ALBERT

Description: Objetives: Analyze the prognostic significance of CD38 expression compared to other prognostic factors. Patients and methods: We studied retrospectively and prospectively at our institution 160 patients (pts) with diagnostic of CLL who met the diagnostic criteria of National Cancer Institute-Working Group (NCI-WG), 97 men and 63 female with an age range of 33 – 90 years (median 62) diagnosed between January 1989 and December 2003 and evaluated up to June 2004. Sixty nine pts showed CD38 positive cells and 91 were CD38 negative. CD38 expression was determined by flow cytometry defining as a higher expression 〉 7% CD38 positive cells. (Krober A et al. Blood15: 1410–1416.2002). Event Free Survival (EFS) and Overall Survival (OS) were analized according to different characteristics at diagnosis. No. Patients %EFS 72 mo p= %OS 72 mo p= Binet Stage A /B-C 129/31 65/30 0.000 90/92 0.245 Rai Stage 0 /I – II – III – IV 92/68 72/37 0.000 94/94 0.339 TDLI 〈 / ≥ 12 mo 23/126 41/63 0.007 65/100 0.001 Light Chains kappa / lambda 94/66 68/50 0.473 90/95 0.702 CD38 Positive / Negative 69/91 32/82 0.000 81/100 0.000 Statistical significant difference was observed in Binet stage, Rai stage, TDLI and CD38 expression for EFS and in TDLI and CD38 expression for OS. Considering these variables with p value of

Description: INTRODUCTION Secondary Acute Myeloid Leukemia (s-AML) evolves from a previous hematopoietic clonal disease such as Myelodysplastic Syndromes (MDS/AML), myeloproliferative neoplasia (NPM/AML), medullary insufficiencies - aplastic anemia - (AA/AML) or exposure to chemo or radiotherapy (t-AML). The objective of this work is to describe and highlight the demographic, pathophysiologic and clinical-therapeutic characteristics of s-AML patients compared with p-AML. METHODS This is a retrospective cohort study based on the casuistry from 34 reference centers in Latin America during a period of 10 years (JAN10'-MAY19'). Patients ≥18 years old with primary AML, excluding the promyelocytic subtype (p-AML), and s-AML were admitted. Age, gender, performance status, comorbidity, cytogenetics, mutations, AML subtypes, extramedullary compromise, treatments and overall survival (OS) were analyzed. Statistically, Graph Pad Prism version 5.00 and, SPSS version 17 were used. RESULTS One thousand eleven patients with newly diagnosed AML were recruited, 693 (68.5%) corresponded to p-AML and 318 (31.5%) to s-AML. The demographic differences between p-AML and s-AML are shown on Table 1. Subtypes of s-AML: t-AML (18.5%), MDS/AML (58.2%), NMP/AML (13.5%), AA/AML (5.7%) and others s-AML (4.1%). Global median age was 58 years (R 18-93) and male 52%. Extramedullary compromise in CNS (3.2%) and other organs (5.5%). Seven hundred ninety-three cytogenetic studies were evaluable (based on MRC classification): High (22.3%), Intermediate (68.3%) and Low Risk (9.3%). FLT3 mutation was more frequently found in p-AML. In s-AML, the multivariate study showed short overall survival associated with ECOG ≥2 (HR:2.0), white blood count ≥ 50x109/L at diagnosis (HR:1.9), poor risk karyotype (HR:1.6) and age over 60 years (HR:1.5). At least, 883 patients received treatment (Table 2). During this study period, 211 patients (21%) were transplanted; 49 (23%) were s-AML; histoidentical related donor (46%), haploidentical (39%), non-related (8%) and autologous (7%). The median survival for all AML was 11.0 months with a statistically significant difference in favor of the p-AML (Figure 1). CONCLUSION Performance status (by ECOG ≥2), age ≥60, level of leukocytes a ≥50x109/L, poor risk karyotype and s-AML subtype at diagnosis had a significant worse impact on overall survival. Most patients with s-AML came from MDS, they were older and their incidence increased as the population aged. They presented more comorbidities and worse performance status. Undoubtedly, our findings showed that s-AML is a distinct high risk subset of myeloid disorder with adverse prognosis and represents a therapeutic challenge. Disclosures No relevant conflicts of interest to declare.

