Kurzfassung: Background: Genetic information has become critical to understand the development of T-cell acute lymphoblastic leukemia (T-ALL) and to elucidate the origin of disease relapse. Several genetic markers, together with measurable residual disease (MRD), are considered strong predictors of patient outcome. However, the prognostic significance of genetic markers can varie according to treatment. Aim: We used targeted deep sequencing to analyze the genetic profile of 125 T-ALL patients enrolled in three consecutive MRD-oriented trials from the Spanish PETHEMA (Programa Español de Tratamientos en Hematología) group. Genomic information was analyzed together with the main clinical and biologic data in a subset of 111 patients with detailed clinical and outcome data to determine the prognostic significance for overall survival (OS) and cumulative incidence of relapse (CIR). Methods: Genetic mutations were detected using a custom gene panel and sequenced on a MiSeq platform. Alignment, variant calling, filtration and annotation of variants were done using standardized pipelines. OS curves were plotted by the Kaplan-Meier method and compared by the log-rank test. CIR was estimated using cumulative incidence functions by competing risks analysis. A Cox proportional hazard regression model was used to identify predictive factors for OS. Statistical significance was set at (two-sided) p-values & lt;0.05. Results: Recurrently mutated genes found in ≥4/125 patients involved transcription factor tumor suppressor genes (PTEN, BCL11B, RUNX1, GATA3, ETV6), epigenetic regulators (PHF6, DNMT3A, EP300, KMT2C, EZH2, TET2), DNA mismatch repair genes (MSH2), ribosomal (RPL5) and RNA splicing (U2AF1) genes, and genes involved in the RAS/MAPK (NRAS), WNT (FAT1, FAT3), IL7R-JAK-STAT (JAK3, JAK1, IL7R) and NOTCH1 signaling pathways, respectively. Mutations in the latest pathway (NOTCH1 & FBXW7) was found in 88/125 (70%) patients. Clinical-genetic correlations revealed that patients with mutations in JAK3, DNMT3A, N/KRAS, IL7R, MSH2 or in U2AF1 were associated with lower OS (vs unmutated patients). None of the mutated genes had impact on CIR. Upon grouping the mutated genes according to their functional role and potential biological impact on T-ALL, two gene signatures were defined. These included the aging gene signature (DNMT3A and U2AF1) characterized by mutations in genes identified in clonal hematopoiesis of indeterminate potential (CHIP); and the treatment resistance gene signature (JAK3, N/KRAS, IL7R and MSH2), defined by mutations in genes involved in resistance to the ALL therapy. Both clusters identified patients with poorer response to therapy (poorer blast clearance on day 14 of induction treatment and lower CR rates). Therefore, we considered together (worse outcome genetics [WOG] signature) for univariate and multivariate analyses. WOG and MRD level (0.1% cut-off) on day 35 after induction therapy (+35d MRD) showed significant prognostic impact in the univariable and multivariable analyses for OS (3y) with a hazard ratio (95% CI) of 2.4 (1.2; 4.8) and 2.7 (1.4; 5.1), respectively (Table 1). OS according to these two variables allowed risk stratification of T-ALL into low, intermediate- and high-risk (HR) patients with significantly different outcomes (p & lt;0.001) (Figure 1). Conclusion: A genetic signature with independent prognostic significance of MRD has been identified in this cohort of patients included in MRD-oriented trials. This gene signature (WOG) together with MRD could help to improve risk-stratification of adult T-ALL patients and would be of interest in the search for new therapies for HR patients Funding: Support from AECC (GC16173697BIGA); ISCIII (PI19/01828 and PI19/01183), co-funded by ERDF/ESF, "A way to make Europe"/"Investing in your future", CERCA/Generalitat de Catalunya SGR 2017 288 (GRC)/ C González-Gil was supported by AGAUR grant (2020 FI_B2 00210). Figure 1 Figure 1. Disclosures Diaz-Beyá: Jazz: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astellas: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; 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, Speakers Bureau. Mercadal: Gilead Sciences, Inc.: Honoraria, Speakers Bureau; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Tormo: Astellas: 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; Jazz Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Barba: Amgen, Celgene, Gilead, Incyte, Jazz Pharmaceuticals, MSD, Novartis, Pfizer and Roche, Jazz Phar,aceuticals: Honoraria; Cqrlos III heqlth Institute, aSOCIACION espanola contra el cancer, PERIS: Research Funding. Maciejewski: Regeneron: Consultancy; Novartis: Consultancy; Bristol Myers Squibb/Celgene: Consultancy; Alexion: Consultancy. Ribera: ARIAD: Consultancy, Research Funding, Speakers Bureau; AMGEN: Consultancy, Research Funding, Speakers Bureau; Pfizer: Consultancy, Research Funding, Speakers Bureau; TAKEDA: Consultancy, Research Funding, Speakers Bureau; NOVARTIS: Consultancy, Speakers Bureau; SHIRE: Consultancy, Speakers Bureau.

