Abstract: Background In newly diagnosed acute myeloid leukemia (AML), the general recommendation is to start treatment immediately after the diagnosis has been made. This paradigm is based both on the observation that untreated acute leukemia has a poor prognosis and on retrospective analyses demonstrating a shorter survival in younger AML patients (pts) in whom treatment was delayed by more than 5 days (Sekeres et al., 2009). A more recent single-center analysis came to a different conclusion, showing no prognostic effect for the time from diagnosis to treatment (TDT; Bertoli et al., 2013). We explored the relationship between TDT and prognosis on a large set of real-world data from the AML registry of the Study Alliance Leukemia (SAL) and compared it to the published cohorts. Methods The SAL runs a transregional AML registry in 46 treatment centers across Germany (NCT03188874). All registered patients with an intensive induction treatment, a minimum follow-up time of 12 months and no acute promyelocytic leukemia were selected (n=2,200). Treatment start was defined by the first day of cytarabine, whereas single agent hydroxyurea (HU) was labeled as pretreatment. We analyzed the influence of TDT on complete remission (CR), early death (ED) and overall survival (OS) in univariable analyses for each day of treatment delay, in groups of 0-5, 6-10, 11-15 and & gt;15 days of TDT, and by using the restricted cubic spline (RCS) method for data modelling. In order to adjust for the influence of established prognostic variables on the outcomes, we used multivariable regression models and propensity score weighting. The influence of HU pretreatment on outcomes was investigated by introducing an interaction term between TDT and the presence of HU pretreatment. Results The median age was 59 years (y) (IQR 50-68), the proportion of pts with favorable, intermediate and adverse genetic risk according to ELN was 27%, 53%, and 20%; & gt;95% of pts received induction treatment with standard 7+3. HU pretreatment was administered in 4% of pts. The median TDT was 3 days (IQR 2-6). Descriptive statistics after grouping of pts showed the highest median age and the lowest proportion of NPM1 mutated and favorable risk in the TDT group 11-15. Of all pts, 79% achieved a CR/CRi; unadjusted CR rates for the patient groups with TDT of 0-5, 6-10, 11-15 and & gt;15 days were 80%, 77%, 74% and 76%, respectively (p=0.317). In multivariable analysis accounting for the influence of ELN risk, age, WBC, LDH, de novo versus secondary AML and ECOG, the OR for each additional day of TDT was 0.99 (95%-CI, 0.97-1.00; p=0.124). Four percent of pts died within the first 30 days from treatment start. The respective rates in the four TDT categories were 4.0%, 3.8%, 5.1% and 4.1% (p=0.960). In multivariable analysis, the OR for TDT was 1.01 (95%-CI, 0.98-1.05; p=0.549). After a median follow-up of 40 months, the 2-y OS of all pts was 51%. The unadjusted 2-y OS rates stratified by TDT of 0-5, 6-10, 11-15, & gt;15 days were 52, 49, 46, and 51% (see Table 1 and Figure 1). The hazard ratio (HR) for each day of treatment delay was 1.00 (95%-CI; 0.99-1.01; p=0.317). In multivariable Cox regression analysis, the HR for TDT as continuous variable was 1.00 (95%-CI, 0.99-1.01; p=0.689). When OS was analyzed separately stratified for age ≤60 and & gt;60 ys and for high versus lower initial WBC defined by a threshold of 50 x 109/L, no significant differences between TDT groups were observed. Multivariable models using TDT as a grouped variable or with RCS did not provide evidence for a significant influence of TDT on outcomes. Propensity score matching of pts in the four TDT groups did not reveal an influence on outcomes. The use of HU was not associated with CR, ED nor OS. Conclusion Our study on 2,200 newly diagnosed registry pts receiving consistent intensive induction with standard-dose cytarabine plus daunorubicin (7+3) suggests that TDT is not related to response or