Description: Introduction: During the last decade, strong prognostic factors and new compounds emerged for the treatment of CLL. The initial experience with the combination of FCR at MDACC as salvage therapy and later in untreated patients (pts) promote us to use these regimen since March 2001. Purpose: To evaluate the efficacy of FCR in improving the complete remission (CR), disease free survival (DFS) and overall survival (OS) rates in pts previously treated with chlorambucil-prednisone as a single therapy and untreated CLL pts. Patients and methods: A total of 32 CLL pts, 16 after relapse and 16 untreated with progressive disease completed treatment and evaluation, 3 pts are still on treatment. FCR consisted of Fludarabine 25 mg/m2 iv on days 1 to 3, Cyclophosphamide 250 mg/m2 iv on day 1 to 3 and Rituximab 375 mg/m2 iv on day 1 given at 4 weeks interval up to 4–6 cycles. Response was assessed 4–8 weeks after treatment. CR was defined by CLL/NCI-WG. Minimal residual disease (MRD) negative was defined as 7% of cells) in 53% and negative in 47% of the cases. Results: The CR was obtained in 66% of the pts, nodular partial remission (NPR) in 19%, PR in 9% and stable disease in 6%. Characteristics Pts. # % CR % MRD negative % DFS 24 mo P= # OS 24 mo P= Untreated Pts 16 81 100 81 0.64 90 0.81 Treated Pts 16 50 81 76 87 CD38 Positive 17 65 82 65 0.01 80 0.28 CD38 Negative 15 67 87 100 100 Total 32 66 84 78 89 Neutropenia grade 3–4 was observed in 31% of the courses, 5% of the pts required hospitalisation due to infeccious episodes. Conclusion: In patients with CLL, FCR induce a high CR, MRD negative and DFS rate. Patients with CD38 negative expression correlated with a better DFS.

Description: Introduction: Treatment-free remission (TFR) is an emerging treatment goal for chronic myeloid leukemia (CML) patients in deep molecular response (DMR). Current evidence shows that 40%-60% of patients relapse while in TFR; and nearly all regain response once tyrosine kinase inhibitors (TKIs) treatment are reinitiated. However a robust predictor of prolonged TFR has not been reported yet. Considering real-life setting, 2 key factors may affect TFR outcome if not properly done: Access to serial molecular monitoring at optimal timepoints and quality laboratory terms as accuracy, sensitivity and rapid results. This motivated the creation of the AST study in our region to guarantee adequate molecular monitoring for TFR in Argentina and characterize new prognostic biomarkers helpful to identify more accurately patients who will be able to sustain TFR. We aimed to assess the proportion of patients with sustained major molecular response (MMR) after TKIs discontinuation and define precise conditions for stopping treatment. Methods: This prospective, multicentre Argentina Stop Trial (AST) trial is recruiting chronic phase CML patients under TKI treatment for at least ≥ 4 years, in DMR (≥MR4.0) sustained for ≥ 2 years in standardized laboratory, confirmed typical BCR-ABL1 transcripts b3a2 and/or b2a2 and aged 〉 18 years. Molecular tests are centralized in 2 harmonized laboratories and performed monthly for the first 6 months, every 2 months until the first year, and every 3 months during the second year. If patients lost MMR, TKI was restarted immediately. Molecular relapse Free Survival was estimated by Kaplan-Meier method. Difference between survival variables was evaluated through log-rank test. Multivariate analysis was performed through Cox proportional hazards model. The cutoffs of the numerical variables were considered according to the log-rank test. Results: Between February 2019 and July 2020, we evaluated 50 CML patients of whom 46 were enrolled from 7 centers in Argentina and 4 were screening failures. Recruitment was interrupted due to COVID-19 pandemic. Patient median age was 57.5 years (range 24-85). Before discontinuation, TKI treatment was as follows: Imatinib 37/46 (80%), Nilotinib 5/46 (11%) and Dasatinib 4/46 (9%), 2G-TKI as 1st line, 11% of the patients received non-branded treatment. Sokal risk score showed to be low in 22 patients (48%), intermediate in 14 (30%) and high in 10 (22%). Median follow-up was 10 months (range 4-17) and the estimated molecular relapse-free survival was 80.2% (95%CI 69-93) at 6 months Fig 1. Longer DMR durations before discontinuation were associated with increased probability of maintaining response at 6 and 12 months: 83.2% for patients who had 〉54 months in DMR vs 70% with