Kurzfassung: Introduction and objective. SARS-CoV-2 pandemic has deeply impacted in Spain. In cancer patients (pts) the lethality has been higher than in normal population, but, little is known on the impact in adults with ALL. Our objective was to analyze the frequency, clinical characteristics and outcome of adult ALL patients infected by SARS-CoV-2. Methods. Between March 1, 2020 and May 31, 2020 (the period of the peak of COVID-19 infection in Spain) two registries from the PETHEMA (Programa Español de Tratamientos en Hematologia) and GETH (Grupo Español de Trasplante Hematopoyético y Terapia Celular) groups were activated to recruit adult patients with ALL and COVID-19 infection confirmed by PCR. The PETHEMA registry was based on ASH proposal (www.ashresearchcollaborative.org/covid-19-registry) and the GETH registry was specifically performed for hematological diseases and COVID-19 infection. Both registries were merged for this study. Eighty-four Spanish centers were contacted and weekly reminds were sent until May 19, 2020. The demographic and clinical characteristics of ALL and COVID-19 infection, the comorbidities, the treatment and outcome were collected. The study was closed for follow in July 10, 2020. Results. Fifty-six of 84 centers answered the survey and 28 patients with ALL and COVID-19 infection were identified in 17 of them, especially on March (n=11) and April (n=15). Median age was 46 (range 20-78) yrs. and 19 were aged over 40 yrs. Fifteen pts were male, 1 was active smoker and 9 showed one or more comorbidities (chronic liver disease [n=2] diabetes [n=1] , hypertension [n=5], cardiopathy [n=2] , prior malignancy [n=1] and hypogammaglobulinemia [n=1] ). ALL was of B-cell precursors in 18 pts (Ph+ in 6) and T in 10. Twenty-six pts were on treatment of LAL (induction [n=10], consolidation [n=3] , maintenance [n=1], HSCT [n=5] , rescue [n=6], and palliative [n=1] ). Eight patients were previously submitted to allogeneic HSCT, CAR T [n=1] or immunotherapy with monoclonal antibodies (inotuzumab, n=4) and 21 were receiving immunosuppressive drugs (corticosteroids in 11, fludarabine in 4, among others). Eleven pts showed neutropenia & lt;0.5x109/L and 18 lymphocytopenia & lt;0.5x109/L. Median value of C reactive protein was 28.7 mg/L (0.9-311.7) and D-dimer 690 ng/mL (120-31,200). The main clinical characteristics of COVID-19 infection were: fever (n=18), cough (n=16), shortness of breath (n=9) and asthenia (n=11) and 5 pts were asymptomatic. The most frequency therapies were hydroxychloroquine/chloroquine (n=23), combined or not with lopinavir/ritonavir. Tocilizumab was given to 8 pts. Twelve pts required oxygen supply and 7 required ICU support (median stay 16 [1-47] days). COVID-19 was solved in 18 pts, although 5 pts showed PCR+ persistence (median 25 [16-91] days) after resolution of symptoms. The treatment of ALL was stopped/modified in 11 pts. Nine pts dead (COVID-19 [n=6] , COVID-19 and ALL progression [n=2] and COVID-19 andPseudomonassepsis [n=1] ). A trend for higher mortality was observed in patients with neutropenia & lt;0.5x109/L and in those with lymphocytopenia & lt;0.5x109/L. Conclusion. The frequency of adult patients with ALL and COVID-19 infection can be considered high, given the low incidence of adult ALL. COVID-19 infection was frequent in patients with advanced age and on ALL therapy. The frequency of severe COVID-19 infection and the mortality were high. Supported in part by 2017 SGR288 (GRC) Generalitat de Catalunya and "la Caixa" Foundation. Disclosures Ribera: Pfizer, Amgen, Ariad, Novartis:Consultancy, Speakers Bureau;Pfizer, Amgen:Research Funding.Barba:Amgen, Celgene, Novartis, Pfizer:Speakers Bureau;Amgen, Celgene, Gilead, Jazz Pharmaceuticals, Novartis, Pfizer, Shire:Consultancy.