survival, neither in younger nor in older pts. Despite multivariable analyses, a bias towards longer TDT intervals in pts judged to be clinically stable by the treating physician cannot be excluded entirely. As treatment stratification in intensive first-line treatment of AML evolves, the TDT data suggests that it may be a safe and reasonable approach to wait for genetic and other laboratory test results in order to assign clinically stable pts to the best available treatment option before the start of intensive treatment. Disclosures Krämer: Daiichi-Sankyo: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bayer: Research Funding; BMS: Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Hänel:Roche: Honoraria; Amgen: Honoraria; Celgene: Other: advisory board; Novartis: Honoraria; Takeda: Other: advisory board. Jost:Daiichi: Honoraria; Sanofi: Honoraria; Gilead: Other: travel grants; Jazz Pharmaceuticals: Honoraria. Brümmendorf:Merck: Consultancy; Janssen: Consultancy; Novartis: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; University Hospital of the RWTH Aachen: Employment; Ariad: Consultancy. Krause:Siemens: Research Funding; Takeda: Honoraria; MSD: Honoraria; Gilead: Other: travel; Celgene Corporation: Other: Travel. Scholl:Novartis: Other: Project funding; Pfizer: Other: Advisory boards; Gilead: Other: Project funding; Daiichi Sankyo: Other: Advisory boards; AbbVie: Other: Advisory boards. Hochhaus:Pfizer: Research Funding; Novartis: Research Funding; BMS: Research Funding; Incyte: Research Funding; MSD: Research Funding. Kiani:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Middeke:Sanofi: Research Funding, Speakers Bureau; Roche: Speakers Bureau; AbbVie: Consultancy, Speakers Bureau; Gilead: Consultancy; Janssen: Consultancy, Speakers Bureau; MSD: Consultancy. Thiede:AgenDix GmbH: Employment, Equity Ownership; Novartis: Research Funding, Speakers Bureau; Bayer: Research Funding; Daiichi-Sankyo: Speakers Bureau. Stoelzel:JAZZ Pharmaceuticals: Consultancy; Neovii: Other: Travel funding; Shire: Consultancy, Other: Travel funding. Platzbecker:Celgene: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding.

Abstract: The presence of a mutated nucleophosmin-1 gene (NPM1 mut ) in acute myeloid leukemia (AML) is associated with a favorable prognosis. To assess the predictive value with regard to allogeneic stem-cell transplantation (SCT), we compared the clinical course of patients with NPM1 mut AML eligible for allogeneic SCT in a donor versus no-donor analysis. Patients and Methods Of 1,179 patients with AML (age 18 to 60 years) treated in the Study Alliance Leukemia AML 2003 trial, we identified all NPM1 mut patients with an intermediate-risk karyotype. According to the trial protocol, patients were intended to receive an allogeneic SCT if an HLA-identical sibling donor was available. Patients with no available donor received consolidation or autologous SCT. We compared relapse-free survival (RFS) and overall survival (OS) depending on the availability of a suitable donor. Results Of 304 eligible patients, 77 patients had a sibling donor and 227 had no available matched family donor. The 3-year RFS rates in the donor and no-donor groups were 71% and 47%, respectively (P = .005); OS rates were 70% and 60%, respectively (P = .114). In patients with normal karyotype and no FLT3 internal tandem duplication (n = 148), the 3-year RFS rates in the donor and no-donor groups were 83% and 53%, respectively (P = .004); and the 3-year OS rates were 81% and 75%, respectively (P = .300). Conclusion Allogeneic SCT led to a significantly prolonged RFS in patients with NPM1 mut AML. The absence of a statistically significant difference in OS is most likely a result of the fact that NPM1 mut patients who experienced relapse responded well to salvage treatment. Allogeneic SCT in first remission has potent antileukemic efficacy and is a valuable treatment option in patients with NPM1 mut AML with a sibling donor.

