Citations

Abstract Studying gene expression and clinical outcome data from 136 clinical trials for patients with cancer (~21,000 patients with 26 cancer types), we found CD25 as one of the strongest predictors of poor clinical outcome in patients with B-cell malignancies, but not in other cancer types. This was unexpected because CD25 is known as one of three chains of the IL2 receptor on T-cells and NK-cells. Interleukin-2 (IL2) functions as essential T-cell growth factor. IL2 signals through β- and γ-, but not α-chains (CD25) of its heterotrimeric receptor. CD25-deficiency causes lymphoproliferation and autoimmunity, however, its mechanistic role is unclear. Our experiments based on genetic mouse models and engineered patient-derived B-cell leukemia and lymphoma xenografts revealed that CD25 expressed on B-cells is not an IL2 receptor chain, but in fact binds the B-cell receptor (BCR) to regulate its activity. Suggesting IL2-independent functions, defects in CD25-/-B-cells were not replicated in IL2-deficient mice. CD25 bound the BCR but not IL2Rβ- and IL2Rγ-chains. IL2Rβ- and IL2Rγ-chains can pair with other chains to form receptors for different cytokine-ligands. However, CD25 represents the first example of a cytokine receptor chain that binds to the BCR for negative feedback regulation. Likewise, in T-cells, CD25 had a bifunctional role and either functioned as IL2 receptor chain or as negative feedback regulator of T-cell receptor signaling. CD25-function was regulated by cell-membrane translocation, which required phosphorylation of its cytoplasmic tail at S268 (see schematic, left). In a family with monogenic autoimmunity, a mutation immediately preceding S268 compromised CD25-surface translocation, which was restored by homology-directed repair of the S268 motif. CD25-interactome analyses identified PKCd as critical effector molecule downstream of CD25 to mediate B-cell selection during normal B-cell development and calibrate oncogenic BCR signaling in B-cell tumors. In B-cell malignancies, BCR-dependent survival and proliferation signals are often substituted by oncogenic BCR-mimics (e.g. BCR-ABL1, JAK2, BRAFV600E, LMP2A, CD79B mutations; see schematic, right). Accordingly, we identified CD25 surface-expression as biomarker of oncogenic BCR-signaling and predictor of poor clinical outcomes. CD25-/-B-cell leukemia failed to initiate fatal disease in transplant recipients. Owing to imbalances of oncogenic BCR-signaling and p53-checkpoint activation, CD25-/- B-cell leukemia failed to initiate fatal disease in transplant recipients. In patient-derived xenograft models of drug-resistant B-cell malignancies, treatment with a CD25-specific antibody drug-conjugate (ADCT-301) extended survival of transplant recipients or eradicated disease. These findings identified CD25 as previously unrecognized feedback regulator of oncogenic BCR-signaling and provide a rationale for therapeutic targeting of CD25 in refractory B-cell malignancies. Figure. Figure. Disclosures Forman: Mustang Therapeutics: Other: Licensing Agreement, Patents & Royalties, Research Funding. Weinstock:Genentech/Roche, Monsanto: Consultancy; Novartis: Consultancy, Research Funding; Novartis, Astra Zeneca, Abbvie, Aileron, Surface Oncology, Daiichi Sankyo: Research Funding; Novartis, Dragonfly, Travera, DxTerity, Travera: Consultancy; Travera: Equity Ownership; Astra Zeneca, JAX, Samumed, Regeneron, Sun Pharma, Prescient: Patents & Royalties. Uzel:Novartis: Research Funding.

Abstract Introduction: The preferred post-remission therapy for older patients (pts) with AML remains uncertain. We compared outcomes for older AML pts in CR1 receiving HCT reported to the CIBMTR to older AML pts achieving CR1 on National Clinical Trials Network induction and non-HCT consolidation therapy (CT) trials. Methods: This study focused on pts 60-75 years of age treated between 2004 to 2013. CT pts (n=211) underwent induction and consolidation on Alliance for Clinical Trials in Oncology, ECOG-ACRIN or SWOG clinical trials for initial therapy for newly diagnosed AML; the CIBMTR provided data for HCT pts (n=431). CT patients received at least one cycle of CT on study and were excluded if HCT occurred at any time. Time to event started at CR1 and pts entered at CT or HCT, respectively, using left-truncation to account for differential entry times. Results: For the CT cohort, first consolidation included standard therapy (e.g., cytarabine or a hypomethylating agent) and additional study drug (e.g., bortezomib, dasatinib, sorafenib, and Zosuquidar, gemtuzumab) or tipifarnib alone. Among HCT pts, the donor was a HLA-matched sibling or unrelated donor (URD) in 66% and the others were partially HLA-matched/mismatched URD (10%) or cord blood (24%). HCT pts were younger and more frequently had high-risk AML (high WBC, secondary AML and unfavorable cytogenetics) (Table). The median time from CR1 to HCT and CT was 3.2 and 0.5 months, respectively. Allogeneic HCT showed worse overall survival (OS) (HR=1.52, p=0.02) prior to 9 months and better OS thereafter (HR= 0.53, p <0.0001) relative to CT (figure 1A). Treatment-related mortality (TRM) was worse after HCT in the first 9 months (HR=2.8, CI: 1.5 -5.2, p=.0009), while relapse was less frequent beyond 9 months after treatment (HR = 0.42, CI: 0.29 to 0.61, p<.0001). Despite higher early TRM, HCT recipients went on to manifest superior OS [5 year OS: HCT 29% (24-34%), CT 13.8% (9 -22%)] (Figure 1A). The benefit of HCT for survival after 9 months was more prominent in those with unfavorable cytogenetics (Figure 1B). Multivariate analysis for OS showed no statistically significant effect of age or performance status, while unfavorable cytogenetics