ALBERT

Description: Background: CD38-targeting antibody Daratumumab (Dara) has been demonstrating significant improvement in (MM) patient's survival. Cyclophosphamide (C), thalidomide (T) and dexamethasone (D) - (CTd) is one of the most used induction protocols worldwide and the MAX-Dara study was the first that combine Dara-CTd as induction for (NDMM) (TE) patients. We hypothesized that this new combo + autologous stem cell transplantation (ASCT) could affect the quantitative recovery of distinct lymphocytes subsets. Objective: Primary endpoint was to quantify lymphocytes subpopulations in (NDMM) (TE) patients at different treatment phases. Secondary endpoint was to evaluate B cells subsets at same times. Methods: Peripheral blood of 10 NDMM TE patients was collected at three different moments: at diagnose, after 4 induction cycles and after two consolidation cycles post- (ASCT). Dara-CTd protocol was for up to four 28-day induction cycles: C-500mg per oral (PO) d 1,8 and 15, T at 100-200mg PO d 1 to 28, Dex at 40mg PO d 1,8,15 and 22 and Dara 16mg/Kg/dose IV on d 1,8,15 and 22 during cycles 1 - 2 and every other week in cycles 3 - 4, followed by ASCT. Consolidation was started at D+30 after ASCT and all patients received up to four 28-day consolidation cycles: Dara 16mg/Kg and (D) at 40mg every other week, associated with T at 100mg PO d 1 - 28. Dara 16mg/Kg was used monthly as maintenance until progression or limiting toxicity. Flow cytometry was used to detect lymphocyte surface by CD3, CD4, CD5, CD8, CD16, CD19, CD20, CD38, CD45 and CD56 in the scatter plot. B cells were isolated and subpopulations (naïve B cells, class and non-class switched memory B cells, , IgD-CD27- memory B cells and plasma blasts) were detected by CD20, CD24, CD27, CD38, CD45 and IgD. Statistical analysis was performed using the SPSS® v25.0. Results: The median number of lymphocytes subsets at diagnosis were 1139 x 10³/μL for T cells, 155 x 10³/μL for B cells and 284 x 10³/μL for NK cells. After four cycles of Dara-CTD the median number of T, B and NK cells had dropped to 834, 7.5 and 8.0 x 10³/μL respectively (p

Description: Background: The inclusion of the CD38-targeting antibody daratumumab (Dara) increases the depth and duration of the response, as demonstrated by Dara-VTd and Dara-VRd protocols to treat NDMM - TE patients (pts). However, the access to new drugs is a challenge for some countries in Latin America. There are many induction protocols and one of the most used inductions worldwide is cyclophosphamide (C), thalidomide (T) and dexamethasone (d)- (CTd). We hypothesized that the combination of daratumumab and CTd (Dara-CTd) could be safe and allow deeper activity in NDMM TE pts. Objective: The primary endpoint was the attainment of VGPR after two consolidation cycles post-autologous stem cell transplantation (ASCT). Secondary endpoints were the overall response rate during all treatment phases and minimal residual disease (MRD), based on the International Myeloma Working Group (IMWG) criteria that includes the next-generation flow by the EuroFlow® and PET-CT and the safety profile. An exploratory endpoint was the analysis of the immunologic change in the lymphocyte profile during the treatment. Methods: This is a phase II, open-label single-center clinical trial. The main inclusion criteria were: NDMM TE, creatinine clearance 〉 30 ml/min, normal cardiac, renal and liver function and the Easter Cooperative Oncology Group (ECOG) performance status = 0 - 2. The protocol scheme was Dara-CTd for up to four 28-day induction cycles: C-500mg oral (PO) on days 1,8 and 15, T at 100-200mg PO on days 1 to 28, Dex at 40mg PO on days 1,8,15 and 22 and Dara at 16mg/Kg/dose intravenous (IV) on days 1,8,15 and 22 during cycles 1 - 2 and every other week in cycles 3 - 4, followed by ASCT. Consolidation was started at D+30 after transplant and all patients received up to four 28-day consolidation cycles: Dara at 16mg/Kg and (d) at 40mg every other week, associated with T at 100mg PO on days 1 - 28. Dara at 16mg/Kg was used monthly as maintenance until progression or limiting toxicity. All patients received antiviral, anti-pneumocystis and anti-thrombotic prophylaxis. Results: The first patient was enrolled in November 2018. A total of 21 pts were included, the median age being 56 (range 38 - 67 years), 18 (85%) were non-white, 3 (14%) had an R-ISS = 1, 12 (57%) had an R-ISS = 2 and 3 (14%), an R-ISS = 3. Five (24%) pts had high-risk chromosomal abnormalities [del17p, t(4;14) or t(14;16)]. To date, 18 pts have completed induction, 12 have received transplants and 10 have completed D+90 post-transplant assessment. In an intention to treatment analysis, after the end of induction (cycle 4), 17 (95%) of the pts obtained 〉 PR and 7 (33%) obtained VGPR or better. Ten patients have completed two consolidation cycles after transplant and 100% obtained 〉 VGPR as best response, 8 (80%) obtained MRD = -10-5 negative remission by flow cytometry and 6 (60%) had negative PET-CTs. Five (50%) patients had both flow and PET-CT negativity. Two patients died from infection, one post-transplant, considered not related to the investigational agent, and another after consolidation, related to the investigational agent. The most common non-hematological adverse events (AEs) grades 3 and 4 before ASCT were neuropathy (n = 6), infusion reaction (n = 6), infection (n = 2), hypertension (n = 1) and rash (n = 1). Conclusion: This is the first study that combined daratumumab with CTd as induction for NDMM TE patients. This preliminary data has shown that the association of Dara-CTd achieved a deep response with a safety profile. Clinical trial information: NCT03792620. Disclosures De Queiroz Crusoe: Janssen: Research Funding.

Description: INTRODUCTION: The occurrence of acute myeloid leukemia (AML) and chronic lymphoid leukemia (B-CLL) simultaneously is rarely described. We describe a case report of AML and B-CLL, diagnosed simultaneously, without any previous treatment for any of the hematological neoplasms [1]. The patient received low-dose cytarabine (ARA-C) and Venetoclax, which is medically indicated on label for both hematological neoplasms. CASE REPORT: A 75-year-old male, presented with edema and joint pain one month before hospital admission, showing pancytopenia on a complete blood count and presence of blasts in peripheral blood. The patient was then referred to the hematology service. The morphological analysis of the bone marrow aspirate showed 67.7% of myeloblasts, compatible with AML. Bone marrow immunophenotyping was performed, which identified 34.10% of myeloblasts, compatible with AML and 50.48% of monoclonal B lymphocytes (chronic B-cell lymphoproliferative disease). In flow cytometry there were two distinct populations of myeloblasts. Type 1 myeloblasts labeling CD7 +, CD13 +, CD34 ++, CD38 ++, CD45 ++, CD56 ++, CD117 ++, CD123 +, HLA-DR +++ and MPO + / ++. The second population marked CD13 + / ++, CD34 + / ++, CD38 ++, CD45 +, CD117 ++, CD123 +, HLA-DR ++ / +++ and MPO + (30%). Monoclonal lymphocytes showed CD11c + / ++ (70%), CD19 ++, CD20 + / ++ (84%), CD22 + (39%), CD23 + / ++, CD25 +, CD31 +/-, CD43 ++, CD45 ++ / +++, CD81 + (38%), CD200 + (85%) and Lambda +. The molecular study was negative for genetic abnormalities: FLT3, KIT and NPM, configuring the patient as an intermediate risk for AML. In the cytogenetic analysis there was no growth of metaphases. Patient received simultaneous diagnosis of AML and B-CLL. As he was ineligle to intensive chemotherapy (IC), we started original protocol Subcutaneous Cytarabin+venetoclax(VIALE C). The patient had grade 2-3 AE(neutropenia managed with GCSF) ending the fourth cycle in July 2020. The evolution of hematimetric parameters and diseases are described in graphics. DISCUSSION: This is the first described case in our knowledge treated upfront with bcl2-inh target therapy for two absolutely different hematological neoplasms: AML and BCLL. Nowadays we are experiencing a new therapeutic model in oncohematology, in which the targeted therapy is gaining ground in relation to IC with excellent results. In this way, the importance of comprehension of the pathophysiological mechanism of the neoplasms and the way we can stop the disease proliferation is progressively guiding the new protocols. Elderly patients are more likely to have early treatment-related death and exhibit therapeutic resistance, limiting alternatives. We decided to start first-line treatment with ARA-C and Venetoclax [2]. Venetoclax associated with ARA-C has a manageable safety profile, producing quick and durable remissions in elderly people with AML ineligible for IC, as well as in B CLL, being the best therapeutic alternative for the case, in our opinion. Venetoclax belongs to a group of drugs called Bcl-2 inhibitors, an anti-apoptotic protein, which works by blocking this protein in the body, causing apoptosis of both neoplastic cells. The high rate of remission and low early mortality, combined with fast and durable remission, make Venetoclax and ARA-C a new and attractive treatment for the elderly [2]. In our case, the intention of the product in the first line was not B-CLL, but it would certainly be a good option for this profile of elderly patients. CONCLUSION: We report the first description of simultaneous diagnosis of AML and B CLL treated with a Bcl-2 inhibitor, demonstrating that antitumor mechanisms can be extremely effective in completely different diseases. We have a long way to go in the search for full knowledge of oncohematological diseases and targeted therapies. However, this case report shows that we are on the right track. References: 1. MUSSAED, Eman Al; OSMAN, Hani; ELYAMANY, Ghaleb. Simultaneous existence of acute myeloid leukemia and chronic lymphocytic leukemia: a case report.Bmc Cancer.Springer Science and Business Media LLC. http://dx.doi.org/10.1186/s12885-016-2780-5. 