Abstract: Deep molecular response (MR 4.5 ) defines a subgroup of patients with chronic myeloid leukemia (CML) who may stay in unmaintained remission after treatment discontinuation. It is unclear how many patients achieve MR 4.5 under different treatment modalities and whether MR 4.5 predicts survival. Patients and Methods Patients from the randomized CML-Study IV were analyzed for confirmed MR 4.5 which was defined as ≥ 4.5 log reduction of BCR-ABL on the international scale (IS) and determined by reverse transcriptase polymerase chain reaction in two consecutive analyses. Landmark analyses were performed to assess the impact of MR 4.5 on survival. Results Of 1,551 randomly assigned patients, 1,524 were assessable. After a median observation time of 67.5 months, 5-year overall survival (OS) was 90%, 5-year progression-free-survival was 87.5%, and 8-year OS was 86%. The cumulative incidence of MR 4.5 after 9 years was 70% (median, 4.9 years); confirmed MR 4.5 was 54%. MR 4.5 was reached more quickly with optimized high-dose imatinib than with imatinib 400 mg/day (P = .016). Independent of treatment approach, confirmed MR 4.5 at 4 years predicted significantly higher survival probabilities than 0.1% to 1% IS, which corresponds to complete cytogenetic remission (8-year OS, 92% v 83%; P = .047). High-dose imatinib and early major molecular remission predicted MR 4.5 . No patient with confirmed MR 4.5 has experienced progression. Conclusion MR 4.5 is a new molecular predictor of long-term outcome, is reached by a majority of patients treated with imatinib, and is achieved more quickly with optimized high-dose imatinib, which may provide an improved therapeutic basis for treatment discontinuation in CML.

Abstract: Biallelic mutations of the CEBPA gene (CEBPAbi) define a distinct entity associated with favorable prognosis; however, the role of monoallelic mutations (CEBPAsm) is poorly understood. We retrospectively analyzed 4708 adults with acute myeloid leukemia (AML) who had been recruited into the Study Alliance Leukemia trials, to investigate the prognostic impact of CEBPAsm. CEBPA mutations were identified in 240 patients (5.1%): 131 CEBPAbi and 109 CEBPAsm (60 affecting the N-terminal transactivation domains [CEBPAsmTAD] and 49 the C-terminal DNA-binding or basic leucine zipper region [CEBPAsmbZIP] ). Interestingly, patients carrying CEBPAbi or CEBPAsmbZIP shared several clinical factors: they were significantly younger (median, 46 and 50 years, respectively) and had higher white blood cell (WBC) counts at diagnosis (median, 23.7 × 109/L and 35.7 × 109/L) than patients with CEBPAsmTAD (median age, 63 years, median WBC 13.1 × 109/L; P & lt; .001). Co-mutations were similar in both groups: GATA2 mutations (35.1% CEBPAbi; 36.7% CEBPAsmbZIP vs 6.7% CEBPAsmTAD; P & lt; .001) or NPM1 mutations (3.1% CEBPAbi; 8.2% CEBPAsmbZIP vs 38.3% CEBPAsmTAD; P & lt; .001). CEBPAbi and CEBPAsmbZIP, but not CEBPAsmTAD were associated with significantly improved overall (OS; median 103 and 63 vs 13 months) and event-free survival (EFS; median, 20.7 and 17.1 months vs 5.7 months), in univariate and multivariable analyses. Additional analyses revealed that the clinical and molecular features as well as the favorable survival were confined to patients with in-frame mutations in bZIP (CEBPAbZIP-inf). When patients were classified according to CEBPAbZIP-inf and CEBPAother (including CEBPAsmTAD and non-CEBPAbZIP-inf), only patients bearing CEBPAbZIP-inf showed superior complete remission rates and the longest median OS and EFS, arguing for a previously undefined prognostic role of this type of mutation.

