Abstract: Despite recent advances, treatment of elderly patients with AML remains a challenge because of adverse disease biology, comorbidities and therapy related toxicities. The balance between effectivity and toxicity of treatment strategies play a key role. Since comparative studies are lacking, a prospective randomized trial was designed among German AML study groups with different treatment strategies to compare outcome. Patients ≥60 years with all AML subtypes except M3 were randomized up-front to a common standard arm (CSA) (10%) and to study specific arms (90%) of the AMLCG or the OSHO. The CSA consisted of one or two inductions of araC 100 mg/m2/d continuous IV (CI) d 1-7 d and daunorubicin (dauno) 60 mg/m2/d IV d 3, 4, 5 and two courses of araC 1 g/m2/d BID IV d 1, 3 and 5 as consolidation (Mayer RJ et al, NEJM 1994). The AMLCG study arm randomized TAD (araC 100 mg/m2/d CI d1-2 followed by BID d 3-8, dauno 60 mg/m2/d IV d 3-5 and 6-thioguanine 100 mg/m2/d po BID d 3-9) and HAM [araC 1 mg/m2/d IV BID d 1-3 and mitoxantrone (mito) 10 mg/m2/d IV d 3-5] versus two courses of HAM with any 2nd course only given if blasts persisted ± G-CSF. Two courses of TAD were given as consolidation followed by maintenance chemotherapy over three years. The OSHO study arm included araC 1 g/m²/d BID IV d 1 + 3 + 5 + 7 and mito 10 mg/m2/d IV d 1 - 3 for one or two induction courses and ara-C 500 mg/m² BID 1h IV d 1 + 3 + 5 in combination with mito10 mg/m2/d IV d 1 + 2 as consolidation. Pegfilgrastim 6 mg s.c. was applied on day 10 of induction and on d 8 of consolidation. The study was approved by the IRB and registered at clinicaltrials.gov (NCT01497002 and NCT00266136). Written informed consent was obtained from all patients prior to randomization. Between April 1st, 2005 and May 26th, 2015 1286 patients were assigned randomly to the CSA (n=132) or to the study groups arm (n=1154). After excluding 139 patients (10.8%), 1147 patients were eligible for analysis, 1120 with follow-up for overall survival (OS) and 1079 for complete remission (CR) analysis. Baseline characteristics of all eligible patients showed median ages of 68 (60-82) years for the CSA and 69 (60-87) and 70 (60-85) years in the study arms A and B, respectively (p=0.05). Proportions of patients with secondary AML differed significantly between study arms (A: 42%, B: 30%, CSA: 36%; p=0.003). The CSA had less flt3 wildtype/npm1 wildtype patients (31%) vs. arm A (51% p=0.040) and arm B (58%, p=0.0455). No differences were observed with respect to cytogenetic risk groups, white blood cell counts, LDH, and npm1 mutant/ flt3-wildtype or mutant. The primary endpoint event free survival (EFS) did not differ between the CSA and study group strategies. Three-year EFS was 12.4% (95% CI: 6.7 - 19.9%) in the CSA, 15.6% (95% CI: 13.1 - 18.3%) in group A and 11.4% (95% CI, 7.4% to 16.4%) in group B (n.s.;Fig.1). With a median follow-up of 67 months, OS did not differ significantly between CSA and study group regimens. The 3-year survival probability was 22.3% (95% CI: 14.7-30.9%) in the CSA, 24.7% (95% CI: 21.6-27.9%) in group A and 22.4% (95% CI, 16.7% - 18.3%) in group B (Fig.2). CR status after 90 days of therapy was evaluated as secondary endpoint. The proportion of patients in CR in the CSA [51% (95% CI: 42-61%)] was comparable to the 50% (95% CI: 47-54%) and 48% (95% CI: 41-55%) of the study group arms (p=n.s.). Persistent leukemia was seen in 16% (95% CI: 10-24%) in the CSA vs 17% (95% CI: 14-19%) and 12% (95% CI: 8-17%) in groups A and B, respectively (both p= n.s.). A total of 226 patients died within 90 days of treatment, 24% (95% CI: 17-33%) in CSA, 19% in group A (95% CI: 16-22%) and 27% (95% CI: 21-33%) in group B; CSA vs A p=0.1859, CSA vs B p=0.5902). Death without AML was 3% in CSA, 2% in group A and 3% in group B, death with AML was 9% in CSA, 6% in group A and 5% in group B and death from indeterminate cause was 12% in CSA, 11% in group A and 20% in group