Kurzfassung: Introduction: Recent studies have shown that young to middle-aged adults who receive a pediatric-inspired chemotherapy regimen for treatment of Ph-neg ALL do not appear to require an alloHSCT if they achieve good response on MRD testing after induction and/or consolidation therapy. Patients (pts) who are not good MRD responders achieve better outcomes with alloHSCT than their counterparts who do not receive alloHSCT. However, it is not clear if this approach can specifically apply to adult ALL pts with HR features at baseline. The aim of the prospective ALL-HR-11 trial (NCT01540812) from the Spanish PETHEMA Group was to evaluate response of HR Ph-neg adult ALL patients to a different post-induction therapy (chemotherapy or alloHSCT) according to MRD levels (centrally assessed by 8-color flow cytometry [FCM] ) at the end of induction (week 5) and consolidation therapy (week 17).. Patients and methods: HR ALL included one or more of the following parameters at baseline: age 30-60y, WBC count & gt;30x109/L for B-cell precursor ALL or & gt;100x109/L for thymic T-ALL, pro-B, early or mature T-ALL, 11q23 or KMT2A rearrangements or complex karyotype. Induction therapy included vincristine, prednisone, daunorubicin and asparaginase (E coli native or PEG according to center availability) for 4 weeks (Induction-1). FLAG-Ida was administered as intensified induction (Induction-2) in pts not achieving CR or in those in CR with MRD≥0.1% at the end of induction. For pts in CR and MRD & lt;0.1% early consolidation therapy included 3 cycles with rotating cytotoxic drugs with high-dose methotrexate, high-dose ARA-C and high-dose asparaginase (E coli native or PEG). These pts continued with delayed consolidation (identical to that of early consolidation) followed by maintenance therapy up to 2y in CR if MRD levels after consolidation were & lt;0.01%; otherwise they were assigned to alloHSCT. Pts in CR after Induction-2 received one consolidation cycle and were assigned to alloHSCT. Main outcome measures were: complete response (CR), overall survival (OS) and cumulative incidence of relapse (CIR), assessed by competing risk analysis. Results: On April 2019, 307 HR ALL pts were evaluable. Median (range) age was 40 (15-60) y, 192 were males, 211 precursor B-ALL and 96 T-ALL, with a median WBC count of 12.9 (0.2-564) x109/L. Results of Induction-1 (n=304, 3 on induction): therapy-related death: 12(4%), resistance: 39(13%), CR: 253(83%). MRD & lt;0.1% at the end of induction was observed in 77% of CR patients. Induction-2 was administered to 88 patients (due to no CR: 37, or to CR and MRD≥0.1%: 51). Overall response rate: 277 (91%). The 5y CIR and OS probabilities for the whole series were of 44%±8% and 48%±7% (median follow-up: 2.06y [range: 0-7.55y]). By intention-to treat after Induction-1, 94 pts were assigned to alloHSCT and 190 to delayed consolidation and maintenance. The 5y CIR and OS probabilities were of 37%±13% and 38%±11%, respectively, for pts assigned to alloHSCT, and of 48%±10% and 55%±10%, respectively, for those assigned to chemotherapy (P & lt;0.001 for OS [Figure 1], and P=0.243 for CIR). Patients with MRD & lt;0.1% at the end of induction and MRD & lt;0.01% at the end of consolidation (n=137) showed a 5y CIR and OS of 42%±11% and 66%±11%, respectively (P & lt;0.001 for both, Figure 2). Patients