Abstract: Background: Acute myeloid leukemia (AML) with t(8;21)(q22;q22) results in the formation of the RUNX1-RUNX1T1 fusion transcript which can be used to monitor minimal residual disease (MRD) by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). Early identification of patients (pts) with a high risk of relapse will allow pre-emptive therapy including allogeneic hematopoietic cell transplantation (alloHCT). Recent studies in AML with NPM1 mutation or the CBFB-MYH11 gene fusion revealed that MRD persistence is significantly associated with a high risk of relapse. However, the prognostic impact of MRD assessment in RUNX1-RUNX1T1-positive AML is not well established. Aims: To assess the prognostic impact of qRT-PCR-based MRD monitoring in bone marrow (BM) of pts with t(8;21)/RUNX1-RUNX1T1-positive AML obtained at defined time-points (diagnosis, first and second cycle of chemotherapy, end of treatment). Methods: In total, 120 pts were included based on the availability of a diagnostic BM sample and at least two subsequent BM samples obtained during therapy and at the end of treatment; 106 pts were enrolled in one of six AMLSG treatment trials: AML HD93 (n=1), AML HD98A (NCT00146120; n=13), AMLSG 06-04 (NCT00151255; n=4), AMLSG 07-04 (NCT00151242; n=43), AMLSG 11-08 (NCT00850382; n=31), AMLSG 21-13 (NCT02013648; n=14); 14 pts were treated outside clinical trials. All pts received anthracycline- and cytarabine-based intensive induction followed by subsequent high-dose cytarabine consolidation cycles. For MRD assessment, qRT-PCR from BM specimens was performed using TaqMan technology; RUNX1-RUNX1T1 transcript levels (TL) were reported as the normalized value of RUNX1-RUNX1T1 per 106 transcripts of the housekeeping gene beta2-microglobulin. The maximum sensitivity of the assay was 10-6. Results: The median age of the pts was 47 years (yrs; range, 18-73 yrs); at the time of diagnosis there was a broad range of RUNX1-RUNX1T1 TL (18490 to 14440000) with a median of 227800. RUNX1-RUNX1T1 TL did not correlate with clinical features (age, WBC, platelets, LDH, BM blasts) or associated gene mutations such as KIT, FLT3-ITD/TKD, NRAS or ASXL2. However, pts with additional FLT3 mutation showed higher TL compared to wild-type pts (median, 412955 vs 219052). Cox regression analysis using RUNX1-RUNX1T1 TL as a log10 transformed continuous variable showed that higher RUNX1-RUNX1T1 TL were significantly associated with a higher cumulative incidence of relapse (CIR), inferior event-free survival (EFS) and shorter overall survival (OS) for the two time points "after first treatment cycle" and "at end of treatment" (CIR: HR, 1.84, p=0.001; HR, 1.60, p=0.03; EFS: HR, 1.59, p=0.01, HR, 1.74, p=0.01; OS: HR, 1.63, p=0.02, HR 2.13, p=0.009, respectively). In univariate analyses achievement of MRD negativity (n=35) at the end of treatment was significantly associated with a superior 4-yr OS (93% vs 67%; p=0.007) and 4-yr EFS (81% vs 61%; p=0.04) whereas achievement of MRD negativity after the first (1/85) and second (20/89) treatment cycle was low not reaching significance for any of the clinical endpoints. Separation of the RUNX1-RUNX1T1 TL according to quartiles of distribution showed significant differences in OS (p=0.04), and remission duration (p=0.006) "after first cycle" whereas "at end of treatment" significant differences were only found for OS (p=0.009). Finally, we evaluated the impact of concurrent KIT mutations on the kinetics of RUNX1-RUNX1T1 TL. Following the first treatment cycle, the median RUNX1-RUNX1T1 TL were significantly lower in the KIT wildtype group compared with the KIT mutated group (p=0.02); the same was true "at the end of treatment" (p=0.02). Conclusions: In our study, achievement of MRD negativity at the end of treatment was significantly associated with a better outcome in t(8;21)-positive AML. The fact that earlier time points did not allow the identification of pts with a high relapse risk is probably due to the high sensitivity of the qRT-PCR assay which is also reflected by the low number of pts achieving qRT-PCR negativity after first and second treatment cycle, respectively. Further analyses are ongoing including multivariable as well as molecular subgroup analyses. *These authors