ALBERT

Description: Purpose: Hypomethylating agents are approved in adults with Acute Myeloid Leukemia (AML) or Myelodysplastic Syndrome (MDS). By contrast, data in pediatric hematologic malignancies are scarce. Herein, we report the off-label administration of Azacitidine (Aza) in a cohort of children, adolescents and young adults (AYA). Methods: Patients from Robert-Debré, Saint-Louis and Armand-Trousseau University Hospitals (Assistance Publique-Hôpitaux de Paris), 25 year-old or younger at initiation of treatment and who received Aza between 2009 and 2019 were included. Data on indication, efficacy and toxicity of the treatment were retrospectively collected. Results: As 3 patients (pts) were treated twice with Aza at different stages of their disease, 35 treatments in 32 patients were analyzed. Median age at diagnosis was 11.7 y (range 0.1-22.4). Diagnosis were: 16 Acute Myeloid Leukemias (AML), 6 Juvenile Myelomonocytic Leukemias (JMML), 7 Myelodysplastic Syndromes (MDS), 2 Mixed Phenotype Acute Leukemias (MPAL) and 1 Interdigitating Dendritic Cells Sarcoma. Aza was administrated after a median of 2 lines of treatment (range 0-6) and front line in 5 out of 32 pts (16%; MDS = 4, JMML = 1). Concomitant therapy was administrated in 15/35 treatments (43%) (Sorafenib = 6, Gemtuzumab Ozogamicin = 2, donor lymphocyte infusions = 2, other = 5). Fourteen out of 35 treatments (40%) were delivered in patients with a history of hematopoietic stem cell transplantation (HSCT). Aza was administrated either intravenously (n = 11) or subcutaneously (n = 24) at a dose of 75mg/m² for 7 (20/35, 57%) or 5 (6/35, 17%) consecutive days every 28 days, i.e. same daily dose as in adults; at reduced doses (≤ 50mg/m²) in 3/35 patients; at a dosing scheme varying from one cycle to another in 6/35 patients. Patients received a median of 3 cycles of Aza per treatment (range 1-31). A total of 137 cycles was delivered. Aza was well tolerated with only 5/137 cycles delayed due to hematological (n = 3) or non-hematological (n = 2) toxicity. Aza was discontinued due to toxicity in 2/137 cycles (1 rectal bleeding, 1 severe sepsis). Anemia was noted in 68/130 cycles (52%), thrombocytopenia in 68/128 cycles (53%), neutropenia in 84/127 cycles (66%) and febrile neutropenia in 25/131 cycles (19%). Two grade 5 side effects were observed: 1 patient died from cerebral hemorrhage in a context of anti-platelet poly-immunization, another from septic shock in a context of neutropenia. Most common non-hematological side effects included: nausea, vomiting, diarrhea, subcutaneous injections lesions (local inflammation or hematoma) and infections. Responses to Aza are detailed in the attached table. Best responses to Aza included: 2 complete remissions (CR) both after 3 cycles, 3 CR with incomplete hematologic recovery (CRi) after a median of 2 cycles (range 1-2), 2 partial remissions (PR) after 2 and 3 cycles, 6 stable diseases (SD) during a median of 2 cycles (range 2-12) and 2 hematologic improvements. Overall response rate (sum of CR, CRi, PRs), was 19% (6/32) (3 non evaluable responses). Three out of the 6 patients treated with Aza combined with Sorafenib (AML = 4, MPAL = 2) obtained a response (CR: 2, CRi: 1). The association led to HSCT for 2 of them; the third patient had a CR maintained almost 3 years without HSCT, before relapsing on therapy. One patient with MDS had a SD for 12 months after palliative treatment with Aza. Overall, Aza treatment allowed to proceed to HSCT in 8 out of 32 patients (25%), 7 out of 8 proceeding to a first HSCT [CR: 1 patient, CRi: 3 patients, PR: 2 patients, SD: 1 patient, progressive disease: 1 patient]. These 8 pts included: 4 pts with AML, alive in CR after a median follow-up of 29.5 months (2 of them received concomitant targeted therapy); 2 pts with JMML (1 alive in CR after a follow-up of 25 months); 2 pts with MDS (both died, 7 and 30 months after Aza initiation). Finally, 24 out of 32 patients died and overall survival at 5 years was 23% (IC95% [11;48]) with no difference according to diagnosis. Conclusion: In a cohort of pediatric and AYA patients with heavily pretreated myeloid malignancies, Aza was well tolerated, and allowed to bridge 25% of patients to HSCT. Further prospective studies are needed to explore combination of Aza with targeted therapy in pediatric patients. Disclosures Boissel: NOVARTIS: Consultancy.