with MRD levels & lt;0.01% on day14 of induction-1, end-induction-1 and end-consolidation (n=17) showed 5y CIR and OS probabilities of 17%±19% and 90%±19%, respectively. Conclusions: This trial, in which post-induction therapy was only based on MRD results assessed by FCM, suggests that avoiding alloHSCT does not hamper the outcome of HR Ph-neg adult ALL pts with adequate MRD response after induction and after consolidation. Better post-remission alternative therapies are specially needed for patients with poor MRD clearance. Supported by grants PI14/01971 FIS, Instituto Carlos III, and SGR225 (GRE), Spain. Disclosures Montesinos: Novartis: Membership on an entity's Board of Directors or advisory committees, Other: Research support, Research Funding, Speakers Bureau; Teva: Membership on an entity's Board of Directors or advisory committees, Other: Research support, Research Funding, Speakers Bureau; Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Research support, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Research support, Research Funding, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Research support, Speakers Bureau; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Other: Research support; Pfizer: Membership on an entity's Board of Directors or advisory committees, Other: Research support, Research Funding, Speakers Bureau. Esteve:Novartis: Consultancy, Research Funding, Speakers Bureau; Roche: Consultancy; Pfizer: Consultancy; Astellas: Consultancy, Speakers Bureau; Amgen: Consultancy; Celgene: Consultancy, Speakers Bureau; Daiichi Sankyo: Consultancy; Jazz Pharmaceuticals: Consultancy.

Kurzfassung: The need for allogeneic hematopoietic stem cell transplantation (allo-HSCT) in adults with Philadelphia chromosome–negative (Ph−) acute lymphoblastic leukemia (ALL) with high-risk (HR) features and adequate measurable residual disease (MRD) clearance remains unclear. The aim of the ALL-HR-11 trial was to evaluate the outcomes of HR Ph− adult ALL patients following chemotherapy or allo-HSCT administered based on end-induction and consolidation MRD levels. Patients aged 15 to 60 years with HR-ALL in complete response (CR) and MRD levels (centrally assessed by 8-color flow cytometry) & lt;0.1% after induction and & lt;0.01% after early consolidation were assigned to receive delayed consolidation and maintenance therapy up to 2 years in CR. The remaining patients were allocated to allo-HSCT. CR was attained in 315/348 patients (91%), with MRD & lt;0.1% after induction in 220/289 patients (76%). By intention-to-treat, 218 patients were assigned to chemotherapy and 106 to allo-HSCT. The 5-year (±95% confidence interval) cumulative incidence of relapse (CIR), overall survival (OS), and event-free survival probabilities for the whole series were 43% ± 7%, 49% ± 7%, and 40% ± 6%, respectively, with CIR and OS rates of 45% ± 8% and 59% ± 9% for patients assigned to chemotherapy and of 40% ± 12% and 38% ± 11% for those assigned to allo-HSCT, respectively. Our results show that avoiding allo-HSCT does not hamper the outcomes of HR Ph− adult ALL patients up to 60 years with adequate MRD response after induction and consolidation. Better postremission alternative therapies are especially needed for patients with poor MRD clearance. This trial was registered at www.clinicaltrials.gov as # NCT01540812.

