Foran, James M.

Background: Myelofibrosis (MF) is associated with bone marrow fibrosis (BMF), splenomegaly, a high symptom burden, and poor prognosis; the JAK/STAT pathway is the central pathway implicated in its pathogenesis. Ruxolitinib, a JAK1/2 inhibitor and the only FDA-approved pharmacotherapy for treatment (Tx) of MF patients (pts), improves splenomegaly, but is unable to control all clinical manifestations of disease. Navitoclax is an orally bioavailable, novel small-molecule that targets and binds with high affinity to multiple antiapoptotic B-cell lymphoma 2 (BCL2) family proteins, including BCL-XL, BCL2, and BCL-W. Preclinical studies have demonstrated cytotoxic activity of navitoclax against myeloproliferative neoplasm-derived cell lines. Herein, the results of a phase 2 study (NCT03222609) evaluating the combination of navitoclax with ruxolitinib in pts with MF are reported. Methods: This phase 2 single-arm, multicenter, open-label study assessed the efficacy and safety of navitoclax combined with ruxolitinib in pts with MF. Eligible pts (≥18 yr, diagnosis of primary MF, post-essential thrombocythemia [PET]-MF, or post-polycythemia vera [PPV]-MF, ECOG 0-2, receiving at least 12 wk of continuous ruxolitinib therapy prior to study Tx initiation) received a starting dose of 50 mg navitoclax once-daily combined with the current stable dose of ruxolitinib (≥10 mg BID). Weekly intra-patient dose-escalation of navitoclax was allowed to a maximum daily dose of 300 mg based on tolerability and platelet count. Tx continued until the end of clinical benefit, unacceptable toxicity, or discontinuation. The primary efficacy endpoint was percentage reduction in splenic volume from baseline. Secondary endpoints included effect on total symptom score (TSS), overall response rate, rate of anemia response, improvement in BMF, and safety profile. Results: As of May 1, 2019, 34 pts (primary MF, n=16; PET-MF, n=5; PPV-MF, n=13) had received ≥1 dose of navitoclax in combination with ruxolitinib. Median age was 68 yr (range 42-86), 68% were male, and 9 pts (26%) had ≥3 prior lines of MF therapy. The median duration of prior ruxolitinib exposure was 745 days (range 134-4549). Of the 34 pts enrolled, 27 (79%) had JAK2 and 7 pts (21%) had CALR mutations. There were no pts enrolled with triple-negative MF. Of 33 pts with available baseline testing, 17 (52%) had high molecular risk, defined by mutations within ASXL1, EZH2, IDH1/2, SRSF2, or U2AF1. The mean baseline platelet count was 231 x 109/L (range 99-706); mean baseline Hgb was 10.8 g/dL; 19 (56%) pts had elevated WBC at baseline (>1.5× ULN). Maximal navitoclax dose of 300 mg was achieved in 23 pts (68%). Of the 25 (74%) pts that enrolled on ruxolitinib doses >10 mg BID, 22 (88%) subsequently had the dose of ruxolitinib reduced to 10 mg BID. At the time of this analysis, 24 pts were evaluable for efficacy, with 20 pts completing ≥24 wk on study and 4 pts with Tx discontinuations prior to 24 wk. At wk 24, 7 of 24 pts (29%) achieved a spleen volume reduction of ≥35% (SVR35) from baseline by MRI as determined by prespecified central review; the median TSS was 7.4 (range 0-23), a 20% improvement from baseline. A SVR35 at any time on study was achieved in 10 pts (42%). Reductions in driver mutation allelic burden