Abstract: Background Double induction using two subsequent 7+3 regimens of cytarabine plus anthracycline is commonly performed in AML patients with an adequate performance status in order to maximize dose intensity upfront. However, for patients with a good early response at day 15 of first induction, there is no prospective randomized evidence on the necessity or value of a second induction cycle. Aims In order to answer the question if good responders of the first 7+3 induction could be spared a second induction cycle, we set up randomized-controlled SAL DaunoDouble trial. The study prospectively assesses the outcome of patients with a good early response with respect to the number of induction cycles (single versus double). We assumed non-inferiority of single induction in terms of complete remission (CR/CRi) rate, based on a margin of 7.5%. Here, we present the results of the planned interim analysis. Methods Patients (pts) 18-65 years with newly diagnosed AML, normal cardiac and organ function received a first induction cycle with seven days of cytarabine plus three days of daunorubicin ("7+3"). Response assessment in bone marrow was done on day 15 after the initiation of chemotherapy and confirmed by central review. A blast count & lt;5% was defined as good response. Pts with good response were randomized to receive a second induction cycle (arm D) or no second induction cycle (arm S). Primary endpoint was CR/CRi after completion of induction, secondary endpoints were RFS, and OS. Results Between 2014 and 2020, 624 evaluable pts were enrolled and received the first induction cycle with 7+3. A marrow blast clearance below 5% on day 15 was achieved in 298 pts (48%), providing eligibility for randomization. Of these patients, 150 were randomized into arm S and 148 into arm D, respectively. Median age was 52 years, 92% had de novo AML, NPM1 mutation was present in 53%, FLT3-ITD in 25% of pts. Favorable, intermediate and adverse risk (ELN 2017) were present in 56%, 34% and 10% of pts, respectively. CR/CRi rates at the end of induction were 86% after single induction and 85% after double induction. The CR/CRi rates in 224 pre-defined per-protocol pts were 88% versus 91%, resulting in a CR difference of 3% (95%-CI -0.047-0.111; p for non-inferiority test 0.145). After a median follow-up time of 24 months, RFS was slightly but not significantly lower after single induction with a 3-year RFS of 53% versus 64% (HR 1.4, p=0.125), whereas no differences were seen in 3-year OS, with a of rate of 74% versus 75% (HR 1.1, p=0.645) after single versus double induction. Conclusion The interim analysis results show that in good responders, the difference between CR rates after single versus double induction was even smaller than the predefined 7.5% margin, suggesting a trend for non-inferiority of single induction, although statistical significance was not reached. The trial continued recruitment. These findings suggest that in good responders, it may be safe to omit a second induction cycle if a second cycle poses a high risk. Figure. CR + CRi, RFS and OS after randomization to single versus double induction. Disclosures Alakel: Pfizer: Consultancy. Jost:Pfizer: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; JAZZ: Other: travel support; Celgene: Other: travel support. Novak:Roche: Consultancy; Janssen: Other: Travel expenses; Takeda: Consultancy; Amgen: Consultancy, Other: Travel expenses; Pfizer: Consultancy; Novartis: Consultancy. Krause:Takeda: Honoraria; Celgene: Other: Travel Support; MSD: Honoraria; Pfizer: Honoraria; Siemens: Research Funding; Gilead: Other: Travel Support. Held:Roche: Consultancy, Other: Travel, Accommodations, Expenses, Research Funding; BMS: Consultancy, Other: Travel, Accommodations, Expenses, Research Funding; MSD: Consultancy; Acrotech: Research Funding; Spectrum: Research Funding; Amgen: Research Funding. Platzbecker:AbbVie: Consultancy, Honoraria; Amgen: Honoraria, Research Funding; Geron: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria. Thiede:AgenDix GmbH: Other: Co-owner and CEO. Müller-Tidow:Daiichi Sankyo: Research Funding; Pfizer: Research Funding, Speakers Bureau; BiolineRx: Research Funding; Janssen-Cilag GmbH: Speakers Bureau.