contributed equally to the work: MA, AC MA was supported by the Else-Kröner-Fresenius-Stiftung (EKFS). Disclosures Paschka: Celgene: Honoraria; Pfizer Pharma GmbH: Honoraria; Bristol-Myers Squibb: Honoraria; Medupdate GmbH: Honoraria; Novartis: Consultancy; ASTEX Pharmaceuticals: Consultancy. Lübbert:Ratiopharm: Other: Study drug valproic acid; Janssen-Cilag: Other: Travel Funding, Research Funding; Celgene: Other: Travel Funding. Fiedler:Amgen: Consultancy, Other: Travel, Patents & Royalties, Research Funding; Teva: Other: Travel; Kolltan: Research Funding; Ariad/Incyte: Consultancy; Novartis: Consultancy; Gilead: Other: Travel; GSO: Other: Travel; Pfizer: Research Funding. Heuser:Karyopharm Therapeutics Inc: Research Funding; Pfizer: Research Funding; Bayer Pharma AG: Research Funding; Celgene: Honoraria; Tetralogic: Research Funding; BerGenBio: Research Funding; Novartis: Consultancy, Research Funding. Schlenk:Pfizer: Honoraria, Research Funding; Amgen: Research Funding.

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). The multi-targeted kinase inhibitor midostaurin combined with intensive chemotherapy has shown activity against AML with FLT3 mutations. However, toxicity and potential drug-drug interactions with strong CYP3A4 inhibitors such as posaconazole may necessitate dose reduction. Aims: To evaluate the impact of age and midostaurin dose-adaptation after intensive induction chemotherapy on response and outcome in AML with FLT3-ITD within the AMLSG 16-10 trial (NCT01477606). Methods: The study included 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. Pts with acute promyelocytic leukemia were not eligible. The presence of FLT3-ITD was analyzed within our diagnostic study AMLSG-BiO (NCT01252485) by Genescan-based DNA fragment-length analysis. Induction therapy consisted of daunorubicin (60 mg/m², d1-3) and cytarabine (200 mg/m², continuously, d1-7); midostaurin 50 mg bid was applied from day 8 until 48h before start of the next treatment cycle. A second cycle was allowed in case of partial remission (PR). For consolidation therapy, pts proceeded to allogeneic hematopoietic-cell transplantation (HCT) as first priority; if alloHCT was not feasible, pts received three cycles of age-adapted high-dose cytarabine (HDAC) in combination with midostaurin starting on day 6. In all pts one-year maintenance therapy with midostaurin was intended. The first patient entered the study in June 2012 and in April 2014, after recruitment of n=147 pts, the study was amended including a sample size increase to 284 pts and a dose reduction to 12.5% of the initial dose of midostaurin in case of co-medication with strong CYP3A4 inhibitors (e.g. posaconazole). This report focuses on age and the comparison between the first (n=147) and the second cohort (n=137) of the study in terms midostaurin dose-adaptation. Results: Patient characteristics were as follows: median age 54 yrs (range, 18-70; younger, 68% 〈 60 yrs; older, 32% ≥ 60 yrs); median white cell count 44.7G/l (range 1.1-1543 G/l); karyotype, n=161 normal, n=16 high-risk according to ELN recommendations; mutated NPM1 n=174 (59%). Data on response to first induction therapy were available in 277 pts; complete remission (CR) including CR with incomplete hematological recovery (CRi) 60%, PR 20%, refractory disease (RD) 15%, and death 5%. A second induction cycle was given in 54 pts. Overall response (CR/CRi) after induction therapy was 76% (76%, younger; 76%, older) and death 6% (4%, younger; 10% older). The dose of midostaurin during first induction therapy was reduced in 53% and 71% of patients in cohort-1 and cohort-2, respectively. Reasons for dose reduction were in 58% and 49% toxicity, and in 9% and 23% co-medication in cohort-1 and cohort-2, respectively. No difference in response to induction therapy was noted between cohorts (p=0.81). Median follow-up was 18 months. Overall 146 pts received an alloHCT, 128 in first CR (n=94 younger, n=34 older; n=92 from a matched unrelated and n=36 from a matched related donor). In pts receiving an alloHCT within the protocol in median two chemotherapy cycles were applied before transplant (range 1-4). The cumulative incidence of relapse (CIR) and death after transplant were 13% (SE 3.2%) and 