of >5% were observed in 10 (42%) pts; 6 pts (25%) had BMF improvement of ≥1 grade. One pt (4%) had an anemia response; the mean Hgb at wk 24 was slightly improved over baseline at 11.3 g/dL. Of the 19 pts with elevated baseline WBC, 16 (84%) reduced to within normal limits during Tx, with a median WBC reduction of 17.7 × 109/L. All pts experienced a Tx-emergent adverse event (TEAE); most common (≥20%) were thrombocytopenia (82%), diarrhea (62%), fatigue (53%), anemia (27%), nausea (27%), contusion (24%), and vomiting (21%). Grade ≥3 TEAEs occurred in 26 pts (77%); most common were thrombocytopenia (n=15, 44%; Grade 4 n=1, 3%) and anemia (n=8, 24%; no Grade 4). Five pts (15%) experienced serious AEs that resolved including anemia, upper abdominal pain, vomiting, chest pain, increased C-reactive protein, and abnormal liver function test (3% each). There were no significant episodes of bleeding and no TEAE-related deaths. Conclusions: Navitoclax in combination with ruxolitinib was well tolerated with clinically meaningful spleen responses, allelic burden reductions, TSS improvements, and encouraging improvements in BMF in pts with MF who have received prior Tx with ruxolitinib. Disclosures Harrison: CTI: Speakers Bureau; Promedior: Honoraria; Roche: Honoraria; Celgene: Honoraria, Speakers Bureau; Gilead: Speakers Bureau; Shire: Speakers Bureau; Incyte: Speakers Bureau; Sierra Oncology: Honoraria; Janssen: Speakers Bureau. Garcia:Genentech: Research Funding; Abbvie: Research Funding. Mesa:CTI: Research Funding; Galena Biopharma: Consultancy; Samus: Research Funding; Genotech: Research Funding; AbbVie: Research Funding; NS Pharma: Research Funding; Baxalta: Consultancy; LaJolla: Consultancy; Shire: Honoraria; PharmaEssentia: Research Funding; Genentech: Consultancy; Celgene Corporation: Research Funding; AOP Orphan Pharmaceuticals: Honoraria, Other: travel, accommodations, expenses; Promedior: Research Funding; Novartis: Consultancy, Honoraria, Other: travel, accommodations, expenses; Incyte: Other: travel, accommodations, expenses, Research Funding; Gilead Sciences: Research Funding; Pfizer: Research Funding; Sierra Oncology: Consultancy. Somervaille:Novartis: Consultancy. Komrokji:pfizer: Consultancy; celgene: Consultancy; DSI: Consultancy; Incyte: Consultancy; Agios: Consultancy; JAZZ: Consultancy; Novartis: Speakers Bureau; JAZZ: Speakers Bureau. Pemmaraju:sagerstrong: Research Funding; celgene: Consultancy, Honoraria; Stemline Therapeutics: Consultancy, Honoraria, Research Funding; Daiichi-Sankyo: Research Funding; samus: Research Funding; novartis: Consultancy, Research Funding; plexxikon: Research Funding; incyte: Consultancy, Research Funding; abbvie: Consultancy, Honoraria, Research Funding; mustangbio: Consultancy, Research Funding; cellectis: Research Funding; affymetrix: Research Funding. Papadantonakis:Agios: Consultancy, Honoraria. Foran:Agios: Honoraria, Research Funding. O'Connell:Astex: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Shionogi: Membership on an entity's Board of Directors or advisory committees. Holes:AbbVie Inc: Employment, Other: Stock/stock options. Jia:AbbVie: Employment, Other: Stock/stock options. Harb:AbbVie Inc: Employment, Other: Stock/stock options. Hutti:AbbVie: Employment, Other: Stock/stock options.