B. Three-year relapse free survival (RFS) was 21.3% (95% CI: 12.2 - 31.0) in the CSA, 28.9% (95% CI: 24.9 -33.0%) in group A and 24.0% (95% CI: 16.8 - 31.9) in group B (both p=n.s.; Fig.3). In multivariate analysis independent variables for EFS and OS were age, type of disease, cytogenetic group and WBC count, but not the allocation to one of the treatment arms. Age and cytogenetic group were determinants for RFS. Conclusion A strictly prospective comparison of different treatment strategies in patients with AML did not show clinically relevant outcome differences when compared to a common standard arm. Figure 1. Figure 1. Figure 2. Figure 2. Figure 3. Figure 3. Disclosures Niederwieser: Novartis Oncology Europe: Research Funding, Speakers Bureau; Amgen: Speakers Bureau. Hoffmann:Novartis Oncology Europe: Research Funding. Al-Ali:Celgene: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding. Hegenbart:Pfizer: Other: Travel grant; Janssen: Honoraria, Other: Travel grant. Sayer:Riemser Pharma: Consultancy. Hochhaus:BMS: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; ARIAD: Honoraria, Research Funding. Fischer:Novartis: Consultancy, Honoraria. Dreger:Novartis: Consultancy; Janssen: Consultancy; Gilead: Consultancy; Gilead: Speakers Bureau; Roche: Consultancy; Novartis: Speakers Bureau. Hiddemann:Roche: Membership on an entity's Board of Directors or advisory committees; Genentech: Other: Grants; Roche: Other: Grants.

Abstract: Introduction: Outcome of patients (pts) with refractory AML or following relapse is considered dismal and usually reported as refractory/relapsed. Here we analyzed long term outcome of refractory and relapsing pts separately over a 10 year (y) period from two prospective, non-age-limited, adult AML studies. Results have been published or presented previously as part of the German AML Intergroup studies1,2. However, incidence, characteristics, treatment and outcome of refractory and relapsed pts have not been evaluated. Patients and Methods: A total of 1621 pts from the OSHO 2002 ≤60 y (n=740) and 2004 & gt;60 y (n=881) with newly diagnosed AML (except acute promyelocytic leukemia) and eligible for chemotherapy were analyzed. The gender was male in 51.7% of pts. AML type was de novo in 66.6%, followed by secondary AML in 25.8% and therapy related in 7.6%. Cytogenetic risk status was normal in 47.9%, intermediate in 16.3%, unfavorable in 15.3%, monosomal in 12.6% and favorable in 7.9%. Molecular analysis revealed wildtype (wt) FLT3 in 80.9% and FLT3 ITD mutated (mut) in 19.1% of pts. NPM was mutated in 30.2% of 1124 pts. In the AML 2002 and 2004 studies (NCT 01414231; NCT 01497002; NCT00266136), pts were randomly (9:1) assigned to remission induction by cytarabine (1 g/m2 bid d 1, 3, 5, 7) and Idarubicin (AML 2002) 12 mg/m2/d d 1-31 or mitoxantrone (AML 2004) 10 mg/m2/d iv d 1 - 32 or to a common arm consisting of a 3+7 scheme 3. Pts in complete remission (CR) received consolidation and stem cell transplantation (HSCT) according to cytogenetic risk and donor availability1,2. Pts with partial remission (PR) or non-response (NR) to two induction cycles were considered refractory. Pts achieving CR and relapsing thereafter were considered relapses and treated with MitoFlag or Flag-Ida4. Results: The majority of pts [median age 62 (range 17-87) y] entered CR or CRi after one or two induction cycles (n=1144; 70.6%). OS was 31.9 (29.5-34.4) % @5y and 26.0 (23.4-28.9) % @10y. Results were age dependent and superior in younger pts with an OS of 46.8 (43.1-50.7) % @5y compared to 19.3 (16.7-22.4) % @ 5y in elderly. Age, cytogenetics and NPM1 were determinants for CR and WBC (p & lt;0,001), gender (p & lt;0,05) and AML type (p & lt;0,01) for OS. FLT3-ITD mut was an important determinant for relapse free survival in pts ≤60y. A total of 238 (14.7%) of 1621 pts, 23.5% in the younger and 76.5% in the elderly study, were refractory (PR 60.1%, NR 39.9%). Pts had a median age of 66 (range 23-83)y. OS of refractory