2. WEI, Andrew H.; et al. Venetoclax Combined With Low-Dose Cytarabine for Previously Untreated Patients With Acute Myeloid Leukemia: results from a phase ib/ii study.Journal Of Clinical Oncology, [S.L.], 20 maio 2019. American Society of Clinical Oncology (ASCO). http://dx.doi.org/10.1200/jco.18.01600. Figure Disclosures De Queiroz Crusoe: Janssen:Research Funding.

Description: Introduction: Lipid rafts are highly ordered membrane domains that are enriched in cholesterol and sphingolipids and provide an environment for signal transduction proteins which control cell survival and cell death. Altered raft assembly has been implicated in cancer progression. Alkylphospholipids (APL) inhibit the AKT pathway and induce apoptosis of malignant cells but not of their normal counterparts when used at the same concentration. LAT2 (Linker for activation of T-cells family member 2) is a lipid raft component which is disrupted by APLs in leukemic cells. In the present study we evaluated the effect of perifosine, an APL with anticancer activity in humans, on the LAT2 and AKT pathways using a Mantle Cell Lymphoma (MCL) cell line (Granta-519 cells) as a model. We selected MCL cells to study because AKT is constitutively phosphorylated in this disease. Methods: We determined whether perifosine induced apoptosis of unmodified Granta-519 cells using flow cytometry, we measured caspase-3 activity with a synthetic peptide and detected cleaved caspases by western blotting. Then, we demonstrated the participation of LAT2 in AKT signaling. We used a stable knockdown of LAT2 (lentiviral sh-RNA). After transduction, Granta-519 cells were selected using 0.5 µg/mL puromycin for 5 days. Stable LAT2 knockdown reduced LAT2 levels by 90% (Figure 1A) and showed impaired AKT phosphorylation in the absence of ligands (Figure 1B). Results: Perifosine treatment induced apoptosis of Granta-519 cells and the effective dose 50% (ED-50) was 20 μM. Apoptosis was triggered after 6 hours of incubation and activation of the extrinsic and intrinsic pathways of apoptosis was demonstrated. Perifosine decreased LAT2 abundance after 3 hours of treatment, also decreasing its presence in lipid rafts, and led to a decrease in AKT phosphorylation and downstream components of AKT signaling. Moreover, perifosine impaired AKT phosphorylation in the presence of stimuli such as CD40L (330 ng/mL) in Granta-519 cells after a few minutes of incubation, resulting in an effect similar to that of the PI3K inhibitor Wortmannin (1 µM). In vivo studies using Granta-519 subcutaneous xenografts in NSG mice revealed that stable knockdown of LAT2 cells showed reduced tumor growth. sh-RNA CT cells (0.75x106) were injected into the right flank of five mice and the same number of sh-RNA LAT2 cells were injected into the left flank of the same animals. After 3 weeks, the tumor weight (mean + SD) was 0.52 ± 0.37 g for sh-RNA LAT2 tumors compared to 1.41 ± 0.19 g for sh-RNA CT tumors (p=0.0065) (Figure 1C and 1D). The LAT2 content of sh-RNA LAT2 cells and AKT phosphorylation were also reduced (Figure 1E and 1F). Conclusions: These results demonstrate that LAT2 is an important protein for supporting constitutive AKT phosphorylation/activation and downstream signaling in MCL and suggest that inhibition of LAT2 by APLs may have therapeutic applications. Acknowledgments: This research was supported by FAPESP, FINEP, and CNPq. C.H.T. received fellowships from FAPESP Proc. No. 13/07675-3. G.A.F. received a fellowship from CNPq Proc. 150126/2014-0. G.A.F. and C.H.T. contributed equally to this work Figure 1 Figure 1. In vivo evaluation of LAT2 stable knockdown cells using the NSG mouse model: (A) LAT2 stable knockdown was obtained from Granta-519 cells via lentiviral transduction of shRNA that targets LAT2. The cell line identified as “B” was used for further studies. (B) AKT activation was suppressed in LAT2 stable knockdown Granta-519 cells. Both cell lines were maintained with or without FBS for 24 hours. (C) Representative picture of the NSG mouse model xenotransplated with Granta-519. Equal amount of cells were injected into the left (sh-RNA LAT2) and right (sh-RNA CT) thigh of the animal. (D) Comparison of tumors weight: sh-RNA CT (1.408 g SD±0.19) and sh-RNA LAT2 (0.523 g SD±0.37). (E) Representative western blotting analysis of tumor cells against LAT2. (F) AKT phosphorylation was evaluated by western blotting (representative of two animals). Disclosures No relevant conflicts of interest to declare.