*equal contribution of AB, RLL, BD and JCB Background: Acute myeloid leukemia (AML) is common with increasing age, and older adults with AML rarely achieve long-term remission with chemotherapy. Gene discovery studies in older adults with AML have shown that this malignancy is characterized by a multitude of somatic genomic alterations beginning with initiating somatic events followed by acquisition of collaborative transforming mutations. Despite these important biologic insights, current therapeutic approaches to AML remain limited, particularly in adults ≥ 60 years of age. The Beat AML trial was designed to assess the feasibility of using genetic profiling to assign patients (pts) to molecularly defined, subtype-specific therapies within 7 days of the initial diagnosis in a multi-center clinical trial setting, and to delineate the role of molecularly informed first-line treatment of AML with mechanism based novel therapies. Methods: Treatment-naïve patients with AML were enrolled in this prospective trial which offered accelerated cytogenetic and comprehensive mutational testing within 7 days followed by treatment assignment using these molecular data. Pt eligibility included age ≥ 60 years with non-APML AML, no known CNS leukemia, no prior hypomethylating agent (HMA) therapy and no clinical need for emergent therapy. Eligible pts were profiled by local cytogenetics analysis and using a central next generation sequencing (NGS) assay (Foundation Medicine, Inc.) with all molecular data required for treatment assignment (TA) obtained < 7 days. TA was made centrally using a pre-determined algorithm considering somatic cytogenetic and molecular alterations in the dominant clone, available targeted therapeutics for specific AML subsets, and the likelihood of cure with intensive chemotherapy. Results: From November 2016 to January 2019, 487 pts with a suspected diagnosis of AML had enrolled at 14 clinical sites; 395 were eligible for the study (77% of the patients not eligible for the study had an alternative diagnosis). The median age of eligible patients was 72 years (range: 60 to 92) with 38% being≥ 75 years and 16% with treatment-related AML. From the 395 eligible patients, 374 (94.7%) were centrally assigned to the different cytogenetic/genomic groups within 7 days. The most common groups were TP53 mutated (19%) and marker negative (18%) molecular groups. The Beat AML trial is dynamic by design, thereby allowing different arms to open over time; all trial arms are designed to evaluate for substantial clinical efficacy in small, molecularly defined patient subsets. As shown in Figure 1, 224 patients (57%) had a TA and consented to a BEAT AML sub-study. Of the remaining 171 patients, 103 received standard therapy defined as induction therapy (7+3) or hypomethylation agent (25 before TA and 78 after TA), 28 received an alternative investigational agent (5 before TA and 23 after TA), 38 received palliative care, and 2 had an unknown treatment status and are grouped with the palliative care patients in subsequent analyses; 9 patients died before TA (2 who received standard therapy and 7 in the palliative care group). Demographic, clinical, performance and molecular characteristics were not largely different between pts who elected targeted therapy as part of the BEAT AML trial versus those who elected standard therapy. As shown in Figure 2, the overall survival was significantly longer for patients enrolled in a targeted therapy arm as part of the BEAT AML trial compared to those who elected standard therapy. (p<0.0001). The 30-day estimated death rate was 3.7% (95% CI: 1.9-7.2) for patients electing treatment on a BEAT AML sub-study, 20.4% (95% CI: 13.0-31.2) for those receiving standard therapy, 0% for those receiving an investigational therapy, and 72.6% (95% CI: 57.8-85.7) for the palliative care group. Conclusion: Our data support the feasibility of a rapid precision medicine approach in older patients with previously untreated AML. Patients with AML who elected treatment assigned based upon cytogenetic and molecular alterations in the dominant clone using a novel precision medicine approach had significantly improved overall survival versus those who elected standard of care treatment. Disclosures Levine: Gilead: Consultancy; Prelude Therapeutics: Research Funding; Celgene: Consultancy, Research Funding; Novartis: Consultancy; Isoplexis: Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Research Funding; Qiagen: Membership on an entity's Board of Directors or advisory committees; Loxo: Membership on an entity's Board of Directors