ALBERT

Description: Background: Guadecitabine (G) is a next generation subcutaneous hypomethylating agent (HMA) resistant to degradation by cytidine deaminase which results in prolonged in vivo exposure to the active metabolite decitabine. We conducted a large global randomized phase 3 study of G vs TC of azacitidine (AZA), decitabine (DEC), or low dose Ara-C (LDAC) in 815 TN AML patients unfit for IC (ASTRAL-1 study). The ITT results for the primary endpoints of Complete Response (CR), and Overall Survival (OS) were previously presented (Fenaux et al, EHA abstract S879, 2019). There is no consensus on definition of disease progression particularly with HMA treatment which may continue to benefit patients in the absence of objective response. EFS analysis based on end of treatment benefit (treatment discontinuation, or start of an alternative therapy, or death) regardless of progression may offer a simpler way of assessing HMA treatment benefit. We describe here the results of the study based on both PFS and EFS analyses and how they compare with OS analyses in the overall ITT population, and in subgroups of patients based on number of cycles administered. M ethods: TN-AML ineligible for IC due to age ≥ 75 y, or comorbidities, or ECOG PS 2-3 were randomized 1:1 to either G (60 mg/m2/d SC for 5-days Q28 days) or a preselected TC of AZA, DEC, or LDAC at their standard regimens. AML diagnosis, and response status by IWG 2003 criteria, were assessed by an independent central pathologist blinded to randomization assignment. CR and OS were co-primary endpoints. PFS was a secondary endpoint calculated from date of randomization to the earliest date of progression by investigators or central assessment, relapse after response, start of an alternative therapy, or death. Since progression date is sometimes difficult to ascertain under HMA treatment, an EFS analysis was conducted post hoc using the concept of time to treatment failure. EFS was therefore calculated from date of randomization to the earliest date of discontinuation of randomized treatment, start of an alternative therapy, or death. PFS, EFS, and OS data are presented for the overall ITT population, and for patients who received at least 4 cycles or 6 cycles, and patients who had an objective response. Results: 815 patients were randomized to G (408) or TC (407). Preselected TCs prior to randomization were DEC (43%), AZA (42%), and LDAC (15%). Baseline variables were well balanced across the 2 treatment arms. The majority of patients were randomized to receive an HMA: 759 patients (93%) with only 56 patients (7%) randomized to receive LDAC. In the primary ITT analysis, CR (19.4% for G and 17.4% for TC), and OS Hazard Ratio (0.97; 95% CI 0.83-1.14) were not significantly different between G and TC. An equal proportion of patients received at least 4 cycles (57.6% for G vs 59.2% for TC), or 6 cycles (45.8% for G vs 46.2% for TC) so there was no obvious bias in terms of adherence to treatment in the 2 study arms. Table shows OS, PFS, and EFS median survival, G/TC HR with 95% CI, and p values for the primary ITT population as well as for patients who received at least 4 cycles (N=476 patients), and those who received at least 6 cycles (N=375 patients). G/TC HR for all analyses favored guadecitabine (HR

Description: Key Points Induction followed by allo-transplantation can achieve long-term disease control in select patients with AML arising from a Ph-MPN. In this population, transplant should be the goal in patients treated with curative intent, as induction alone provides limited benefit.