16% (SE 3.5%) without differences (p=0.97, p=0.41, respectively) between younger and older patients. So far maintenance therapy was started in 86 pts, 61 pts after alloHCT and 25 pts after HDAC. Fifty-five adverse events 3°/4° were reported being attributed to midostaurin; cytopenias after alloHCT were the most frequent (29%). CIR in patients starting maintenance therapy was 20% one year after start of maintenance without difference between alloHCT and HiDAC (p=0.99). In addition, no difference in CIR was identified in patients after consolidation with alloHCT or HDAC according to dose reduction of midostaurin during first induction therapy (p=0.43, p=0.98, respectively). Median overall survival was 25 months (younger, 26 months; older 23 months; p=0.15). Conclusions: The addition of midostaurin to intensive induction therapy and as maintenance after alloHCT or HDAC is feasible and effective without an impact of age and dose adaptation on outcome. Disclosures Schlenk: Amgen: Research Funding; Pfizer: Honoraria, Research Funding. Fiedler:GSO: Other: Travel; Pfizer: Research Funding; Kolltan: Research Funding; Amgen: Consultancy, Other: Travel, Patents & Royalties, Research Funding; Gilead: Other: Travel; Ariad/Incyte: Consultancy; Novartis: Consultancy; Teva: Other: Travel. Lübbert:Celgene: Other: Travel Funding; Janssen-Cilag: Other: Travel Funding, Research Funding; Ratiopharm: Other: Study drug valproic acid. Greil:Janssen-Cilag: Honoraria; Genentech: Honoraria, Research Funding; Mundipharma: Honoraria, Research Funding; Merck: Honoraria; AstraZeneca: Honoraria; Boehringer-Ingelheim: Honoraria; GSK: Research Funding; Ratiopharm: Research Funding; Cephalon: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Novartis: Honoraria; Bristol-Myers-Squibb: Consultancy, Honoraria; Pfizer: Honoraria, Research Funding; Roche: Honoraria, Research Funding; Sanofi Aventis: Honoraria; Eisai: Honoraria; Amgen: Honoraria, Research Funding. Greiner:BMS: Research Funding. Paschka:ASTEX Pharmaceuticals: Consultancy; Novartis: Consultancy; Medupdate GmbH: Honoraria; Bristol-Myers Squibb: Honoraria; Pfizer Pharma GmbH: Honoraria; Celgene: Honoraria. Heuser:Bayer Pharma AG: Research Funding; Karyopharm Therapeutics Inc: Research Funding; Novartis: Consultancy, Research Funding; Celgene: Honoraria; Pfizer: Research Funding; BerGenBio: Research Funding; Tetralogic: Research Funding.

Abstract: High CD33 expression in acute myeloid leukemia (AML) with mutated NPM1 provides a rationale for the evaluation of gemtuzumab ozogamicin (GO) in this AML entity. We conducted a randomized trial to evaluate GO in combination with intensive induction and consolidation therapy in NPM1-mutated AML. PATIENTS AND METHODS Between May 2010 and September 2017, patients ≥ 18 years old and considered eligible for intensive therapy were randomly assigned up front for induction therapy with idarubicin, cytarabine, etoposide, and all- trans-retinoic acid with or without GO. The early ( P = .02) primary end point of event-free survival (EFS) was evaluated 6 months after completion of patient recruitment. RESULTS Five hundred eighty-eight patients were randomly assigned (standard arm, n = 296; GO arm, n = 292). EFS in the GO arm was not significantly different compared with that in the standard arm (hazard ratio, 0.83; 95% CI, 0.65 to 1.04; P = .10). The early death rate during induction therapy was 10.3% in the GO arm and 5.7% in the standard arm ( P = .05). Causes of death in both arms were mainly infections. The cumulative incidence of relapse (CIR) in patients achieving a complete remission (CR) or CR with incomplete hematologic recovery (CRi) was significantly reduced in the GO arm compared with the standard arm ( P = .005), with no difference in the cumulative incidence of death ( P = .80). Subgroup analysis revealed a significant beneficial effect of GO in female, younger (≤ 70 years), and FLT3 internal tandem duplication–negative patients with respect to EFS and CIR. CONCLUSION The trial did not meet its early primary end point of EFS, mainly as a result of a higher early death rate in the GO arm. However, in patients achieving CR/CRi after induction therapy, significantly fewer relapses occurred in the GO compared with the standard arm.

Abstract: To assess the impact of allogeneic hematopoietic stem-cell transplantation (HSCT) from matched related donors (MRDs) and matched unrelated donors (MUDs) on outcome in high-risk patients with acute myeloid leukemia (AML) within a prospective multicenter treatment trial. Patients and Methods Between 1998 and 2004, 844 patients (median age, 48 years; range, 16 to 62 years) with AML were enrolled onto protocol AMLHD98A that included a risk-adapted treatment strategy. High risk was defined by the presence of unfavorable cytogenetics and/or by no response to induction therapy. Results Two hundred sixty-seven (32%) of 844 patients were assigned to the high-risk group. Of these 267 patients, 51 patients (19%) achieved complete remission but had adverse cytogenetics, and 216 patients (81%) had no response to induction therapy. Allogeneic HSCT was actually performed in 162 (61%) of 267 high-risk patients, after a median time of 147 days after diagnosis. Graft sources were as follows: MRD (n = 62), MUD (n = 89), haploidentical donor (n = 10), and cord blood (n = 1). The 5-year overall survival rates were 6.5% (95% CI, 3.1% to 13.6%) for patients (n = 105) not proceeding to HSCT and 25.1% (95% CI, 19.1% to 33.0%; from date of transplantation) for patients (n = 162) receiving HSCT. Multivariable analysis including allogeneic HSCT as a time-dependent covariable revealed that allogeneic HSCT significantly improved outcome; there was no difference in outcome between allogeneic HSCT from MRD and MUD. Conclusion Allogeneic HSCT in younger adults with high-risk AML has a significant beneficial impact on outcome, and allogeneic HSCT from MRD and MUD yields similar results.

Abstract: Background: Pancreatic ductal adenocarcinoma (PDAC) is highly resistant to standard chemo- and radiotherapy. Recently, a new class of non-platinum-based halogenated molecules (called FMD compounds) was discovered that selectively kills cancer cells. Here, we investigate the potential of 1,2-Diamino-4,5-dibromobenzene (2Br-DAB) in combination with standard chemotherapy and radiotherapy in murine and human PDAC. Methods: Cell viability and colony formation was performed in human (Panc1, BxPC3, PaTu8988t, MiaPaCa) and three murine LSL-KrasG12D/+;LSL-Trp53R172H/+;Pdx-1-Cre (KPC) pancreatic cancer cell lines. In vivo, preclinical experiments were conducted in LSL-KrasG12D/+;p48-Cre (KC) and KPC mice using 2Br-DAB (7 mg/kg, i.p.), +/- radiation (10 × 1.8 Gy), gemcitabine (100 mg/kg, i.p.), or a combination. Tumor growth and therapeutic response were assessed by high-resolution ultrasound and immunohistochemistry. Results: 2Br-DAB significantly reduced cell viability in human and murine pancreatic cancer cell lines in a dose-dependent manner. In particular, colony formation in human Panc1 cells was significantly decreased upon 25 µM 2Br-DAB + radiation treatment compared with vehicle control (p = 0.03). In vivo, 2Br-DAB reduced tumor frequency in KC mice. In the KPC model, 2Br-DAB or gemcitabine monotherapy had comparable therapeutic effects. Furthermore, the combination of gemcitabine and 2Br-DAB or 2Br-DAB and 18 Gy irradiation showed additional antineoplastic effects. Conclusions: 2Br-DAB is effective in killing pancreatic cancer cells in vitro. 2Br-DAB was not toxic in vivo, and additional antineoplastic effects were observed in combination with irradiation.