Kurzfassung: Background: ETP-ALL was included as a provisional identity in the 2016 WHO classification of ALL. This subtype was first identified by Coustan-Smith et al. in 2009. However, this immunophenotype-based classification does not fully enclose all ETP-ALL cases identified by gene expression profile (GEP). Although early studies in small series of ETP-ALL suggested a very poor outcome for ETP ALL more recent and larger series have showed improvement in outcome treating children with a contemporary protocol based on chemotherapy schedules, or after allogeneic stem cell transplantation (allo-SCT) in adults. Aim: To investigate the clinical and biological features of ETP-ALL cases in the Spanish cohort of adult T-cell ALL (T-ALL) patients and to assess the potential impact of high-risk therapy on their outcome. Method: One hundred eighty-five adults with T-ALL treated according to two consecutive MRD-oriented high-risk adult PETHEMA protocols -ALL-HR-2003 (NCT00853008) and ALL-HR-11 (NCT01540812; still ongoing)- were included in this study. The EGIL criteria were used to define the immunologic subtype of T-ALL after central review of immunophenotype reports, and the criteria proposed by Zuurbier et al. (Zuurbier L. et al. Haematologica 2014; 99:94-102) were used to define ETP-ALL. These later criteria consist of a combination of immunophenotypic markers (absence of CD1a-/CD4-/CD8-, cut-off 〈 10%, and expression of the stem cell marker CD34+and/or at least one myeloid marker such as CD13+or CD33+, cut-off 〉 25%), that resemble those published by Coustan-Smith, with the advantage that include most ETP-ALL cases, as identified by GEP, avoiding the use of partial expression of CD5 marker to immuno-classify these patients. Results: Thirty-four out of 167 evaluable patients (20%) with T-ALL showed an ETP-ALL immunophenotype. Patients with ETP-ALL were older (mean 39 [SD 12] vs. 33 [12] yr; p=0.011), showed more frequently lymph node involvement (79% vs. 56%; p=0.021) and lower WBC counts at diagnosis (mean, 72 [155] vs. 97 [112] x109/L; p=0.004). At genetic level, ETP-ALL patients were associated with the absence of deletions in CDKN2A/B gene cluster (91% vs. 26%; p 〈 0.001) (10/11 cases) and with the absence of bi-allelic deletions in TCRG gene (67% vs. 5%; p=0.001) (6/9 cases). In turn, ETP-ALL patients showed poorer response to induction therapy: 82% of ETP-ALL had poorer early cytologic response ( 〉 10% BM blasts on day+14) vs. 37% of non-ETP (p 〈 0.001), and 23% of ETP-ALL patients did not reach CR vs. 6% non-ETP T-ALL cases (p=0.005). Flow-MRD data at CR (available in 141/167 patients) showed MRD levels ≥0.1% in 65% of ETP-ALL vs. 18% of non-ETP ALL (p 〈 0.001), and MRD level ≥0.01% in 85% vs. 37%, respectively (p 〈 0.001). Forty-six percent of ETP-ALL patients required a second induction treatment compared to 8% of non-ETP-ALL (p 〈 0.001). Consequently, more ETP-ALL patients underwent allo-SCT (70% vs. 21%, p 〈 0.001). The OS of ETP-ALL patients was poorer after censoring or not the follow-up at the time of transplant (Figures 1A and B). Conclusions: ETP-ALL accounts for 20% of adult T-ALL in the PETHEMA cohort and it is associated with a poorer initial response to treatment (lower CR rate, poorer MRD clearance) than the remaining T-ALL patients. Such poorer outcome is not overcome by allo-SCT in our series. Supported by grants from: Asociación Española Contra el Cáncer, AECC (GC16173697BIGA), Instituto Carlos III (PI14/01971 FI), 2017-SGR288 (GRC), CERCA Program from Generalitat de Catalunya, and "La Caixa" Foundation. Figure 1. Figure 1. Disclosures Montesinos: Daiichi Sankyo: Consultancy, Speakers Bureau; Novartis: Research Funding, Speakers Bureau.

