Abstract: Background: Internal tandem duplications (ITD) in the receptor tyrosine kinase FLT3 occur in roughly 25% of younger adult patients (pts) with acute myeloid leukemia (AML), implicating FLT3 as a potential target for kinase inhibitor therapy. The multi-targeted kinase inhibitor midostaurin shows potent activity against FLT3 as a single agent but also in combination with intensive chemotherapy. Aims: To evaluate the feasibility and efficacy of midostaurin in combination with intensive induction therapy and as single agent maintenance therapy after allogeneic hematopoietic stem cell transplantation (alloHSCT) or high-dose cytarabine (HIDAC). Methods: The study includes adult pts (age 18-70 years (yrs)) with newly diagnosed FLT3-ITD positive AML enrolled in the ongoing single-arm phase-II AMLSG 16-10 trial (NCT: NCT01477606). Pts with acute promyelocytic leukemia are not eligible. The presence of FLT3-ITD is analyzed within our diagnostic study AMLSG-BiO (NCT01252485) by Genescan-based fragment-length analysis (allelic ratio & gt;0.05 required to be FLT3-ITD positive). Induction therapy consists of daunorubicin (60 mg/m², d1-3) and cytarabine (200 mg/m², continuously, d1-7); midostaurin 50 mg bid is applied from day 8 onwards until 48h before start of the next treatment cycle. A second cycle is optional. For consolidation therapy, pts proceed to alloHSCT as first priority; if alloHSCT is not feasible, pts receive three cycles of age-adapted HIDAC in combination with midostaurin from day 6 onwards. In all pts maintenance therapy for one year is intended. This report focuses on the first cohort of the study (n=149) recruited between June 2012 and April 2014 prior to the amendment increasing the sample size; the amendment to the study is active since October 2014. Results: At study entry patient characteristics were median age 54 years (range, 20-70, 34% ≥ 60 yrs); median white cell count (WBC) 48.4G/l (range 1.1-178G/l); karyotype, n=103 normal, n=3 t(6;9), n=2 t(9;11), n=20 intermediate-2 and n=7 high-risk according to ELN recommendations, n=14 missing; mutated NPM1 n=92 (62%). Data on response to first induction therapy were available in 147 pts; complete remission (CR) 58.5%, partial remission (PR) 20.4%, refractory disease (RD) 15% and death 6.1%. A second induction cycle was given in 34 pts. Overall response after induction therapy was CR 75% and death 7.5%. Adverse events 3°/4° reported during the first induction cycle were most frequently gastrointestinal (n=34) and infections (n=81). During induction therapy midostaurin was interrupted, dose-reduced or stopped in 55% of the pts. Overall 94 pts received an alloHSCT, 85 in first CR (n=65 age & lt;60 yrs, n=20 age ≥60 yrs) and 9 pts after salvage outside the protocol or after relapse (n=70 from a matched unrelated and n=24 from a matched related donor). In pts receiving an alloHSCT within the protocol in median 2 chemotherapy cycles were applied before transplant (range 1-4) and the cumulative incidence of relapse and death at 12 months were 9.2% (SE 3.3%) and 19.5% (SE 4.8%). Maintenance therapy was started in 52 pts, 40 pts after alloHSCT and 12 pts after HIDAC. Only 4 adverse events 3°/4° were attributed to midostaurin. First analyses revealed a low cumulative incidence of relapse irrespective of the FLT3-ITD mutant to wildtype ratio ( & lt;0.5 versus ≥0.5) in patients proceeding to alloHSCT with 12% and 5% as well as for those after HIDAC consolidation with 28% and 29%, respectively. Conclusions: The addition of midostaurin to intensive induction therapy and as maintenance after alloHSCT or HIDAC is feasible and compared to historical data may be most effective in those patients with a high FLT3-ITD mutant to wildtype ratio. Disclosures Schlenk: Novartis: Honoraria, Research Funding. Salwender:Celgene: Honoraria; Janssen Cilag: Honoraria; Bristol Meyer Sqibb: Honoraria; Amgen: Honoraria; Novartis: Honoraria. Götze:Celgene Corp.: Honoraria; Novartis: Honoraria.