Description: INTRODUCTION: Long-term survival of patients with chronic myeloid leukemia (CML) has significantly improved since the introduction of BCR-ABL1 tyrosine kinase inhibitors (TKIs). Several considerations about the side effects, risks and cost associated with the lifetime treatment, have led patients and physicians to explore the possibility of TKI discontinuation after achievement of a sustained deep molecular response (DMR), so-called treatment-free remission (TFR). Several clinical trials show that approximately half of patients who achieve a sustained DMR during TKI treatment maintain molecular remission after suspension of TKIs. There is currently no biomarker that reliably predicts TFR in CML, mainly due to different study designs that have generated inconsistent data. Thus, further investigations are needed to identify factors that consistently favor achievement of TFR. With the aim of developing a biomarker for TFR prediction we analyzed the phenotype of Natural Killer (NK) cells and their relation to successful TKI cessation. METHODS: This analysis was conducted as a substudy of the Argentina Stop Trial. Altogether, 50 consecutive chronic phase CML patients who participated in the clinical trial were recruited from 7 Argentinian centers. Peripheral blood samples were collected before stopping TKI treatment, at month 3, 12 and at any time when MR3.0 was lost. Freshly isolated mononuclear cells from 46 patients were immunophenotyped by staining with CD3, CD16, CD25, CD56, CD57, CD158, NKp30, NKp44, NKp46, NKG2A, NKG2C, NKG2D and PD-1 antibodies and NK cells subpopulations were analyzed by flow cytometry (BD FACS Canto™II). Molecular recurrence-free survival was estimated by the Kaplan-Meier method and compared within groups by the log-rank test. The cutoffs of the numerical variables were optimized according to the log-rank test. Quantitative variables were dichotomized according to receiver operating characteristics (ROC) curves in order to describe sensibility and specificity. Multivariate analysis was performed through Cox proportional hazards model. Main results are provided with hazard ratio (HR) at 6 months and 95% confidence intervals (95% CI). RESULTS: At the time of discontinuation the median proportion of NK cells (CD3-CD56+) among lymphocytes was significantly increased in patients compared with controls (15% vs 9%, P = 0.0016). A significant difference between molecular relapsed vs no-relapsed patients was observed when optimal cutoff (0.43) for CD56bright low and high was determined (at 6 months 74% vs 100% respectively, log rank test, p=0.023). At this time of follow up, no significant difference was observed for CD56dim NK cells. Phenotypic markers for adaptive-like NK cells were analyzed, however, no significant differences were observed between the non-relapsing and relapsing groups. Nevertheless, molecular non-relapsing patients had significantly higher frequencies of PD-1+ NK cells as compared with molecular relapsing patients (at 6 months 85% vs 64%, Log Rank test, P=0.009). Based on the ROC and Youden Index analysis, at 6 months the 1.2 cutoff shows an 80% specificity and 50% sensitivity. Moreover, after multivariable Cox proportional analysis, including age, time of treatment, deep molecular response time, Sokal risk, NK cells and PD-1+ NK cells, the last subpopulation was identified as an independent prognostic factor for molecular-relapse-free survival (Hazard ratio = 3.63; 95% CI 1.3 - 10.1; P=0.014). CONCLUSIONS: The clinical impact of NK cells in patients who have discontinued TKIs is controversial. The effects of TKIs against immune cells, including NK cell subsets, could depend on the type of TKIs; this aspect is particularly relevant in Argentinian treated patients real world, since many different copies of TKIs are routinely used in the clinical setting. Our study is the first, to our knowledge, to report a significant increase in PD-1 expression in NK cells at TKI cessation in patients who do not relapse. Accordingly to recent reports, PD-1 expression is more abundant on NK cells with an activated and more responsive phenotype and does not mark NK cells with an exhausted phenotype. To fully understand how PD-1 on NK cells modulates immune responses we are planning to carry out functional studies. In the future, we are also planning a comprehensive study of immune suppressors, including regulatory T cells and myeloid-derived suppressor cells. Disclosures Moiraghi: Novartis: Speakers Bureau; BMS: Speakers Bureau. Varela:Novartis: Consultancy, Speakers Bureau. Pavlovsky:Varifarma: Speakers Bureau; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Other: Travel grants, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: travel grants, Speakers Bureau. Pavlovsky:Pint Pharma: Speakers Bureau; Pfizer: Speakers Bureau; BMS: Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.