Description: Between June 2000 and December 2004, 68 adult patients with newly diagnosed ALL were treated at Princess Margaret Hospital in Toronto, Canada using a modified Dana Farber Cancer Institute pediatric ALL protocol (DFCI 91-01). This protocol includes a remission induction phase, a CNS prophylaxis phase with intrathecal chemotherapy and 12 Gy cranial irradiation, a 30-week intensification phase, and a 72-week maintenance phase. Since 2002, bcr-abl+ patients received concurrent therapy with imatinib mesylate. Before 2002, all patients in CR1 were referred for allogeneic stem cell transplant (alloSCT) if a suitable matched sibling donor was identified (n=11); after 2002, only high-risk patients were referred for alloSCT (n=14). In addition bcr-abl+ and t(4:11) patients were considered for matched unrelated donor alloSCT. Median age was 34.5 years (range, 17–61 years). Sixteen (23.5%) patients were bcr-abl+ and 13 (19.1%) pre-B with WBC 〉 30. Ten of 16 (62.5%) of the bcr-abl+ patients received concurrent imatinib mesylate; 11 of 16 (69%) of these subsequently underwent alloSCT. The complete remission (CR) rate was 85.4% (58/68), with a 5.9% induction death rate. CNS prophylaxis was administered to 54 patients and was well tolerated. Fifty-seven patients proceeded to therapy in the intensification phase, which consisted of vincristine (VCR) 2 mg × 10 doses, L-asparaginase (l-asp) 12,500 IU/m2 weekly × 30 doses, doxorubicin 30 mg/m2 × 7 doses, 6-mercaptopurine, dexamethasone and methotrexate. Thirty-four patients completed this phase, while 18 patients had an abbreviated course of intensification before proceeding to alloSCT. Major side effects during the intensification phase included grade 3–4 neutropenia (63%), peripheral neuropathy (40%), thrombosis (17.5%) and central venous catheter infection (18.2%). Intensification was administered on an outpatient basis with 12/57 (21%) requiring hospitalization for any reason. Maintenance therapy was given to 32 patients and was well tolerated. At a median follow-up of 2.7 years (range, 0.05–5.8 years), both median overall survival (OS) and relapse free survival (RFS) were 4.9 years. Among non-transplanted patients (n=44), Kaplan-Meier 3-year OS and RFS were 65.5% and 77.3%, respectively with most deaths occurring in induction or from progressive leukemia in primary non-responders. For the entire group, younger age (〈 25 years) was associated with improved OS and RFS (p= 0.03) whereas bcr-abl positivity was not. Due to neuropathy, vinblastine (VBL) was substituted for VCR in 13/33 (39.4%) patients during intensification without affecting RFS and OS (p=0.22). Of the 34 patients who completed intensification without relapse, those who received 〉80% of the targeted l-asp dose had a significantly longer OS (p=0.02) and RFS (p=0.04). These results demonstrate the feasibility of administering the pediatric DFCI protocol to adults up to the age of 61 years with acceptable toxicity. As with the DFCI pediatric experience (Blood2001; 97(5): 1211-8), the ability to deliver 〉80% of the targeted l-asparaginase dose during the intensification phase appears to produce improved efficacy. Longer follow-up will be needed to further characterize the anti-leukemic efficacy of this regimen in adults.

Description: Abstract 1036 Poster Board I-58 Introduction: Consolidation chemotherapy is frequently administered on an outpatient basis in younger AML patients. However, the safety of this maneuver in older patients is unclear owing to increased co-morbidities and declines in performance status (PS) in these patients. Methods: 215 newly diagnosed AML patients aged 〉60 years were referred to Princess Margaret Hospital between 2002 and 2005. Of these, 108 received non-protocol treatments (32 non-intensive experimental therapy, 12 intensive chemotherapy on a study protocol, and 64 palliative therapy). The remaining 107 (50%) received standard induction