Description: Background: Using a chemosensitivity screening assay, we previously demonstrated that decitabine and thioguanine combinations can rescue therapeutic efficacy in primary leukemia cells isolated from patients with relapsed and refractory acute myeloid leukemia (AML). Although both decitabine and thioguanine have single-agent anti-leukemic activity, they have not previously been used concurrently. To test the safety and preliminarily assess possible additive/synergistic activity of this combination, we are performing a Phase I dose escalation trial of thioguanine given with decitabine. Patients and Methods: Patients with untreated AML over 60 years who are not suitable candidates for standard induction therapy, as well as those with relapsed/refractory AML, advanced myelodysplastic syndrome, and chronic myelomonocytic leukemia (CMML) are eligible. Three thioguanine dose levels are being evaluated: 80, 120, and 160 mg/m2/day, given in two divided doses on Days 1-12 of each induction course for up to two cycles and Days 1-7 of maintenance cycles. Decitabine 20 mg/m2 is administered IV on Days 3-12 during induction cycles and on Days 3-7 during maintenance cycles. In addition to standard safety measures and clinical outcomes, the biologic activity of the combination is assessed by patient specific pharmacodynamic measures. These measures include an in vitro chemosensitivity assay, genome-wide analysis of DNA methylation changes, and BH3 profiling in order to measure the degree to which samples are primed to undergo apoptotic cell death. Results: Six patients (median age, 69 yrs; range, 66–83 yrs) with newly diagnosed AML (n=2), relapsed/refractory AML (n=3), and newly diagnosed CMML (n=1) have been treated to date with thioguanine at the 80 mg/m2 dose. Dose-limiting toxicity was seen in one patient who developed acute renal failure (ARF) requiring hemodialysis. Infectious complications were the most common toxicity and included two episodes of grade 3 neutropenic colitis in one patient, grade 3 pseudomonal bacteremia, grade 3 staphylococcal bacteremia, and a dental infection requiring extraction. No other grade 3–4 non-hematologic toxicities were observed. Three patients remain on active treatment three to seven months from the initiation of therapy. Two patients were removed from study due to disease progression (n=1) and grade 4 ARF noted above (n=1). A patient with CMML was removed to undergo allogeneic hematopoietic stem cell transplantation after achieving a hematologic remission with red cell transfusion independence and platelet count normalization. The median number of cycles administered was 3 (range, 1-5). Bone marrow blast reductions to less than 5% were seen in all 4 evaluable patients with AML and included 1 CR and 1 CRi. The overall response rate in this high risk patient population was 67% (4 of 6 patients). Importantly, the patient who achieved a CR was 83 years old with relapsed disease following 4 previous cycles of single-agent decitabine therapy, demonstrating that this regimen can rescue previous hypomethylating agent failures. Clinical activity was well-correlated with the in vitro cytotoxicity assays. The chemosensitivity assay results for thioguanine on pre-treatment mononuclear cells directly correlated with clinical outcome in both response to therapy and clinical resistance. BH3 profiling was also performed on pre-treatment myeloblasts. Significant apoptotic priming corresponded to good initial clinical response. In addition, in the single patient who responded and subsequently relapsed, decreased apoptotic priming was observed in the relapsed sample, suggesting that the thioguanine/decitabine regimen applies selective pressure for reduction in apoptotic priming. Detailed analysis of treatment-related changes in DNA methylation will be presented and compared to prior work showing decitabine-induced hypomethylation in CD34+ leukemic cells during single agent therapy with decitabine. Conclusions: Combination decitabine and thioguanine has been well-tolerated and has shown surprising anti-leukemic activity at the lowest dose level studied. Importantly, the in vitro chemosensitivity testing and BH3 profiling accurately predicted the observed clinical responses while also confirming the etiology of the loss of therapeutic response. Accrual to this trial continues at higher dose levels to determine the maximum tolerated dose. Disclosures Letai: AbbVie, Inc: Consultancy, Research Funding; Tetralogic: Consultancy, Research Funding.