Abstract: Targeted therapy with the BCR-ABL tyrosine kinase inhibitor imatinib induces high response rates in chronic myeloid leukemia (CML) patients (pts). Nevertheless, residual disease remains in virtually all pts on imatinib monotherapy as a potential cause of relapse. In July 2002, the German CML-Study Group activated the four-armed randomized controlled trial comparing imatinib 400mg/d with imatinib+IFN, imatinib+Ara-C, and imatinib after IFN failure in newly diagnosed pts with chronic phase CML. Randomization is stratified according to prognostic risk groups and not biased by consecutive allogeneic stem cell transplantation (SCT). High-risk pts are randomly assigned to primary imatinib-based therapies including a treatment arm with 800mg/d imatinib. By 7/05, 632 pts were randomized: imatinib 400mg/d (n=129), imatinib+IFN (n=179), imatinib+Ara-C (n=156), imatinib after IFN failure (n=157), and imatinib 800mg/d (n=11). According to the Hasford score, 35% of pts were low risk, 54% intermediate risk, and 11% high risk. At baseline, median WBC count was 67/nl (3–529), median platelet count 391/nl (34–2,799) and median hemoglobin 12.6 g/dl (6.1–16.6). We sought to evaluate results of pts with a & gt;12 months follow-up (n=416), recruited between 7/02 and 6/04 (imatinib 400mg/d, n=102; imatinib+IFN, n=126; imatinib+Ara-C, n=104; imatinib after IFN failure, n=81; imatinib 800mg/d, n=3) and of pts with a & gt;24 months follow-up (n=232), recruited between 7/02 and 6/03 (imatinib 400mg/d, n=55; imatinib+IFN, n=74; imatinib+Ara-C, n=54; imatinib after IFN failure, n=49) with respect to response, resistance, and progression. After 12 months of treatment cytogenetic data are available from 238/335 pts (71%) randomized to primary imatinib based therapies. 209 pts (63%) achieved a major cytogenetic remission (MCR; Ph+ & lt;35%), being complete in 53%. Q-PCR data were available in 270 pts (81%). 89 pts (27%) achieved a major molecular response (MMR; ratio BCR-ABL/ABL & lt;0.12%). After 24 months cytogenetic data are available from 141/183 pts (77%). 126 pts (69%) achieved a MCR, being complete in 60%. Q-PCR data were available in 149 pts (81%). 73 pts (40%) achieved a MMR. 12/177 pts lost CCR (7%) during the 1st year and 6/110 pts (5%) during the 2nd year of treatment. Within the 1st year 13/335 pts (6 low, 3 intermediate, 4 high risk; 4%) progressed to blast crisis, 4 of them revealed clonal evolution (complex aberrant karyotype, n=3; +8, n=1), two others BCR-ABL mutations (E355G and M244V). Within the 2nd year 3/232 pts (1 each low, intermediate, and high risk; 1%) progressed to blast crisis. During the 1st year of treatment imatinib therapy was stopped due to side effects or resistance in 6% of pts in the imatinib 400mg arm, in 2% of pts in the imatinib+IFN, and in 2% of pts in the imatinib+Ara-C arm. IFN was stopped in 21%, Ara-C in 18% of pts. This interim analysis of a prospective randomized trial with imatinib and imatinib in combination for newly diagnosed pts with CML has proven feasibility of imatinib combinations in addition to high response and low progression rates. Long-term observation will demonstrate whether the promising results will be maintained and will improve survival.

Abstract: Abstract 3411 Background: Dose of therapy and time to response may be different in the elderly as compared to younger patients with CML. This has been reported previously for interferon α (Berger et al., Leukemia 2003). For imatinib, contradictory results have been presented (Rosti et al. Haematologica 2007, Guliotta et al. Blood 2009). Aims: An analysis comparing dose-response relationship in patients more or less than 65 years (y) of age is warranted. Methods: We analysed the German CML-Study IV, a randomized 5-arm trial to optimize imatinib therapy by combination, dose escalation and transplantation. Patients older and younger than 65y randomized to imatinib 400 mg (IM400) or 800 mg (IM800) were compared with regard to time to hematologic, cytogenetic and molecular remissions, imatinib dose, adverse events (AEs) and overall survival (OS). Results: From July 2002 to April 2009, 1311 patients with Ph+ CML in chronic phase were randomized, 623 patients were evaluable, 311 patients for treatment with IM400 and 312 for IM800. 84 (27%) and 66 (21%), respectively, were older than 65 years. All patients were evaluable for hematologic, 578 (140 〉 65y and 438 〈 65y) for cytogenetic, and 600 (143 and 457, respectively) for molecular responses. Median age was 70y vs. 49y for IM400 and 69y vs. 46y for IM800. The median dose per day was lower for elderly patients with IM800 (517mg vs. 666mg) and the same with IM400 (400mg each). Patients' characteristics at baseline were evenly distributed in all groups regarding gender, follow-up, hemoglobin, platelet count and spleen size. Leukocyte counts were significantly lower in elderly patients (IM400: 50/nl vs. 78/nl, IM800: 36/nl vs. 94/nl). EURO score was different due to age in elderly patients (low risk: IM400: 11% vs. 43%, IM800: 14% vs. 42%; intermediate risk: IM400: 79% vs. 44% and IM800: 73% and 43%). There was no difference in cytogenetic and molecular analyses between treatment groups. With regard to efficacy, there was no difference for older patients in achieving a complete cytogenetic remission (CCR) and major molecular remission (MMR) if IM400 and IM800 were compared together. If treatment groups were analyzed separately, older patients treated with IM400 reached CCR and MMR statistically significant slower than younger patients (CCR: median 14.2 months vs. 12.1 months, p=0.019; MMR: median 18.7 months vs. 17.5 months, p=0.006). There was no difference with IM800 (CCR: median 7.7 months vs. 8.9 months, MMR: median 9.9 months vs. 10.0 months). 