or advisory committees; Imago Biosciences: Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria; Lilly: Honoraria. Mims:Abbvie: Membership on an entity's Board of Directors or advisory committees; Agios Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Astellas Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; PTC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Borate:Novartis: Consultancy; Takeda: Consultancy; Pfizer: Consultancy; Daiichi Sankyo: Consultancy; AbbVie: Consultancy. Stein:Agios: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astellas Pharma US, Inc: Membership on an entity's Board of Directors or advisory committees; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees; PTC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Syros: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo, Inc.: Membership on an entity's Board of Directors or advisory committees; Bioline: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Patel:France Foundation: Honoraria; Dava Oncology: Honoraria; Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Baer:Takeda: Research Funding; Incyte: Research Funding; Kite: Research Funding; Forma: Research Funding; AI Therapeutics: Research Funding; Abbvie: Research Funding; Astellas: Research Funding. Stock:Daiichi: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Research to Practice: Honoraria; UpToDate: Honoraria; Kite, a Gilead Company: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees. Deininger:Pfizer: Consultancy, Honoraria, Research Funding; Ascentage Pharma: Consultancy, Honoraria; TRM: Consultancy; Sangoma: Consultancy; Fusion Pharma: Consultancy; Adelphi: Consultancy; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Humana: Honoraria; Incyte: Honoraria; Novartis: Honoraria; Sangamo: Consultancy; Blueprint: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Blum:Boehringer Ingelheim: Research Funding; Celgene: Research Funding; Astellas,: Research Funding; Xencor: Research Funding; Forma: Research Funding; AmerisourceBergen: Consultancy. Schiller:Amgen: Other, Research Funding; Agios: Research Funding, Speakers Bureau; Celgene: Research Funding, Speakers Bureau; Constellation Pharmaceutical: Research Funding; Daiichi Sankyo: Research Funding; Eli Lilly and Company: Research Funding; FujiFilm: Research Funding; Genzyme: Research Funding; Gilead: Research Funding; Incyte: Research Funding; J&J: Research Funding; Jazz Pharmaceuticals: Honoraria, Research Funding; Karyopharm: Research Funding; Novartis: Research Funding; Onconova: Research Funding; Pfizer Pharmaceuticals: Equity Ownership, Research Funding; Sangamo Therapeutics: Research Funding; Bristol Myer Squibb: Research Funding; Astellas: Research Funding; Biomed Valley Discoveries: Research Funding. Olin:Daiichi Sankyo: Research Funding; Astellas: Research Funding; Genentech: Consultancy, Research Funding; Pfizer: Research Funding; Jazz Pharmaceuticals: Consultancy, Honoraria; Revolution Medicine: Consultancy; AstraZeneca: Research Funding; Clovis: Research Funding; Ignyta: Research Funding; MedImmune: Research Funding; Mirati Therapeutics: Research Funding; Novartis: Research Funding; Spectrum: Research Funding. Foran:Agios: Honoraria, Research Funding. Lin:Pfizer: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Honoraria. Traer:AbbVie: Consultancy; Agios: Consultancy; Astellas: Consultancy; Daiichi Sankyo: Consultancy; Notable Labs: Equity Ownership. Odenike:AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Research Funding; Astra Zeneca: Research Funding; Astex Pharmaceuticals: Research Funding; NS Pharma: Research Funding; Gilead Sciences: Research Funding; Janssen Oncology: Research Funding; Oncotherapy: Research Funding; Agios: Research Funding; CTI/Baxalta: Research Funding. Arellano:Gilead: Consultancy. Vergilio:Roche Holding AG: Equity Ownership; Foundation Medicine: Employment. Brennan:Foundation Medicine: Employment. Vietz:Foundation Medicine: Employment. Druker:ALLCRON: Membership on an entity's Board of Directors or advisory committees; Pfizer: Research Funding; Aileron Therapeutics: #2573, Constructs and cell lines harboring various mutations in TNK2 and PTPN11, licensing fees , Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Patents & Royalties, Research Funding; Burroughs Wellcome Fund: Membership on an entity's Board of Directors or advisory committees; Cepheid: Consultancy, Honoraria; The RUNX1 Research Program: Membership on an entity's Board of Directors or advisory committees; GRAIL: Equity Ownership, Other: former member of Scientific Advisory Board; Patient True Talk: Consultancy; Dana-Farber Cancer Institute (antibody royalty): Patents & Royalties: #2524, antibody royalty; Pfizer: Other: PI or co-investigator on clinical trial(s) funded via contract with OHSU., Research Funding; Merck & Co: Patents & Royalties: Dana-Farber Cancer Institute license #2063, Monoclonal antiphosphotyrosine antibody 4G10, exclusive commercial license to Merck & Co; OHSU (licensing fees): Patents & Royalties: #2573, Constructs and cell lines harboring various mutations in TNK2 and PTPN11, licensing fees ; Amgen: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Aptose Biosciences: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Beta Cat: Membership on an entity's Board of Directors or advisory committees, Other: Stock options; Blueprint Medicines: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Vivid Biosciences: Membership on an entity's Board of Directors or advisory committees, Other: Stock options; Beat AML LLC: Other: Service on joint steering committee; CureOne: Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy; Gilead Sciences: Other: former member of Scientific Advisory Board; ICON: Other: Scientific Founder of Molecular MD, which was acquired by ICON in Feb. 2019; Monojul: Other: former consultant; Novartis: Other: PI or co-investigator on clinical trial(s) funded via contract with OHSU., Patents & Royalties: Patent 6958335, Treatment of Gastrointestinal Stromal Tumors, exclusively licensed to Novartis, Research Funding; Bristol-Myers Squibb: Other: PI or co-investigator on clinical trial(s) funded via contract with OHSU., Research Funding. Byrd:Novartis: Other: Travel Expenses, Speakers Bureau; BeiGene: Research Funding; Pharmacyclics LLC, an AbbVie Company: Other: Travel Expenses, Research Funding, Speakers Bureau; Acerta: Research Funding; Ohio State University: Patents & Royalties: OSU-2S; Genentech: Research Funding; Gilead: Other: Travel Expenses, Research Funding, Speakers Bureau; TG Therapeutics: Other: Travel Expenses, Research Funding, Speakers Bureau; Janssen: Consultancy, Other: Travel Expenses, Research Funding, Speakers Bureau.

Abstract Background: As of 2013, approximately 558,340 people are living with non-Hodgkin lymphoma (NHL). Outcome disparities have been reported in lymphoid malignancies but a comprehensive analysis, especially with expanding ethnic minorities is necessary. We undertook a large Surveillance Epidemiology and End Results (SEER) based analysis to describe outcome disparities in different subgroups of T-cell and B-cell NHL patients (pts), with a focus on various ethnicities. Methods: The SEER 18 Registry data (1973-2011) was utilized for pts with a confirmed diagnosis of T-cell or B-cell NHL. Cases that received a diagnosis at death certificate or autopsy, no follow-up records, no documented age at diagnosis, sex, or race/ethnicity were excluded. Cox proportional hazards models, adjusted for gender, age, race, year (yr) of diagnosis, and stratified by SEER registries were used to evaluate association between pt characteristics and survival. All statistical tests were two-sided and utilized the SAS software (v9.4) with a two-sided significance level of 0.05. Results: The final analysis included 7,662 pts with T-cell NHL and 84,910 pts with B-cell NHL. The pt demographics are shown in Table 1. Pts were stratified based on yr of diagnosis to study the impact of therapeutic developments on pt outcomes (Table 1). Pts were also divided by T-cell NHL subtype: mature T-cell (9702/3) 51%, angioimmunoblastic T-cell (9705/3) 16%, anaplastic large cell (ALCL) (9714/3) 32%, and hepatosplenic gamma-delta cell (HSϒd) (9716/3) 0.8%. Median age at diagnosis was youngest for AA pts (54 yrs) and oldest for Asian pts (65 yrs) (Figure 1 A). Survival analysis revealed that females had a better median OS than males (3.3 yrs vs. 2.3 yrs, HR 0.876; 95% CI 0.824, 0.932; p<0.001). Increasing age was an independent predictor of worse overall survival, with pts age 18-44 having a median OS 9.4 yrs (HR 0.345; 95% CI 0.312, 0.382) and pts age ≥75 having a median OS of 1.0 yr (p<0.001). There was no statistically significant difference seen in median OS for pts with respect to yr of diagnosis (p=0.081). Among the different T-cell NHL subtypes, pts with ALCL had the best (3.8 yrs, HR 0.766; 95% CI 0.714, 0.822) and pts with HSϒd had the worst median OS (0.7 yrs HR 1.959; 95% CI 1.424, 2.695) (p<0.001). AA pts (1.7 yrs, HR 1.292; 95% CI 1.176, 1.419) and Hispanic pts (1.9 yrs, HR 1.215; 95% CI 1.087, 1.357) had significantly worse OS compared to White pts who had the longest median OS (3.1 