Description: Introduction: Pts with AML often present with hyperleukocytosis, defined with a white blood cell count (WBC) of 〉50 or 〉100 × 109/L. Hyperleukocytosis is associated with higher rates of complications and death especially when associated with clinical leukostasis. There are no clear guidelines outlining the best cytoreductive strategy and the use of leukapheresis is based on institutional practice. Limited data is available regarding characteristics of AML pts with hyperleukocytosis, treatment patterns, short and long-term clinical outcomes. Methods: Data were collected retrospectively from 12 centers in the United States and Europe. Eligible pts had newly diagnosed AML, WBC 〉 50 × 109/L, and had received intensive chemotherapy (IC). Pts with hyperleukocytosis who did not receive IC are described in a separate abstract. Kaplan-Meier methods estimated overall survival (OS) from time of presentation till death or end of follow-up. Clinical evidence of leukostasis was defined as new onset hypoxia, chest pain, headache, focal neurological symptoms, priapism, intestinal ischemia and acute renal failure attributed to hyperleukocytosis by the primary provider of the pt. Results: Among 1050 pts with AML and hyperleukocytosis whose data were collected, 787 were reported to have received intensive chemotherapy and were included in this analysis. The median age was 55 years (range [R], 15-86), and 51% were male (Table 1). Median WBC at presentation was 109 × 109/L (R, 47-561) and 57% had WBC 〉 100 × 109/L. Median hemoglobin was 9.2 g/dL (R, 3.6-126) and median platelet count was 31 x 109/L (R, 3-1268). A good, intermediate and poor risk karyotype were present in 31%, 51% and 18% of pts, respectively. Clinical leukostasis, tumor lysis syndrome (TLS) and disseminated intravascular coagulation (DIC) were present in 27%, 28% and 18% of pts at time of presentation, respectively (Table 1). Organs affected by leukostasis were the lung, CNS, retina, heart, kidney and GI tract in 44%, 36%, 6%, 6%, 5% and 4%, respectively. Leukapheresis was administered in 117 pts (15%) (Figure 1). Four centers did not use leukapheresis. 31% of pts with clinical leukostasis underwent leukapheresis and 10% of pts without clinical leukostasis received leukapheresis (p

Description: Introduction: Hyperleukocytosis, defined as a white blood cell count (WBC) of 〉50 × 109/L or 〉100 × 109/L, is seen in newly diagnosed AML and often results in leukostasis, increased risk of complications, and potentially early death. Those pts often require urgent evaluation and therapy. Leukapheresis is also sometimes used despite limited evidence supporting its use. There is limited data regarding the impact of time (day/night) and day (weekday/weekend) of admission and time to initiation of IC on outcomes in pts with hyperleukocytosis. Methods: Data were collected from 12 centers in USA and Europe (EU). Eligible pts had newly diagnosed AML, presented with a WBC 〉 50 × 109/L, and received IC. Univariate and multivariable logistic regression models stratified by centers (EU vs. USA) estimated odds ratios for death during induction (30-day mortality) and achievement of composite complete response (CRc) defined as CR+CR with incomplete count recovery (CRi). Univariate and multivariate Cox proportional hazard models stratified by centers (EU vs. USA) estimated hazards ratios (HR) for overall survival (OS). We evaluated the impact of leukapheresis, day of presentation (weekend vs. weekday), time of presentation (nighttime = 6pm-6am vs. daytime=6am-6pm), and time to initiation of IC. Studied covariates included age, Eastern Cooperative Oncology group performance status (ECOG PS), cytogenetics and molecular abnormalities, WBC, hemoglobin, platelet count, bone marrow and blood blast percentage, and presence of clinical leukostasis, tumor lysis syndrome (TLS) or disseminated intravascular coagulation (DIC) at presentation. Results: Among 1050 pts with AML and hyperleukocytosis whose data were collected, 787 were reported to have received IC and were included in this analysis. Of 787 pts receiving IC, 16.6% (95%CI, 13.9-19.3%) died during the first 30 days of IC. Leukapheresis was used in 117 pts (15%) in 8 of the 12 centers. In univariate analyses, neither weekend nor nighttime presentation nor use of leukapheresis impacted odds of death in the first 30 days. In multivariate analysis, higher odds of death during first 30 days were associated with age ³ 55 years (OR 3.2, p=0.015), ECOG PS ³ 2 (OR 4.4, 0.004), WBC 〉 100 × 109/L (OR 6.0, p=0.01) and presence of leukostasis (OR 4.5, p=0.005) and TLS (HR, 3.2, p=0.049). However, neither initiation of IC beyond 48 hours of presentation (vs. less than 48 hours) or use of leukapheresis significantly affected the odds of death in first 30 days (Figure 1A). Median OS of the entire cohort was 12.6 months (95%CI, 11.5-14.9) (Figure 2A). In multivariate analyses, age ³ 55 years (HR 2.6, p

Description: Context . AML patients (pts) with a high number of drivers have a poor prognosis (Papaemmanuil, NEJM 2016). Whether this unfavorable outcome is caused by clonal heterogeneity or by a high mutational load in the dominant clone remains undetermined. So far, the prognostic impact of clonal heterogeneity in AML has only been studied in pts with complex karyotypes, where it worsens prognosis (Bochtler, JCO 2013). We addressed this question in a two-center cohort of AML pts treated with IC. Methods . We retrospectively evaluated AML pts treated with IC from 2 centers with targeted sequencing of a 43-gene myeloid panel (mean depth 1193X). Variant allele frequencies were adjusted for copy number variation to estimate Cancer Cell Fractions (CCFs). Clone size for each mutation was derived from differences in CCF, assuming a linear accumulation of mutations. Relative clone sizes were then used to derive the Shannon Index (SI), a standard metric of genetic diversity (Maley, Nat Rev Cancer 2017, Figure A). Pts with no gene mutation were not evaluable for SI. Pts with a single mutation have a SI of 0, with increasing SI corresponding to greater dispersal of clone sizes, and thus indirectly of CCFs. Results . We included 292 pts (median age 57y, 37% ELN-2017 adverse risk), 269 (92.1%) with ≥ 2 mutations. Median number of drivers, including both mutations and cytogenetic alterations (the latter defined as in [Papaemmanuil, NEJM 2016]) was 4. SI increased with the number of drivers (Figure B, p60y (HR=1.48, p=0.022), WBC 〉 50x109/L (HR=1.74, p=0.005), and ELN 2017 adverse-risk AML (HR=1.74, p=0.001). There was no significant statistical interaction between number of drivers and SI. OS was also independently poorer in patients with higher number of drivers (HR=1.19, p=0.021) and with lower SI (HR=0.65, p=0.03) in a similar Cox model. Because of the positive correlation between the number of drivers and SI, but inverse prognostic role, we defined pts with high clonal diversity (132 [49.0%] of the 269 pts with ≥2 driver lesions) as those with a SI higher than the median value of SI of all AMLs with the same number of drivers (Figure B). In those 269 pts, median EFS was 11.3 months in pts (n=73) with ≥5 drivers vs 22.2 months in those with

Description: Context. AML is an oligoclonal disease. Intratumoral genetic heterogeneity (ITH) is pervasive in cancers and has often been linked to poor outcome. Except in patients (pts) with complex karyotypes (Bochtler, J Clin Oncol 2013), the clinical relevance of ITH remains unknown in AML. We assessed ITH in a real-life AML cohort. Methods. Since Nov 2015, all newly diagnosed AML pts at our institution were analyzed by targeted sequencing with a 60-gene myeloid panel at an average depth of 815X. Variant Allele Frequencies (VAF) were adjusted for copy number variation to estimate Cancer Cell Fractions (CCFs) and rank mutations by decreasing CCFs. Mutations were segregated into different clones when distant by 〉10% CCF. Ancestral (as opposed to secondary) mutations are defined as those belonging to the first clone (Figure). We could next derive for each pt the total number of clones and the ITH index, defined as the ratio of secondary to ancestral mutations (according to Turajlic, Cell 2018). Results. We studied 201 consecutive AML pts (median age 67 years, secondary AML 24%). The median number of mutations was 4 (range 0-12). Clonal heterogeneity (〉1 clone) was found in 71% of pts with a median of 2 clones per pt (range 1-5). 140 pts received intensive chemotherapy (IC), 50 hypomethylating agents (HMA) and 11 best supportive care (BSC) only. Signaling (FLT3, NRAS, KRAS, KIT, JAK2, CBL, CSF3R, BRAF, NF1, PTPN11, RIT1, CALR and MPL, 60%), DNA methylation (DNTM3A, TET2, IDH1/2, 54%), NPM1 (29%), spliceosome (U2AF1, SRSF2, SF3B1, ZRSR2, PRPF8, 27.9%) and tumor suppressors (PHF6, TP53, WT1, 27.4%) were the most frequently mutated pathways. ELN 2017 risk category was favorable, intermediate, adverse and not evaluable in 35%, 27%, 35% and 3% of pts respectively. Increasing ITH was associated with a higher number of clones (p=0.001) and of mutations (p0.05. ITH was not different among ELN 2017 risk categories (p=0.15). ITH was independent of age, WBC count and type of AML (secondary vs de novo), all p〉0.2. There was no significant difference in the number of mutations (p=0.12), clones (p=0.58) or ITH indexes (p=0.38) according to IC/HMA/BSC treatment strategies. We next performed a preliminary analysis of the prognostic impact of ITH in the 140 pts treated with IC (median age 58y), with a median follow-up of only 12.5 months. 117 (84%) pts achieved CR and 32 (23%) were transplanted in first CR. Median event-free survival (EFS) was 18.7 vs 8.0 months in pts with adv and non-adv ELN risk, respectively (p=0.016). In univariate analyses, DNA methylation (p=0.04) and spliceosome (p=0.007) mutations were the two pathways predicting adverse outcome. The number of mutations (p=0.6) or of clones (p=0.8) had no impact on EFS. Pts with fewer secondary than ancestral mutations (ITH

Description: Introduction: Hyperleukocytosis at time of acute myeloid leukemia (AML) diagnosis is associated with increased disease-related complications as well as early mortality. Many AML patients are not candidates for intensive chemotherapy (IC) because of disease-related or patient-specific factors. Limited data is available regarding the characteristics and outcomes of newly-diagnosed AML who present with hyperleukocytosis and do not receive IC. Methods: We retrospectively analyzed data from patients with newly-diagnosed AML and hyperleukocytosis (defined as white blood cell count [WBC] of 50 × 109/L or greater) who were reported not to have received IC at 12 major institutions in the United States, Spain, Germany and France from 1982 to the end of 2016. Collected variables included age, sex, Eastern Cooperative Oncology Group Performance Status (ECOG PS), WBC, hemoglobin level, platelet count, renal and hepatic chemistry parameters, cytogenetic risk group, molecular abnormalities (if available), presence of tumor lysis syndrome (TLS), disseminated intravascular coagulation (DIC), clinical evidence of leukostasis, admission to an intensive care unit (ICU) at presentation, receipt of hydroxyurea, and administration of leukapheresis. Clinical evidence of leukostasis was defined as new onset hypoxia, chest pain, headache, focal neurological symptoms, priapism, intestinal ischemia and acute renal failure attributed to hyperleukocytosis by the primary provider of the patient. Kaplan-Meier analysis was used to estimate overall survival (OS) from time of presentation until death or end of follow-up. Patients with hyperleukocytosis who received IC are described in a separate abstract. Results: Of 1050 patients with AML and hyperleukocytosis reported to our dataset, 220 patients were reported not to have received IC and were included in this analysis. For those 220 patients, median age was 75 years, 57.7% were male, and most (62.8%) had an ECOG PS of 2 or greater. Median WBC, hemoglobin, and platelet count at presentation were 131.4 × 109/L (range [R], 50.4-620), 8.96 g/dL (R, 3.6-15.9), and 34 (R, 3-393), respectively; 61.5% presented with a WBC greater than 100 × 109/L. Cytogenetically-defined poor risk AML was diagnosed in 26.1% of patients. TLS, DIC or clinical leukostasis was present in 25.6%, 15.7%, and 32.5% of patients, respectively. Pulmonary, central nervous system, renal, cardiac, gastrointestinal, or retinal clinical evidence of leukostasis was present in 52.9%, 17.1%, 11.4%, 10%, 5.7% and 2.9%, respectively, of those with clinical leukostasis. The majority (72.9%) of patients received initial therapy with hydroxyurea with a median time from presentation to administration of 12 hours (R, 1-144). Only 15% of patients underwent leukapheresis. Commonly-used non-IC therapies included hypomethylating agents, clofarabine, low dose cytarabine, or best supportive care. The median OS of the entire cohort was only 22 (95%CI: 13-37) days. The 30-day mortality was 57.4%. The 60-day, 90-day, 180-day, and one-year OS probabilities were 37%, 31%, 20%, and 12%, respectively. Only 4.3% of patients proceeded to allogeneic stem cell transplant. Patients presenting with WBC 〉100 × 109/L (N=79) had a worse OS than those presenting with WBC

Description: Objectives: Tisagenlecleucel (CTL019) is a chimeric antigen receptor T cell- therapy that reprograms autologous T cells to target CD19+ leukemia cells, approved in the US (2017) and in the EU (2018). This study reports the feasibility, safety and efficacy of CTL019 in patients with relapsed/refractory B-cell acute lymphoblastic leukemia (B-ALL) treated in Robert-Debré and Saint-Louis University Hospitals (Assistance Publique-Hôpitaux de Paris/Université de Paris). Methods: Patients (pts) with an apheresis performed between march 1, 2016 and june 15, 2019, included in sponsored-clinical trials or treated within the French compassionate program or with the commercial product, were analyzed. All infused pts received a fludarabine-cyclophosphamide based lymphodepletion before a single infusion of CAR-T cells (2 to 5 x 106 CTL019/kg if less than 50 kg; a fixed dose of 1 to 2.5 x 108 CTL019/kg if 〉 50 kg) Results: 55 pts were referred from 25 French centers. Forty-one pts with a median number of relapses of 2 (range, 1-5) were infused with CTL019 at a median age of 18.2 y (range, 1-29.2). Eight pts were not infused due to progressive disease (n=4), screen failure (n=3) or fatal septic shock (n=1). Six pts were waiting to be infused at time of analysis. Out of the 41 infused pts, 26 had a prior history of allogeneic SCT (63%), 11 had received blinatumomab (27%). Among the 40 pts evaluable at one month post-infusion, 38 were in CR/CRi (95%) (one progression at day 5 after infusion and one toxic death at D6), 35/38 (92.1%) being clone-specific Ig-TCR MRD negative. After 3 months 21 out of 26 evaluable pts (81%) had a negative MRD. The 5 remaining MRD positive pts did relapse. No pt underwent allogeneic HSCT while in CR after CTL019 infusion. Median event free survival (EFS) and overall survival (OS) were not reached with a median follow up of 7.2 months (range, 0.2-36.3). The 18-month OS probability was 80% (95%CI, 58%-92%). The 18-month EFS probability was 58 % (95%CI, 37%-74%). Ten pts relapsed after a median time of 3.4 months (range, 1.9-10): 3 relapses were CD19+ and 5 CD19- (4 out of these 5 pts had a preexposure to blinatumomab), 2 being of undetermined status. Loss of B-cell aplasia (BCA) occurred in 9 pts after a median time of 3 months (range, 2-12), followed by relapse for 2 pts (one concomitant with loss of BCA and one 7 months later). Three pts received a second infusion of CTL019 for loss of BCA with no further expansion of CAR-T cells. Prior treatment with blinatumomab was a significant predictive factor for relapse (HR=6.082, 95%CI, 1.2-30, p=0.0005) in a univariate analysis. There was a trend toward increased risk of relapse with increased disease burden (≥ 5%) before lymphodepletion regimen (HR=2.4, 95%CI, 0.7-8, p=0.14). Twenty-two pts experienced a CRS (≥ grade 3: n=13, all ≥ 10 y). ICU was required for 14 pts (34%). One 29 year-old pt died of an uncontrollable CRS at day 6. Ten pts received tocilizumab, 4 pts siltuximab and 9 pts corticosteroids. Age ≥ 10 y (p=0.04) and a high disease burden just before lymphodepletion (marrow blasts ≥ 5%) (p=0.01) were associated with a higher risk of CRS ≥ grade 3. Nine neurological events have been reported, being reversible except in 2 cases (one death in combination with grade 5 CRS-cf supra-, one HHV6-related encephalitis with neurological sequelae). Among the 9 pts who presented neurological events, 8 experienced CRS grade ≥ 3 (RR=17.2, 95%CI, 3.22-100.3, p=0.0001). By day 28, unresolved neutropenia grade ≥ 3 was reported for 13 pts. G-CSF treatment was required in 21 pts overall. Thrombocytopenia grade ≥3 was reported for 14 pts. Conclusion: CTL019 confirms its efficacy with a high response rate after infusion and very encouraging early outcomes in a cohort of pts heavily pretreated for refractory or multiply relapsed B-ALL. Persistent remissions with a potential for cure were observed without additional HSCT, relapses occurring within the first year after infusion of CTL019. Accurate assessment of a potentially deleterious effect of Blinatumomab preexposure notable on CD19 negative relapse will need more pts and a longer follow-up. Toxicity profile was tolerable and manageable thanks to collaboration between intensivists, neurologists and hematologists. The identification of severe CRS predictive risk factors (high disease burden just before lymphodepletion and age ≥ 10 y) points towards the reinforcement of toxicity monitoring and treatment anticipation in these cases. Disclosures Boissel: NOVARTIS: Consultancy. Baruchel:NOVARTIS: Consultancy.