Patel, Jay P.

Abstract Background: Novel therapies are required to improve the outcome of patients with AML. New agents are asked to demonstrate an overall survival (OS) benefit before qualifying for FDA approval. The long duration of clinical trials required in order to achieve this endpoint hampers quick evaluation of candidate therapies, including novel agents. Identification of reliable surrogate endpoints for OS in AML is needed. Here we compare the results of therapy for patients with untreated AML ages 16-60 years on the Eastern Cooperative Oncology Group 1900 trial (E1900) of induction chemotherapy followed by consolidation and autologous transplant in order to evaluate the validity of an event free survival (EFS) endpoint as a surrogate for OS. Methods:OS was measured from randomization for induction therapy to death from any cause (censored at last contact). EFS was measured from randomization to induction treatment failure, relapse after compete response (CR), or death in remission (censored at last contact). Hazard ratios (HR) were computed using Cox proportional hazards models. The association between EFS and OS was evaluated using the Kendall tau-a rank correlation for censored data. Results:There were657 patients enrolled of which 426 patients relapsed or had induction treatment failure before death or date of last contact. Median EFS and OS were 8.0 months (95% CI, 6.3 to 9.7 months) and 23.6 months (95% CI, 16.9 to 23.6 months), respectively. With a median follow-up of 80.1 months, there is a statistically significant correlation between EFS and OS (Kendall tau-a = 0.467, 95% confidence interval (CI) = (0.425, 0.510), p<0.001). This correlation was similarly significant at a median follow-up of 25.2 months (Kendall tau-a = 0.361, 95% CI (0.323, 0.400), p <0.001) when the E1900 trial was originally reported (Fernandez et al. NEJM 2009). Key findings reported based on the original OS endpoint are similar when analyzed with an EFS endpoint (Table 1). High-dose daunorubicin (90 mg/m2) (DNR 90) confers both an EFS and OS benefit in patients aged < 50 years and patients with intermediate cytogenetic risk, and does not confer an EFS or OS benefit in older patients and patients with unfavorable cytogenetic risk, on univariate analysis. Divergent results are only seen in the small subset of favorable cytogenetic risk patients, where DNR 90 conferred an OS benefit (p=0.027) without an EFS benefit (p=0.32). Both EFS and OS endpoints consistently reflect the impact of mutation status on survival. The presence of a FLT3-ITD or DNMT3A mutation has a negative impact on both EFS and OS while an IDH2 mutation has a favorable impact on EFS and OS. The presence of a NPM1 mutation confers a favorable impact on EFS and OS in patients who received DNR 90 and did not impact EFS or OS in patients receiving standard-dose daunorubicin (45 mg/m2) (DNR 45). The presence of an IDH1 mutation does not impact EFS or OS. Conclusions:The results of E1900 demonstrating superiority of DNR 90 in AML induction in patients up to age 60 are concordant when using an EFS or OS endpoint. This is true for the group as a whole as well as for subgroups for which targeted agents are in development (FLT3/IDH2 inhibitors). Further investigation of whether EFS is a reliable surrogate for OS is warranted in AML. If confirmed, its use as a primary endpoint could be adopted by regulatory agencies in order to allow more rapid completion of clinical trials in AML and bring new therapies to AML patients in a timely fashion. Table 1. Results of E1900 based on an EFS endpoint versus an OS endpoint. Subgroup N OS HR (DNR 90/DNR 45) & 95% CI Wald P EFS HR (DNR 90/DNR 45) & 95% CI Wald P DNR 45 DNR 90 Age < 50 yrs ³ 50 yrs 188 142 172 155 0.66 (0.50, 0.85) 0.81 (0.62, 1.06) 0.002 0.118 0.64 (0.50, 0.82) 0.86 (0.67, 1.10) 0.0004 0.23 Cytogenetic Favorable Intermediate Unfavorable 38 141 59 51 127 63 0.51 (0.28, 0.93) 0.68 (0.50, 0.92) 0.79 (0.54, 1.16) 0.027 0.012 0.225 0.76 (0.44, 1.31) 0.63 (0.47, 0.83) 0.72 (0.49, 1.05) 0.32 0.001 0.09 Subgroup N OS HR (MUT/WT) & 95% CI Wald P EFS HR (MUT/WT) & 95% CI Wald P FLT3-ITD WT MUT 456 147 1.62 (1.31, 2.01) <.0001 1.48 (1.21, 1.82) 0.0002 DNMT3A WT MUT 371 119 1.30 (1.03, 1.65) 0.03 1.23 (0.98, 1.54) 0.07 IDH1 WT MUT 465 36 0.88 (0.59, 1.33) 0.55 0.91 (0.62, 1.34) 0.64 IDH2 WT MUT 451 50 0.63 (0.43, 0.93) 0.02 0.68 (0.48, 0.97) 0.03 NPM1 DNR 45 DNR 90 245 257 0.84 (0.61, 1.16) 0.60 (0.41, 0.89) 0.30 0.01 0.90 (0.66, 1.22) 0.59 (0.41, 0.84) 0.49 0.004 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 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.

Key Points High-dose daunorubicin benefits AML patients with favorable and intermediate cytogenetics and with FLT3-ITD, NPM1, and DNMT3A mutations. High-dose daunorubicin is required for the favorable impact of the NPM1 mutation in AML.

Key Points Serum 2HG analysis by LC-MS can accurately identify patients with AML with and without IDH mutations. Oncometabolite testing of serum 2HG is indicated as a diagnostic, prognostic, and therapeutic monitoring tool in AML.

Abstract We determined the prognostic relevance of CD25 (IL-2 receptor-α) expression in 657 patients (≤ 60 years) with de novo acute myeloid leukemia (AML) treated in the Eastern Cooperative Oncology Group trial, E1900. We identified CD25POS myeloblasts in 87 patients (13%), of whom 92% had intermediate-risk cytogenetics. CD25 expression correlated with expression of stem cell antigen CD123. In multivariate analysis, controlled for prognostic baseline characteristics and daunorubicin dose, CD25POS patients had inferior complete remission rates (P = .0005) and overall survival (P < .0001) compared with CD25NEG cases. In a subset of 396 patients, we integrated CD25 expression with somatic mutation status to determine whether CD25 impacted outcome independent of prognostic mutations. CD25 was positively correlated with internal tandem duplications in FLT3 (FLT3-ITD), DNMT3A, and NPM1 mutations. The adverse prognostic impact of FLT3-ITDPOS AML was restricted to CD25POS patients. CD25 expression improved AML prognostication independent of integrated, cytogenetic and mutational data, such that it reallocated 11% of patients with intermediate-risk disease to the unfavorable-risk group. Gene expression analysis revealed that CD25POS status correlated with the expression of previously reported leukemia stem cell signatures. We conclude that CD25POS status provides prognostic relevance in AML independent of known biomarkers and is correlated with stem cell gene-expression signatures associated with adverse outcome in AML.