Corresponding overall survival rates were 96.2% (95% CI, 91.1-100.0%) and 93.1% (95% CI, 85.6-100.0%), respectively. Thirty (53.6%) patients had treatment-related adverse events (TRAE). The most frequent TRAEs were hypertension (n=6), skin lesion (n=2), increased lipase (n=2), rash (n=2) and pain in extremity (n=2). The only hematologic TRAE reported was thrombocytopenia (n=1). Dose interruptions occurred in 13 patients: for TRAEs (n=5, 38.5%), medical decision (n=4, 30.8%) or other causes (n=4, 30.8%; comprising death in 3 cases and 1 attempt at treatment-free remission). Conclusions. Data show that ponatinib has a favorable efficacy and safety profile in patients with CML treated in standard clinical practice in Italy. By Month 6, most patients had achieved CCyR and 44% of patients achieved MMR in 2/3L. Furthermore, the probability of survival at 2 years was more than 90%. No new safety signals emerged with ponatinib treatment than those previously reported. The early use of ponatinib (84% of patients received it as 2/3L treatment) as well as careful dose selection appear key to the safety and efficacy outcomes observed in this preliminary study evaluation. Disclosures Iurlo: Incyte: Other: Speaker Honoraria; Pfizer: Other: Speaker Honoraria; Novartis: Other: Speaker Honoraria. Annunziata:Pfizer: Consultancy; Incyte: Consultancy; Novartis: Consultancy. Albano:Incyte: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Spadano:Incyte: Speakers Bureau; Pfizer: Speakers Bureau. Bonifacio:BMS: Honoraria; Amgen: Honoraria; Pfizer: Honoraria; Incyte: Honoraria; Novartis: Honoraria. Abruzzese:BMS: Consultancy; Incyte: Consultancy; Novartis: Consultancy; Pfizer: Consultancy. Pellegrino:Inycte Biosciences Italy S.R.L: Employment. Galimberti:Inycte Biosciences Italy S.R.L: Employment. Foà:Celltrion: Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Speakers Bureau; Roche: Consultancy, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Consultancy, Speakers Bureau; Shire: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Consultancy, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Shire: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celltrion: Membership on an entity's Board of Directors or advisory committees. Breccia:Celgene: Honoraria; BMS: Honoraria; Novartis: Honoraria; Pfizer: Honoraria; Incyte: Honoraria.

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer and accounts for about a quarter of adult acute leukemias, and features different outcomes depending on the age of onset. Improvements in ALL genomic analysis achieved thanks to the implementation of next-generation sequencing (NGS) have led to the recent discovery of several novel molecular entities and to a deeper understanding of the existing ones. The purpose of our review is to report the most recent discoveries obtained by NGS studies for ALL diagnosis, risk stratification, and treatment planning. We also report the first efforts at NGS use for minimal residual disease (MRD) assessment, and early studies on the application of third generation sequencing in cancer research. Lastly, we consider the need for the integration of NGS analyses in clinical practice for genomic patients profiling from the personalized medicine perspective.

The family of retinoic acid receptors (RARs: RARα, -β, and -γ) has remarkable pleiotropy characteristics, since the retinoic acid/RARs pathway is involved in numerous biological processes not only during embryonic development, but also in the postnatal phase and during adulthood. In this review, we trace the roles of RA/RARs signaling in the immune system (where this pathway has both an immunosuppressive role or is involved in the inflammatory response), in hematopoiesis (enhancing hematopoietic stem cell self-renewal, progenitor cells differentiation or maintaining the bone marrow microenvironment homeostasis), and in bone remodeling (where this pathway seems to have controversial effects on bone formation or osteoclast activation). Moreover, in this review is shown the involvement of RAR genes in multiple chromosomal rearrangements generating different fusion genes in hematological neoplasms, with a particular focus on acute promyelocytic leukemia and its variant subtypes. The effect of different RARs fusion proteins on leukemic transformation, on patients’ outcome, and on therapy response is also discussed.