chemotherapy with curative intent, consisting of cytarabine 100 mg/m2/day CIVI x 7 days and dauorubicin 60 mg/m2 IV daily x 3 (3+7). Patients achieving CR were eligible to receive two consolidations, with 3+7 (C#1) followed by mitoxantrone 10 mg/m2 daily x 5 plus etoposide 100 mg/m2 IV daily x 5 (C#2). All patients underwent cardiac assessment prior to each cycle with MUGA scan. If the ejection fraction (EF) dropped to 〈 50% or had fallen by 〉10%, amsacrine (100 mg/m2 IV daily x 5) was substituted for the anthracycline. Consolidation was administered on an inpatient or outpatient basis according to physician discretion. Inpatient consolidations were administered to patients judged to have significant co-morbidities and poor PS post-induction, while the remaining patients were given consolidation on an outpatient basis, with twice weekly monitoring until hematologic recovery. Oral antibiotic and antifungal prophylaxis was used. Febrile neutropenia (FN) was treated with inpatient IV broad-spectrum antibiotics. Results: The median age of patients was 68 years (range, 60-84). 59 of 107 pts (55%) achieved a CR and a further 5 patients a leukemia free state with induction chemotherapy. 55 patients achieving CR proceeded to consolidation therapy on protocol. 38/55 pts. (69%) received C#1 as outpatient; the rate of admission for FN in these patients was 45%. 39/55 pts (71%) went on to receive a second consolidation cycle. Reasons for attrition post-C#1 included medically unfit (6 pts), persistent aplasia (3) and relapse (4). 32/39 (82%) pts received C#2 as outpatient; the rate of admission for FN was 59%. There were no treatment related deaths during consolidation therapy. Among patients proceeding to consolidation, 35/55 (63%) had a significant decline in LVEF during, or at completion of, treatment: 〉10% drop in LVEF in 31 pts. and LVEF

Description: A strong link between asparaginase-containing (ase +) chemotherapy regimens and venous thrombotic events (VTE) has been established for pediatric acute lymphoblastic leukemia (ALL), but this association has not been studied in adult ALL. We recently adopted as our first-line therapy for adult ALL a treatment protocol (DFCI 00–01) that employs weekly high-dose ase throughout a 27 week intensification phase. We reviewed the records of 92 adult patients consecutively accrued at Princess Margaret Hospital (from Jan 2000 to Dec 2003) for venous thrombotic events (VTE). Median age at diagnosis of ALL was 41±17 y, or 19±3 y for those who presented after a history of pediatric ALL (n=6), and 42±16 y for adults who presented with de novo ALL (n=86). Thirty-five (37%) were female, 59 (63%) male. Twenty-four (26%) were Philadelphia-chromosome positive; 71% of these received regimens containing imatinib. At least 1 symptomatic, radiologically confirmed VTE was seen in 19 patients (21%), with 3 (3%) diagnosed prior to any antileukemic therapy. Overall survival (OS) versus thrombosis-free survival (TFS) is illustrated in the Kaplan-Meier curve below. Median time to VTE was 94±92 d [95% CI]. Average age of patients with VTE was 44 ±15y; no events were observed in patients with a prior pediatric history of ALL. The sites of VTE were: 10/22 (46%) in the lower extremities, 5/22 (23%) propagating from central venous access catheters (CVAC), 4/22 (18%) as pulmonary emboli (2 in isolation), and 3/22 (14%) CNS (2 cerebral venous sinus and 1 retinal venous thrombus). The first antileukemic regimen administered was DFCI 00–01 ± imatinib in 79/92 (86%), HyperCVAD ± imatinib in 7 (8%), an unclassified ase+ regimen in 1 (1%), or an unclassified asparaginase-excluding (ase−) regimen in 5 (5%). A significant difference in the rate of ase-dependent VTE was observed when all regimens (1° or subsequent) were counted, with 18 VTE during 103 ase+ regimens (17.5%), versus only 1 VTE in 32 ase− regimens (3.1%), [p=0.04]. Median time to VTE in DFCI 00-01was 109±98d, most often occurring during the intensification phase. The odds ratio for VTE with any T-cell subtype of ALL compared to any B-cell subtype was 4.6 [p=0.0043]. Conclusions : A high, significant VTE rate (~18%) was observed in adults with ALL undergoing ase+ antileukemic therapy, nearly 6X the rate observed either prior to treatment or during ase− regimens (~3%). Ase is thus strongly associated with VTE, warranting improved surveillance and antithrombotic prophylaxis. Risk factors (underlying thrombophilias, leukemic subtypes) similarly deserve further study. Figure Figure