Description: Introduction: Autophagy is a paradoxical and evolutionarily conserved cellular process that is fundamental to eliminating harmful intracellular components and allowing cells to adapt to nutrient starvation or stress conditions. Ruxolitinib, a selective JAK1/2 inhibitor approved by the FDA for treatment of intermediate and high-risk primary myelofibrosis and polycythemia vera patients, provides clinical benefits, but fail to eliminate the myeloproliferative neoplasm (MPN)-initiating cells. Frequency of mutations in autophagy-related genes has recently been reported in myeloid neoplasms (Visconte et al. Leukemia 2017). Considering that JAK2V617F mimics constitutive growth factors signal and leads to mTOR/PI3K activation, we hypothesized that ruxolitinib induces autophagy as a mechanism of resistance. Aims: To investigate the effects of ruxolitinib treatment on autophagy-related genes and cellular processes, the potential benefit of autophagy inhibitors plus ruxolitinib in JAK2V617F cells, and to verify frequency and clinical impact of autophagy-related genes mutations in MPN patients. Methods: SET2 cells (JAK2V617F-positive) were treated with increasing doses or exposure to ruxolitinib and subjected to protein extraction or autophagy analysis. Ruxotilinib (300 nM) and autophagy inhibitors (3-methyladenine [1 mM], bafilomycin A1 [10 nM] and chloroquine [20 μM]) were used in monotherapy or in combination. The expression of 79 autophagy-related genes was investigated in SET2 cells upon ruxolitinib treatment by RNA-seq (data obtained from Meyer et al. Cancer Cell 2015) and validated by qPCR and Western blot. Autophagy was evaluated by acridine orange staining and LC3BI/II or SQSTM1/p62 consumption, apoptosis by annexin V/PI staining and caspase 3 cleavage, and mitochondrial damage by JC-1 staining. Mutations in 124 autophagy-related genes were investigated by whole genome sequencing in a cohort of 65 MPN patients from a single Institution. ANOVA and Bonferroni post-test and Mann-Whitney test were used as appropriated. Kaplan-Meyer curves, log-rank test, and cox regression analysis were applied for survival analysis. Results: Ruxolitinib treatment promoted an accumulation of acidic vesicular organelles and consumption of LC3BI/II and SQSTM1/p62 proteins, characterizing autophagy induction. Using a 1.3-fold cutoff in both directions, treatment with ruxolitinib modulated the expression of 26 out of 79 autophagy-related genes investigated. BCL2 and BCL2L1 downregulation, BAX upregulation and stable BECN1 expression were validated, which impacted BCL2/BAX and BCL2/BECN1 ratios. In SET2 cells, ruxolitinib treatment reduced important autophagy regulators in a dose-dependent manner, including STAT3Y705, STAT5Y694, mTORS2448, p70S6KT421/S424 and 4EBP1T70 phosphorytation, and BCL2 and BCL-XL expression. All autophagy inhibitors significantly suppressed the ruxolitinib-induced autophagy, being bafilomycin A1 (reduction of 89%) and chroloquine (reduction of 70%) more efficient than 3-methyladenine (reduction of 10%) (all p

Description: Introduction: MF is a Philadelphia-negative myeloproliferative neoplasm (Ph-negative MPN) with an heterogeneous outcome. In 2009, Cervantes et al. published the International Prognostic Score System (IPSS) to better determine outcomes in this disease. In the last decade, several recurrently mutated genes have been described in MF, some of them associated with prognostic impact in survival. We propose a novel prognostic score that incorporates molecular and cytogenetic data in patients with MF. Methods: We analyzed clinical, cytogenetic and molecular data from 623 patients with a diagnosis of primary MF (N=445), post-PV MF (N=109) and post-ET MF (N=69). Data was extracted from medical records at time of sample collection for analysis. Mutation data was obtained by next-generation sequencing analysis, performed with either paired tumor-normal whole exome sequencing (N=46) or selected gene panel for genes associated with myeloid malignancies (N=577). The