yrs) (p<0.001) (Figure 1 B). To compare and contrast with aggressive B-cell NHL, similar analyses were performed using diffuse large B-cell (DLBCL) NHL (9680/3). DLBCL showed similar trends regarding sex, age and race. Ethnic minorities had significantly worse median OS including Hispanic (2.8 yrs, HR 1.154; 95% CI 1.111, 1.198) and AA pts (3.3 yrs, HR 1.261; 95% CI 1.212, 1.312) compared to White pts with a median OS of 5.8 yrs (p<0.001). B-cell NHL pts had a significant improvement in median OS over time with pts diagnosed in 2007-2011 having more than 3 times the median OS of pts diagnosed in 1973-1991 (7 yrs vs. 2.4 yrs; p<0.001). Conclusions: Studies of outcome disparities are important for evaluating disease characteristics and their relationship to specific pt populations over time. We have performed the largest population-based analysis for T-cell and B-cell NHL including various ethnicities in the novel therapeutic agent era. We observed that males, older pts and ethnic minorities had worse median OS for both T-cell and B-cell NHL. Despite novel therapeutics targeting T cells there has been no statistically significant improvement in OS over time. In contrast, significant improvement in B-cell NHL OS has been noted, presumably due to the advent of monoclonal antibodies. These results underline the urgency for the development of novel therapeutics as well as aggressive studies of disease biology and healthcare utilization for better triage of healthcare resources, especially for ethnic minorities. Table 1. Table 1. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Abstract FMS-like tyrosine kinase 3 internal tandem duplications (FLT3-ITD) in acute myeloid leukemia (AML) are associated with early relapse after standard chemotherapy and poor survival. Quizartinib (AC220) is an oral FLT3 receptor tyrosine kinase inhibitor that has shown the highest level of single agent activity seen with a FLT3 targeted agent in FLT3+ relapsed AML to date. This Phase 1 dose escalation study is the first study to report data with quizartinib in combination with standard induction and consolidation chemotherapy in patients aged 18-60 years with newly diagnosed AML, regardless of FLT3-ITD status. The dose escalation was conducted using a modified 3+3 design, where 6 pts were enrolled at each dose level. The pts were given cytarabine 200 mg/m2 x 7 days and daunorubicin 60 mg/m2 x 3 days (7+3) for induction and high dose cytarabine 3 g/m2(HiDAC) q12hours on days 1, 3, and 5 for consolidation. Quizartinib was administered daily for either 7 or 14 days, starting at Day 4 of induction and/or consolidation chemotherapy. Patients were allowed to proceed directly to a stem cell transplant after achieving a response or receive further quizartinib as maintenance therapy after consolidation if they were not transplant eligible. Three dose levels were tested; dose level 1 (DL1) at 60 mg for 7 days, dose level 2 (DL2) 60 mg for 14 days, and dose level -1 (DL-1), 40 mg for 14 days. Through May 31, 2013 18 pts were enrolled in the study, and the safety information at all 3 dose levels are presented. The median age of pts was 43 years (range 22 to 60). Of the 18 patients, 16 had the FLT-ITD mutation. At DL1, one of the 6 patients had a DLT (grade 3 hyponatremia). At DL2, two of the 6 patients had a DLT (grade 3 QTc prolongation and grade 4 pericarditis) which exceeded the pre-specified criteria so DL-1 was then explored. At DL-1, one of the 6 patients had a DLT (grade 3 constrictive pericarditis). The most common (20%) treatment-related adverse events (AEs) were nausea (42%), diarrhea (32%), anemia (26%), febrile neutropenia (26%), neutropenia (21%), fatigue (21%), pyrexia (21%) and thrombocytopenia (21%). The most common (10%) Grade 3 or 4 treatment-related AEs were febrile neutropenia (26%), thrombocytopenia (21%) anemia (21%)), neutropenia (21%), leucopenia (16%), and nausea (11%). The data from this Phase 1 study demonstrates for the first time that quizartinib can be safely administered with induction and/or consolidation chemotherapy in newly diagnosed younger patients with AML. The MTD was identified as 40 mg for 14 days or 60 mg for 7 days. The efficacy results from this Phase 1 study will be available at the time of presentation. Based on these findings, multiple Phase 3 studies in newly diagnosed AML patients are planned. Disclosures: Altman: Novartis: Consultancy; Araid: Consultancy; BMS: Consultancy; Teva: Consultancy; Astellas: Consultancy. Foran:Astellas: Research Funding. Trone:Ambit: Employment. Gammon:Ambit: Employment. Cortes:Ambit: Research Funding.