Kurzfassung: Introduction and objective. Despite a high complete remission (CR) rate obtained with frontline therapy most adults with T-ALL eventually relapse. Although promising therapies are emerging, salvage options for T-ALL are currently limited. Little is known about outcome of patients (pts) with relapsed T-ALL (R T-ALL) treated with contemporary MRD-oriented trials. Our goal was to analyze the outcome of pts with R T-ALL included in two successive MRD-oriented trials (ALL-AR-03 and ALL-HR-11) from the Spanish PETHEMA Group. Methods. Retrospective study of R T-ALL adults diagnosed between 2003 and 2019 and included in the protocols ALL-AR-03 (NCT00853008) and ALL-HR-11 (NCT01540812). The clinical characteristics at baseline and at relapse, salvage therapies and outcomes (CR and OS) were analyzed and a study of prognostic factors for OS was performed. Results Forty-nine patients were identified (ALL-AR-03 [n=27], ALL-HR-11 [n=22] ). Median age (range) at diagnosis was 29 (16-58) yrs, 38 males (78%), CNS involvement 6 (12%), mediastinal mass 30 (61%), WBC count 40.8 x109/L (0.6-351.0), early T-cell precursor 11 (23%), pre-T 8 (16%), cortical 16 (33%), mature 9 (18%), T unspecified 5 (10%). Post-induction-1 MRD level ≥0.1%: 14/42 (33%), ≥0.01%: 17/39 (44%). Nine pts (18%) required 2nd induction therapy (resistant disease after induction-1 [n=5], MRD≥0.1% after induction-1 [n=4] ). Allogeneic HSCT in CR1: 8 pts. Interval CR1-relapse: 11.2 [0.1-36.7] months. Relapse was located in BM (n=20, 41%), BM+extramedullary (n=16, 33%) and extramedullary (n=13, 26%). CNS at relapse was involved in 18 pts (37%, isolated in 8 cases). Median number of rescue lineages was 2 (range 1-5). The most frequent first salvage schedules were FLAG-Ida (n=24, 49%), HyperCVAD (n=8, 16%) and nelarabine (n=4, 8%) (other schedules in 13 pts). Second CR was attained in 21/48 pts (44%). The patients with poor morphologic and/or poor MRD response after Induction-1 in first line therapy (n=9) did not respond to first salvage therapy (0/9 vs. 21/39, p=0.003). AlloHSCT was performed in 19 pts (15 in CR2) (HLA-identical sibling: 9, URD: 9, haploidentical: 1, myeloablative conditioning: 16). Thirty-nine pts died (progression: 27, toxicity of rescue regimens: 7, TRM: 5) and 9/10 alive patients were submitted to HSCT (the remaining is on rescue therapy). Median OS (95%CI) was 6.1 (4.9-7.2) months, 5yr OS probability 21% (9%-33%) (Figure 1). By multivariable analysis, only the CR after first salvage regimen emerged as favorable prognostic factor for OS (HR 3.110, 95%CI: 1.579-6.124) (Figure 2). Conclusion. This study shows poor outcome of adults with R T-ALL, with CR to first salvage therapy of 44% and a median OS of 6 months. Poor early response to first line therapy correlated with poor response to salvage-1. The only independent predictor for better survival was CR to first salvage regimen. This study highlights the unmet need for novel effective therapies for T-ALL. Supported in part by grant 2017 SGR288 (GRC) Generalitat de Catalunya and "La Caixa" Foundation; ISCIII (PI19/01828), co-funded by ERDF/ESF, "A way to make Europe"/"Investing in your future". Disclosures Ribera: Pfizer, Amgen, Ariad, Novartis: Consultancy, Speakers Bureau; Pfizer, Amgen: Research Funding. Barba:Amgen, Celgene, Gilead, Jazz Pharmaceuticals, Novartis, Pfizer, Shire: Consultancy; Amgen, Celgene, Novartis, Pfizer: Speakers Bureau. Tormo:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria; MSD: Honoraria; Daiichi Sankyo: Honoraria; Servier: Honoraria; Roche: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees. Sanchez:Abbvie: Other: travel grants; Amgem: Other: travel grants; Janssen: Other: travel grants; Celgene: Other: travel grants; Roche: Other: travel grants. Giménez Conca:AbbVie: Honoraria, Speakers Bureau.