pts was 11.4 (7.9-16.6)% @5y, and dependent upon PR [(13.1 (8.1-21.1) % @10y] and NR [5.2 (2.1-12.6) % @5y; p=0.0003] . Intensive chemotherapy ± HSCT and hypomethylating agents (HMA) were able to induce CR in 24.8% of pts. CR and non-CR pts had an OS of 42.7 (31.4-58.2) % @5y and an OS of 3.7 (1.7-8.0) % @2y, respectively. Risk factors for OS in refractory pts were age and type of therapy (p & lt;0.0001). Almost all long term survivors were treated with HSCT. Of the 1144 CR/CRi pts, 582 relapsed 1-121 months (mts) after CR. Relapse occurred in 34.0% ≤6 mts, in 38,8% between 7-18 mts and in 12,2% & gt;18 mts. Age, cytogenetic risk, type of AML, interval CR to relapse and HSCT were the dominant factors for relapse. CR2 was achieved after intensive chemotherapy ± HSCT, ± DLI and HMA in 227 pts (39.0%), 54.5% in the AML 2002 and 28.4% in the AML 2004. OS of relapsed pts was 13.8 (11.1 - 17.3) % @5y and 10.9 (7.4 - 16.2) % @10y and was higher in the younger with 23.4 (18.2-29.9) % @5y as compared to elderly pts 6.9 (4.4 - 11.0) % @5y. Pts with CR2 had a LFS of 24.9 (19.5-31.7) % @5y and was highest in patients & lt;60y when intensive chemotherapy followed by HSCT was involved. Independent risk factors for OS in relapsed pts were age, cytogenetic risk, interval CR1 to relapse and type of therapy. Relapsed pts with HSCT in CR1 showed a trend for reduced survival. Conclusions Outcome of pts with refractory and relapsed AML is unsatisfactory but consistent & gt;10% @5y. A differential response is observed in refractory and relapsed pts and is dependent upon PR, NR and the achievement of CR. Increase of CR rate in younger but especially in elderly pts with second generation TKI, reduction of TRM using FLT3-inhibitor monotherapy and the option to treat pts ineligible to chemotherapy promise better outcome in refractory and relapsed AML. 1Büchner et al. JCO 2012; 2Niederwieser et al Blood 2016; 3Mayer et al. NEJM 1994; 4Thiel et al. Ann Oncology 2015 Disclosures Niederwieser: Daichii: Speakers Bureau; Cellectis: Consultancy. Scholl:Gilead: Other: Project funding; Daiichi Sankyo: Other: Advisory boards; AbbVie: Other: Advisory boards; Pfizer: Other: Advisory boards; Novartis: Other: Project funding. Zojer:Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Sayer:Novartis: Other: none. Schwind:Daiichi Sankyo: Honoraria; Novartis: Honoraria, Research Funding. Maschmeyer:Gilead, Janssen Cilag, Astra Zeneca; BMS, Merk-Serono: Honoraria. Hochhaus:Pfizer: Research Funding; Novartis: Research Funding; BMS: Research Funding; Incyte: Research Funding; MSD: Research Funding. Al-Ali:Celgene: Research Funding; Novartis: Consultancy, Honoraria, Research Funding; CTI: Honoraria.

Abstract: Background: Despite the recent approval of DNA-hypomethylating agents (HMAs) for treatment of elderly AML patients (pts) ineligible for induction, their prognosis is still poor, and rational, effective HMA-based combination treatments are under study. Histone deacetylase inhibitors (HDACi) show synergism with HMAs in vitro. ATRA - as single agent clinically ineffective in non-M3 AML - in combination with HMAs also shows in vitro synergistic antileukemic activity in non-M3 AML cells. We previously conducted a non-randomized phase II trial in elderly non-fit AML pts with DAC (3-dy schedule), given alone or combined with ATRA (45 mg/m2 dy 4-28, only during course 2), with encouraging results (Lübbert et al., Haematologica 2012). We now expanded this approach to a 4-arm randomized phase II study (2x2 factorial design) asking whether the addition of either VPA (HDACi activity) or ATRA or both to DAC as first-line treatment of elderly AML pts might improve the effect of DAC monotherapy (NCT00867672). Patients and Methods: Inclusion criteria: newly diagnosed pts 〉 60 yr unfit for induction (reasons for treatment decision prospectively captured) with non-M3 AML (WHO, de novo or after antecedent hematologic disorder [AHD], therapy-associated [t] AML), ECOG performance