3y-OS for older patients 〉 65y was 94.7% and for patients 〈 65y was 96.1%. Some differences were observed in the safety analyses. 530 patients (IM400: 278, IM800: 252) were evaluated on common toxicity criteria (WHO). Some hematologic AEs were documented slightly more often in the elderly than in the younger patients: for IM400 anemia grade 1–2 (60 vs. 42%) and leukopenia grade 3–4 (5.6 vs. 1.4%) and for IM800 anemia grade 1–4 (64 vs.47% and 7.2 vs. 5.7%) and thrombocytopenia grade 3–4 (9.3 vs. 7.1%). Non hematologic AEs were more prominent in IM800 and were mainly gastrointestinal symptoms (IM400: 33 vs. 31%, IM800: 48 and 44%) and edema (IM400: 28 vs. 29%, IM800: 35 vs. 50%). There was no difference for grade 3/4 non-hematological AEs in older patients in both groups. Conclusions: Imatinib 400 mg and 800 mg are well tolerated also in the elderly. The IM800 dosage was more tolerability-adapted for the elderly, but there was no difference in reaching a CCR and MMR in contrast to the IM400 where a significantly slower response was detected in the elderly. Whether this difference is clinically relevant has yet to be determined. Updated results will be presented. Disclosures: Haferlach: MLL Munich Leukemia Laboratory: Employment, Equity Ownership, Research Funding. German CML-Study Group:Deutsche Krebshilfe: Research Funding; Novartis: Research Funding; Roche: Research Funding; BMBF: Research Funding; Essex: Research Funding.

Abstract: Background: Standard therapy of acute promyelocytic leukemia has long relied on the combination of All-trans-retinoic acid (ATRA) and chemotherapy. The introduction of arsenic trioxide (ATO) in APL treatment has allowed achievement of similarly high remission and survival rates coupled with significantly reduced myelosuppression. Recent results of the APL0406 trial by the GIMEMA-AMLSG-SAL study groups showed that the combination of ATRA and arsenic trioxide (ATO) is superior to standard ATRA and chemotherapy (CHT) in front-line therapy of low/intermediate risk acute promyelocytic leukemia (APL). The implications of these results for the clinical practice of APL patients in Germany have been uncertain given the fact that ATO is not formally licensed for front-line therapy of APL. Aim:In order to provide evidence and a reflection of the clinical reality of APL patient care in Germany an intergroup APL registry (National acute promyelocytic leukemia (APL) observational study, NAPOLEON) was recently initiated by several AML study groups. Methods:Eligible patients are adults at least 18 years of age with newly diagnosed or relapsed APL not beyond the first year of diagnosis. Here we report the first analysis on the series of patients prospectively enrolled into this registry. The study was conducted in accordance with the Declaration of Helsinki, received IRB approval by all participating centers and was registered at ClinicalTrials.gov (NCT02192619). Results: As of August 1st 2016, 88 patients have been included into the study with a median age of 57 years (range 22-87). All had newly diagnosed APL (100%) with 66% (n=58) being of low/intermediate risk according to the Sanz score. Out of those patients 76% (n=44) received an ATO-ATRA based induction regimen followed by a median of 4 courses of consolidation (according to the APL 0406 study).Of 41 patients evaluable for response to induction, 40/41 (98%) patients achieved complete remission (CR) with the ATRA-ATO arms. Early death rate within 30 days of therapy was 2% (1/44). After a median follow-up of 12 months, the event-free survival, cumulative incidence of relapse and overall survival at 12 months for these patients were 97%, 0% and 97%, respectively. Therapy was well tolerated and no new safety signals have been obtained. Conclusion:These real life data from a prospective German registry provide further evidence for the safety and sustained anti-leukemic efficacy of ATRA-ATO in low/intermediate risk APL. These results further support ATRA-ATO as the new standard of care in this clinical setting. Table Demographic, clinical and laboratory characteristics of the eligible patients. Table. Demographic, clinical and laboratory characteristics of the eligible patients. Disclosures Platzbecker: TEVA: Honoraria, Research Funding. Greiner:BMS: Research Funding. Thiede:AgenDix: Employment, Other: Ownership. Hochhaus:BMS: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; ARIAD: Honoraria, Research Funding.