Abstract: DNMT3A mutations are frequent in younger adults with AML and have no significant impact on survival end points. Only moderate effects on outcome, depending on molecular subgroup and DNMT3A mutation type, could be observed.

Abstract: The addition of valproic acid to intensive induction therapy in combination with all-trans retinoic acid did not result in an improvement of clinical outcome. Valproic acid-related hematologic toxicity and higher death rates were observed when valproic acid and idarubicin were given in parallel.

Abstract: Patients with acute myeloid leukemia (AML) and a FLT3 internal tandem duplication (ITD) have poor outcomes to current treatment. A phase 2 hypothesis-generating trial was conducted to determine whether the addition of the multitargeted kinase inhibitor midostaurin to intensive chemotherapy followed by allogeneic hematopoietic cell transplantation (alloHCT) and single-agent maintenance therapy of 12 months is feasible and favorably influences event-free survival (EFS) compared with historical controls. Patients 18 to 70 years of age with newly diagnosed AML and centrally confirmed FLT3-ITD were eligible: 284 patients were treated, including 198 younger (18-60 years) and 86 older (61-70 years) patients. Complete remission (CR) rate, including CR with incomplete hematological recovery (CRi) after induction therapy, was 76.4% (younger, 75.8%; older, 77.9%). The majority of patients in CR/CRi proceeded to alloHCT (72.4%). Maintenance therapy was started in 97 patients (34%): 75 after alloHCT and 22 after consolidation with high-dose cytarabine (HiDAC). Median time receiving maintenance therapy was 9 months after alloHCT and 10.5 months after HiDAC; premature termination was mainly a result of nonrelapse causes (gastrointestinal toxicity and infections). EFS and overall survival at 2 years were 39% (95% confidence interval [CI] , 33%-47%) and 34% (95% CI, 24%-47%) and 53% (95% CI, 46%-61%) and 46% (95% CI, 35%-59%) in younger and older patients, respectively. EFS was evaluated in comparison with 415 historical controls treated within 5 prospective trials. Propensity score-weighted analysis revealed a significant improvement of EFS by midostaurin (hazard ratio [HR], 0.58; 95% CI, 0.48-0.70; P & lt; .001) overall and in older patients (HR, 0.42; 95% CI, 0.29-0.61). The study was registered at www.clinicaltrials.gov as #NCT01477606.

Abstract: In FLT3-ITD–positive AML, high allelic ratio and ITD insertion site in TKD1 predict for low complete remission rates and poor survival. In FLT3-ITD–positive AML, allogeneic HSCT in first CR outweighs the negative impact of high allelic ratio on survival.

Abstract: MRD assessment in t(8;21) AML allows identification of patients at high relapse risk at defined time points during treatment and follow-up. MRD− after treatment is the most favorable factor for relapse risk and survival, and serial MRD analyses define cutoffs predicting relapse.