status (PS) 0-2. Pts with 〉 30,000 WBC/µl were to receive a short course of hydroxyurea. Treatment: DAC 20 mg/m2 dy 1-5 (treatment arms A/B/C/D), VPA p.o. continuously (target serum levels: 50-110 mg/l) from dy 6 (arms B/D), ATRA p.o. dy 6-28 (arms C/D) of each 28-dy course (repeated until relapse/progression, prohibitive toxicity, withdrawal or death). Key endpoints: objective response rate (ORR): CR/CRi/PR (ELN criteria), overall survival (OS). Sample size calculation was based on the primary endpoint ORR, assuming an ORR of 25% in arm A (Lübbert et al., Haematologica 2012). For a power of 80% (test in this phase II study at 1-sided alpha=0.1) for an increase of ORR to 40% with VPA or ATRA, 176 pts were necessary, planned sample size 200. Efficacy analyses were performed in the intention-to-treat (ITT) population including all randomized pts for whom treatment was started. VPA was investigated by comparing arms B+D vs arms A+C, ATRA by comparing arms C+D vs arms A+B. ORR was analyzed with logistic regression, OS with Cox regression, without adjustment for prognostic factors. Odds ratios (OR) for the effect on ORR and hazard ratios (HR) for the effect on death with 95% confidence intervals (CI), and two-sided p values of the tests of no treatment effect are presented. Central hematopathological review by an independent morphologist was conducted in a blinded fashion as to treatment arms. Results: Between 12/2011 and 2/2015, 204 pts were randomized (4 were excluded from the analysis because no treatment was administered). Median age: 76 yrs (interquartile range 72-79, range 61-92), ECOG PS 0/1/2-3: 19/61/20%: 52% had an HCT-CI 〉 3, 16.5% WBC 〉 30.000/µl, 31.5% poor cytogenetics (ELN), 51% had an AHD, 13.5% tAML (characteristics overall balanced across all 4 treatment arms). A median of 3 DAC courses were administered (per arm: 2/3/5.5/4), however 53 pts (26.5%), who were older, with reduced PS and a higher HCT-CI compared to the other 147 pts, received only a single course. The ORR (usually achieved only after 〉 3 courses) was 17.5%, median OS 6.2 mths (arm A: 8.5% and 4.8 CI [2.8,7.6] mths, arm B: 17.5% and 6.1 CI [3.7,7.2] mths, arm C: 26.1% and 8.4 CI [4.0,14.0] mths, arm D: 18% and 7.7 CI [4.6,11.2] mths, respectively). Effect on ORR of VPA vs no VPA (17.8 vs 17.2%): OR 1.06, CI [0.51,2.21], p=0.88; of ATRA vs no ATRA (21.9 vs 13.5%): OR 1.80, CI [0.86,3.79] , p=0.12. Effect on OS of VPA vs no VPA (6.2 vs 6.4 mths median OS): HR 0.94, CI [0.70,1.28], p=0.70; of ATRA vs no ATRA (8.2 vs 5.1 months median OS): HR 0.65, CI [0.48,0.88] , p=0.006 (after adjustment for PS, HCT-CI, WBC, LDH: HR 0.59, CI [0.43,0.82], p=0.002). Improved survival with ATRA was also seen in pts with poor cytogenetics. Toxicities (predominantly hematologic) did not show relevant differences between the 4 treatment arms. Conclusions: Based on this ITT analysis of a randomized trial, the addition of ATRA to standard-dose DAC resulted in a higher ORR and in a clinically relevant extension of OS, without additional (hematologic and non-hematologic) toxicity. In contrast, the addition of VPA did not affect ORR or OS. Disclosures Lübbert: Celgene: Other: Travel Funding; Janssen-Cilag: Other: Travel Funding, Research Funding; Ratiopharm: Other: Study drug valproic acid. Schlenk:Pfizer: Honoraria, Research Funding; Amgen: Research Funding. Heuser:Pfizer: Research Funding; Tetralogic: Research Funding; BerGenBio: Research Funding; Karyopharm Therapeutics Inc: Research Funding; Bayer Pharma AG: Research Funding; Celgene: Honoraria; Novartis: Consultancy, Research Funding. Bug:Janssen: Other: Travel Grant; Astellas: Other: Travel Grant; Teva Oncology: Other: Travel Grant; Novartis: Honoraria, Research Funding; Celgene: Honoraria, Other: Travel Grant; Nord Medica: Consultancy. Giagounidis:Celgene Corporation: Consultancy. Brugger:Astrazeneca: Employment. Niederwieser:Amgen: Speakers Bureau; Novartis Oncology Europe: Research Funding, Speakers Bureau.

