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: The addition of sorafenib to standard induction and consolidation therapy in newly diagnosed patients (pts) ≤60 years (yrs) with acute myeloid leukemia (AML) led to significant prolongation of event-free survival (EFS) and relapse-free survival (RFS) in the randomized placebo-controlled SORAML trial (NCT00893373). After a median follow-up of 3 yrs, a benefit for sorafenib treated pts was observed also in overall survival (OS), but this difference was not significant. Here, we present updated survival data and information on relapse treatment and outcome. Methods: In the SORAML trial, 267 newly diagnosed untreated fit AML pts up to 60 yrs of age and irrespective of FLT3 mutation status received two cycles of induction chemotherapy with DA (daunorubicin 60 mg/m2 days 3-5 plus cytarabine 100 mg/m2 cont. inf. days 1-7), followed by three cycles of high-dose cytarabine consolidation (3 g/m2 b.i.d. days 1, 3, 5). Allogeneic stem cell transplantation (SCT) was scheduled for all intermediate-risk pts in first complete remission (CR) with a sibling donor and for all high-risk pts with a matched related or unrelated donor. At study inclusion, pts were randomized to receive either sorafenib (2x400 mg/day) or placebo as add-on to standard treatment in a double blinded fashion. Study medication was given on days 10-19 of DA I+II, from day 8 of each consolidation until 3 days before the start of the next consolidation and as maintenance for 12 months (mos) after the end of consolidation. The primary endpoint of the trial was EFS. The results after follow-up of 3 yrs were presented at ASH 2014 (Röllig et al., Blood 2014; 124: 6) and fully published (Röllig et al., Lancet Oncol 2015; 16: 1691-9). Here, we present the results after prolonged follow-up. For this analysis, information on remission and survival status, mode and outcome of relapse treatment including SCT were collected for all randomized pts and analyzed by standard statistical methods. Results: Of 267 treated pts, 134 were randomized in the sorafenib arm and 133 in the placebo arm with a resulting CR rate of 60% and 59%, respectively. After a median observation time of 78 mos, the primary study endpoint EFS in the placebo vs sorafenib arm was 9 mos vs 26 mos (HR 0.68, p=0.01) in univariate Kaplan Meier analysis. The beneficial effect of sorafenib on EFS was confirmed in multivariate Cox regression analysis with a HR of 0.61 (p=0.005). Median RFS in the placebo vs sorafenib arms was 22 vs 63 mos, corresponding to a HR of 0.64 (p=0.033). Exploratory analyses were performed in the 70 relapsing pts (40 after placebo vs 30 after sorafenib treatment). Among relapsing pts, 82% vs 73% achieved a second CR. In these two groups, 88% and 87% of pts received a SCT as part of salvage treatment. A lower proportion of pts in the placebo arm received a second SCT as salvage treatment (5% vs 13%). In the context of salvage SCT, the proportion of haploident donors in the placebo and sorafenib group was 3% vs 15% and the incidence of Grade 3/4 GVDH was 17% vs 0%. SCT-related non-relapse mortality (NRM) was similar in both groups, but the cumulative incidence of second relapse (CIR) was higher in the sorafenib group (35% vs 54% after 48 mos). Therefore, median OS from relapse in the placebo vs sorafenib groups were 27 mos vs 10 mos, corresponding to a HR of 1.68 (p=0.098). The projected median OS from randomization is 83 mos in the placebo arm and was not reached for the sorafenib arm, corresponding to a 5-year OS of 52% vs 61% (HR 0.81, p=0.263). Conclusion: Mature follow-up data confirms the antileukemic efficacy of sorafenib in younger AML pts with and without FLT3 mutation. The addition of sorafenib to standard chemotherapy resulted in a significantly longer EFS and clinically relevant 36% risk reduction for relapse or death. Five pts need to be treated (NNT) to prevent one relapse or death at 3 years and six pts at 5 yrs. Exploratory analyses in relapsing pts show that survival after relapse is shorter after sorafenib which might be due to i) a higher rate of second SCTs and a higher incidence of haploidentical SCT despite the lower frequency of severe GVHD, most likely by chance and not explainable by systematic reasons and ii) a lower response to salvage treatment after sorafenib therapy. Despite these observations, primary sorafenib treatment led to an OS benefit with a 19% risk reduction for death which was not statistically significant since this phase II trial was not adequately powered to detect OS differences. Figure Figure. Disclosures Rollig: Bayer: Research Funding; Janssen: Research Funding. Hüttmann: Gilead, Amgen: Other: Travel cost; Bristol-Myers Squibb, Takeda, Celgene, Roche: Honoraria. Giagounidis: Acceleron: Consultancy; Celgene: Consultancy. Mackensen: AMGEN: Research Funding. Hänel: Roche: Honoraria; Novartis: Honoraria. Thiede: Roche: Consultancy; Novartis: Consultancy, Speakers Bureau; Bayer: Consultancy, Speakers Bureau; Agendix: Employment. Schetelig: Sanofi Aventis: Consultancy, Research Funding; Roche: Honoraria; Abbvie: Honoraria; Janssen: Consultancy, Honoraria.

Abstract: PURPOSE: Cure of Helicobacter pylori infection is associated with remission induction in the majority of patients with low-grade gastric mucosa associated lymphoid tissue (MALT) lymphoma in localized stages; however, limited data exist as to whether these patients may be cured of their lymphoma. The present study was performed to investigate whether the polymerase chain reaction (PCR) for the rearranged immunoglobulin heavy chain region may be used to define “molecular” remission. PATIENTS AND METHODS: Ninety-seven patients who suffered from low-grade gastric MALT lymphoma stage I E were observed with central pathology and molecular biology after cure of H pylori infection. PCR was performed with the use of consensus primers for the framework regions 1, 2, and 3 and monoclonality was corroborated by sequence analysis. In selected cases, microdissection was performed to study the origin of the monoclonal B cells. RESULTS: Of the 97 patients, 77 obtained complete endoscopic and histologic remission (CR). Twenty of 44 patients with PCR monoclonality at diagnosis and with sufficient molecular follow-up displayed monoclonal bands for a median time of 20.5 months after CR (range, 0 to 50.4 months). These B cells were related to the original lymphoma clone by sequence analysis. Microdissection analysis identified basal lymphoid aggregates as the source of these monoclonal B cells. Local relapse occurred in and was observed by PCR in four patients. All four patients displayed monoclonal PCR before relapse, and three of these four showed ongoing PCR monoclonality throughout their course, indicating the persistence of malignant cells. CONCLUSION: Half of all patients with gastric MALT lymphoma show long-term PCR monoclonality up to several years after cure of H pylori infection and CR. Patients with monoclonal PCR should be observed closely, whereas long-term PCR negativity may indicate cure of the disease.

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: Tandem-duplication mutations of the UBTF gene ( UBTF -TDs) coding for the upstream binding transcription factor have recently been described in pediatric patients with acute myeloid leukemia (AML) and were found to be associated with particular genetics (trisomy 8 (+8), FLT3 -internal tandem duplications ( FLT3 -ITD), WT1 -mutations) and inferior outcome. Due to limited knowledge on UBTF- TDs in adult AML, we screened 4247 newly diagnosed adult AML and higher-risk myelodysplastic syndrome (MDS) patients using high-resolution fragment analysis. UBTF -TDs were overall rare ( n  = 52/4247; 1.2%), but significantly enriched in younger patients (median age 41 years) and associated with MDS-related morphology as well as significantly lower hemoglobin and platelet levels. Patients with UBTF -TDs had significantly higher rates of +8 (34% vs. 9%), WT1 (52% vs. 7%) and FLT3 -ITD (50% vs. 20.8%) co-mutations, whereas UBTF -TDs were mutually exclusive with several class-defining lesions such as mutant NPM1 , in-frame CEBPA bZIP mutations as well as t(8;21). Based on the high-variant allele frequency found and the fact that all relapsed patients analyzed ( n  = 5) retained the UBTF -TD mutation, UBTF -TDs represent early clonal events and are stable over the disease course. In univariate analysis, UBTF -TDs did not represent a significant factor for overall or relapse-free survival in the entire cohort. However, in patients under 50 years of age, who represent the majority of UBTF -mutant patients, UBTF -TDs were an independent prognostic factor for inferior event-free (EFS), relapse-free (RFS) and overall survival (OS), which was confirmed by multivariable analyses including established risk factors such as age and ELN2022 genetic risk groups (EFS [HR: 2.20; 95% CI 1.52–3.17, p   〈  0.001], RFS [HR: 1.59; 95% CI 1.02–2.46, p  = 0.039] and OS [HR: 1.64; 95% CI 1.08–2.49, p  = 0.020]). In summary, UBTF -TDs appear to represent a novel class-defining lesion not only in pediatric AML but also younger adults and are associated with myelodysplasia and inferior outcome in these patients.

Abstract: Purpose Mutations of the isocitrate dehydrogenase-1 (IDH1) and IDH2 genes are one of the most frequent alterations in acute myeloid leukemia (AML) and can be found in ~20% of patients at diagnosis. Several IDH inhibitors are currently in late stage clinical development with Enasidenib, an IDH2 inhibitor, being recently approved by the FDA. Previous analyses have reported differential impact on response to chemotherapy and outcome, depending on the IDH-mutation type, co-occurring mutations and cytogenetic abnormalities, as well as the variant allele frequency (VAF) of IDH mutations. In order to better understand its prognostic role, we analyzed newly diagnosed AML patients enrolled in prospective trials of the Study Alliance Leukemia (SAL) to investigate the impact of IDH1/2 mutations on outcome. Patients and Methods All AML patients consecutively enrolled into intensive AML treatment protocols of the SAL or into the SAL registry were included in this analysis. Next-generation sequencing (NGS) on an Illumina MiSeq-system was performed to detect IDH1/2 mutations using pre-treatment samples. Overall survival (OS) and response to therapy were analyzed for all patients with intensive treatment and according to the mutational status. Results Overall, samples of 3898 patients were analyzed. The median follow-up was 91 months (95% CI 87.2 - 93.9). Patients' characteristics are shown in Tbl.1. Three-hundred twenty-nine patients (8.4%) had IDH1 mutations and 423 (11%) had IDH2 mutations; both mutations were found in 12 pts, so the overall mutation rate in IDH1 and 2 was 19% (740/3898 patients). Of the IDH1 variants, the most common ones were the R132C found in 143 patients (43%) and R132H in 137 patients (42%). For IDH2, 324 patients had the R140Q (77%) and 80 patients the R172K (19%) variant. According to the two main variants of the more common IDH2 mutations, as reported before, the IDH2 R172K was mutually exclusive with NPM1 and/or FLT3-ITD mutations. Overall, there was a trend for increased OS for patients with IDH2 R172K (26 vs. 15 months) as compared to those with R140Q. Considering only patients with a normal karyotype and no NPM1/FLT3-ITD mutation, these patients (n=27) had a highly significant better OS than patients with IDH2 R140Q (46.3 vs. 13.1 months, p=.012), supporting the findings published by Papaemmanuil et al. (NEJM 2016). In IDH1-mutated patients, we observed statistically significant differences in baseline characteristics between the two most common mutation types, IDH1 R132C and R132H. Patients carrying the R132C mutation were older (62 vs. 55 years, p=.001), had lower WBC (3.6 vs. 21 Gpt/L, p≤.001) and were less likely to have a normal karyotype (43% vs. 66%, p=.002), NPM1 (23% vs. 66%, p= 〈 .001), and FLT3-ITD mutations (8% vs. 27%, p 〈 .001) than those with the R132H variant. In univariate testing, the CR rate was also statistically significant lower in patients with IDH1 R132C (53% vs. 72%, p≤.001), with a median OS of 12.9 months compared to 17.4 months for patients with R132H variant (p=.08). In multivariate analysis including age, WBC, NPM1 and FLT3 status, and ELN risk, the CR rate was significantly lower in patients with the IDH1 R132C variant (p=.038). The median IDH VAF was 38% (range, 0.1 - 58) with no difference according to the different types of mutation. Patients with a VAF 〉 30% had a significantly higher BM blast count (73% vs 40% for VAF≤5%) and WBC (21.2 Gpt/L vs. 3.7 Gpt/L) at baseline, but there was no clear impact on CR rate or OS found in multivariate analysis. Conclusion In this large cohort of AML patients with IDH1/2 mutations, we found significant and so far not reported differences for one of the two most prominent mutations types of IDH1. The R132C variant was associated with increased age, lower WBC, and lower NPM1 and/or FLT3 co-mutation rate. Further, these patients had lower CR rates and a trend for shorter OS. For IDH2 we were able to reproduce findings on co-mutations and showed a favorable outcome for intensively treated patients with a normal karyotype and no NPM1/FLT3-ITD mutation and the IDH2 R172K variant, providing additional evidence for classification as a separate AML entity. Disclosures Middeke: Roche: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Membership on an entity's Board of Directors or advisory committees. Rollig:Bayer: Research Funding; Janssen: Research Funding. Kramer:Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Bayer: Research Funding; Daiichi Sankyo: Consultancy. Scholl:Alexion: Other: Travel support; Abbivie: Other: Travel support; Novartis: Other: Travel support; Deutsche Krebshilfe: Research Funding; Carreras Foundation: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees; MDS: Other: Travel support; Jazz Pharma: Membership on an entity's Board of Directors or advisory committees. Hochhaus:Incyte: Research Funding; Pfizer: Research Funding; Takeda: Research Funding; Bristol-Myers Squibb: Research Funding; Novartis: Research Funding. Brümmendorf:Takeda: Consultancy; Pfizer: Consultancy, Research Funding; Janssen: Consultancy; Merck: Consultancy; Novartis: Consultancy, Research Funding. Burchert:Novartis: Research Funding; Pfizer: Honoraria; Bristol Myers Squibb: Honoraria, Research Funding; AOP Orphan: Honoraria, Research Funding; Bayer: Research Funding. Krause:Novartis: Research Funding. Hänel:Amgen: Honoraria; Novartis: Honoraria; Roche: Honoraria; Takeda: Honoraria. Platzbecker:Celgene: Research Funding. Mayer:Johnson & Johnson: Research Funding; Roche: Research Funding; Eisai: Research Funding; Affimed: Research Funding; Novartis: Research Funding. Serve:Bayer: Research Funding. Ehninger:Cellex Gesellschaft fuer Zellgewinnung mbH: Employment, Equity Ownership; Bayer: Research Funding; GEMoaB Monoclonals GmbH: Employment, Equity Ownership. Schetelig:Gilead: Consultancy, Honoraria, Research Funding; Abbvie: Honoraria; Janssen: Consultancy, Honoraria; Roche: Honoraria; Sanofi: Consultancy, Research Funding; Novartis: Consultancy, Honoraria, Research Funding. Thiede:AgenDix: Other: Ownership; Novartis: Honoraria, Research Funding. Stoelzel:Neovii: Speakers Bureau.