Abstract: BACKGROUND: Midostaurin is a first-generation, type I multi-targeted kinase inhibitor with inhibitory activity against FLT3-ITD and -TKD mutations. Midostaurin is approved by FDA and EMA in combination with intensive induction and consolidation chemotherapy for adult patients with AML exhibiting an activating FLT3 mutation; the EMA label also includes single-agent maintenance therapy following consolidation chemotherapy. We conducted a phase-II trial (AMLSG 16-10) to evaluate midostaurin with induction chemotherapy followed by allogeneic hematopoietic-cell transplantation (HCT) and a one-year midostaurin maintenance therapy in younger and older patients with acute myeloid leukemia (AML) and FLT3 internal tandem duplication (ITD). METHODS: Patients 18 to 70 years of age with newly diagnosed FLT3-ITD-positive AML were eligible. Primary and key secondary endpoints were event-free (EFS) and overall survival (OS); results were compared to those of a historical control cohort of 415 patients with FLT3-ITD AML. Statistical analysis was performed using a double-robust adjustment with propensity score weighting and covariate adjustment. Major differences in trial design compared to the pivotal CALGB 10603/RATIFY trial were: i) only AML with FLT3-ITD were eligible; ii) AML with FLT3 tyrosine kinase domain mutations (only) and core-binding factor AML were not eligible; iii) older patients 60-70 years of age were eligible; iv) all patients were assigned to allogeneic HCT; v) a one-year maintenance treatment with midostaurin was included also after allogeneic HCT; vi) a continuous dosing schedule of midostaurin was applied with the aim to achieve a better target inhibition. Results: The trial accrued 440 patients, including 312 younger (18-60 yrs) and 128 older (61-70 yrs) patients. Complete remission (CR)/CR with incomplete hematologic recovery rate, median EFS and OS of the 440 patients were 74.9%, 13.6 and 36.2 months, respectively. Multivariate analysis of EFS showed a highly significant hazard reduction for an event for patients treated within AMLSG 16-10 trial compared to the historical controls (HR 0.55; 95%-confidence interval [CI], 0.47, 0.65; P & lt;0.001); this effect was significant in the younger (HR 0.59; 95%-CI, 0.49, 0.71; P & lt;0.001) and the older patient cohort (HR 0.42; 95%-CI, 0.30, 0.60; P & lt;0.001). Multivariate analysis also showed a highly significant beneficial effect on OS (HR 0.57; 95%-CI, 0.47, 0.68; P & lt;0.001), again for both age subgroups. Allogeneic HCT in first CR/CRi was performed according to protocol in 199 of 440 (45%) patients (48% and 38% in younger and older patients, respectively), and an additional 60 patients received allogeneic HCT in firstline therapy (n=33 pts. in CR/CRi after salvage therapy and 27 pts. with active disease); the treatment effect of midostaurin remained significant in sensitivity analysis including allogeneic HCT (n=259) as a time-dependent covariate. Addition of midostaurin to chemotherapy was safe in younger and older patients. Conclusions: In comparison to a historical control cohort, the addition of midostaurin to intensive therapy led to a significant improvement in EFS and OS in both younger and older adult patients with AML and FLT3-ITD. Figure: Survival distribution for the primary endpoint event-free survival (EFS) and key secondary endpoint overall survival (OS) according to study population and age group. A EFS by cohort and age group (≤60 versus & gt;60 years) B OS by cohort and age group (≤60 versus & gt;60 years) Figure 1 Figure 1. Disclosures Döhner: Astellas: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria; Astex: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding; Agios: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria, Research Funding; GEMoaB: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria, Research Funding; Berlin-Chemie: Consultancy, Honoraria; Helsinn: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Jazz: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Oxford Biomedicals: Consultancy, Honoraria; Pfizer: Research Funding; Roche: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Ulm University Hospital: Current Employment. Fiedler: Servier: Consultancy, Other: Meeting attendance, Preparation of information material; Stemline: Consultancy; Daiichi Sanyko: Consultancy, Other: Meeting attendance, Preparation of information material; Pfizer: Consultancy, Honoraria, Research Funding; Novartis: Honoraria; MorphoSys: Consultancy, Honoraria; Jazz: Consultancy, Honoraria, Other: Meeting attendance, Preparation of information material; Celgene: Consultancy, Honoraria; Ariad/Incyte: Honoraria; Amgen: Consultancy, Honoraria, Other: Meeting attendance, Preparation of information material, Patents & Royalties, Research Funding; Abbvie: Consultancy, Honoraria, Other: Meeting attendance, Preparation of information material. Wulf: Gilead: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Clinigen: Consultancy, Honoraria. Salih: BMS: Honoraria; Celgene: Honoraria; Pfizer: Honoraria; Synimmune GmbH: Honoraria; Novartis: Honoraria. Lübbert: Imago BioSciences: Honoraria; Janssen: Honoraria, Research Funding; Pfizer: Honoraria; Syros: Honoraria; Aristopharm: Research Funding; Cheplapharm: Research Funding; Janssen: Research Funding; Teva: Research Funding; Hexal: Honoraria; Astex: Honoraria; Abbvie: Honoraria. Kühn: Abbvie: Honoraria; Kura Oncology: Honoraria, Research Funding; Pfizer: Honoraria. Schroeder: Abbvie: Honoraria; Astellas: Honoraria; Celgene: Honoraria; Janssen: Honoraria; Jazz: Honoraria; Novartis: Honoraria; Takeda: Honoraria; Pfizer: Honoraria. Salwender: Oncopeptides: Honoraria; GlaxoSmithKline: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Sanofi: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Takeda: Honoraria; Amgen: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Chugai: Honoraria; AbbVie: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Janssen-Cilag: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Bristol-Myers Squibb/Celgene: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Pfizer: Honoraria. Götze: Abbvie: Honoraria; Celgene/BMS: Honoraria, Research Funding. Westermann: Amgen: Consultancy, Honoraria; BMS: Honoraria; Novartis: Consultancy, Honoraria; Stem Cell Line: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Astellas: Honoraria. Fransecky: Abbvie: Honoraria, Research Funding; Takeda: Honoraria; Amgen: Honoraria; Novartis: Honoraria; Medac: Honoraria. Mayer: Novartis: Other: Travel support; Celgene: Other: Travel support; Roche: Other: Travel support; Amgen: Other: Travel support; BMS: Other: Travel support; Pfizer: Other: Travel support; Jazz: Other: Travel support; Astellas: Other: Travel support. Hertenstein: Sanofi: Honoraria; Novartis: Honoraria; Celgene: Honoraria; BMS: Honoraria. Tischler: AstraZeneca: Other: Travel support; Novartis: Other: Travel support; Janssen: Honoraria; GSK: Other: Travel support; Sanofi-Aventis: Other: Travel support; Abbvie: Other: Travel support. Paschka: Abbvie: Honoraria, Other: Travel support; Agios: Honoraria, Speakers Bureau; Astellas: Honoraria, Speakers Bureau; Astex: Honoraria; Celgene: Honoraria, Other: Travel support; Jazz: Honoraria; Novartis: Honoraria, Other: Travel support; Otsuka: Honoraria; Pfizer: Honoraria; Sunesis: Honoraria; BMS: Other, Speakers Bureau; Celgene: Honoraria; Janssen: Other; Takeda: Other. Gaidzik: Janssen: Speakers Bureau; Pfizer: Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Thol: Abbvie: Honoraria; Astellas: Honoraria; BMS/Celgene: Honoraria, Research Funding; Jazz: Honoraria; Novartis: Honoraria; Pfizer: Honoraria. Heuser: Tolremo: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer Pharma AG: Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Astellas: Research Funding; Jazz: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Honoraria; BMS/Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm: Research Funding; BergenBio: Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding. Schlenk: Astellas: Honoraria, Research Funding, Speakers Bureau; Celgene: Honoraria; Daiichi Sankyo: Honoraria, Research Funding; Hexal: Honoraria; Neovio Biotech: Honoraria; Novartis: Honoraria; Pfizer: Honoraria, Research Funding, Speakers Bureau; Roche: Honoraria, Research Funding; AstraZeneca: Research Funding; Boehringer Ingelheim: Research Funding; Abbvie: Honoraria; Agios: Honoraria. Bullinger: Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria; Astellas: Honoraria; Bristol-Myers Squibb / Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bayer: Research Funding; Daiichi Sankyo: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Hexal: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceutical: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Menarini: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees. Döhner: Amgen: Honoraria; BMS/Celgene: Honoraria, Research Funding; Janssen: Honoraria; Jazz: Honoraria; Novartis: Honoraria, Research Funding; Roche: Honoraria; Daiichi Sankyo: Honoraria; Agios: Research Funding; Astex: Research Funding; Astellas: Research Funding. Ganser: Novartis: Honoraria; Jazz Pharmaceuticals: Honoraria; Celgene: Honoraria. OffLabel Disclosure: Midostaurin as single-agent maintenance therapy following allogeneic hematopoietic cell transplantation