Description: Background: Epigenetic silencing of genes has been documented in AML. This phase I trial evaluates the safety, tolerability, and maximum tolerated dose (MTD) of two schedules of administration of the hypomethylating agent decitabine in combination with the pan-selective histone deacetylase inhibitor vorinostat. Methods: Patients receive escalating doses of oral vorinostat administered either sequentially [100 mg bid (n=4), 200 mg bid (n=4), or 200 mg tid (n=8) Days 6–21] or concurrently [100 mg (n=3) or 200 mg (n=6) bid Days 1–21 or 200 mg tid (n=2) Days 1–14] with decitabine (20 mg/m2/d IV Days 1–5) every 28 days. Results: Twenty-seven patients with AML have been treated. Median age was 67 years (range, 32–82 years). Median ECOG status 1 (range, 0 to 2). Eighteen patients (67%) had received prior therapy (median, 1 regimen; range, 0 to 4 regimens); 3 had received a prior allogeneic stem cell transplant. A total of 85 cycles have been administered, with a median of 2 cycles (range, 1 to 13 cycles); 10 patients (37%) have received 3 or more cycles of therapy. One of 7 patients treated at dose level 3 of the sequential schedule developed dose-limiting toxicities (DLT), consisting of grade 3 fatigue, weakness, and mucositis. Therefore, the MTD was not reached in the 3 planned dose levels of the sequential schedule. One DLT (grade 3 fatigue) occurred in 6 patients treated at dose level 2 of the concurrent schedule. Most common drug-related non-hematological toxicities of any grade (all CTCAE grades 1 or 2) were nausea (71%), fatigue (54%), diarrhea (54%), vomiting (42%), anorexia (25%), constipation (13%), abdominal pain (13%), dehydration (13%), and headache (13%). No other non-hematological grade 3 or 4 toxicities were observed. Of the 25 evaluable patients, one patient achieved an incomplete CR (without neutrophil recovery), one a morphologic leukemia-free state (without blood count recovery), and three partial remissions (1 achieved red cell transfusion independency and a second normalization of platelet counts). Seven of these patients remain on study for 2.7 to 13.5+ months. Correlative studies examining histone acetylation and gene promoter methylation in leukemic cells at baseline and after treatment, as well as plasma pharmacokinetic levels for both decitabine and vorinostat are being evaluated. Conclusions: The combination of decitabine and vorinostat is safe, well-tolerated, and has clinical activity in patients with AML. Enrollment is ongoing.

Description: Introduction: Mutations localized in the tyrosine kinase domain activation loop of FLT3 (FLT3-TKD), representing point mutations in codon D835/I836 and rarely deletions of codon I836, 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, particularly in the presence of NPM1 mutations, is not well established. The phase 3 RATIFY trial [NCT00651261; Stone et al. N Engl J Med. 2017] showed that in combination with standard chemotherapy, midostaurin (PKC412) improved survival outcomes across all 3 FLT3 stratification subgroups (ITD high allelic ratio [≥ 0.7], ITD low allelic ratio [〈 0.7], and TKD) vs placebo in patients with newly diagnosed FLT3-mutated AML. Here, we evaluated the prognostic impact of FLT3-TKD and NPM1 mutations in a post hoc analysis from the RATIFY trial. Methods: In RATIFY, newly diagnosed patients with AML 