ALBERT

Description: Background: Because infections are a major cause of morbidity and mortality after AML induction chemotherapy, patients typically remain hospitalized for monitoring and rapid antimicrobial therapy until hematopoietic recovery. With declining early mortality and improved oral antimicrobials, interest in moving post-induction care to the outpatient setting has emerged. In the 5-year period since completing a prospective phase 2 trial evaluating an Early Hospital Discharge (EHD) strategy, EHD following AML-like induction chemotherapy has become routine at our institution. In recent retrospective analyses, we found 〉80% of EHD patients required hospital readmission, primarily for neutropenic fever. Still, the EHD strategy was safe and reduced healthcare resource utilization, and EHD patients spent 〉70% of their post-chemotherapy time as outpatients. Here, we investigated differences in the pattern of infectious complications between patients managed as outpatients following induction chemotherapy and those who remain hospitalized until hematopoietic recovery. Methods: We retrospectively identified all adults ≥18 years with untreated AML/high-grade myeloid neoplasms (≥10% blasts in blood/ bone marrow) who started intensive induction chemotherapy ("7+3" or a regimen of similar/higher intensity) at our institution from 8/1/2014-7/31/2018. Patients were considered "EHD" if they were discharged from the hospital

Description: Key Points CMV reactivation after HCT is associated with a reduced risk of early relapse in patients with AML but not other disease groups. The benefit, however, is offset by an increased risk of nonrelapse mortality.

Description: Abstract 2191 Background: Treatment protocols for newly diagnosed AML typically use age (often 60 years) alone to restrict eligibility to either younger or older patients. Implied in this practice is the assumption that age is the principal predictor of therapeutic failure in AML due to either early treatment-related mortality (TRM) or resistance to therapy in patients who do not incur TRM. Yet, clinical observation and previous studies indicate that other prognostic factors modulate the effect of age on TRM and resistance, suggesting that age as sole or primary criterion for treatment allocation may be suboptimal. Methods: To test this hypothesis in newly-diagnosed non-APL AML, we quantified the relative effects of age and other covariates using 1,127 patients (median age: 57 years) treated on Southwest Oncology Group (SWOG) trials from 1986–2009 and 1,604 patients (median age: 61 years) treated on various protocols at M.D. Anderson Cancer Center (MDA) from 2000–2008. We calculated weekly hazard rates (the probability of death in week × given that the patient was alive at the beginning of the week) for both cohorts overall and in various age subgroups. We used the area under the receiver operator characteristic curve (AUC) to quantify the effects of covariates for prediction of TRM and resistance (no TRM but patient does not enter CR or relapses within 1 year of CR), where an AUC of 1 indicates that a covariate is perfect at prediction while an AUC of 0.5 indicates no prediction (i.e. it is no better than flipping a coin). Results: Despite the use of different treatment protocols, survival in the SWOG and MDA cohorts was virtually superimposable. In both cohorts, the maximum weekly hazard occurred at weeks 3 and 4 from start of treatment, after which it decreased. The maximum hazard was relatively independent of age and remained between weeks 3 and 5 in patients age 70 years, respectively. The existence of such a discrete cut-point suggested that patients who die early are qualitatively distinct and prompted us to examine the relative effect of age and other covariates in patients who (a) died within the first 30 days of treatment (our empirically-based definition of TRM, 9% of MDA and 12 % of SWOG patients, respectively) and (b) survived at least 30 days but did not enter complete remission or relapsed within 1 year (“resistant”, 43% of MDA and 59% of SWOG patients, respectively). A model including age alone to predict early mortality had an AUC of 0.67, while a model including performance status (PS) alone had an AUC of 0.72. By comparison, a more refined model hat included PS, age, platelet count, cytogenetics, secondary AML, albumin, white blood cell count, peripheral blood blast count, and LDH yielded an AUC of 0.86. Elimination of age resulted in a model with an AUC that was only minimally lower (0.85). Prediction of resistance was more difficult with a model including age, secondary AML, cytogenetics, peripheral blood blasts, race, hemoglobin, and marrow neutrophils giving an AUC of only 0.70. Elimination of age had little effect (AUC 0.67) while age alone gave an AUC of 0.64. Conclusion: Age alone appears inadequate in predicting resistance and particularly TRM. The use of models based on several covariates improves predictive ability, but the ability to predict resistance is still limited, suggesting the value of randomized trials to assess treatment designed to reduce resistance. The observation that elimination of age has little effect on the predictive ability of such models, suggests that age is primarily a surrogate for other covariates. Disclosures: No relevant conflicts of interest to declare.