following 16 genes were analyzed in all 623 patients and were considered as the common denominator for analysis: ASXL1, CALR, DNMT3A, EZH2, FLT3, IDH1, IDH2, JAK2, KIT, KRAS, MPL, NRAS, RUNX1, TET2, TP53, WT1. RAS mutations were considered as oncogenic mutations in NRAS and/or KRAS. Molecular high risk (MHR) mutations were considered as mutations in any one of the 4 genes: ASXL1, EZH2, IDH1, IDH2 (SRSF2 mutations were not included since they were not evaluated in all cases). Cytogenetic data was stratified into 4 risk categories (based on Tam et al, Blood 2009): (1) Diploid; (2) Del(13q)/Del(20q)/Trisomy 9; (3) Abnormalities of chromosomes 5, 7, 17 and complex karyotype; (4) Other abnormalities. To develop the model, the data was split into a training dataset (N=434) and a test dataset (N=189). Variables initially included in the initial training model were those with a p-value65 years), hemoglobin (25x109/L), peripheral blood blasts (〉1%), presence of constitutional symptoms, sex (male vs female), platelet count (

Description: Introduction It has been previously reported that increased fluid accumulation during peripheral blood hematopoietic stem cell (HSC) mobilization is associated with poor outcome in patients with amyloidosis who undergo autologous HSCT. It is unknown whether increased fluid accumulation during the early phases of HSCT is associated with poor survival in patients undergoing HSCT for other diseases. Objective To determine the impact of fluid accumulation during conditioning and in the first 10 days post HSC infusion on survival and risk of complications of patients who underwent both autologous and allogeneic HSCT. Methods We retrospectively reviewed the medical charts of 257 consecutive patients who underwent HSCT at our institution from January, 2007 until December, 2012. Information on patients' body weight (BW) was measured daily, starting at admission. The highest BW recorded until HSC infusion (D0) and until the first 10 days post-SCT (D+10) was used to calculate the BW increase in relation to the baseline BW. A ROC curve was built to determine the best cut-off point in BW increase that predicted for mortality. Information on the incidence of post-transplant complications was extracted from the time period that patients were admitted for transplant until discharge from the hospital. Endpoints analyzed included the presence or absence of respiratory failure, acute renal failure, sinusoidal obstruction syndrome (SOS), septic shock and requirement of diuretic use, hemodialysis, mechanical ventilation and ICU admission. Overall survival (OS) was estimated from the time of HSCT until death, and surviving patients were censored at last follow-up. Variables entered into the multivariate Cox analysis were those with a p-value

Description: Abstract 1933 Introduction: Infection by BK virus in the allo-HSCT setting is associated with the development of HC, which is a major cause of morbidity. There are few studies evaluating the impact of BK virus-associated HC on survival post allo-HSCT. Objectives: To evaluate the incidence of HC by BK virus in patients after allo-HSCT and its impact on survival. Methods: We retrospectively reviewed the medical charts of 107 patients who underwent allo-HSCT at Hospital Israelita Albert Einstein from July 2007 until November 2011. HC was defined by the presence of any degree of unexplained hematuria and positivity for BK virus in a urine sample by quantitative polymerase chain reaction (PCR) assay. CMV reactivation was defined as positivity in the antigenemia assay or greater than 165 copies in a quantitative PCR assay. Three patients were excluded because PCR results for BK virus were inconclusive, with 104 patients being analyzed in the final cohort. Cumulative incidence (CI) of HC, CMV reactivation and acute graft-versus-host disease (GVHD) were estimated taking into account the competing risk of death. Overall survival (OS) was estimated by the Kaplan-Meier method. Gray model was used for regression analysis of factors associated