18-60 years old were randomly assigned to receive midostaurin or placebo together with standard induction and consolidation therapy followed by 12 28-day cycles of maintenance therapy with midostaurin or placebo. FLT3-TKD mutation was detected by PCR and capillary electrophoresis at 9 reference laboratories. Patients 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 have not been adjusted for multiplicity. Results: Of the total randomized 162 FLT3-TKD patients, 134 with available NPM1 data had consented for exploratory analysis and thus were included in this study (see Table for subgroup distribution). Overall, 47.8% of patients were male, and the median age was 49 years (95% CI, 45.5-51.1 years). The median white blood cell (WBC) count was higher in patients with NPM1-mut than in patients with NPM1-WT (34.1 vs 15.5 × 109/L, P = .0011). CR rates (during the first 60 days) were higher in patients with FLT3-TKD/NPM1-mut vs FLT3-TKD/NPM1-WT (66% vs 53%); however, this was driven by the higher rate of CR in the midostaurin arm (76% NPM1-mut vs 44% NPM1-WT) rather than the placebo arm (53% NPM1-mut vs 60% NPM1-WT). The overall CR rate (regardless of NPM1 genotype) was 64% for midostaurin and 56% for placebo in FLT3-TKD patients. The prognostic effect of the NPM1 mutation concurrent with FLT3-TKD was seen for all endpoints consistently with hazard ratios (HRs) around 0.50 or lower (Figures 1 and 2 and Table). Overall (regardless of treatment) OS, EFS, and DFS estimates at 3 years were 73% vs 52%, 48% vs 25%, and 74% vs 47%, respectively, in patients with FLT3-TKD/NPM1-mut vs FLT3-TKD/NPM1-WT. Whereas the HRs for midostaurin vs placebo were 0.73 for both OS and EFS, the impact of treatment on outcomes varied between the individual NPM1/TKD subgroups and was not consistently observed when endpoints were censored at stem cell transplant (SCT) (Table). It should be noted that the number of patients in each subgroup was small and therefore the HRs with 95% CIs should be interpreted with caution. Multivariate analyses in these FLT3-TKD patients revealed that NPM1 genotype was an independent prognostic factor for OS, EFS and DFS (2-sided P 〈 .05), whereas study drug, age, sex, WBC at baseline and SCT (no/yes) did not reach this level of significance in the Cox model. Conclusions: This post hoc analysis of the FLT3-TKD patient subset in the RATIFY trial showed the high prognostic value of NPM1 mutational status. Whereas midostaurin showed an overall benefit in the FLT3-TKD patients for OS, EFS, CR and DFS, the impact of treatment on outcome varied between the individual NPM1 subgroups within these FLT3-TKD patients and was not consistently observed.Further analyses using additional endpoints and additional multivariate analyses are planned. Support: U10CA180821, U10CA180882, U10CA180820, U10CA180791, U10CA180888, U10CA180863, (CCSRI) #704970, U24CA196171; ClinicalTrials.gov Identifier: NCT00651261 Disclosures Voso: Celgene: Research Funding, Speakers Bureau. Larson:Ariad/Takeda: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; BristolMyers Squibb: Consultancy, Research Funding. Heuser:Janssen: Consultancy; Pfizer: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; StemLine Therapeutics: Consultancy; Astellas: Research Funding; BergenBio: Research Funding; Karyopharm: Research Funding; Bayer Pharma AG: Consultancy, Research Funding; Tetralogic: Research Funding; Sunesis: Research Funding; Daiichi Sankyo: Research Funding. Wei:Novartis: Honoraria, Other: Advisory committee, Research Funding, Speakers Bureau; Pfizer: Honoraria, Other: Advisory committee; Amgen: Honoraria, Other: Advisory committee, Research Funding; Abbvie: Honoraria, Other: Advisory board, Research Funding, Speakers Bureau; Servier: Consultancy, Honoraria, Other: Advisory committee, Research Funding; Celgene: Honoraria, Other: Advisory committee, Research Funding. Brandwein:Lundbeck: Consultancy; Celgene: Consultancy; Pfizer: Consultancy; Novartis: Consultancy; Boehringer Ingelheim: Consultancy, Research Funding. de Witte:Novartis: Research Funding; Amgen: Consultancy, Research Funding; Celgene: Honoraria, Research Funding. Medeiros:Celgene: Consultancy, Research Funding; Genentech: Employment. Tallman:Cellerant: Research Funding; Orsenix: Other: Advisory board; BioSight: Other: Advisory board; ADC Therapeutics: Research Funding; AROG: Research Funding; AbbVie: Research Funding; Daiichi-Sankyo: Other: Advisory board. Schlenk:Pfizer: Research Funding, Speakers Bureau. Ganser:Novartis: Membership on an entity's Board of Directors or advisory committees. Cheng:Novartis: Employment. Gathmann:Novartis: Employment. Tiecke:Novartis: Employment. Thiede:AgenDix: Other: Ownership; Novartis: Honoraria, Research Funding. Döhner:AbbVie: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria; Celator: Consultancy, Honoraria; Sunesis: Consultancy, Honoraria, Research Funding; Bristol Myers Squibb: Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria; AROG Pharmaceuticals: Research Funding; Sunesis: Consultancy, Honoraria, Research Funding; Astellas: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; AROG Pharmaceuticals: Research Funding; Celator: Consultancy, Honoraria; Astex Pharmaceuticals: Consultancy, Honoraria; Bristol Myers Squibb: Research Funding; Agios: Consultancy, Honoraria; Agios: Consultancy, Honoraria; Astellas: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Astex Pharmaceuticals: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Jazz: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Jazz: Consultancy, Honoraria; Pfizer: Research Funding; Pfizer: Research Funding; Novartis: Consultancy, Honoraria, Research Funding. Stone:Otsuka: Consultancy; Argenx: Other: Data and Safety Monitoring Board; Amgen: Consultancy; Agios: Consultancy, Research Funding; Orsenix: Consultancy; Ono: Consultancy; Novartis: Consultancy, Research Funding; Astellas: Consultancy; Arog: Consultancy, Research Funding; Merck: Consultancy; Cornerstone: Consultancy; Fujifilm: Consultancy; Jazz: Consultancy; Celgene: Consultancy, Other: Data and Safety Monitoring Board, Steering Committee; Pfizer: Consultancy; Sumitomo: Consultancy; AbbVie: Consultancy.

Description: Background: Midostaurin (M) is a multi-targeted small molecule FLT3 inhibitor which has single agent activity in both internal tandem duplication (ITD) and tyrosine kinase domain (TKD) mutant FLT3 AML. The objective of this global rand phase III trial was to determine if the addition of M to ind and consol therapy followed by one year of maint would improve overall survival (OS) compared to standard chemotherapy in younger adults with activating FLT3 muts. Methods: Between May 2008 and October 2011, 3279 previously untreated AML pts age 18-60 (exclusive of acute promyelocytic leukemia) in 225 sites/17 countries were screened for FLT3 muts at one of 7 academic labs (subject to extensive assay cross-validation). Hydroxyurea was allowed for up to 5 d prior to beginning ind therapy while awaiting results of mut testing. Pts were rand for the duration of therapy to M or P stratified by FLT3 mut subtype (TKD v ITD high allelic mut fraction (〉0.7) vs low mut fraction (0.05-0.7). Ind therapy consisted of D 60 mg/m2 IV d1-3 and C 200 mg/m2 d1-7 CIV plus M or P (50 mg po bid, d 8-22). Re-treatment with a second blinded course was allowed if residual AML was noted on a d 21 marrow exam. Pts achieving complete remission (CR) received 4 cycles of C 3g/m2 over 3h q 12h on days 1, 3, and 5 plus M or P (50 mg po bid, d 8-22) followed by a year of maint therapy with M or P (50 mg po bid). Transplantation (SCT) was allowed. With a sample size of 717 pts, the trial was powered to detect an improvement from 16.3 (P) to 20.9 (M) months in median OS (HR = 0.78) using a one-sided alpha of 0.025 and power of 84%. The final analysis was to occur after 509 deaths, but given the slow rate of events (359 deaths by April 2015), the trial was amended to change the timing of the OS analysis, and promote event free survival (EFS, defined as the earliest of death, relapse, or no CR within 61 d of the start of ind) as a key secondary endpoint. The critical value for this primary analysis is set at 0.02286 (1-sided) accounting for the alpha spent at the interim analysis (0.5%). Support: U10CA180821, U10CA180882, CA31946, Novartis Results: 717 pts (341 FLT3 ITD-Low, 214 FLT3 ITD-High; 162 FLT3 TKD) were rand to either M (n=360) or P (n=357). There were no significant differences between the arms in age (median, 48y), race, FLT3 subtype, or baseline CBC except for gender (M, 48.2% male; P, 40.6% male; p=.04). All pts are off active treatment, with a median follow-up of 57 months for surviving pts. No statistically significant differences were observed in the overall rate of grade 3 or higher hematologic or non-hematologic adverse events (AEs) between M and P (regardless of attribution). A total of 37 grade 5 AEs were reported (M, 5.3%; P, 5.0%; p=1.0). No differences in treatment-related grade 5 AEs were observed (M, 3.1%; P, 2.5%; p=0.82). CR rate is 59% (M) and 54% (P) (p=0.18). The HRs comparing M to P for OS is 0.77 (one-sided p = 0.007; Figure 1), and for EFS is 0.80 (one-sided p = 0.004; Figure 2). 402/717 (57%) pts received an allogeneic SCT (M, 58%; P, 54%) at any time; 177/717 (25%) in CR1 (M, 27%; P, 22%). Median time to allogeneic SCT was similar on each arm (M, 5.0 months; P, 4.6; p=0.23). Secondary analyses for OS and EFS censoring at the time of SCT provided similar results (Table). The benefit of M was consistent across all FLT3 subgroups for both EFS and OS (Figure 3). Conclusions: The C10603 trial demonstrated that a prospective trial in a pre-therapy genetically defined subgroup of AML pts was feasible and that the addition of the multi-kinase inhibitor M to standard chemotherapy and for one year of maint therapy significantly improved EFS and OS (in both uncensored and censored for transplant analyses) in pts whose blasts had a TKD or ITD (low or high FLT3 mut burden). These findings may lead to improved outcomes through the use of M as a component of therapy in younger adults with mutant FLT3 AML. Table.ArmMedian, mos (95% CI)p-value 15-year Event rate% (95% CI)HR2(95% CI)OSM74.7 (31.5, * )0.00750.8 (45.4-55.9)0.77 (0.63, 0.95)P26.0 (18.5, 46.5)43.1 (37.6-48.4)OS, SCT censoredM* (*,*)0.04762.6 (54.6-69.7)0.77 (0.56,1.05)P* (36.9, *)54.9 (46.2-62.8)EFSM8.0 (5.3, 10.6)0.004426.7 (22.2-31.5)0.80 (0.67, 0.95)P3.0 (1.9, 5.8)19.1 (15.1-23.6)EFS, SCT censoredM8.2 (5.5, 10.7)0.02524.2 (18.9-29.8)0.84 (0.70, 1.0020)P3.0 (1.9, 5.8)21.8 (16.8-27.3)1Stratified on FLT3 subtype; one-sided, log-rank p-value.2Cox model stratified on FLT3 subtype.*= not attained Figure 1. Figure 1. Figure 2. Figure 2. Figure 3. Figure 3. Disclosures Stone: Celgene: Consultancy; Sunesis: Consultancy, Other: DSMB for clinical trial; Novartis: Research Funding; Amgen: Consultancy; Agios: Consultancy; Roche/Genetech: Consultancy; Merck: Consultancy; Pfizer: Consultancy; AROG: Consultancy; Celator: Consultancy; Juno: Consultancy; Abbvie: Consultancy; Karyopharm: Consultancy. Off Label Use: midostaurin- FLT 3 inhibitor. Thiede:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AgenDix GmBH: Equity Ownership. Niederwieser:Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Medeiros:Celgene: Honoraria, Research Funding; Agios Pharmaceuticals: Honoraria. Schlenk:Daiichi Sankyo: Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Research Funding; Arog: Honoraria, Research Funding; Teva: Honoraria, Research Funding; Boehringer-Ingelheim: Honoraria; Janssen: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Research Funding. Larson:Novartis: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy; Ariad: Consultancy, Research Funding; Pfizer: Consultancy.

Description: Obatoclax antagonizes the BH3-binding groove of the bcl-2 family of anti apoptotic proteins. It is active in chronic lymphocytic leukemia(CLL; O’Brien et al, ASH 2005) with a recommended phase II dose of 28 mg/m2 given over 3 h every 3 weeks with DLT of grade 3 infusional CNS toxicities. We evaluated prolonged infusions to minimize these toxicities while maintaining clinical activity. An initial trial established a Phase II dose of 28 mg/m2 over 24 h every 2 weeks with dose limiting toxicities (DLTs) at 40 mg/m2 and responses in 4/8 MDS patients (Borthakur et al., ASH 2006). We report on 21 patients who received obatoclax 20–28 mg/m2/24 h weekly (n=9) or 20 mg/m2/24 h for 2, 3 or 4 consecutive days every 2–3 weeks (n=12). The final dose level of 28 mg/m2/24 h for 4 days is now open. Median age was 61 (range 26–75) and 11 patients were male. Diagnoses included: acute myelogenous leukemia (AML; 13), myelodysplastic syndromes (MDS; 6), acute lymphocytic leukemia (ALL; 1) and CLL (1). A total of 180 infusions of 24 h were administered. The most common adverse events (AE) were euphoric mood (57%), fatigue (57%), febrile neutropenia (43%), gait disturbance (43%), chills (33%), diarrhea (33%), nausea (33%), somnolence (33%), dizziness (29%). All were of Grades 1–2 with the exception of 7 grade 3 AEs of febrile neutropenia (unrelated to obatoclax administration) and 1 each of diarrhea, fatigue and gait disturbance. There were no DLTs. Multiple day infusions were well tolerated; for the 20 mg/m2/24 h x 4days dose level, 4/6 patients received ≥ 4 cycles, with two ongoing at this time. Plasma concentrations of obatoclax reached a steady state before end of infusion. Mean Cmax values at 20 mg/m2/24 h during1x24, 2x24, 3x24,4x24 h, and 28 mg/m2/24 h during 1x24 h infusions was 15.3, 8.4, 10.1, 15.7 and 10.8 ng/mL, respectively. The mean AUC(0–tlast) values at 20 mg/m2/24 h associated with 1x24, 2x24, 3x24, 4x24 h, and 28 mg/m2/24 h associated with 1x24 h infusions were 264.3, 396.9, 624.3, 1109.3 and 211.1 ng · hr/mL, respectively, increasing as expected with the duration of the infusion. One patient with treatment-related AML with a t(9;11)(p22;q23) translocation achieved a cytogenetic complete response (CR) with complete hematological recovery and transfusion independence on Day 9 following the start of weekly 24 h infusions of obatoclax. This CR was sustained 〉 8 months while the patient received a total of 35 weekly infusions of 20 mg/m2 without cumulative toxicities. Conclusions: obatoclax can be administered by prolonged infusions without eliciting novel or cumulative toxicities. The dramatic response observed in a patient with AML with immediate recovery of peripheral blood counts supports that the cytotoxic effects of obatoclax are specific to malignant cells while sparing normal bone marrow, as did our earlier reports of improvement in cytopenias in patients with MDS and CLL. The infusional schedules described here will be attractive to combine with standard chemotherapy regimens for AML and other indications to improve treatment outcomes where they may be limited by overexpression of Bcl-2 family members.