Abstract: Abstract 339 Initial reports that high dose imatinib results in better responses more rapidly than standard dose imatinib remain controversial. The German CML Study Group therefore compared imatinib 800 mg (IM 800) with standard dose imatinib +/- IFN (IM 400, IM 400 + IFN) in newly diagnosed, not pretreated CML with regard to molecular response at 12 months and survival in a randomized clinical trial. By April 30, 2009, 1026 chronic phase CML patients have been randomized (326 for IM 400, 338 for IM 800, 351 for imatinib + IFN). Comparison was for molecular and cytogenetic remissions, overall (OS) and progression free (PFS) survival and toxicity. 1015 patients were evaluable at baseline, 904 for survival analysis (294 for IM 400, 286 for IM 800, 324 for IM 400+IFN), 790 for cytogenetic (analysis of at least 20 metaphases required) and 823 for molecular response. The three treatment groups were similar regarding median age, sex, median values of Hb, WBC, platelets and distribution according to the EURO score. Median follow-up was 25 months in the imatinib 800 mg arm and 42 months in the imatinib 400 mg +/-IFN arms. The difference is due to the fact that at first the IM 800 arm was designed for high risk patients only and opened up to all risk groups in July 2005. The median daily doses of imatinib were 626 mg (209- 800 mg) in the IM 800 arm and 400 mg (184- 720 mg) in the IM 400 +/- IFN arms. Of 218 patients receiving imatinib 800 mg and evaluable for dosage at 12 months, 100 (45.9%) received more than 700 mg/day, 27 (12.4%) 601-700 mg, 37 (17.0%) 501-600 mg, 48 (22.0%) 401-500 mg and only 6 (2.8%) 400 mg/day or less. The cumulative incidences at 12 months of complete cytogenetic remission (CCR) were 52.3%, 64.9% and 50.6%, and of major molecular remission (MMR) 30.2%, 54.3% and 34.6% with IM 400, IM 800 and IM 400 +IFN, respectively. The cumulative incidences of achieving CCR and MMR with IM 400, IM 800 and IM 400+IFN at 6, 12, 18 and 24 months after start of treatment are summarized in the table. MMR at 12 months was reached faster with IM 800 than with IM 400 (p=0.0003) or IM400+IFN (p=0.0131). Optimal molecular response (OMR= 〈 0.01% BCR-ABL according to the international scale) was reached with IM 800 after a median of 31.3 months vs. 47.5 and 42.5 months with IM 400 +/- IFN. Also CCR was reached faster with IM 800 (p 〈 0.01). The more rapid achievement of MMR with IM 800 was observed in low and intermediate risk patients with little or no difference in high risk patients. In an analysis “as treated” patients receiving more than 600 mg/day reached remissions faster than those receiving lower dosages (CCR after a median of 7.8 vs. 8.9 months, MMR after a median of 10.4 vs. 12.9 months). At the time of this evaluation, OS (92% at 5 years) and PFS (88% at 5 years) showed no difference. Type and severity of adverse events (AE) at 12 months did not differ from those expected (all grades and grades III/IV). Hematologic (thrombocytopenia 7% vs. 4%) and non-hematologic AEs (gastrointestinal 35% vs. 15-24% and edema 29% vs. 16-19%) were more frequent with IM 800, fatigue (14% vs. 7-13%) and neurological problems (15% vs. 6-7%) more frequent with IM 400 + IFN (all grades). These data show a significantly faster achievement of MMR at 12 months with IM 800 as compared to IM 400 +/-IFN. So far, this faster response rate did not translate into better OS or PFS. Hence IM 400 should still be considered as standard of care. With some individual dose adjustments tolerability of IM 800 was good. Longer observation is required to determine whether this more rapid achievement of MMR and CCR will have a long term impact or not. Disclosures: German CML Study Group: Deutsche Krebshilfe: Research Funding; Novartis: Research Funding; European LeukemiaNet: Research Funding; Kompetenznetz Leukämie: Research Funding; Roche: Research Funding; Essex: Research Funding.