Description: Background Post-remission therapies for patients with AML such as high-dose cytarabine (HiDAC) and allogeneic stem cell transplant (alloSCT) have led to improved outcomes for younger patients, but disease recurrence remains prevalent with ~40% 5-year OS. CD33 is a cell surface receptor expressed in ~90% of AML, representing a promising target for therapy. Vadastuximab talirine (33A) is a CD33-directed antibody conjugated to 2 molecules of a pyrrolobenzodiazepine (PBD) dimer. Methods This phase 1b dose-escalation study (NCT02326584) evaluates the safety and anti-leukemic activity of 33A in combination with consolidation therapy (HiDAC) or as a single agent for maintenance therapy. AML patients (ECOG status 0-1) must be in 1st remission (CR or CRi) after standard induction therapy and be able to receive HiDAC (consolidation cohort) or be in 1st remission and have completed planned post-remission therapies, either chemotherapy and/or alloSCT (maintenance cohort). For maintenance post-alloSCT, patients were between Day 60 and 100 post-transplant without significant GVHD. Prior to HiDAC administration (3 gm/m2 q12h Day 1, 3, 5), 33A is given on Day 1 for up to 4 cycles (28-day cycle). For maintenance therapy, 33A is given as a single agent on Day 1 for up to 8 cycles (6-wk cycle). Results Consolidation cohort: 21 patients (57% male) with a median age of 52 years (range, 21-64) were treated with 5, 10, or 20 mcg/kg of 33A with HiDAC. Patients received a median of 2 cycles (range, 1-4). As anticipated, all patients experienced Grade 4 myelosuppression. At 20 mcg/kg, 1 DLT (lack of recovery of platelets [25K] and/or ANC [500] by Day 42) occurred in Cycle 1. At 10 mcg/kg, no DLTs were observed but delay of subsequent cycles of treatment occurred in 4 of 10 patients, primarily due to thrombocytopenia. No DLTs were observed in the 8 patients treated at 5 mcg/kg and 1 non-hematologic-related dose delay was reported (otitis externa). Non-hematologic treatment-emergent adverse events (AE) in ≥25% of patients regardless of relationship included nausea (38%) and fatigue (33%). No infusion-related reactions (IRRs) or events of veno-occlusive disease were reported. The 30- and 60-day mortality rates were 0%. Of the 19 efficacy evaluable patients, 15 (79%) have maintained remission, 18 patients are alive and 3 patients (14%) remain on treatment. Reasons for treatment discontinuation were completion of planned consolidation therapy (38%), AE (thrombocytopenia, 14%), leukemic relapse (5%), and other non-AE (29%). Nine patients (43%) went on to receive an alloSCT. Maintenance cohort: 22 patients (41% male) with a median age of 45.5 years (range, 23-71) have been treated with 5 mcg/kg of 33A. Patients were a median of 6.2 months from diagnosis (range, 3.4-21.5); 12 patients completed chemotherapy-based treatment alone and 10 patients completed standard chemotherapy with an alloSCT in 1st remission. Patients received a median of 3 cycles (range, 1-6); no DLTs were reported. AEs reported in ≥15% of patients were fatigue (41%), neutropenia (41% [36% ≥G3]), nausea (36%), thrombocytopenia (36% [27% ≥G3]), diarrhea, dyspnea, headache, and vomiting (18% each); no IRRs were observed. Of the 20 efficacy evaluable patients, 15 (75%) have maintained remission. Reasons for treatment discontinuation were AEs (41%, primarily myelosuppression), leukemic relapse (14%), completion of planned therapy (9%), and other non-AE reasons (19%); 4 patients (18%) remain on treatment. Median OS is not yet reached and 19 patients are alive. Pharmacokinetic data in patients receiving post-remission therapy with 33A demonstrate that exposure appears to be greater than in patients with active disease, possibly due to a decrease in target-mediated disposition. Conclusions 33A can be safely administered in combination with HiDAC and as monotherapy in the post-remission setting. In combination with HiDAC, non-hematologic toxicities of 33A were consistent with effects reported with HiDAC alone. As a single agent, 33A administered as maintenance post-chemotherapy and/or alloSCT results in predictable on-target myelosuppression, with mild non-hematologic adverse effects. Disclosures Yang: Seattle Genetics: Research Funding. Ravandi:Seattle Genetics: Consultancy, Honoraria, Research Funding; BMS: Research Funding. Advani:Seattle Genetics: Consultancy, Research Funding. Walter:Emergent Biosolutions: Consultancy; Seattle Genetics: Research Funding; CSL Behring: Research Funding; Celator Pharmaceuticals: Research Funding; Amgen: Research Funding; Abbvie: Research Funding; Pfizer: Consultancy; Amphivena Therapeutics, Inc.: Consultancy, Research Funding; Astra-Zeneca: Consultancy; Covagen AG: Consultancy; Agios: Consultancy; Arog: Research Funding. Faderl:Seattle Genetics: Research Funding; Pfizer: Research Funding; Astellas: Research Funding; Celator Pharmaceuticals: Research Funding; BMS: Research Funding; Ambit Bioscience: Research Funding; Karyopharm: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; JW Pharma: Consultancy; Amgen: Speakers Bureau. Stein:Seattle Genetics: Research Funding; Amgen: Consultancy, Research Funding, Speakers Bureau; Stemline Therapeutics: Consultancy, Research Funding; Argios: Research Funding; Celgene: Research Funding. Erba:Celgene: Consultancy, Speakers Bureau; Amgen: Consultancy, Research Funding; Agios: Research Funding; Pfizer: Consultancy; Novartis: Consultancy, Speakers Bureau; Juno: Research Funding; Jannsen: Consultancy, Research Funding; Ariad: Consultancy; Millennium Pharmaceuticals, Inc.: Research Funding; Astellas: Research Funding; Incyte: Consultancy, DSMB, Speakers Bureau; Seattle Genetics: Consultancy, Research Funding; Gylcomimetics: Other: DSMB; Daiichi Sankyo: Consultancy; Sunesis: Consultancy; Celator: Research Funding. Fathi:Agios Pharmaceuticals: Other: Advisory Board participation; Seattle Genetics: Consultancy, Other: Advisory Board participation, Research Funding; Merck: Other: Advisory Board participation; Celgene: Consultancy, Research Funding; Bexalata: Other: Advisory Board participation. Levy:Amgen: Speakers Bureau; Jansen: Speakers Bureau; Millennium: Speakers Bureau; Seattle Genetics: Research Funding. Wood:Pfizer: Honoraria, Other: Laboratory Services Agreement; Amgen: Honoraria, Other: Laboratory Services Agreement; Juno: Other: Laboratory Services Agreement; Seattle Genetics: Honoraria, Other: Laboratory Services Agreement. Feldman:Seattle Genetics: Employment, Equity Ownership. Voellinger:Seattle Genetics: Employment, Equity Ownership.

Description: Survival expectations for acute myeloid leukemia (AML) patients remain poor, highlighting the need for further treatment options. The majority of AML blasts express CD123, the alpha subunit of the IL-3 receptor, which regulates the proliferation, survival and differentiation of hematopoietic cells. CD123 is also robustly expressed on leukemic stem cells and is a marker for minimal residual disease (MRD, Roug et al. 2012). Poor prognosis has previously been associated with elevated expression of CD123 on leukemic stem cells and blasts (Vergez et al. 2011, Testa et al. 2002). These findings identify CD123 as a rational therapeutic target in AML. Here we report the preclinical development of a novel CD123-directed immunoconjugate SGN-CD123A, consisting of a humanized anti-CD123 antibody conjugated to a highly potent DNA binding pyrrolobenzodiazepine (PBD) dimer drug via a protease-cleavable dipeptide linker. An engineered cysteine on each heavy chain attaching the PBD dimer to the antibody allows uniform drug loading of approximately two PBD dimers per antibody. Fluorescence microscopy studies show that SGN-CD123A is rapidly internalized and traffics to lysosomes within hours of binding to CD123-positive AML cells. Uptake of the antibody-drug-conjugate (ADC) induced DNA damage as measured by dose-and time-dependent increases in the phosphorylation of histone 2AX (γH2AX) and cell death associated with G2-M cell cycle arrest, caspase-3 activity, formation of cleaved poly ADP-ribose polymerase, and DNA fragmentation in target cells. The anti-leukemic activity of SGN-CD123A was assessed in cytotoxicity assays in 12 AML cell lines and 23 primary AML patient samples with variable cytogenetic abnormalities (favorable, intermediate and adverse) and multi-drug resistance (MDR) status. SGN-CD123A was highly active in 11 of 12 AML cell lines tested (mean IC50, 6 ng/ml; range of 0.02 to 38 ng/ml), including 4 of 5 MDR-positive cell lines, whereas it was inactive in CD123-negative HEL92.1.7 AML cells. SGN-CD123A was also active against 20 of 23 primary samples isolated from AML patients (mean IC50 of responsive samples, 0.8 ng/mL; range of 0.06 to 2.5 ng/ml). In both AML panels, molecular abnormalities, including the presence of a p53 mutation, FLT3-ITD, as well as MDR positivity, did not affect the in vitro cytotoxic activity of SGN-CD123A. In vivo antitumor activity was evaluated in AML xenograft models established with CD123-positive, MDR-negative Molm-13, HNT-34, and THP-1 cell lines and the MDR-positive KG-1 cell line. In all of the in vivo models, a single dose of SGN-CD123A delivered significant antitumor activity. SGN-CD123A dosed once at 10 mcg/kg yielded complete cures and significant survival advantage in the Molm-13 disseminated model of AML (p 〈 0.0001 compared to untreated or control ADC groups). Durable complete regressions were observed with a single dose of 25 or 75 mcg/kg in the MDR-negative HNT-34 subcutaneous model (p =0.0019 to control ADC group). In the THP-1 model, a single 100 mcg/kg dose of SGN-CD123A yielded durable complete regressions in 2 of 8 mice (p=0.0003 to untreated) whereas a higher dose of 300 mcg/kg gave complete tumor regressions in all mice (p 〈 0.0001 to untreated group). SGN-CD123A was also effective in a MDR-positive model of AML. A single dose of 100 mcg/kg SGN-CD123A significantly decreased tumor growth (p=0.003 to controls) whereas a single dose of 300 mcg/kg yielded durable complete regressions compared to the control groups in the KG-1 subcutaneous model of MDR-positive AML (p =0.008). Early evidence of the antitumor activity of SGN-CD123A was found in tumors harvested from THP-1 mice. Within 48h of dosing with SGN-CD123A, tumor cells showed elevated levels of the DNA damage marker γH2AX and changes in nuclear morphology. These data demonstrate that SGN-CD123A exhibits significant antitumor activity against a broad panel of primary AML samples and in preclinical models of MDR-positive AML that are characteristically resistant to chemotherapy. CD123-directed delivery of PBD may represent a promising new approach for the treatment of AML. Disclosures Sutherland: Seattle Genetics, Inc.: Employment. Yu:Seattle Genetics, Inc: Employment, Equity Ownership. Walter:Seattle Genetics, Inc: Consultancy, Research Funding. Westendorf:Seattle Genetics, Inc: Employment. Valliere-Douglass:Seattle Genetics, Inc: Employment. Pan:Seattle Genetics, Inc: Employment. Sussman:Seattle Genetics, Inc: Employment. Anderson:Seattle Genetics, Inc: Employment. Zeng:Seattle Genetics, Inc: Employment. Stone:Seattle Genetics, Inc: Employment. Klussman:Seattle Genetics, Inc: Employment. Ulrich:Seattle Genetics, Inc: Employment. Jonas:Seattle Genetics, Inc: Employment. Senter:Seattle Genetics, Inc: Employment. Drachman:Seattle Genetics, Inc: Employment. Benjamin:Seattle Genetics, Inc: Employment.

Description: Background: Optimal treatment for medically less fit adults with acute myeloid leukemia (AML) remains uncertain. Retrospective data suggest intensive therapy may lead to better outcomes in these patients. However, these findings must be interpreted cautiously because of the possibility of selection bias and other confounders. Ideally, the optimal treatment intensity is defined via randomized trial but whether patients and their physicians are amenable to such a study is unknown. We therefore designed a trial (NCT03012672) to 1) evaluate the feasibility of randomization between intensive and non-intensive therapy in this population and 2) examine the impact of treatment intensity on response rate and survival. We used CLAG-M as high-dose cytarabine-based intensive induction therapy. Rather than selecting different classes of drugs in the 2 treatment arms- which may have different modes of action and therefore confound the question of treatment intensity - we used reduced-dose ("mini") CLAG-M as the non-intensive comparator. Methods: Adults ≥18 years were eligible if they had untreated AML or high-grade myeloid neoplasms (≥10% blasts in blood or marrow) and were medically less fit as defined by having a "treatment related mortality" (TRM) score of ≥13.1, corresponding to a 〉10-15% 28-day mortality with intensive chemotherapy. Left ventricular ejection fraction ≤45% was the only organ function exclusion. Patient-physician pairs were first asked if they were amenable to randomized treatment allocation. If so, they were randomized 1:1 to mini- vs. regular-dose CLAG-M. If not, in order to evaluate our secondary endpoints, the patient or physician could choose the treatment arm and still enroll on study. Patients and physicians then completed surveys elucidating their decision-making processes. Up to 2 induction courses were given with mini- vs. regular-dose CLAG-M: cladribine 2 or 5 mg/m2/day (days 1-5), cytarabine 100 or 2,000 mg/m2/day (days 1-5), G-CSF 300 or 480µcg/day for weight

Description: Introduction: Many patients with newly diagnosed acute myeloid leukemia (AML) or myelodysplastic syndrome with 10-19% blasts (MDS-EB2) do not enter complete remission (CR) following initial induction chemotherapy. At an academic referral center, such patients often stay to receive additional treatment, or return to their home communities for further care. For patients and providers alike, the decision about whether to stay or go after initial treatment failure is often fraught. To better inform such decision-making, in this retrospective single-center analysis, we compared covariate-adjusted survival for patients who elected to stay for further treatment at our center and those who returned to their home communities for subsequent care. Methods: We included adults ≥ age 18 years of age with newly-diagnosed AML or MDS-EB2 treated at our institution between January 2012 and May 2018 who failed to enter CR (〈 5% morphologic bone marrow blasts) or CR with incomplete hematologic recovery (CRi) after their first cycle of induction chemotherapy. We excluded patients who died before they could begin re-induction therapy. Patients who stayed at our institution for additional treatment are referred to as the "stay" group (n=86); patients who left are considered the "go" group (n=35). Multivariable Cox regression analysis was used to account for other measured covariates possibly influencing survival. Results: The go group was older and had a higher median treatment-related mortality (TRM) score (Table 1), the latter predictive of the probability of death within the first 28 days of initial induction therapy. Forty-seven percent of stay patients received high-intensity re-induction (containing cytarabine at individual doses ≥1g/m2) while 50% received low-intensity treatment (e.g. azacitidine, decitabine, or low-dose cytarabine). Twenty-nine percent of go patients received treatment (mostly low-intensity) in the community setting, while 63% received supportive care only. The stay patients had a median of 2 subsequent hospitalizations (range 0-12) and spent a median of 27 days hospitalized after initial treatment failure (range 0-124). Survival was longer in the stay group compared to the go group (median 8.3 vs. 1.8 months, p

Description: Background: Less-fit patients with acute myeloid leukemia (AML) or high-risk myelodysplasia (MDS) age 60 years and older constitute the majority of patients with AML/MDS but are not well represented in clinical trials. DNA-methyltransferase inhibitor (HMA) monotherapy (e.g. azacitidine or decitabine) is usual. Overall response rates (ORR) are low; improvement in overall survival relative to supportive care alone is modest, highlighting the critical need for efficient identification of effective novel therapies. Blocking programed cell death protein-1 (PD-1) signaling with nivolumab may increase the sensitivity of AML cells to azacitidine and improve outcomes and is the focus of one arm of the S1612 trial. Signaling through PD-1 contributes to tumor immune evasion and growth in AML [Chen, Cancer Biol Ther 2008]. Increased expression of PD-1 (~40% of AML), is associated with poor HMA response [Ørskov, Oncotarget 2015]. A single center azacitidine/nivolumab non-randomized phase II study in relapsed/refractory AML reported ORR of 33% (23/70), including 22% complete remission/complete remission with incomplete hematologic recovery [Daver, Cancer Discovery 2018]. About 25% of the patients developed grade 2-4 immune toxicities; nivolumab immune-related adverse events led to treatment discontinuation in nearly 1 in 7 patients. Study Design and Methods:The S1612 trial [NCT03092674] is a platform randomized phase II/III clinical trial with a common azacitidine control arm (CA) and two currently active experimental arms (EA). Therapy is intended for community setting: azacitidine/nivolumab; and azacitidine/midostaurin. The innovative design utilizes a phase II go/no-go decision comparing each EA with the CA independently when there are 100 pts/arm and 104 deaths on the EA and CA combined. EAs will proceed to phase III if the null hypothesis (HR=1) is rejected in favor of the EA (15% one-sided alpha). When the two currently active EAs complete phase II accrual, a third EA (decitabine/cytarabine) will open. The CA stays open the entire length of the trial and only concurrently randomized patients will be compared across arms. If an EA proceeds to phase III, 200 additional patients (300 total patients) will be accrued. Phase III analysis occurs 1.5 years after accrual or at 414 deaths (in the respective EA and CA), whichever comes first. The phase III tests the null hypothesis with 4.5% two-sided alpha and 83% power for each EA to detect an improvement in median OS from 10.4 to 15.6 months. Eligible pts are age ≥60 years, newly diagnosed AML with ≥ 20% blasts or myelodysplastic syndrome with excess blasts-2 (MDS-EB-2); deemed by the treating physician unfit for standard cytotoxic chemotherapy; and no prior HMA permitted. Trial in Progress Issues:Between December 2017 and October 2018, 113 patients were screened and 78 randomized to study treatment (median/range age: 75/61-86 years; median/range performance status 1/0-3). Two concerns challenged this trial: 1) required administration of 7-day azacitidine at the enrolling sites created a burden for this population and 2) an early excess grade 5 toxicity signal in the azacitidine/nivolumab arm compared with the control arm. Without a control comparison, this safety signal likely would have been missed. Strategies to address these concerns were developed by the study team. Discussion with the sponsor and US Food and Drug Administration (FDA) focused on allowance of standard-of-care protocol-directed azacitidine administration in the patient's primary care doctor's office rather than at the oncology center. Because of the toxicity concern, the trial was placed on partial clinical hold for further evaluation and possible nivolumab-arm eligibility changes, along with new surveillance and pre-emptive action including prompt steroid initiation for suspected immune-related toxicities. The S1612 trial highlights special concerns when enrolling vulnerable populations onto leukemia clinical trials, and the importance of collaborative strategies including with the FDA to preserve clinical trial integrity for patient benefit. It also demonstrates the efficiency this novel platform design has for therapeutic investigation and, importantly, very early identification of serious toxicity. Updates on accrual and resolution and of these issues will be presented. Disclosures Hay: Kite: Research Funding; Gilead: Research Funding; AbbVie: Research Funding; Janssen: Research Funding; MorphoSys: Research Funding; Seattle Genetics: Research Funding; Takeda: Research Funding; Celgene: Research Funding; Roche: Research Funding; Novartis: Research Funding. Assouline:Janssen: Consultancy, Honoraria, Speakers Bureau; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria, Speakers Bureau; Abbvie: Consultancy, Honoraria. Walter:Pfizer: Consultancy, Research Funding; Race Oncology: Consultancy; New Link Genetics: Consultancy; Agios: Consultancy; Amphivena Therapeutics: Consultancy, Equity Ownership; Seattle Genetics: Research Funding; Aptevo Therapeutics: Consultancy, Research Funding; Argenx BVBA: Consultancy; Astellas: Consultancy; BioLineRx: Consultancy; BiVictriX: Consultancy; Boehringer Ingelheim: Consultancy; Boston Biomedical: Consultancy; Covagen: Consultancy; Daiichi Sankyo: Consultancy; Jazz Pharmaceuticals: Consultancy; Kite Pharma: Consultancy; Amgen: Consultancy. Foran:Agios: Honoraria, Research Funding. Radich:TwinStrand Biosciences: Research Funding; Novartis: Other: RNA Sequencing. Othus:Celgene: Other: Data Safety and Monitoring Committee; Glycomimetics: Other: Data Safety and Monitoring Committee. Erba:Astellas Pharma: Consultancy; Amgen: Consultancy; Amgen: Consultancy; ImmunoGen: Consultancy, Research Funding; Novartis: Consultancy, Research Funding, Speakers Bureau; MacroGenics: Consultancy, Other: Lecture fees, Research Funding; Pfizer: Consultancy; Pfizer: Consultancy; ImmunoGen: Consultancy, Research Funding; Covance: Other: Fees for serving as chair on an independent review board for AbbVie Phase III studies; Astellas Pharma: Consultancy; Covance: Other: Fees for serving as chair on an independent review board for AbbVie Phase III studies; MacroGenics: Consultancy, Other: Lecture fees, Research Funding; AbbVie: Consultancy, Other: Chair, IRC for phase III studies, Research Funding; AbbVie: Consultancy, Other: Chair, IRC for phase III studies, Research Funding; Seattle Genetics: Consultancy; Seattle Genetics: Consultancy; Celgene: Consultancy, Other: chair, AML Registry Scientific Steering Committee, Speakers Bureau; Celgene: Consultancy, Other: chair, AML Registry Scientific Steering Committee, Speakers Bureau; Daiichi Sankyo: Consultancy, Research Funding; Daiichi Sankyo: Consultancy, Research Funding; GlycoMimetics: Consultancy, Other: Chair, data and safety monitoring board, Research Funding; GlycoMimetics: Consultancy, Other: Chair, data and safety monitoring board, Research Funding; Agios: Consultancy, Speakers Bureau; Agios: Consultancy, Speakers Bureau; Incyte: Consultancy, Speakers Bureau; Incyte: Consultancy, Speakers Bureau; Jazz Pharmaceuticals: Consultancy, Speakers Bureau; Jazz Pharmaceuticals: Consultancy, Speakers Bureau; Novartis: Consultancy, Research Funding, Speakers Bureau. Michaelis:Pfizer: Equity Ownership, Research Funding; Incyte: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Novartis: Consultancy; TG Therapeutics: Consultancy, Research Funding; JAZZ: Other: Data Safety Monitoring Board, uncompensated, Research Funding; BMS: Research Funding; Bioline: Research Funding; ASTEX: Research Funding; Janssen: Research Funding; Millenium: Research Funding; Macrogeneics: Research Funding. OffLabel Disclosure: Off label experimental combination therapies in newly diagnosed AML/MDS will be discussed, including nivolumab and azacitidine.

Description: Abstract 3551 Background: With intensive chemotherapy, many acute myeloid leukemia (AML) patients will enter complete remission (CR). Empirically, the bone marrow is typically examined 14 days after initiating induction therapy, and re-treatment is commonly considered if significant residual blasts remain. However, many patients receiving single induction will enter CR without additional therapy despite substantial amounts or residual marrow blasts on day 14, leaving considerable uncertainty about the value of early marrow assessments. An emerging alternative approach to predict the efficacy of induction therapy includes the assessment of peripheral blood blast (PBB) dynamics. Rapid clearance of PBB, determined either by review of manual differential counts or flow cytometry is predictive of CR (likelihood of 76–90%) and overall survival. We investigated whether mathematical modeling of early PBB dynamics using automated complete blood cell (CBC) counts and the manual differential could further refine our ability to predict CR. Patients and Methods: We identified 111 adult patients with circulating PBB who underwent curative-intent, single-cycle induction chemotherapy for newly diagnosed AML between April 1999 and December 2011. Therapy regimens included “7+3”-like (56.8%), and regimens of similar/higher (29.7%) or lower (13.5%) intensity. PBBs were quantified as WBC count from the automated CBC times percentage of blasts by manual differential (100 cells). Cytogenetic abnormalities, NPM1/Flt3 status, day 14 and recovery bone marrow data were extracted from patient records. In the 62 patients with 〉3 measurable PBB counts, the rate of PBB clearance was calculated by fitting an exponential decay curve to the data points of absolute PBB counts, starting on day 1 of chemotherapy. This subgroup of patients had similar baseline parameters as the whole group, including age, WBC count at diagnosis, cytogenetic risk, percent of secondary AML, therapy regimens were similar, and CR rates were identical (69 vs. 68%). Results: An exponential decay curve [N(t) = N0×e-xt, with x=decay constant] resulted in an excellent goodness of fit of early PBB dynamics (mean r2=0.93). Rapid PBB clearance was highly predictive of CR achievement, with an optimal cut-off of x=1.4 (corresponding to a 4.2-log reduction in tumor burden if maintained over the course of a weeklong chemotherapy) based on the receiver operating characteristic (ROC) curve. All but 1 of the 27 patients with x〉1.4 achieved CR (positive predictive value [PPV]=96%) the only non-responder with x〉1.4 had a combination of negative prognostic factors including secondary AML, unfavorable cytogenetics, older age, and lower intensity treatment. PPV of PBB clearance rate of 96% for predicting CR compared favorably to alternative previously published approaches such as day of PBB clearance or percentage of day 14 bone marrow blasts (84 and 85% respectively in our study). Day 14 marrow assessments did not add prognostic information in 26/27 patients who had fast PBB clearance rate (x〉1.4). In univariate analyses, CR achievement was significantly correlated with a higher PBB clearance rate, younger age, primary AML, more favorable cytogenetics, and treatment intensity. In multivariate analyses including age, primary vs. secondary AML, cytogenetics, type of therapy, and PBB clearance rate (57 patients), only the PBB clearance rate remained statistically significantly associated with CR achievement. Importantly, information from CBC differentials is routinely available in most institutions and associated costs are low. Unlike determination of the exact day of PBB clearance that coincides with profound cytopenia, the PBB clearance rate is measured while PBB are still abundant, rendering the latter method less prone to sampling and observer errors. Conclusion: our findings suggest that early marrow assessment may not be necessary in AML patients who experience rapid PBB clearance upon induction treatment initiation as they have an almost 100% chance of achieving CR. Disclosures: Vainstein: Neumedicines Inc: Employment.

Description: Background Adults with newly diagnosed or relapsed acute myeloid leukemia (AML) and high-risk myelodysplastic syndromes (MDS) typically receive intensive chemotherapy to achieve disease remission. Generally, these patients remain hospitalized until blood count recovery due to the risk for infections and bleeding during pancytopenia. However, a recent small pilot study at our institution suggested that early discharge (ED) following induction/salvage therapy for MDS/AML may be safe and may reduce cost. We therefore conducted a phase 2 study to test this care strategy in a larger cohort of patients (NCT01235572). Methods Patients aged 18-75 years with high-risk MDS or AML (other than acute promyelocytic leukemia) were enrolled before or during induction or salvage chemotherapy and provided with outpatient care teaching. Patients were considered eligible for ED if they fulfilled the following medical and logistic criteria: ECOG performance status of 0-1, adequate organ function; no active bleeding; agreeable to close outpatient follow-up; reliable caregiver; and residency within 60 minutes of the outpatient clinic. Patients who met medical but not logistic criteria served as inpatient controls. If readmitted, ED was again possible if all medical/logistic criteria were met. Patients remained on protocol until blood count recovery, additional chemotherapy was administered, or a maximum of 45 days. Our goal was to compare the number of early deaths, healthcare costs and resource utilization among ED patients versus inpatient controls. Safety was monitored with early stopping if the early death rate was 〉7% in the ED group, with a predefined interim analysis after 30 patients. All data are provided as median (range). Results One hundred and seven eligible patients were enrolled over a 2-year period. Two patients died during chemotherapy. Twenty-seven patients failed to meet medical ED criteria after completion of chemotherapy and were taken off study, mostly due to poor performance status. Eighteen patients, age 51.4 (22-70) years, met medical but not logistic ED criteria and served as controls; they were followed for 14 (9-41) days, with 7 patients taken off study at the time of hospital discharge before blood count recovery. Sixty patients, age 51.6 (22-71) years, met all ED criteria and were discharged upon completion of induction (n=19) or salvage (n=41) chemotherapy for AML (n=50) or MDS (n=10). A median number of 1 (1-3) readmission occurred in 53 of these patients, primarily for neutropenic fever; 8 patients were readmitted twice and 3 patients were readmitted 3 times prior to coming off study. Overall, ED patients spent 12.8 (0-38) and 7.5 (0-33) days as out- and inpatients, respectively, for a total of 62.7% (0-100%) of the study time spent as outpatients. ED patients required 0.41 (0-1.9) clinic visits and 0.13 (0-0.66) physician visits per outpatient day. Duration of IV antibiotics was similar in ED and control patients (10 [0-40] vs 12 [0-40] days; p=0.38) as was number of red blood cell transfusions (0.27 [0.0-0.94] vs 0.29 [0.08-0.548] units/study day; p=0.21). In contrast, ED patients required fewer platelet transfusions (0.21 [0.09-1.25] vs 0.33 [0.21-0.80] units/ study day; p=0.02). Six patients in the ED group required between 1-6 days of intensive care unit (ICU) care (p= 0.17 for the difference in ICU days between discharges and controls). Three deaths occurred in the ED group during the study period: two of sepsis (2 and 7 days after readmission), and one of fungal sinusitis (11 days after readmission). The median daily total professional and facility charges, dated from the day of re-evaluation until removal from protocol, were significantly lower for patients discharged early compared to inpatient controls: $3,871 [$360.86-$13,361] vs $6,283 [$4,868-$11,898], p