Kurzfassung: Introduction: Recent studies have shown that young to middle-aged adults who receive a pediatric-inspired chemotherapy regimen for treatment of Ph-neg ALL do not appear to require an alloHSCT if they achieve good response on MRD testing after induction therapy. Patients (pts) who are not good MRD responders achieve better outcomes with alloHSCT than their counterparts who do not receive alloHSCT. However, it is not clear if this approach can be translated to adult ALL pts with HR features at baseline. The aim of the prospective ALL-HR-11 trial from the Spanish PETHEMA Group was to evaluate the response to a differentiated post-induction therapy (chemotherapy or alloHSCT) according to MRD levels (assessed by 8-color, centrally-performed flow cytometry at the end of induction-week 5- and consolidation therapy-week 17-) in HR Ph-neg adult ALL patients. Patients and methods: HR ALL included one or more of the following parameters at baseline: age 30-60 yr, WBC count 〉 30x109/L for B-cell precursor ALL or 〉 100x109/L for thymic T-ALL, pro-B, early or mature T-ALL, 11q23 or MLL rearrangements or complex karyotype. Induction therapy included vincristine, prednisone, daunorubicin and asparaginase (E coli native or PEG according to center availability) for 4 weeks (Induction-1). FLAG-Ida was administered as intensified induction (Induction-2) in pts not achieving CR or those in CR with MRD≥0.1% at the end of induction. For pts in CR and MRD 〈 0.1% early consolidation therapy included 3 cycles with rotating cytotoxic drugs with high-dose methotrexate, high-dose ARA-C and high-dose asparaginase (E coli native or PEG). These pts continued with delayed consolidation (identical to that of early consolidation) followed by maintenance therapy up to 2 yr. in CR if MRD levels after consolidation were 〈 0.01%, otherwise they were assigned to alloHSCT. Pts in CR after Induction-2 received one consolidation cycle and were assigned to alloHSCT. Results: On June 2015, 115 HR ALL pts were evaluable [mean (SD) age 38(13) yr, 67 males, 80/114 precursor B-ALL, 34/114 T-ALL, WBC count 56(96) x109/L]. Results of Induction-1: therapy-related death: 4(4%), resistance: 11 (10%), CR: 95(86%). MRD 〈 0.1% at the end of induction was observed in 75% of CR patients. Induction-2 was administered to 33 patients (no CR: 11, CR and MRD≥0.1%: 22). No differences in the CR rate or in the rate of MRD clearance after induction were observed according to the type of asparaginase administered, although significantly increased hepatic toxicity in consolidation was observed in patients treated with PEG-asparaginase. The 2-yr DFS and OS probabilities for whole series were 51%±18% and 62%±13%. By intention-to treat after Induction-1 36 pts were assigned to alloHSCT and 68 to delayed consolidation and maintenance. The 2-yr DFS and OS probabilities were 54%±25% and 49%±20%, respectively, for pts assigned to alloHSCT, and 50%±22% and 73%±17%, respectively, for those assigned to chemotherapy (P=0.002 for OS comparison). Patients with MRD 〈 0.1% at the end of induction and 〈 0.01% at the end of consolidation (n=51) showed a 2-yr DFS and OS of 55%±25% and 81%±18%, respectively. Conclusions: The preliminary results of this trial, in which the post-induction therapy decision is only based on MRD results, suggest that in HR, Ph-neg adult ALL pts with adequate MRD response after induction and after consolidation the results of therapy are not hampered by avoiding alloHSCT. Supported by grants RD12/0036/0029 (RTICC, FEDER), PI14/01971 FIS, Instituto Carlos III, and SGR225 (GRE), Spain Disclosures No relevant conflicts of interest to declare.

Kurzfassung: Background and objective. Asparaginase (ASP) is an essential drug for ALL treatment. Two types of E.coli ASP (native and pegylated) are used in clinical trials for treatment of children and adults with ALL, but to our knowledge direct comparison between these two types of ASP in the same protocol has not been performed. This study aimed to compare the efficacy and safety of native vs. PEG-ASP in adult patients with HR, Ph-negative ALL. Patients and methods. HR ALL included one or more of the following parameters at baseline: age 30-60 yr., WBC count 〉 30x109/L for B-cell precursor ALL or 〉 100x109/L for thymic T-ALL, pro-B, early or mature T-ALL, 11q23 or MLL rearrangements or complex karyotype. Induction therapy consisted of vincristine, prednisone, daunorubicin and ASP (native 10,000 IU/m2, i.v., days 16-20 and 23-27 or PEG 2,000 IU/m2, iv, day 15 depending on center decision) for 4 weeks (Induction-1). FLAG-Ida was administered as intensified induction (Induction-2) in patients not achieving CR or in those in CR with MRD≥0.1% at the end of induction, and those patients proceeded to allogeneic HSCT if CR was attained. Patients in CR and MRD 〈 0.1% proceeded to early consolidation therapy including 3 cycles with rotating cytotoxic drugs with high-dose methotrexate, high-dose ARA-C and ASP (native 20,000 IU/m2 on day 3 of each cycle or PEG 2,000 IU/m2 on day 3 of each cycle). Patients continued with delayed consolidation (identical to that of early consolidation) followed by maintenance therapy up to 2 yr. in continuous CR if MRD levels after consolidation were 〈 0.01%, otherwise they were assigned to allogeneic HSCT. The cumulated doses of native ASP and PEG-ASP for patients who completed the induction and early+delayed consolidation were 220,000 IU/m2 and 14,000 IU/m2, respectively. No ASP levels were assessed. Results. Ninety-onepatients received native ASP and 35 PEG-ASP in Induction-1. The two groups of patients were comparable for the main clinical and hematologic ALL parameters. No differences were observed in the CR rate (86% vs. 86%), in the frequency of MRD level 〈 0.1% after Induction-1 (63% vs. 70%), and that of MRD level 〈 0.01% after early consolidation (74% vs. 92%, p=0.19), as well as in the proportion of patients submitted to allogeneic HSCT (20% vs. 14%). No differences were found in overall survival or disease-free survival probabilities at 3-years according to the type of ASP (OS: 60% [95%CI: 47% ; 73%] vs. 57%[95%CI: 36% ; 78%] , p=0.872 and DFS: 40% [95%CI: 25% ; 55%] vs. 58% [95%CI: 36% ; 80%] , p=0.302). Abnormalities in the coagulation parameters were significantly more frequent in patients receiving PEG-ASP in Induction-1 (18% vs. 35%, p=0.045). These abnormalities, together with hepatic toxicity were significantly more frequent in patients receiving PEG-ASP in early consolidation (1% vs. 13%, p=0.003, and 5% vs. 34, p 〈 0.001, respectively). A trend for more allergic reactions was seen in patients receiving native ASP (18% vs. 5%, p=0.1) No differences in the frequency of ASP discontinuation rate were observed (6 % vs. 3%). Conclusions. In HR, Ph-negative adult ALL patients included in the PETHEMA ALL-HR 11 protocol the type of E.coli ASP (native vs. PEG) did not have impact on response and outcome. Allergic reactions were more frequently seen with native ASP and coagulation abnormalities and hepatic toxicity were most frequent with PEG-ASP. Most of the differences in toxicity can be explained by the schedule of ASP given in consolidation (single dose of native ASP vs. single dose of PEG-ASP in each cycle). Supported in part by grants RD12/0036/0029 (RTICC, FEDER), PI14/01971 FIS, Instituto Carlos III, and SGR225 (GRE), Spain Disclosures No relevant conflicts of interest to declare.

Kurzfassung: The prognostic significance of low‐hypodiploidy has not been extensively evaluated in minimal residual disease (MRD)‐oriented protocols for adult acute lymphoblastic leukaemia (ALL). We analysed the outcome of hypodiploid adult ALL patients treated within Programa Español de Tratamientos en Hematología (PETHEMA) protocols. The 5‐year cumulative incidence of relapse (CIR) of low‐hypodiploid B‐cell precursor (BCP)‐ALL was significantly higher than that of high‐hypodiploids (52% vs. 12%, P  = 0.013). Low‐hypodiploid BCP‐ALL patients aged ≤35 years showed superior survival (71% vs. 21%, P  = 0.026) and lower 5‐year CIR (17% vs. 66%, P  = 0.090) than low‐hypodiploids aged 〉 35 years. Older adults and elderly low‐hypodiploid BCP‐ALL patients show dismal prognosis although achieving an end‐induction good MRD response.

Kurzfassung: The prognosis of t(1;19)(q23;p13)/transcription factor 3‐pre‐B‐cell leukaemia homeobox 1 ( TCF3‐PBX1 ) in adolescent and adult patients with acute lymphoblastic leukaemia (ALL) treated with measurable residual disease (MRD)‐oriented trials remains controversial. In the present study, we analysed the outcome of adolescent and adult patients with t(1;19)(q23;p13) enrolled in paediatric‐inspired trials. The patients with TCF3‐PBX1 showed similar MRD clearance and did not have different survival compared with other B‐cell precursor ALL patients. However, patients with TCF3‐PBX1 had a significantly higher cumulative incidence of relapse, especially among patients aged ≥35 years carrying additional cytogenetic alterations. These patients might benefit from additional/intensified therapy (e.g. immunotherapy in first complete remission with or without subsequent haematopoietic stem cell transplantation).