Medeiros, Bruno C.

Abstract Background: Treatment of elderly AML patients considered unfit for conventional chemotherapy is inadequate and hypomethylating agents are commonly used alternatives. In the case of azacitidine, responses are typically seen after 3–6 cycles of therapy, and a recent large randomized trial in elderly unfit patients reported a complete response (CR)/CR with incomplete blood count recovery rate of 28% (Dombret et al, EHA 2014). Pevonedistat (MLN4924) is an investigational, first-in-class NEDD8-activating enzyme (NAE) inhibitor. A phase 1 trial previously reported pevonedistat single-agent clinical activity in relapsed/refractory AML patients. Preclinical studies of pevonedistat and azacitidine identified synergistic lethality in AML cell lines and murine xenografts. The current phase 1b dose-escalation study evaluated the safety and tolerability of pevonedistat combined with azacitidine in elderly AML patients considered unfit for conventional chemotherapy. Methods: The primary objective was to assess the safety and tolerability of pevonedistat combined with azacitidine. Secondary objectives included assessment of pevonedistat pharmacokinetics (PK) and clinical activity. Treatment-naïve AML patients aged ≥60 years who were considered unfit for standard induction therapy received pevonedistat via 1-hour IV infusion on days 1, 3, and 5 of 28-day cycles. Dose escalation began at 20 mg/m2 and used an adaptive Bayesian continual reassessment method. Azacitidine 75 mg/m2 was administered (IV or SC) on days 1–5 and 8–9. Patients were treated until disease progression or unacceptable toxicity. Adverse events (AEs) were graded per NCI-CTCAE v4.03. Responses were assessed according to International Working Group response criteria for AML. Serial blood samples were obtained for PK analysis following dosing on days 1 and 5 of cycle 1. Results: As of May 30, 2014, 25 patients (median age 75.0 years [range 63–85]; 16 [64%] male) had received pevonedistat 20 mg/m2 (n=22) and 30 mg/m2 (n=3). Primary diagnoses were 16 (64%) de novo AML and 9 (36%) secondary AML. Fourteen (56%) patients had intermediate- and 6 (24%) had adverse-risk cytogenetics (5 [20%] undetermined). During dose escalation, dose-limiting toxicity (DLT) at the 30 mg/m2 pevonedistat dose level included reversible grade 2 increased bilirubin (n=1) and grade 3/4 increased transaminases (n=1) without clinical sequelae. In 1 of the 22 patients treated at the maximum tolerated dose (20 mg/m2 pevonedistat plus 75 mg/m2 IV/SC azacitidine), 1 additional DLT (grade 4 AST/ALT elevation) was seen in the expansion cohort. This patient was successfully re-challenged with a reduced pevonedistat dose. The most common all-grade AEs are shown in table 1. Twelve (48%) patients experienced drug-related grade ≥3 AEs (table 1). The nature and frequency of the reported toxicities (excluding DLTs) were similar to previous reports for azacitidine alone. Preliminary PK data showed that addition of azacitidine did not alter the known PK profile of single-agent pevonedistat. In the 18 response-evaluable patients, there were 6 (33%) CRs and 4 (22%) PRs (table 2), for an overall response rate of 56%. Nine of the 10 responses occurred within the first two cycles of therapy and included 1 patient with bone marrow blasts >80%. Conclusions: Combination therapy with pevonedistat and azacitidine was generally well-tolerated. The characteristics of the observed responses suggest added benefit from the addition of pevonedistat compared with azacitidine alone. Table 1 Common all-grade AEs n (%) Most frequent (≥10%) drug-related grade ≥3 AEs n (%) Febrile neutropenia 9 (36) Febrile neutropenia 4 (16) Constipation 8 (32) Thrombocytopenia 3 (12) Decreased appetite 7 (28) – – Thrombocytopenia 7 (28) – – Table 2 Responders* Tumor Type Cytogenetic Risk Group Current Status Response Molecular CR 1st Response 1st CR 1 De novo AML Adverse C12 C4 – – 2 Undetermined C4† C1 C1 Y 3 Adverse C9 C1 C1 Y 4 Undetermined C5‡ C1 C2 Y 5 Intermediate C5† C1 C2 N 6 Intermediate C7 C1 C4 Y 7 Intermediate C2 C2 – – 8 Secondary AML Undetermined C4 C2 C2 – 9 Normal C4 C1 – – 10 De novo AML – C1 C1 – – Molecular CR, complete remission confirmed by molecular studies *All received 20 mg/m2 pevonedistat except #4, who started on 30 mg/m2 and had a dose reduction to 20 mg/m2. †Patient off study ‡Patient off treatment and in follow-up Disclosures Swords: Novartis: Consultancy; KaloBios Pharmaceuticals, Inc.: Consultancy; Millennium: The Takeda Oncology Company: Consultancy. Savona:Novartis: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees; Gilead Sciences, Inc.: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Karyopharm Pharmaceuticals: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Erba:Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Consultancy, Research Funding; Incyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda Pharmaceuticals International Co.: Research Funding; Astellas Pharma: Research Funding; Celgene: Honoraria, Speakers Bureau; Seattle Genetics: Consultancy, Research Funding. Foran:Takeda Pharmaceuticals International Co.: Research Funding. Hua:Takeda Pharmaceuticals International Co.: Employment. Faessel:Takeda Pharmaceuticals International Co.: Employment, Equity Ownership. Dash:Takeda Pharmaceuticals International Co.: Employment. Sedarati:Takeda Pharmaceuticals International Co.: Employment. Dezube:Takeda Pharmaceuticals International Co.: Employment. Medeiros:Millennium: The Takeda Oncology Company: Consultancy, Honoraria; Takeda Pharmaceuticals International Co.: Research Funding.