Abstract: Introduction Aberrant DNA methylation is a common feature of acute myeloid leukemia (AML) and increases with age. DNMT inhibitors such as Azacitidine (AZA) can induce meaningful responses and remissions in AML as monotherapy. The combination of AZA with standard chemotherapy (7+3) has not been tested in a randomized trial. Patients and study design The AML-AZA trial compared AZA directly followed by standard induction therapy, AZA followed by standard consolidation, and further Azacitdine maintenance with standard induction and consolidation without AZA in older patients with AML. All patients received standard Cytarabine (100 mg/sqm) and Daunorubicin (60 mg/sqm) induction (“7+3”) and up to two cycles of intermediate dose Cytarabine (1 g/sqm q12hr days 1, 3, 5) as consolidation therapy. AZA (75 mg/sqm for 5 days) preceded each therapy cycle in the AZA arm. In addition, AZA maintenance for up to 1 year was also scheduled for patients in the AZA arm. 105 patients were randomized to receive AZA plus Cytarabine plus Daunorubicin as induction therapy (AZA + 7+3) and 109 patients to receive 7+3 only (control group). Median age was 70 years in both treatment arms. Patient cohorts were well balanced with regard to blast counts in bone marrow, secondary versus de novo AML and molecular genetics risk group. More patients in the AZA + 7+3 arm (39/105; 37.1%) than in the control group (25/109; 22.9%) showed high risk cytogenetics (p=0.057). Event free survival (EFS) was the primary end point. Secondary endpoints were overall survival (OS), complete remission (CR) rate, toxicity and different treatment response according to molecular markers. Results Overall, 214 of 216 planned patients were enrolled into the AML-AZA trial. Due to a higher number of severe adverse events (SAE), AZA administration was stopped after recruitment of 214 patients whereas chemotherapy was continued as planned. Percentages of patients in the AZA arm with AZA doses as initially planned were as follows: 99% for first induction cycle, 72% for the second induction cycle. AZA as maintenance therapy for at least one cycle was delivered to 18% of patients in the AZA group. At least one SAE occurred in 51% of AZA + 7+3 patients compared to 31% of 7+3 patients (p=0.005). Cardiac disorders with CTCAE grade 3-5 occurred more frequently in the AZA + 7+3 arm (n = 15) than in the 7+3 arm (n = 6) (not significant). Leukopenia was prolonged by one day (median 23 vs 22 days) in the AZA + 7+3 group (p=0.043), whereas time of thrombocytopenia was not different. The early death rates at 30, 60 and 90 days did not differ significantly between treatment groups. Efficacy analyses were performed on an intention-to-treat basis. Median EFS as the primary endpoint was 6 months in both treatment arms (p=0.96). Median OS was 16 months for patients treated with AZA + 7+3 and 21 months for 7+3 (p=0.35). Median relapse free survival was 12 months in both treatment arms (p=0.95). 48 of 100 patients (48%) in the AZA + 7+3 arm achieved complete remission (CR) after induction therapy versus 57 of 109 patients (52%) in the 7+3 arm (p=0.58). DNMT3A exon 23 mutations were detected in 30 out of 162 analyzed patients. Exploratory analyses were performed to detect a potential interaction between AZA + 7+3 response and DNMT3A mutation status. Trends for improved EFS and OS were noted for AZA + 7+3 treatment in DNMT3A mutated patients. Conclusion AZA as addition prior to standard induction and consolidation chemotherapy does not prolong EFS and OS in unselected older AML patients and it is more toxic. However, a trend towards better efficacy in patients with DNMT3A mutation was observed and should be further explored. Disclosures Müller-Tidow: Celgene: Honoraria, Research Funding. Thiede:AgenDix GmbH: Equity Ownership, Research Funding; Illumina: Research Support, Research Support Other. Kiehl:Roche: Membership on an entity's Board of Directors or advisory committees. Brümmendorf:Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Ehninger:GEMoaB GmbH: Consultancy, Patents & Royalties.