with the development of HC. Hazard ratios (HRs) were estimated by a Cox multivariable proportional hazards model, considering HC, CMV reactivation and acute GVHD as discrete time-varying covariates. Results: Median age was 28 years (range 6 months–76 years), and 60.5% of patients were male. About 37% had high-risk disease (refractory leukemia/lymphoma or 2nd-transplantation). Source of HSCs included matched related donors (37%), 10/10 HLA-matched unrelated donors (24%) and cord blood/haploidentical donors in 39%. The conditioning regimen was myeloablative in 81% of cases. The median follow-up of the whole cohort was 450 days (range 9–1624 days). At 1 year, the cumulative incidence of HC was 30.5% (95% confidence interval [CI] 21.8%–39.7%). The 1-year incidence of CMV reactivation and acute GVHD (all grades) was 57.1% and 39.7%, respectively. In a multivariate analysis taking into account age, sex, risk of disease, source of HSCs, intensity of conditioning, CMV reactivation and acute GVHD, only receiving cells from cord blood/haploidentical donors was associated with an increased incidence of HC (subhazard ratio 4.04, 95% CI 1.31–12.49, p = 0.015). The 1 year-OS of the whole cohort was 55% (95% CI 44–62%). Patients who developed HC had an inferior OS (1 year: 18% vs. 70%; HR= 4.40, p

Description: Introduction: Chronic myeloid leukemia (CML) is a hematological malignancy associated with the BCR-ABL1 fusion gene, which drives the proliferative disease phenotype by activating multiple signaling pathways. Most CML cases are successfully treated with tyrosine kinase inhibitors (TKIs) targeting BCR-ABL1. However, in some cases, drug resistance limits TKIs efficacy, and the identification of other crucial proteins in the BCR-ABL1 signaling pathways may contribute to optimize anti-CML approaches. IRS1 mRNA expression has been previously identified as positively correlated with overall survival in BCR-ABL1-positive adult acute lymphoblastic leukemia. In K562 cells, IRS1 has been identified as a binding partner of BCR-ABL1 protein and was capable of activating PI3K/Akt/mTOR and MAPK pathways. Recently, a pharmacological IRS1/2 inhibitor (NT157) has been developed and has shown promising results in preclinical studies on solid tumors. We herein aimed to investigate IRS1 and IRS2 expression and the effects of IRS1/2 inhibition on cell proliferation, apoptosis and clonogenicity in BCR-ABL1 positive and normal hematopoietic cells. Materials and Methods: Total bone marrow cells from healthy donors (n=11) and CML patients at the time of diagnosis (n=24) were submitted to gene expression analysis by quantitative PCR with specific primers for IRS1, IRS2 and β-actin. All subjects provided informed written consent and the study was approved by the ethics committee of the Institution. K562 cells were submitted to IRS1/2 pharmacological inhibition using NT157 (0.2, 0.4, 0.8, 1.6, 3.2 and/or 6.4 µM) for 24, 48 and 72 hours and were evaluated for cell viability (MTT assay), proliferation (Ki-67), apoptosis (Annexin V/PI), and protein expression/activation (Western blot). Alternatively, cells were submitted to IRS1 and IRS2 gene silencing using specific shRNA lentiviral delivery, and submitted to functional studies. NT157 effects were analyzed by in vitro hematopoietic colony formation of bone marrow cells from two patients with CML at diagnosis, and of normal cord blood cells from one individual. Cells were seeded at 4.5x104 per well in a culture system for 14 days. Statistical analyses were performed by Student's t-test or Mann-Whitney test, as appropriate. Results: IRS1 and IRS2 mRNA expression was similar between normal donors and CML samples (p ≥.05). NT157 treatment reduced K562 cell viability in a time and dose-dependent manner; using a nonlinear regression analysis, IC50 for cytotoxicity was 9.8, 0.6 and 0.68 µM for 24, 48 and 72 hours, respectively. NT157 0.8 and 3.2 µM reduced cell viability in 14% and 19% at 24 hours, 50% and 61% at 48 hours and in 59% and 68% at 72 hours of treatment (all p