Background:Mutations localized in the tyrosine kinase domain activation loop of FLT3 (FLT3‐TKD), induce constitutive tyrosine phosphorylation, and activation of the receptor tyrosine kinase similarly to FLT3 internal tandem duplication (ITD) mutations. However, the prognostic role of FLT3‐TKD in AML is not well established. In the phase 3 RATIFY trial [CALGB 10603/Alliance; NCT00651261; Stone et al. N Engl J Med. 2017] midostaurin, in combination with standard chemotherapy, improved survival outcomes across all three FLT3 stratification subgroups (ITD high allelic ratio (AR) [≥ 0.7], ITD low AR [< 0.7] and TKD) vs placebo.Aims:Here, a post hoc analysis was used to establish the efficacy of midostaurin in patients (pts) in the RATIFY trial stratified by FLT3‐TKD AR and NPM1 mutational status.Methods:In RATIFY, newly diagnosed pts with AML 18–60 years (y) old were randomly assigned to receive midostaurin or placebo together with standard induction and consolidation therapy followed by twelve 28‐day cycles of maintenance therapy with midostaurin or placebo. FLT3‐TKD mutation was detected by PCR and capillary electrophoresis at nine reference laboratories. The FLT3‐TKD AR was calculated as the ratio between the areas under the curve of mutant to wild‐type allele. Pts were categorized as NPM1 mutated (mut) or NPM1 wild‐type (WT) using PCR. Efficacy outcomes included complete remission (CR), overall survival (OS), event‐free survival (EFS) and disease‐free survival (DFS). EFS and DFS analyses were performed considering CR within a 60‐day window. P values presented were not adjusted for multiplicity.Results:Of 163 FLT3‐TKD pts, 134 with available NPM1 data had consented for exploratory analysis and were included in this study. Overall, 58.9% of pts had NPM1‐mut, 47.8% were male and the median age was 49 y (range: 19.3–59.9 y). The median white blood cell (WBC) count was higher in pts with NPM1‐mut than in pts with NPM1‐WT (34.1 vs 15.5 × 109 /L). The median FLT3‐TKD AR was 0.4 (range: 0–2.7). Overall CR rate (regardless of NPM1 genotype) was 64% for midostaurin and 56% for placebo in FLT3‐TKD pts. Pts with FLT3‐TKD AR ≥ 0.4 treated with midostaurin showed a trend towards improved OS and reduced cumulative incidence of relapse (CIR) (Figure). In FLT3‐TKD AR ≥ 0.4 pts, the presence of a NPM1 mutation had a significant prognostic effect for all endpoints consistently with hazard ratios (HRs) around 0.50 or lower. Regardless of treatment OS, EFS, and DFS estimates at 3 y were 73% vs 52%, 48% vs 25%, and 74% vs 47%, respectively, for the 45 pts with FLT3‐TKD/NPM1‐mut vs the 25 pts with FLT3‐TKD/NPM1‐WT. It should be noted that the number of pts in each subgroup was small. Multivariate analyses in these FLT3‐TKD pts revealed that NPM1 genotype was an independent prognostic factor for OS and EFS (2‐sided P < 0.05), whereas study drug, age, sex, TKD AR, WBC at baseline and stem cell transplantation (SCT) (no/yes) did not reach this level of significance in the Cox model.Summary/Conclusion:This post hoc analysis of the subset of FLT3‐TKD pts in the RATIFY trial showed the high prognostic value of NPM1 mutational status. Midostaurin showed an overall benefit in the FLT3‐TKD pts for OS, EFS, CR and DFS, with the impact of treatment on outcome for NPM1‐mut pts being greatest in those with higher FLT3‐TKD allelic burden. U10CA180821, U10CA180882, U24CA196171, U10CA180861; Novartis; htt∗∗∗ps://acknowledgments.alliancefound.orgimage

Abstract Pracinostat, a potent oral pan-histone deacetylase inhibitor with modest single-agent activity in acute myeloid leukemia (AML), has shown synergistic antitumor activity when combined with azacitidine. This single-group, multicenter phase 2 study assessed the safety and efficacy of pracinostat combined with azacitidine in patients who were at least 65 years old with newly diagnosed AML and who were ineligible for standard induction chemotherapy. Patients received pracinostat 60 mg/d, 3 d/wk, for 3 consecutive weeks, plus azacitidine 75 mg/m2 daily for 7 days in a 28-day cycle. Primary endpoints were complete remission (CR), CR with incomplete count recovery (CRi), and morphologic leukemia-free state (MLFS) rates of the combination. Secondary endpoints included safety, progression-free survival (PFS), and overall survival (OS) of the regimen. Fifty patients (33 de novo, 12 secondary, and 5 therapy-related AML) were enrolled. Twenty-six patients (52%) achieved the primary endpoint of CR (42%), CRi (4%), and MLFS (6%). Median OS and PFS were 19.1 months (95% confidence interval [CI], 10-26.5 months) and 12.6 months (95% CI, 10-17.7 months), respectively, with a 1-year OS rate of 62%. Forty-three patients (86%) experienced at least 1 grade 3 or worse treatment-emergent adverse event with the combination, with infections (52%), thrombocytopenia (46%), and febrile neutropenia (44%) reported as the most common toxicities. The 30- and 60-day all-cause mortality rates were 2% and 10%, respectively. DNA sequencing revealed somatic mutations at baseline, and clearance rates correlated with response to treatment. Pracinostat plus azacitidine is a well-tolerated and active regimen in the frontline treatment of older patients with AML unfit for intensive therapy. A larger controlled trial is ongoing. This trial was registered at www.clinicaltrials.gov as #NCT01912274.

7034 Background: In a phase II study in 50 elderly patients (pts) with AML who were not eligible for intensive chemotherapy, treatment with pracinostat + azacitidine (AZA) was well tolerated, led to 42% complete remission (CR) rate and a median overall survival (OS) of 19.1 months (Blood 2016: 128;100). Here we investigate the impact of somatic mutations and their clearance on disease response and patient outcomes. Methods: 88 samples from 41 study pts were sequenced. All 41 pts were analyzed pre-treatment, and a median of 3 longitudinal samples were analyzed from 19 pts between Cycle 2 and 9. Mutations were assayed by SureSelect targeted capture exon sequencing (Agilent) of 295 genes that are recurrently mutated in hematologic malignancies. Longitudinal mutation clearance was analyzed by plotting variant allele frequency (VAF). Results: At baseline, 96 mutations in 28 genes were detected in 38 pts, with the most frequent being in SRSF2 (27%), DNMT3A (20%), IDH2 (17%), RUNX1 (17%), and TET2(17%). Mutations associated with CR rate and OS are indicated in the Table. A CR was achieved in 10/19 pts that had longitudinal sequencing analysis and at the time of CR, 9 (90%) had persistently detectable mutations in their bone marrow. In 7 of them, continued exposure to pracinostat + AZA lowered the VAF or cleared residual mutations. In 2 pts, relapsed samples showed re-expansion of the founder clone. Conclusions: Mutations in NPM1, and DNA methylation pathway were associated with a better response to pracinostat + AZA, while TP53 mutation was associated with a poor response. Persistent mutation at the time of CR suggests residual preleukemic clonal hematopoiesis in this elderly population. Benefit of prolonged exposure to pracinostat + AZA was also confirmed at molecular level where continued decline of mutation VAF was seen after achieving CR. Clinical trial information: NCT01912274. [Table: see text]

SummaryIntroductionWhile the presence of disseminated intravascular coagulation (DIC) has been implicated in worse clinical outcome in acute leukemia, the relationship between different subtypes of acute leukemia and the clinicopathologic features of DIC has not been systematically well studied.MethodsIn this study, we retrospectively reviewed 149 cases of newly diagnosed acute leukemia and assessed the utility of evaluating red blood cell morphologic features, and coagulation parameters in determining the presence of DIC as well as differentiating subtypes of acute leukemia.ResultsReview of our cohort demonstrates a novel finding, that elevated D‐dimer concentrations ≥19 000 ng/mL fibrinogen equivalent units (FEU) are a sensitive diagnostic indicator of acute promyelocytic leukemia (APL) with moderate specificity, sensitivity 96%, specificity 92% in acute leukemia subtyping. Similar to other studies, APL showed an increased incidence of DIC (P < 0.01) compared to other subtypes of acute leukemia. Surprisingly, the presence of schistocytes on the peripheral blood smear was not a statistically significant indicator of DIC, sensitivity of 36% and specificity of 89%. Finally, the presence of DIC was not a significant indicator of poorer prognosis amongst all patients with AML.ConclusionOverall we identify elevated D‐dimer concentrations ≥19 000 ng/mL FEU are a sensitive indicator of acute promyelocytic leukemia (APL), with a sensitivity of 96% and specificity of 92% in the subtyping of acute leukemias, and that the presence of schistocytes in peripheral blood smears is not a diagnostically sensitive screening test for DIC with a sensitivity of 36%.