were detrimental (HR=1.74, p<.0001). Conclusions. Allogeneic HCT led to heightened early risks from TRM, but resulted in superior long-term survival in older AML pts receiving HCT relative to CT by reducing relapse. Efforts to attenuate early TRM after allogeneic HCT may further improve HCT outcomes for older pts. Disclosures Ustun: novartis: Speakers Bureau. Attar:Agios: Employment, Equity Ownership. Larson:Pfizer: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; BristolMyers Squibb: Consultancy, Research Funding; Ariad/Takeda: Consultancy, Research Funding. Roboz:Roche/Genentech: Consultancy; Eisai: Consultancy; Cellectis: Research Funding; Aphivena Therapeutics: Consultancy; Sandoz: Consultancy; Janssen Pharmaceuticals: Consultancy; Otsuka: Consultancy; Jazz Pharmaceuticals: Consultancy; Sandoz: Consultancy; AbbVie: Consultancy; Celltrion: Consultancy; Cellectis: Research Funding; Eisai: Consultancy; Astex Pharmaceuticals: Consultancy; Argenx: Consultancy; Pfizer: Consultancy; Celgene Corporation: Consultancy; Novartis: Consultancy; Jazz Pharmaceuticals: Consultancy; Bayer: Consultancy; Bayer: Consultancy; Roche/Genentech: Consultancy; Orsenix: Consultancy; Astex Pharmaceuticals: Consultancy; Celgene Corporation: Consultancy; Daiichi Sankyo: Consultancy; Pfizer: Consultancy; Janssen Pharmaceuticals: Consultancy; Otsuka: Consultancy; Orsenix: Consultancy; Daiichi Sankyo: Consultancy; Celltrion: Consultancy; Novartis: Consultancy; Aphivena Therapeutics: Consultancy; Argenx: Consultancy; AbbVie: Consultancy. Uy:GlycoMimetics: Consultancy; Curis: Consultancy. Stone:Fujifilm: Consultancy; Ono: Consultancy; Orsenix: Consultancy; Otsuka: Consultancy; Agios: Consultancy, Research Funding; AbbVie: Consultancy; Argenx: Other: Data and Safety Monitoring Board; Celgene: Consultancy, Other: Data and Safety Monitoring Board, Steering Committee; Arog: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Jazz: Consultancy; Astellas: Consultancy; Merck: Consultancy; Pfizer: Consultancy; Sumitomo: Consultancy; Amgen: Consultancy; Cornerstone: Consultancy. Foran:Agios: Research Funding; Xencor, Inc.: Research Funding. Weisdorf:Seattle Genetics: Consultancy; Equillium: Consultancy; FATE: Consultancy; SL Behring: Consultancy; Pharmacyclics: Consultancy.

Abstract Background Activating mutations in FLT3 - and in particular FLT3-ITD (internal tandem duplication) - are common in younger patients with AML, and are associated with relapse and with inferior overall survival (OS), however their prevalence and impact in older adults remains uncertain. We performed an analysis of FLT3-ITD mutations in patients age ≥60 yrs in the large prospective multicenter ECOG-ACRIN (E-A) E2906 Phase III trial. Methods Eligible patients (pts) age ≥60 yrs (n=727) were randomized to 'Standard' therapy with 7&3 (Dauno 60mg/m2) induction, and 2 cycles of intermediate dose Ara-C (1.5g/m2 x 12 doses; 6 doses if age ≥70yrs) consolidation (Arm A); or single agent clofarabine (CLO) induction and consolidation (2 cycles) (Arm B). As previously reported (Foran et al, ASH #217a, 2015), there was superior overall survival (OS) with standard therapy. AML diagnostic samples collected prospectively in the central E-A Leukemia Translational Research Lab (LTL) were used to detect mutations in the FLT3 gene by PCR using cDNA from total RNA. LTL investigators were blinded to treatment assignment. Patients with no RNA available or blast count <10% (threshold of sensitivity for the PCR assay) on the submitted sample were excluded. Statistical analysis was performed using X2 (categories) and Wilcoxon rank sum (continuous) tests to compare baseline patient and disease characteristics. Log-rank tests and multivariate Cox models stratified by treatment arm and adjusted for patient and disease variable (including WBC, cytogenetics, sex, performance status, secondary AML) were used to examine FLT3-ITD effect on OS and disease-free survival [DFS; relapse or death after complete remission (CR)/CRi (CR with incomplete CBC recovery)]. Results In the first 231 pts tested, FLT3-ITD mutations were identified in 43 (18.6%) pts, and the remainder were FLT3-ITD-negative (i.e. non-ITD). The proportion with FLT3-ITD was the same for patients age 60-69 yrs (18.8%) vs. ≥70 yrs (18.3%). In comparison to non-ITD, FLT3-ITD+ pts had significantly higher WBC (median 18.1 vs. 6.3, p=0.002) and BM blasts (80% vs. 51.5%, p=0.0004) at AML diagnosis, and were more likely to have intermediate risk (79.1% vs. 59%) vs. unfavorable risk (7.0 % vs. 31.4%) cytogenetics (p=0.002). There was no difference in CR/CRi rate overall (p=0.40), however standard (Arm A) pts with FLT3-ITD had a significantly higher CR/CRi rate (78.9% vs. non-ITD 51.5%, p=0.04). With median follow-up 53.5 months, FLT3-ITD patients tended to have worse OS (HR 1.24, 95%CI 0.85-1.81) but this was not statistically significant (Figure 1, p=0.26), and results were similar for both Arms A/B. DFS similarly tended to be worse overall for FLT3-ITD (HR 1.44, 95%CI 0.65-2.43) (p=0.17), and DFS was significantly worse for FLT3-ITD+ Arm A/Standard pts (Figure 2, p=0.033), while Arm B/CLO pts had a worse DFS regardless of FLT3 mutation status (Arm B, FLT3-ITD vs. non-ITD, p=0.93). More patients with FLT3-ITD underwent allogeneic transplantation (25.6% vs. non-ITD 19.7%), although this was not significant (p=0.41). Conclusions FLT3-ITD mutations are prevalent in older and elderly (age ≥70 yrs) patients with AML, and while they occur at somewhat lower rates than reported for younger adults, FLT3-ITD+ AML in this population has a leukemia phenotype similar to that reported in younger patients. Despite significantly higher CR/CRi rates with Standard therapy, older pts with FLT3-ITD also have significantly worse DFS following intensified Ara-C consolidation therapy than non-ITD pts. These results support routine assessment of FLT3-ITD status in older AML patients, and the incorporation of novel post-remission treatment strategies to improve outcome in FLT3-ITD+ pts ≥60 yrs. Disclosures Foran: Agios: Research Funding; Xencor, Inc.: Research Funding. Lazarus:Pluristem Ltd.: Consultancy. Tallman:BioSight: Other: Advisory board; AbbVie: Research Funding; Daiichi-Sankyo: Other: Advisory board; Cellerant: Research Funding; Orsenix: Other: Advisory board; ADC Therapeutics: Research Funding; AROG: Research Funding.

Abstract Background. Gene mutation profiling is increasingly employed for diagnosis, risk stratification, and clinical management in patients with MDS. However, current World Health Organization MDS classification is still based on histologic findings (with the exception of SF3B1 for MDS-RS), and guidelines generally suggest that clinical decisions be guided by clinico-pathologic risk stratification tools such as Revised International Prognostic Scoring System (IPSS-R). We sought to study beliefs and patterns of practice with respect to gene mutation profiling among health care providers who manage patients with MDS. Methods. A link to a 23-question web-based survey was emailed to members of the Eastern Cooperative Oncology Group (ECOG)-ACRIN Cancer Research Group, Alliance for Clinical Trials in Oncology (Alliance), and the Southwest Oncology Group (SWOG), and the Cancer Trials Support Unit (CTSU) on 5/1/2018 with 6 subsequent weekly reminders. The Qualtrics survey platform was used to record anonymous responses. We used descriptive statistics to analyze the data. No incentive was provided for responses. Results. Of 371 received responses, 262 were received from providers who did not manage MDS patients or lacked analyzable data and therefore were excluded. Of 109 eligible responses, 108 responders were from institutions representing 31 US states (one respondent was from South America). Median age of respondents was 48 years (range, 33-75); 43 (39%) were women. A third of responders (32%) worked at a university hospital, while 25%, 17%, and 5% worked at a community hospital, private practice, or other settings, respectively. While 37% of participants worked at institutions with guidelines for clinical care of MDS patients, 28% reported that their institutional guidelines recommended MDS-specific gene mutation profiling. Such testing was performed at institutions of 13% participants; institutions of 26% of responders tested a general AML panel that included MDS-specific genes. The total number of respondents whose institutions sent out either an MDS-specific gene panel or a general AML gene panel with MDS-specific genes was similar, 25% and 12%, respectively (Fig. 1). Of those who routinely perform molecular testing, 94% do so at diagnosis, 56% at relapse, 33% during preparation for stem cell transplant, 31% after the failure of hypomethylating agents (HMA), 24% during screening for a clinical trial, and 15% at initial treatment (Fig. 2). MDS gene mutation profiling was felt to be most helpful in diagnosis (rarely 11%; sometimes 49%; often 30%; always 9%), risk stratification (sometimes 31%; often 51%; always 15%), and prognosis (sometimes 31%; often 51%; always 14%); its role was more limited in response assessment (never 12%; rarely 25%; sometimes 44%; often 14%) and to predict responses to HMAs (never 5%; rarely 28%; sometimes 52%, often 14%) (Fig. 3). Various types of evidence were used to stratify MDS risk and prognosis: genetic mutations were used by nearly everyone (95%); 70% relied on morphologic findings, while gene expression/transcriptome profiling was used by 40%. Eighty-four percent of responders reported relying on conventional prognostic models like IPSS-R to identify high-risk patients for whom they would consider intensive treatment options. For this purpose, 62% would also rely on mutation profiling, and 32% would also consider higher frequency of gene mutations. While mutations in the p53 pathway were felt to be helpful in terms of risk stratification and treatment decisions by 70% of responders, 43%, 39%, 31%, 26% 23%, 20%, and 3% considered mutations in spliceosome, DNA methylation, transcription factors, histone modification, signaling, RAS pathway, and cohesin genes, respectively, to be useful as well. Approximately 31% of responders were not certain as to which mutations would affect risk stratification and management choices and said they needed to review literature. The respondents also cited multiple limitations to wider clinical use of MDS gene mutation profiling (Fig. 4). Conclusions. Our survey demonstrates widespread use of gene mutation profiling in the management of patients with MDS, but also reveals substantial variability in beliefs, practices, testing logistics, and interpretation of molecular profiling. Our findings emphasize the need for high-quality data to develop consensus evidence-based guidelines for gene profiling of MDS patients. Disclosures Sekeres: Opsona: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Opsona: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Bejar:AbbVie/Genentech: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Foundation Medicine: Consultancy; Astex/Otsuka: Consultancy, Honoraria; Modus Outcomes: Consultancy; Takeda: Research Funding; Genoptix: Consultancy. Gore:Celgene: Consultancy, Research Funding. Zeidan:Ariad: Consultancy, Speakers Bureau; Gilead: Consultancy; Incyte: Employment; Celgene: Consultancy; Abbvie: Consultancy; Agios: Consultancy; Novartis: Consultancy; Pfizer: Consultancy.

Abstract Introduction B progenitor acute lymphoblastic leukemia (B-ALL) is a leading cause of childhood cancer death. Many chimeric genes have been identified and led to a refined classification of B-ALL and tailored therapies. Still, up to 30% of B-ALL cannot be classified into established subtypes, and the outcome for many is poor. Methods To identify novel subtypes of B-ALL, we performed integrative genomic analysis including transcriptome sequencing (RNA-seq) of 1,988 cases from St. Jude, Children's Oncology Group and adult cooperative group studies and analyzed chromosomal rearrangements, gene-expression profiles (GEP), somatic mutations and chromosome-level copy-number alterations. Cases lacking known or putative subtype-defining alterations underwent whole genome sequencing. Effects on proliferation and transformation of novel lesions were assessed by retroviral expression in cell lines and point-mutation knock-in mice using CRISPR/Cas9 genome editing. Results Using integrated genetic alterations and gene expression profiling, we classified 23 B-ALL subtypes (Table and Figure). Three groups included cases with similar GEP as canonical subtypes (ETV6-RUNX1, KMT2A-rearranged, and ZNF384-rearranged), but lacking the expected drivers (e.g., ETV6-RUNX1-like, n=42). Eighteen cases (0.9%) had rearrangements of BCL2, MYC and/or BCL6 showing a distinct GEP; they were mostly adults (n=16) with very poor outcome. These alterations, rarely seen in ALL, are identical to those observed in "double/triple hit" lymphoma, and are of pre-B immunophenotype. Eight cases with tightly clustered GEP comprised a novel subtype defined by IKZF1 N159Y missense mutation. N159Y is in the DNA-binding domain of IKZF1, and is known to perturb IKZF1 function, with distinct nuclear mislocalization and induction of aberrant intercellular adhesion. We identified two subtypes with distinct GEP characterized by PAX5 alterations. One, herein termed PAX5 altered (PAX5alt), comprised 148 (7.4%) cases, was characterized by diverse PAX5 alterations including rearrangements (n=57), sequence mutations (n=46) and/or focal intragenic amplifications (n=8). These PAX5 alterations were found in 73.6% of PAX5alt cases and different alteration types were mutually exclusive. Other PAX5 alterations, including deletions and large-scale amplifications were also assessed using SNP array, but were not enriched in the PAX5alt group. Clinically, PAX5alt pediatric and adult patients had favorable (96.8±3.2%) and intermediate (42.1±10.2%) 5-year overall survival (OS), respectively. The other GEP distinct subtype comprised 44 cases, all with PAX5 P80R missense mutations. In 30 of these cases, PAX5 P80R was homozygous due to deletion of the wild-type (WT) PAX5 allele or copy-neutral loss of heterozygosity. Of the other 14 cases with heterozygous PAX5 P80R mutations, 13 had a second frameshift (n=7), nonsense (n=2) or deleterious missense (n=4) PAX5 mutation. Four of the remaining 1,944 cases also had the PAX5 P80R mutation, but all were heterozygous with preservation of a WT PAX5 allele, consistent with the notion that homozygous or compound heterozygous PAX5 P80R mutation is the hallmark of this subtype. Adult PAX5 P80R cases (n=14) showed better 5-year OS (61.9±13.4%) than those in PAX5alt subtype (42.1±10.2%). To examine the effects of PAX5 P80R on B-cell maturation, WT PAX5, PAX5 P80R, V26G and P34Q were expressed in Pax5-/- lineage-depleted bone marrow cells. Expression of WT PAX5, PAX5 V26G and P34Q resulted in near complete rescue of B cell differentiation; however, expression of PAX5 P80R blocked the differentiation at the pre-pro-B stage of B-cell maturation. Further, Pax5 P80R heterozygous or homozygous mice developed pre-B-ALL with a median latency of 166 and 87 days, respectively, with heterozygous mice acquiring alterations on the second allele. In contrast, Pax5+/- mice, and those harboring G183S mutation observed in familial leukemia, do not spontaneously develop B-ALL. Conclusions These results show the utility of transcriptome sequencing in defining subtypes and founding genetic alterations in B-ALL, provide a revised taxonomy of the disease across the age spectrum, and reinforce the central role of PAX5 as a checkpoint in B lymphoid maturation and leukemogenesis. Disclosures McKay: ImmunoGen Inc.: Employment. Tallman:Orsenix: Other: Advisory board; AROG: Research Funding; BioSight: Other: Advisory board; Cellerant: Research Funding; AbbVie: Research Funding; Daiichi-Sankyo: Other: Advisory board; ADC Therapeutics: Research Funding. Stock:Jazz Pharmaceuticals: Consultancy. Konopleva:Stemline Therapeutics: Research Funding. Relling:Shire Pharmaceuticals: Research Funding. Mullighan:Cancer Prevention and Research Institute of Texas: Consultancy; Amgen: Honoraria, Speakers Bureau; Abbvie: Research Funding; Loxo Oncology: Research Funding; Pfizer: Honoraria, Research Funding, Speakers Bureau.

Abstract The International ALL trial, conducted jointly by the MRC in the UK and ECOG in the US (UKALL XII/E2993), recruited 1929 patients between 1993 and 2006. All patients aged 16 to 64 years with newly diagnosed ALL, received the identical two phases of induction therapy. Patients with an HLA-identical sibling were assigned to a sibling allogeneic transplant and those who were Ph-positive could also get an unrelated-donor transplant. Patients who did not have a donor were to be randomized between a single autologous transplant, after conditioning with etoposide/total body irradiation, versus consolidation/maintenance therapy for 2.5 years. Following randomization, but prior to receiving the assigned or randomized therapy, all patients received intensification with 3 cycles of high-dose methotrexate. After excluding patients assigned to an allogeneic transplant, 1028 patients were eligible for randomization but, as in other major transplant studies, only 457 were randomized. The rationale underlying the randomization was based on the fact that protracted consolidation/maintenance therapy in adults, extrapolated from the pediatric experience, had never been prospectively evaluated in the era of intensive chemotherapy. Given that the mortality from autotransplant is not higher than chemotherapy (Goldstone et al. Blood. 2008), it was postulated that if a single autologous transplant is at least as good as standard protracted chemotherapy that may make it the preferable option, except possibly in females in whom fertility may be an issue. The overall survival and the event-free survival were significantly superior among the chemotherapy patients (p = .05) as previously reported (Goldstone et al. Blood. 2008). Because the literature contains reports suggesting a trend in favor of autologous transplantation in some patients with ALL (Dhédiu et al. Leukemia, 2006), an analysis was performed to see if any subgroup of patients could be identified in whom: 1. chemotherapy may not be superior to autologous transplant and 2. autologous transplant may be superior. The table lists a detailed analysis of overall survival looking at various age groups, B- versus T-lineage, the rapidity with which a complete remission was achieved –after phase I or only after phase II of induction. Detailed analysis was also performed by cytogenetics looking at those with standard risk versus those with high risk abnormalities [ t(9;22), t(4;11), t(8;14)] and low hypodiploidy/near triploidy or a complex karyotype (Moorman et al. Blood. 2007)]. In all groups, the chemotherapy group was at least as efficacious as the autograft group, and in some was even significantly superior to autologous transplantation. There is no evidence that other risk factors, such as relapse rate or treatment-related mortality, influenced these overall survival data. In addition, the tests for heterogeneity were not significant across any group. In conclusion, the overall survival was longer in patients randomized to chemotherapy, although the superiority was not statistically significant in most of the groups. There is no clinical indication for autologous transplantation at any age and particularly this should not be considered for patients over age 50, those with high-risk cytogenetics or T-lineage, and late remitters, for whom it might appear most attractive. Overall Survival (OS) at 5 years in 457 Randomized Patients Chemo Auto Subgroups n OS n OS P (log rank) Age (years) < 20 50 58% 43 46% > 0.1 20–29 61 52% 70 43% > 0.1 30–39 46 39% 46 32% > 0.1 40–49 38 31% 35 31% > 0.1 50 + 33 38% 35 31% > 0.1 B-lineage 169 46% 158 35% 0.03 T-lineage 45 54% 54 49% > 0.1 Time to CR phase I 193 48% 190 41% 0.1 phase II 26 36% 29 19% 0.08 Cytogenetics standard-risk 109 51% 122 44% > 0.1 high-risk 29 23% 27 7% 0.02

Abstract Abstract 2568 Background: Obesity is associated with an increased risk of development of adult AML (Relative Risk approx. 2-fold) (Ross J, Cancer Epidemiol Biomarkers Prev 2004;13:1810) and significantly higher mortality in pediatric AML (Lange B, JAMA 2005;293:203). We therefore examined the association of obesity with presenting characteristics in 2 recent large ECOG phase III adult AML trials to determine whether there was a unique clinical and genetic phenotype, and also the impact of obesity on clinical outcomes (complete remission - CR; early death - ED; overall survival - OS) in association with other known risk factors. The impact of obesity on receiving full-dose daunorubicin (D) was also evaluated in these studies. We included patients (pts) from E1900 receiving standard infusional cytarabine with intensified D (45 vs. 90mg/m2) in adults age ≤60 yrs (NEJM 2009;361:1249), and from E3999 receiving conventional intensive chemotherapy +/− the MDR-inhibitor zosuquidar in adults age >60 yrs (Blood 2010;116:4077). Obesity was defined as Body Mass Index (BMI) >30kg/m2. Methods: Pt baseline characteristics were compared using Fisher's exact (categories variables) or Wilcoxon rank sum tests (continuous variables). Logistic regression models were used to examine the association between obesity and CR or ED; Cox models stratified on induction treatment arms were used to examine the association between obesity and OS. Multivariate models to examine the effect of Obesity controlled for known prognostic factors (including cytogenetics & secondary AML - sAML). Results: A total of 1089 pts (E1900, n=651; E3999, n=438) with available BMI data were included, the median follow-up of living pts is 4.7 yrs. Obesity was prevalent, with n=359 (33%) of pts with a BMI>30 at presentation. For all patients, median BMI was 27.1 (range 16.7–93.0); for non-obese patients median BMI was 25.0 (range 16.7–29.96) while for obese patients the median BMI was 34.0 (range 30.0–93.0). Obese pts were older (p=0.06), and significantly more likely female gender (p=0.05), ECOG PS>0 (p=0.01), & Intermediate Risk cytogenetics (p=0.006) but not sAML (14% overall, p=ns). Genotyping for FLT3 & MLL was performed in E1900 pts (age ≤60yrs): there was no difference in incidence of FLT3-ITD, but lower incidence of MLL-PTD was observed (p=0.08) in obese pts (not performed in E3999) (See Table). Overall, only 3.7% of pts received <90% of intended D dose. However obesity was significantly associated with receiving <90% intended D dose: in E1900, 11% of obese pts received <90% intended D (45mg/m2 cohort, p<0.001; 90mg/m2 cohort p=0.002), while in E3999 4% obese pts received <90% intended D (45mg/m2, p=0.07). There was no clear difference in toxicity/adverse events during initial induction therapy reported in obese vs. non-obese pts. On multivariate analysis obesity was not significantly associated with achieving CR (p=0.09), and had no direct independent association with ED (p=0.38). Kaplan-Meier plots of OS are shown in Figure. On multivariate analysis, age (p<0.001); ECOG PS (p<0.001); cytogenetic risk group (p<0.001); sAML (p=0.03); gender (p=0.05); and peripheral blasts (p=0.003) but not obesity were significantly associated with OS. Receiving <90% intended D dose was marginally associated with increased hazard ratio for OS (HR 1.50, 95%CI 0.98–2.28, p=0.06). Conclusion: Obesity is associated with specific presenting clinical characteristics in adult AML (female, older, PS>0, Int. risk cytogenetics, less frequent MLL-PTD), but has no direct impact on CR, ED or OS in the setting of a controlled therapeutic trial. Obese pts are at risk of receiving <90% intended D dose, which may impact OS. This analysis suggests that factors that predispose to adult AML may present with a unique clinical phenotype. Disclosures: No relevant conflicts of interest to declare.

Abstract Background: Eastern Cooperative Oncology Group trial E1900 (E1900) showed that induction therapy with a high daily dose of daunorubicin (90 mg/m2) (DNR 90) improves survival in younger patients (pts) (<50 yrs) and intermediate (int) cytogenetic risk AML, but at 2 years of follow-up no benefit was seen in older pts (50-60 yrs), or in those with unfavorable cytogenetic risk or FLT3-ITD mutant AML (Fernandez et al. N Engl J Med 2009). Here we update results of E1900 with longer follow-up, focusing on the benefit of DNR 90 in cytogenetic and common molecular subgroups. Methods: Overall survival (OS) was measured from randomization for induction therapy to death from any cause (censored at last contact). Hazard ratios (HR) for death were computed using univariate and multivariable Cox proportional hazards models; multivariable Cox models were adjusted for sex, age, hemoglobin level, leukocyte count, platelet count, and cytogenetic profile. All conclusions regarding the impact of DNR 90, unless noted, are similar based on univariate and multivariable analysis. Results: Overall, 657 pts were enrolled with a median follow-up of 80.1 months. The HR for death in the DNR 90 group as compared with the standard-dose daunorubicin (45 mg/m2) (DNR 45) group was 0.74 (p=0.001). Pts <50 yrs benefited from DNR 90 (p = 0.002) while those >=50 yrs were not proven to benefit (p = 0.12). Pts with favorable (fav) and int. cytogenetic risk benefited from DNR 90 (p = 0.03 and p = 0.02, respectively). A benefit for pts with unfavorable cytogenetic risk was seen on multivariable analysis (p = 0.04). Impact of DNR 90 by mutation status: The 3 most common mutations were FLT3-ITD (24%), NPM1 (26%), and DNMT3A (24%). AML pts with any of these 3 mutations benefited from DNR 90 (p = 0.009, p = 0.002, and p = 0.02, respectively). FLT3-ITD pts who received DNR 90 had a 4-yr OS of 31%. Benefit was seen in pts age 50-60 with FLT3-ITD or NPM1 mutation (p = 0.02 and p = 0.04, respectively). No benefit of DNR 90 was seen in a small cohort of pts with MLL-PTD (p = 0.06). Benefit of DNR 90 in FLT3-ITD, NPM1, and DNMT3A mutant AML was confirmed in the int. cytogenetic risk group. Impact of DNR 90 on prognostic impact of NPM1: The presence of an NPM1 mutation conferred an improvement in OS in the DNR 90 group which was not seen in the DNR 45 group (p = 0.01 vs p = 0.3). This finding was confirmed in the int. cytogenetic risk group. Conclusion: With median follow-up of over 6 years on E1900, we confirm that DNR 90 improves outcome in pts with fav/int cytogenetic risk, DNMT3A or NPM1 mutant AML, or age < 50 (Patel et al. N Engl J Med 2012). Additionally, we now demonstrate that DNR 90 additionally benefits pts with FLT3-ITD AML, and pts with unfavorable cytogenetic risk, regardless of age. Moreover, we show that the favorable prognostic impact of the NPM1 mutation is only present when pts receive DNR 90. Given the benefit of DNR 90 across all cytogenetic risk groups as well as common molecularly defined subgroups of AML, DNR 90 should be the standard for all pts up to age 60 who are candidates for induction chemotherapy. Table HR for death by AML cohort. Subgroup N Univariate Model DNR 45 DNR 90 HR (DNR 90/DNR 45) & 95% CI Wald P All patients (n=657) Overall 330 327 0.74 (0.61, 0.89) 0.001 Age < 50 yrs³ 50 yrs 188 142 172 155 0.66 (0.50, 0.85) 0.81 (0.62, 1.06) 0.002 0.12 Cytogenetic Favorable Intermediate Unfavorable 38 232 59 51 212 63 0.51 (0.28, 0.93) 0.76 (0.61, 0.96) 0.79 (0.54, 1.16) 0.03 0.02 0.22 FLT3-ITD WT MUT 215 83 241 64 0.74 (0.59, 0.92) 0.61 (0.42, 0.89) 0.008 0.009 MLL-PTD WT MUT 290 16 296 15 0.70 (0.58, 0.86) 0.46 (0.21, 1.04) 0.0004 0.06 NPM1* WT MUT 180 65 192 65 0.70 (0.55, 0.89) 0.50 (0.32, 0.78) 0.003 0.002 DNMT3A WT MUT 177 61 194 58 0.66 (0.52, 0.85) 0.62 (0.41, 0.94) 0.001 0.02 * Statistically significant test of interaction (p<0.2) Figure 1A: Overall Survival by NPM1 Mutation Status and Treatment Arm Figure 1A:. Overall Survival by NPM1 Mutation Status and Treatment Arm Figure 1B: Overall Survival of FLT-ITD Mutant AML Patients by Treatment Arm Figure 1B:. Overall Survival of FLT-ITD Mutant AML Patients by Treatment Arm Disclosures No relevant conflicts of interest to declare.

Abstract Introduction: The therapy of relapsed/refractory AML remains poor and new treatment options are sorely needed. The Leukemia Committee of ECOG devised a randomized phase II trial of 3 novel regimens to determine overall response rates could be improved. Methods: Patients between the ages of 18 and 70 years with a prior diagnosis of AML who relapsed <1 year after initial achievement of complete remission (CR) or who were refractory to initial induction therapy (<2 courses) or to first reinduction after a relapse (<1 course) were eligible for this trial. Eligible patients were randomized equally to one of three regimens described in Table 1 below. The primary endpoint was achievement of a morphologic complete remission (CR) or a CR with incomplete blood count recovery (CRi). A 2 stage statistical design was planned with 18 patients (assuming 16 eligible) to be accrued in the first stage. If at least 3 CR+CRi were seen among the 16 eligible patients, an additional 19 patients (assuming 17 eligible) would be entered in the second stage. If 8 or more CR+CRi were seen in the 33 eligible patients, this would be considered evidence of a promising response rate. Results: This study activated October 16, 2008 and closed August 2, 2013 with a total of 92 patients accrued (91 eligible). The eligibility criteria were amended during the study to lower the upper age limit from 70 to 65 years because 6 treatment related deaths occurred in the initial 27 patients accrued to the FLAM regimen. All of these patients died of septic shock or multi-organ failure and 5 of the 6 died within 1 month of the start of therapy. Most of these patients were over age 65 ( 53, 62, 67, 68, 69 and 69 years). At the first stage analysis, of the first 16 eligible patients accrued to each arm there were 2 CR and 2 CRi in the CT arm, 2 CR and 2 CRi in the FLAM arm and 2 CR in the sirolimus-MEC arm. Thus, the sirolimus-MEC arm was closed to accrual with a total of 20 eligible patients and second stage accrual continued for the CT and FLAM arms. Among the 35, 36 and 20 eligible patients accrued to arms A, B and C, respectively, there were 2 CR and 3 CRi in the CT arm, 6 CR and 4 CRi in the FLAM arm, and 2 CR and 1 CRi in the sirolimus-MEC arm. All 10 CR or CRi of the FLAM arm were among the first 33 eligible patients, therefore FLAM was the only regimen to achieve our target. The overall response rates for arms A, B and C were 14% (90% CI 7.1% - 34.7%), 28% (90% CI 16.1% - 43.0%) and 15% (90% CI 4.2% - 34.4%), respectively. Among the 92 patients accrued, there were 5, 10 and 2 grade 5 events within 30 days of the end of therapy in arms A, B and C, respectively. The vast majority of these deaths were attributed to infection and multi-organ failure except two which were secondary to disease. Conclusion: In this high risk group of AML patients the FLAM regimen showed an encouraging response rate. A randomized phase II trial has also recently been completed exploring its use in the front-line setting with newly diagnosed high-risk AML. While the FLAM regimen was excessively toxic in elderly patients with relapsed or refractory disease, it is a suitable option for younger patients in this setting. Arm A: CT Carboplatin 150 mg/m2/day over 24 hours by continuous infusion IV for 5 days (days 1-5) Topotecan 1.6 mg/m2/day over 24 hours by continuous infusion IV for 5 days (days 1-5) Arm B: FLAM Flavopiridol 30 mg/m2 for ½ hour followed by 60 mg/m2 over 4 hours IV per day for 3 days Cytarabine 667 mg/m2 over 24 hours by continuous infusion IV for 3 days (days 6-8) Mitoxantrone 40 mg/m2 IV over 1-2 hours (day 9) Arm C: Sirolimus-MEC Sirolimus 12 mg by mouth on day 1, followed by 4 mg by mouth daily for 8 days (days 2-9) Mitoxantrone 8 mg/m2/day over 15 minutes IV for 5 days (days 4-8) Etoposide 100 mg/m2/day over 1 hour IV for 5 days (days 4-8) Cytarabine 1000 mg/m2/day over 3 hours IV for 5 days (days 4-8) Table 2. Responses Table 1. Chemotherapy Regimens Regimen n Median age (range), years Responses (%) Deaths (first 30 days) (%) CT 35 55 (23-67) 5 (14%) 5 (14%) FLAM 36 62 (19-69) 10 (28%) 10 (28%) Sirolimus-MEC 20 52 (22-68) 3 (15%) 2 (10%) Disclosures Off Label Use: Sirolimus-potentiate chemotherapy Carboplatin-chemotherapy for AML treatment Topotecan-chemotherapy for AML treatment.

Abstract Abstract 3619 Extramedullary (EM) acute myeloid leukemia (AML) is generally associated with a poor prognosis. We evaluated the baseline characteristics, response and survival characteristics in a subset of patients age ≤ 60 years with de novo AML and EM manifestations at presentation, treated on the Eastern Cooperative Oncology Group E1900 protocol: daunorubicin 45 or 90 mg /m2 x3 days in conjunction with cytarabine 100 mg/m2 × 7 days followed by risk-stratified consolidation. (Fernandez et al New Engl J Med 2009) Methods: Patient baseline characteristics were compared using Fisher's exact test if they were categories and Wilcoxon rank sum tests if they were continuous. Logistic regression models were used for complete remission (CR) rates and Cox regression models were used for overall survival (OS) and disease-free survival (DFS). The univariate models included indication of whether patient had extramedullary disease involvement, adjusted by induction treatment. The multivariate models were further adjusted for age, gender, cytogenetic risk, ECOG PS, WBC, platelets, marrow blast, hemoglobin, peripheral blasts, and secondary AML. All P values were based on 2-sided tests. Results: 58 (8.9%) of 651 patients in the study presented with evidence of EM at diagnosis. Patients with EM disease were younger and presented with higher peripheral WBC counts and circulating blasts than those without. Immunophenotyping did not demonstrate a difference in baseline CD56 expression (p=0.77). Sites of EM involvement included gingival hypertrophy (n= 33), skin (n= 7), central nervous system (n= 6), lymphadenopathy (n=6), mediastinum (n=2) and other (n=6). 3 patients had multiple sites. Cytogenetic risk in the EM subgroup was favorable (8.6%), indeterminate (inadequate/missing) (34.5%), intermediate (37.9%) and unfavorable (19%) and did not differ statistically from those without EM disease. The complete remission (CR) rates were similar for patients with EM disease compared to those patient's without, regardless of the anthracycline dose (univariate model p= 0.93; multivariate model p=0.88. DFS (patients in CR) and OS of patients with EM disease was not significantly different in the univariate (p= 0.99, p=0.49) or multivariate models (p= 0.92, p=0.37), respectively. On multivariate modeling patients with EM AML who received the standard-dose of daunorubicin had a shorter OS (HR 1.86, 95% CI 1.20 to 2.91, p=0.006). OS was not improved in EM patients treated with high-dose daunorubicin (HR 0.62, 95% CI 0.34 to 1.14, p=0.12) (Table). There was a significant difference in OS for patients with EM treated with the 90 mg/m2 dose of daunorubicin compared to patients with EM treated with the 45 mg/m2 dose (multivariate model: HR 0.30, 95% CI 0.12 to 0.76, p=0.01). Conclusion: Younger patients with de novo EM AML are sensitive to higher doses of anthracycline in induction therapy and should be treated in a similar fashion as patients without EM involvement. For both groups the higher doses of anthracycline are recommended as CR rates, DFS and OS are improved. Further evaluation of immunophenotypic and molecular/ genetic characteristics should be undertaken in this subset of patients. Disclosures: No relevant conflicts of interest to declare.