Abstract: Background The German AML Intergroup conducted two randomized studies in younger ( 〈 60 years) and elderly (≥60 years) patients in which the study arms were compared to a common standard arm. Here, we compared the two studies in younger and elderly patients focusing on disease characteristics and outcome. Patients and Methods The East German Study Group (OSHO) and the Acute Myeloid Leukemia Cooperative Group (AMLCG) each entered patients from 18 to 59 years into one study and patients aged 60 years and older into another. Each study group randomized upfront 10% of all AML patients into a common standard arm and 90% in the study group specific arm. All patients with de novo AML or AML after myelodysplastic syndrome or cytotoxic treatment were eligible. Chi-squared and Mann-Whitney-U tests were used to detect significant differences between the age groups regarding demographic, clinical and cytogenetic characteristics at baseline. Complete Remission (CR) at 90 days and cumulative probabilities of death were determined for outcome. To avoid bias due to the higher probability of death in older patients, cumulative probabilities of death were calculated for relapsed patients or those who did not achieve CR after 90 days. Other deaths were considered as a competing risk. Results A total of 2435 AML patients were analyzed, 1132 in the study 〈 60 years and 1303 in the study ≥60 years. Significant differences in patient characteristics were noted between the studies. The elderly patient group contained a higher proportion of males than the younger group (55% vs 49% respectively, p=0.0031) and a higher percentage of secondary AML (40% vs 21% respectively, p 〈 0.0001). In contrast, younger patients had higher median WBC count [13x109/L (range 0.03-798) for 〈 60 years and 6.9x109/L (range 0.23-450) for ≥60 years, p 〈 0.0001] and higher median lactate dehydrogenase [442U/L (range 35-19,624) for 〈 60 years and 350U/L (range 51-9,486) for ≥60 years, p 〈 0.0001]. Cytogenetic risk was similarly distributed in both groups (favorable: 12% in both age groups, intermediate: 66% in 〈 60 years and 63% in ≥60 years, adverse: 22% in 〈 60 years and 25% in ≥60 years, p=0.1672). However, the favorable combination of FLT3-ITDwt and NPM1mut in normal karyotype was more common in the younger (35%) than in the older group (27%; p=0.0212). A higher rate of CR at 90 days was observed in the younger (66%) than in the older (51%) patients (p= 〈 0.0001). Of the younger patients 14.8% died (3.8% with persisting AML, 3.3% without AML and 7.7% without evaluable disease status) while of the older patients 21.8% died (6.2% with persisting AML, 2.5% without AML and 13.1% without evaluable disease status) during this period (p=0.0001). Relapse at 90 days was seen in 1% of the younger and in 2% of the older patients. The cumulative probability of AML-related death was lower in younger patients than in older patients (p 〈 0.0001). Of the younger patients 29% (95% CI: 26% to 31%) and 44% (95% CI: 40% to 46%) died after one and three years due to AML; in the older group the corresponding frequencies were 45% (95% CI: 42% to 48%) and 62% (95% CI: 59% to 65%; Figure 1a). The probability of dying from AML was lowest for the younger patients with de novo AML [27% (95% CI 24% to 29%) at 1 year and 41% (95% CI 38% to 44%) at 3 years] and highest for those with secondary AML [38% (95% CI 32% to 44%) at 1 year and 56% (95% CI 49% to 62%) at 3 years (p=0.0001)] , with similar differences being observed in the older patients (p=0.0001, Figure 1b). In the younger patients, CR at 90 days was lower in the standard (58%) than in the study arm (66%, p=0.0558), while AML related death was 29% and 27% at 1 year and 44% and 39% at 3 years respectively. In the older patients CR at 90 days was 52% vs. 51%, AML related death at 1 year 45% and 45% and at 3 years 63% and 69% for study arm and standard arm, respectively (Figure 1c). Conclusion This analysis reveals significant differences in gender, laboratory characteristics and proportion of secondary AML in elderly compared to younger AML patients. While there was no clear difference in cytogenetic risk groups, favorable molecular markers were more frequent in younger patients. Clear differences in CR rates after 90 days of therapy and AML related death rate were seen in regard to age ( 〈 60 years and ≥60 years) and disease type (de novo and secondary AML). As the common standard arm in both of the studies was age adapted, the differences between the two age groups are likely to be related to disease biology. Disclosures Niederwieser: Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Hoffmann:Novartis Oncology Europe: Research Funding. Krug:Sunesis; Clavis Pharma; usa Pharma, Catapult Cell Therapy, Gilead, Roche: Membership on an entity's Board of Directors or advisory committees; Sunesis: Speakers Bureau; Boehringer Ingelheim: Research Funding; Novartis; BMS; Roche; Boehringer Ingelheim; Bayer: Honoraria. Hegenbart:Janssen: Honoraria, Other: travel support. Pfirrmann:Novartis Pharma: Consultancy, Honoraria; BMS: Consultancy, Honoraria. Kraemer:TEVA: Other: travel support. Al-Ali:Celgene: Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding.