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Abstract Abstract 4954 Background Multiple Myeloma (MM) remains incurable with current approaches and newer therapies targeting the abnormal disease biology need to be developed. The malignant plasma cell is highly dependent on the marrow microenvironment, which promotes tumor cell proliferation as well as survival. There is increased bone marrow vascular density in patients with MM and the degree of neo-angiogenesis appear to be prognostic in this disease. Studies have also shown that vascular endothelial growth factor (VEGF) is intricately involved in the interaction between the marrow microenvironment and the myeloma cell. These findings suggested that the VEGF pathway may be a valuable target for therapeutic approach in this disease. Patients and Methods We designed a phase 2 trial of Sunitinib in patients with relapsed multiple myeloma who had received less than three prior therapies. Sunitinib malate (SU11248; Sutent) is a novel, multi-targeted, small molecule inhibitor of the receptor tyrosine kinases (RTKs), including vascular endothelial growth factor receptor-1 (VEGFR-1), -2, and -3, and platelet-derived growth factor receptor (PDGFR) -α and -β. The treatment consisted of Sunitinib 37.5 mg given daily in a continuous fashion in six-week cycles. Toxicities were graded according to CTCAE response version 3.0 and responses were assessed according to the International Myeloma Working Group consensus criteria. Response rate of single agent Sunitinib was the primary endpoint of the study. Results 13 patients were accrued between July of 2007 and April 2009 before the study was closed. The median age of the study population was 61 years (range, 53 - 84), and included nine females (69%). The median time from diagnosis to registration was 39.2 months (range, 4.5 - 88) and 10 patients had received previous stem cell transplant. Previous therapy included lenalidomide in 7 patients, thalidomide in 5 patients and bortezomib in 2 patients. All 13 patients were alive at last follow up with a median follow-up of 11.2 months (range, 1.3 -21.2). All patients have gone off study, disease progression being the most common cause (9 patients), followed by adverse events (3 pts) and alternate treatment in the remaining patient. A hematological grade 3 or higher adverse event was documented in 6 patients and a grade 3 or higher non-hematological adverse event was seen in 8 patients. A grade 3 or higher neutropenia was observed in 5 pts and thrombocytopenia in 2 pts. Fatigue was common and was seen in 11 pts. The median number of cycles administered was one (range, 1-5) and the total number of cycles across 13 patients was 22. Treatment delays or interruptions were seen in five and six patients respectively. The most common reason for treatment delays was hematologic adverse events. No responses (PR or better) were seen, and stable disease was seen in eight of the 13 patients as the best response. The median time to progression was 2.9 months. Conclusions Single agent Sunitinib has no clinically relevant efficacy in this group of patients with relapsed myeloma with one or two previous therapies. Hematological toxicity was higher than anticipated. Whereas these results indicate that VEGFR TK inhibitors are not active in previously treated myeloma, it does not preclude the possibility that VEGF targeting strategies may enhance the efficacy of other therapies. Disclosures Kumar: CELGENE: Research Funding; MILLENNIUM: Research Funding; BAYER: Research Funding; GENZYME: Research Funding; NOVARTIS: Research Funding. Gertz:celgene: Honoraria; millenium: Honoraria, Membership on an entity's Board of Directors or advisory committees. Dispenzieri:Celgene: Research Funding.

Abstract Abstract 429 Background: Patients with MM who have progressed after multiple novel agents have limited treatment options. Pomalidomide (CC4047) is the newest immunomodulatory (IMiD) agent that has demonstrated response rates of 63% in a Phase 2 trial of Pom/dex in patients with relapsed MM (in press, JCO). To better define the response rate in this group, we treated an additional cohort of patients who were truly resistant/refractory to lenalidomide. Methods: To be eligible, patients must:be refractory to lenalidomide therapy defined as relapsing on or within 60 days of stopping lenalidomide. Pomalidomide was given orally 2 mg daily on days 1–28 of a 28-day cycle. Dexamethasone was given orally at a dose of 40 mg daily on days 1, 8, 15 and 22 of each cycle. Response was assessed by the International Myeloma Working Group Uniform Response criteria. All patients received aspirin 325 mg daily as prophylaxis against DVT. Pom/dex regimen would be declared promising if we observed at least 4 confirmed responses out of 34 patients based on a single stage Fleming design. Results: 34 patients (23 male and 11 female) resistant/refractory to lenalidomide were enrolled. The median age was 62 years (range, 39-77). The median time from diagnosis to enrollment was 62 months (range 8-179). 12 patients had high risk molecular markers including loss of 17p (6 pts), t(4;14) (1 pt) and del 13 by cytogenetics (5 pts). 70% had ≥3 prior regimens including 38% with ≥5 prior regimens; 56% had prior thalidomide, 59% had prior bortezomib, and 68% had prior SCT. Toxicity (at least possibly related to treatment) was mild and consisted primarily of myelosuppression: grade 3/4 neutropenia (21%); grade 3 thrombocytopenia (9%); and grade 3 anemia (12%). Grade 3/4 non-hematologic toxicities occurred in 24%: pneumonia (3%), non-infectious pneumonitis (3%), hyperglycemia (3%), edema(3%), fatigue(9%) skin rash(3%). Neuropathy occurred in 18% (12% grade 1; 6% grade 2). No thromboembolic events have occurred so far. Nine (26%) patients were confirmed responders (all PR), surpassing the threshold for a positive trial, and 18 (53%) had SD. With a median follow-up of 4 months (range:0-8), 65% remain progression free; 88% remain alive; and 12% have died, all due to progressive MM. Conclusions: Pom/dex is active and well tolerated in this heavily pre-treated population of lenalidomide-refractory MM patients. The majority of patients have not progressed and objective responses are seen in 26%. This study confirms that pomalidomide has non-cross resistance with lenalidomide and offers benefit for patients who have relapsed after other novel therapies. Disclosures: Lacy: Celgene: Research Funding. Gertz:celgene: Honoraria; millenium: Honoraria, Membership on an entity's Board of Directors or advisory committees. Kumar:celgene: Honoraria; millenium: Honoraria, Membership on an entity's Board of Directors or advisory committees. Bergsagel:Genentech, Inc.: Consultancy; Amgen: Consultancy; Celgene: Consultancy; Merck: Research Funding. Stewart:Takeda-Millenium, Celgene, Novartis, Amgen: Consultancy; Takeda, Millenium: Research Funding; Genzyme, Celgene, Millenium, Proteolix: Honoraria.

Abstract Background: The combination of lenalidomide and dexamethasone (RD) has been shown to be highly effective as initial therapy for multiple myeloma. More recently, a phase III trial demonstrated improved survival with use of lenalidomide and low dose dexamethasone (Rd). Further improvements by incorporating other active agents may increase the depth of response and may improve long-term outcome. We report the results from a phase II trial combining lenalidomide and low dose dexamethasone with cyclophosphamide (RCd) as initial therapy for newly diagnosed MM. Methods: The trial was initiated in July 2006 and completed the initial target accrual of 33 patients by July 2007 (Cohort 1). Due to high rate of dose reductions in cohort 1, between July 2007 and May 2008 an additional 20 patients were enrolled with lower doses of cyclophosphamide (Cohort 2). The treatment protocol consisted of lenalidomide given orally at a dose of 25 mg daily on days 1–21 of a 28-day cycle. Dex was given orally at a dose of 40 mg on days 1, 8, 15, and 22 of each cycle. Cyclophosphamide at a dose of 300 mg/m2 was given on days 1, 8, and 15 of each cycle in cohort 1 and 300 mg on days 1, 8, and 15 of each cycle in cohort 2. Patients also received an aspirin once daily as thromboprophylaxis. Response was defined as a decrease in serum monoclonal (M) protein by 50% or higher and a decrease in urine M protein by at least 90% or to a level less than 200 mg/24 hours. Responses were assessed on intent to treat basis. Results: 53 patients were enrolled. The median age was 64 years (range, 37–82). 14 patients (29%) had ISS stage III disease. The median number of cycles was 4 (range: 1 – 20). The best response based on all enrolled patients on an intent to treat basis was 83%, including CR:1 (2%), VGPR: 20 (38%), PR: 23 (43%), and less than PR: 9 (17%). The CR plus VGPR rate was 40%. Among the 20 patients in cohort 2 who were enrolled after optimization of the cyclophosphamide dosing, 16 (80%) have already achieved a partial response or better with 17 patients in this cohort still receiving study treatment. Overall, 25 of the 53 enrolled patients have discontinued study treatment. Reasons for ending treatment are: completed study per protocol (14), disease progression (5), adverse event (3) and alternate treatment (3). This includes 3 patients from cohort 2, one completed treatment per protocol, one went to alternate therapy and one patient went off for progression. Hematological toxicity was the most common with grade 4 toxicity seen in 8 patients (only 1 from cohort 2). Non-hematological toxicities included neuropathy, diarrhea, cystitis, and thrombosis. There were 6 patients with grade 4 non-hematological toxicities (none from cohort 2) attributed to the drug (thrombosis, confusion, depression and sepsis). Thirteen patients had dose adjustments, most commonly due to hematological toxicity attributed to lenalidomide or cyclophosphamide. One patient has died off study, of intracranial hemorrhage. The median follow-up for the remaining patients is 7.8 months. Conclusions: The combination of lenalidomide, cyclophosphamide, and dexamethasone (RCd) has excellent activity in the setting of newly diagnosed myeloma. Seventeen patients continue on study and the response rates are likely to be higher with additional followup. Myelosuppression was a significant toxicity leading to dose reductions and cycle delays, and is lower with decreased dose of CTX in cohort 2 without any apparent loss of responses.

Abstract Background: Thalidomide and its analogue lenalidomide have high response rates among patients with newly diagnosed as well as previously treated myeloma. Pomalidomide (CC4047) is the newest immunomodulatory (IMiD) agent that has shown single-agent activity in phase I studies. We report on the first Phase 2 trial of pomalidomide combined with low dose dexamethasone (Pom/dex) in patients with relapsed or refractory multiple myeloma. Methods: 37 patients (21 male and 16 female) were enrolled. Pomalidomide was given orally 2 mg daily on days 1–28 of a 28-day cycle. Dexamethasone was given orally at a dose of 40 mg daily on days 1, 8, 15 and 22 of each cycle. Response was assessed by the International Myeloma Working Group Uniform Response criteria. All patients received aspirin 325 mg daily as prophylaxis against DVT. Results: The median age was 66 years (range, 40 – 88). All patients were evaluable for response and toxicity, and all analysis were done on intent to treat basis. All patients had received prior therapy; 38% had 3 prior regimens; 35% had 2 prior regimens and 27% had one prior regimen. 76% had previous autologous stem cell transplant (ASCT) and 24% had 2 prior ASCT. 62% had previous IMiD therapy. Toxicity was mild and consisted primarily of myelosuppression. Grade 3 neutropenia occurred in 31%; grade 3 thrombocytopenia 3%; grade 3 anemia 3 %. Other grade 3/4 toxicities seen in less than 5% pts included: diarrhea, atrial fibrillation, pneumonia, dehydration and renal insufficiency. 16 % had grade 1/2 neuropathy. No grade 3 neuropathy was seen and there have been no thromboembolic events. Thirty (81%) patients are continuing study treatment. Seven patients have discontinued treatment due to: disease progression (5), died on study (1) and the medical doctor’s discretion (1). Twenty three of 37 patients (62%) achieved an objective response to therapy; including 9 (24%) with VGPR; 14 patients (38%) with PR; 6 (16%) with stable disease. Objective responses were seen in 4 of 13 patients (29%) who were refractory to lenalidomide. Conclusions: Pomalidomide plus dexamethasone (Pom/dex) is highly active and well tolerated for treatment of relapsed/refractory multiple myeloma with an objective responserate of 62%, including a 29% response rate among patients who are lenalidomiderefractory.

Abstract Abstract 680 Cytogenetics play an essential role in determining the prognosis of patients with AML. However, there is still no validated cytogenetics grouping scheme that specifically applies to patients undergoing allogeneic stem cell transplantation, which hampers accurate prognostication and risk stratification. We studied 821 adult patients (median age 41, range 18–74) who underwent SCT between 1999 and 2004 for AML (excluding APL) in CR1 or CR2 and who were reported to the CIBMTR from centers with >20 patients meeting study criteria. 75% of patients received a myeloablative conditioning. 496 patients had a normal karyotype. The primary cytogenetics reports were manually reviewed for 92% of the patients with an abnormal karyotype. We compared the ability of the 6 existing grouping schemes (MRC, CALGB, EORTC/GIMEMA, SWOG/ECOG, DFCI, and Monosomal Karyotype (MK) classifications) to stratify patients, using both the Akaike Information Criterion in multivariable models and the C-statistic. Among all existing schemes, the DFCI system provided a marginally superior stratification for overall and leukemia-free survival. We also built a new classification using individual cytogenetic abnormalities in a Cox model that included other significant covariates (performance status, therapy-related disease, conditioning intensity, graft source, donor match, duration of CR1, and gender match). This CIBMTR scheme (see Table), which is similar to the DFCI scheme except for the inclusion of patients with t(8;21) in the intermediate group, could stratify patients into 3 groups with similar treatment-related mortality but significantly different overall survival, leukemia-free survival, and incidence of relapse. This scheme appeared to apply to both patients in CR1 and in CR2 (see FiguresF2). This transplant-specific scheme could be adopted for prognostication purposes and to stratify patients with karyotypic abnormalities entering transplantation clinical trials. Future studies may clarify the relative outcome of patients with t(8;21) and refine this scheme with the inclusion of molecular abnormalities. 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 Abstract 852 Adult acute lymphoblastic leukemia (ALL) is an aggressive disease with <30% long-term survival. This relatively poor outcome can be explained in part by an increased frequency of high-risk molecular subtypes compared to childhood ALL, such as BCR/ABL (20%-40% in adults vs 2%-5% in children). We hypothesized that aberrant epigenetic gene regulation contributes to the pathogenesis and clinical features of adult ALL. We therefore performed genome-wide DNA methylation and gene expression microarray studies of 215 adult patients with B-lineage ALL enrolled in the ECOG E2993 phase III trial. Patients had a median follow-up 4.75 years (3.5 months to 13 years) and median age 39 years (17 to 63 years). BCR/ABL(+) cases (n=83) had a worse overall survival (OS, p=0.08) than BCR/ABL(-) cases (n=132). The smaller difference in survival in this series between BCR/ABL(+) and (-) cases is likely due to the use of imatinib in some of these patients. The HELP microarray assay was used to measure DNA methylation at 50,000 CpGs annotated to ∼22,000 RefSeq promoters. The accuracy of HELP was confirmed by extensive quantitative single locus validation studies. Supervised analysis revealed the presence of a markedly aberrant DNA methylation signature (166 genes) in BCR/ABL(+) ALL with the cutoff values of p<0.001 (FDR<0.002) and log fold change>1, and a differential gene expression profile of 416 genes at p<0.001 (FDR<0.004) and log fold change>1. Integrative analysis of expression and DNA methylation indicated that many of these genes are functionally connected within a gene network centered around IL8, which was over expressed and hypomethylated in BCR/ABL(+) cases, along with IL2RA(CD25), CEBPB, ABL1, ID1, IL15, BCL2L13, CD69, NOV, S100A8 and S100A9. KEGG and BioCarta pathway analysis also showed enrichment for IL8 signaling, NF-kB Activation, B Cell Development and Antigen Presentation pathways, suggesting these cytokine networks might play central and distinct roles in BCR/ABL(+) ALL. To identify a core set of functionally relevant genes, we explored the overlap of the DNA methylation and gene expression signatures. The overlap consisted of 13 genes, among which 11 showed inverse correlation, including CD200, GAB1, HLA-DQA1, HLA-DQB1, IL2RA (CD25), LST1, LTB, NOV, ROB04, S100A9, and CD38. Consistent with previous ECOG findings, CD25 positivity was a more dominant predictor than BCR/ABL, and could further stratify BCR/ABL(+) patients into a favorable (CD25-) and a poor (CD25+) outcome group (OS, p=0.07). When comparing CD25(+) and CD25(-) groups among BCR/ABL(+) cases, we found RhoH and UBE2J1 as the top differentially methylated and IL2RA(CD25) as the top differentially expressed genes, and all three genes showed concordant corresponding changes in expression and methylation. The aberrant DNA methylation signature of MLL/AF4 cases was even more dramatic, with 469 identified as differentially methylated (p<0.001 (FDR<0.015), log fold change>1) and 1108 genes differentially expressed (p<0.001 (FDR<0.009), log fold change>1). Integrated analysis of DNA methylation and expression implicated gene pathways centered around TNFA and MYC, respectively. A core set of 44 genes were identified overlapping between the methylation and gene expression signatures, among which 34 showed inverse correlation, including ANXA5, BRE, CAPG, CEBPA, FAIM, FLT3, FUT4, IGFBP7, IL1R2, ITGA7, ITGAE, MAP1A, MAP7, MRPL33, PARP8, RBKS, SLITRK4 and TFR2 with overexpression and hypomethylation, and BTBD3, CCR6, FYN, GAB1, GYPC, HPS4, IL2RA, KCNK3, LCK, LST1, LTB, PRKCH, QPCT, S100A13, SGPL1 and ZAP70 with underexpression and hypermethylation in MLL/AF4(+) ALL. All signatures were independent of B-ALL differentiation stage. Using univariate Cox Hazard Regression model adjusted by age, WBC, CD25 and BCR/ABL status, we furthermore identified 259 expression and 115 methylation markers which were significantly correlated with patient OS risk (p<0.01). Molecularly or immunophenotypically defined poor prognosis adult B- ALLs thus feature specific aberrant DNA methylation profiles with associated inversely correlated gene expression. These gene sets delineate specific biological functions that may contribute to disease phenotype and offer an opportunity for development of targeted therapy. Aberrantly methylated genes in adult B-ALL correlate with clinical risk independent of other clinical or molecular risk factors. 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 851 Clinical studies have demonstrated that acute myeloid leukemia (AML) is heterogeneous with respect to presentation and to clinical outcome, and many studies have shown that cytogenetics can be used to improve prognostication. More recently, it has been shown that FLT3, NPM1, and CEBPA mutations can be used to further risk stratify AML patients. Although recent studies have identified novel, recurrent somatic mutations in AML in genes including TET2, ASXL1, IDH1, IDH2, and PHF6, their prognostic value has not yet been evaluated among patients treated on a large phase III clinical trial. Here we report full-length DNA resequencing of FLT3, NPM1, CEBPA, H/K/NRAS, KIT, WT1, TET2, ASXL1, IDH1/2, TP53, RUNX1, PTEN, and PHF6 in pre-treatment genomic DNA from 398 patients with de novo AML younger than 60 years of age enrolled in the ECOG E1900 protocol. We could identify a clonal alteration, defined as a somatic mutation or cytogenetic abnormality, in 91.2% of all patients; 42% had 1 somatic alteration, 36.4% had 2 alterations, 11.3% had 3 alterations and 1.5% had 4 or more somatic alterations. Mutational Analysis: We identified somatic mutations in FLT3 (37% total; 30% ITD, 7% TKD), NPM1 (14%), CEBPA (10%), TET2 (10%), NRAS (10%), WT1 (10%), KIT (9%), IDH2 (8%), IDH1 (6%), RUNX1 (6%), ASXL1 (4%), PHF6 (3%), KRAS (2.5%), TP53 (2%), and PTEN (1.5%) (Figure 1A). We then performed correlation analysis to determine the frequency of different mutational combinations in AML patients. In addition to previously identified mutational correlations (FLT3 and NPM1, KIT and core binding factor leukemia), we found that FLT3 and ASXL1 mutations were mutually exclusive in this large cohort (p =0.0008). In addition, we found that IDH1/IDH2 mutations were mutually exclusive of both TET2 (p=0.02), and WT1 (p=0.01) mutations consistent with overlapping roles in AML pathogenesis (Figure 1B). Integration of mutational data with response data and outcome: Mutations in ASXL1 (CR rate 33.3% versus 66.5% for ASXL1-WT patients; p= 0.009) were enriched in patients who did not respond to induction chemotherapy. We found that mutations in FLT3 (p=0.0005), ASXL1 (p=0.005; Figure 1C), and PHF6 (p=0.02) were associated with reduced OS. Notably, the adverse effects of ASXL1 and PHF6 mutations on outcome were restricted to patients treated with standard dose daunorubicin (p<0.01 for each mutational cohort); ASXL1 and PHF6 mutational status did not affect outcome in patients treated with high-dose daunorubicin, demonstrating that increased intensity induction chemotherapy can improve outcomes in genetically defined poor risk AML subsets. We also found that mutations in CEBPA (p= 0.04) and in IDH2 (p=0.003) were associated with improved OS; the favorable impact of IDH2 mutations on outcome was exclusive to patients with IDH2 R140Q mutations (Figure 1D). Within the subset of patients with cytogenetically defined intermediate risk AML, we found, as expected, that FLT3-ITD mutations were associated with reduced OS and CEBPA mutations were associated with improved OS. Importantly, we found that IDH2 R140Q mutations were associated with improved OS (p=0.003) in patients with intermediate risk AML regardless of FLT3 mutational status. In contrast, TET2 mutations (P=0.0002) and PHF6 (p<0.0001) were associated with reduced OS in intermediate risk, FLT3-WT, AML. Summary: These data provide important clinical implications of genetic alterations in AML and provides insight into the multistep pathogenesis of adult AML. We identified novel mutations that impact response to induction chemotherapy and predict overall outcome, including ASXL1, PHF6, TET2 and IDH2, suggesting these mutations can be used to improve AML risk stratification and therapeutic decisions in AML patients 18–60 years of age. Most importantly, we identify TET2, IDH1/2, and WT1 mutations as mutually exclusive somatic alterations that form a novel mutational complementation group that contributes to AML pathogenesis. Figure 1. A) Circos diagram depicting relative frequency and pairwise co-occurrence of mutations in de novo AML patients enrolled in the ECOG protocol E1900. B) Circos diagram showing mutational events in IDH1/2, TET2, and WT1 mutant AML patient. C) Overall survival in AML patients with and without ASXL1 mutations (p=0.005). D) Overall survival in AML patients with and without IDH2 R172 and R140 mutations (p=0.003). Figure 1. A) Circos diagram depicting relative frequency and pairwise co-occurrence of mutations in de novo AML patients enrolled in the ECOG protocol E1900. B) Circos diagram showing mutational events in IDH1/2, TET2, and WT1 mutant AML patient. C) Overall survival in AML patients with and without ASXL1 mutations (p=0.005). D) Overall survival in AML patients with and without IDH2 R172 and R140 mutations (p=0.003). Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 863 Background: Patients with MM who have progressed after multiple novel agents have limited treatment options. Pomalidomide (CC4047) is the newest immunomodulatory (IMiD) agent. Pom/dex using a dose of 2 mg/day has demonstrated response rates (≥PR) of 63% in relapsed MM (Lacy, JCO 2009, 27:5008-5014) and 32% in a lenalidomide-refractory cohort (Lacy, Leukemia, in press). The maximum tolerated dose has been determined to be 4 mg/day for 21 of 28 days (Richardson, ASH, 2009), We opened two sequential phase II trials using the Pom/dex regimen at differing doses to study the efficacy of this regimen in patients who have failed both lenalidomide and bortezomib. Methods: Patients refractory to both lenalidomide and bortezomib therapy; defined as relapsing on or within 60 days of stopping each regimen, were enrolled. Pomalidomide was given orally 2 mg daily (Cohort A) or 4mg daily (Cohort B) on days 1–28 of a 28-day cycle with oral dexamethasone given 40 mg daily on days 1, 8, 15 and 22. Response was assessed by the International Myeloma Working Group Uniform Response criteria. All patients received aspirin 325 mg daily for DVT prophylaxis. Results: 35 patients with relapsed and resistant/refractory to both lenalidomide and bortezomib were enrolled in each cohort. The median age was 62 years (range, 39–77) in Cohort A and 61 (range, 45–77) years in Cohort B. The median time from diagnosis to enrollment was 57 months for Cohort A (range 12–249) and 72 months(range, 13–183) for Cohort B. 15 patients had high risk molecular markers in Cohort A and 16 in Cohort B. The median number of prior regimens was 6 in both groups. The median (range) duration on treatment was 5(1-13) and 2(0-6) cycles in cohorts A and B respectively. Toxicity at least possibly attributed to drug consisted primarily of myelosuppression: grade 3/4 neutropenia (37% Cohort A vs. 55% Cohort B); grade 3/4 thrombocytopenia (11% Cohort A vs. 13% Cohort B); and grade 3/4 anemia (9% Cohort A vs. 16% Cohort B). Grade 3/4 non-hematologic toxicities occurred in 23% Cohort A vs. 13% Cohort B. Grade 1 or 2 fatigue was the most common non-hematologic toxicity seen in 43% Cohort A vs. 52% Cohort B. Grade 1 or 2 neuropathy occurred in 17% Cohort A vs. 16% Cohort B. Other non-hematologic toxicities occurring in <5% included pneumonitis, hyperglycemia, renal failure, thrombosis. One patient in cohort B had grade 4 hepatitis. Confirmed responses in Cohort A consisted of VGPR 14%, PR 11%, and MR 24% (ORR 49%, 95% CI: 31–66), and responses in Cohort B consisted of VGPR 9%, PR 20%, and MR 12% (ORR 40%, 95% CI: 23–58). The median follow-up on alive patients was 7.5 months, and 3 months in Cohorts A and B, respectively. The median PFS in cohorts A and B are respectively 6.4 months (95% CI: 4.7-NR) and 3.3 months (95% CI: 2.3-NR). Conclusions: Pom/dex is remarkably active and well tolerated in this heavily pre-treated population of dual bortezomib/lenalidomide-refractory MM patients. The majority of patients have not progressed and objective responses (MR or better) are seen in 40–49%. This study confirms therapeutic benefit for Pom/dex in patients relapsing after other novel therapies. These studies do not show an advantage for the 4 mg/day on days 1–28 of each 28 day cycle did not show an advantage over the 2 mg/day on days 1–28 of each 28 day cycle. Disclosures: Lacy: Celgene: Research Funding. Gertz:Celgene: Honoraria; Millennium: Honoraria, Membership on an entity's Board of Directors or advisory committees. Dispenzieri:Celgene: Honoraria, Research Funding; Binding Site: Honoraria. Kumar:Celgene: Consultancy, Research Funding; Millennium: Research Funding; Merck: Consultancy, Research Funding; Novartis: Research Funding; Genzyme: Consultancy, Research Funding; Cephalon: Research Funding. Fonseca:Genzyme: Consultancy; Medtronic: Consultancy; BMS: Consultancy; AMGEN: Consultancy; Otsuka: Consultancy; Celegene: Consultancy, Research Funding; Intellikine: Consultancy; Cylene: Research Funding; Onyx: Research Funding; FISH probes prognostication in myeloma: Patents & Royalties. Bergsagel:Celgene: Consultancy; Centocor: Consultancy; Genentech: Consultancy; Amgen: Consultancy; Novartis: Consultancy. Stewart:Celgene: Honoraria.