BACKGROUND: Axi-cel is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy that is approved for treatment of relapsed/refractory (R/R) large B-cell lymphoma and is associated with high response rates and durable remissions. Recent data show that axi-cel is effective across various adverse prognostic features, namely cell of origin, disease bulkiness, and extranodal disease, among others. Hypoalbuminemia is a known adverse prognostic factor in lymphomas. It is unknown if axi-cel overcomes the adverse prognostic feature of hypoalbuminemia in R/R large B-cell or transformed follicular lymphoma. METHODS: We conducted a retrospective analysis of patients treated with axi-cel across three Mayo Clinic campuses (Rochester, Jacksonville, and Phoenix) from 06/01/2018 until 04/01/2019. The primary objective of this analysis was to assess the impact of hypoalbuminemia (defined at day 0, prior to infusion) on outcome after axi-cel therapy. RESULTS: A total of 50 (male=37, 74%) patients (pts), median age of 53 (26-67) years received axi-cel. The median number of prior lines of therapy was 3 (2-8) (Table 1). Two pts had no available serum albumin levels at time of axi-cel infusion. Seven (15%) of 48 pts had serum albumin levels lower than 3.5 g/dL (median= 3.3 g/dL (range 2.6-3.4)) and the median follow up of survivors was 7.6 (1.9-14.3) months. The best overall response rate (ORR) and complete remission (CR) rates in these pts were 57% and 57%, respectively. One (14%) patient had stable disease and 2 (29%) had disease progression. The median overall survival (OS) for pts with hypoalbuminemia was not reached. On the other hand, 41 (85%) pts had a normal serum albumin level (median=4.0 (range 3.5-5.1) g/dL) and the median follow up for survivors was 6.3 months. The best objective response rate (ORR) and complete remission (CR) rates in these pts were 82% and 44%, respectively. The median OS for pts with normal serum albumin was 14 (95%CI=6.3-29.6) months. There was no significant difference at 6-months and 1-year OS between pts with hypoalbuminemia vs. those with normal baseline serum albumin levels [6-month=100% vs. 79%(95%CI=64-93%); 1-year (100% vs. 54% (95%CI=26-82%), p=0.17] (Figure 1). All grades cytokine release syndrome (CRS) was diagnosed in all 7 pts with hypoalbuminemia (100%) and in 38 of 41 (92%) pts without hypoalbuminemia. There was no difference in the median duration of CRS between pts with or without hypoalbuminemia [6 (range 1-11) days vs 5 (range 1-19) days, p=0.89]. Neurotoxicity (all grades) was observed in 5 (71%) pts with hypoalbuminemia compared 26 (63%) with normal albumin levels. There was no statistically significant difference in median duration of neurotoxicity between pts with hypoalbuminemia and those with normal baseline albumin levels [9 (range 1-10) days vs. 3 (range 0-25) days, p= 0.72]. CONCLUSIONS: Hypoalbuminemia does not have a significant impact on the outcomes of axi-cel therapy, including the incidence of CRS or neurotoxicity. These results need to be validated in a large collaborative multicenter study. Further investigation is needed to assess the prognostic impact of severe hypoalbuminemia (<3g/dL) on axi-cel therapy. Disclosures Ansell: Mayo Clinic Rochester: Employment; Seattle Genetics: Research Funding; Trillium: Research Funding; Trillium: Research Funding; Mayo Clinic Rochester: Employment; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Affimed: Research Funding; Regeneron: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; LAM Therapeutics: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Trillium: Research Funding; Regeneron: Research Funding; Trillium: Research Funding; Affimed: Research Funding; LAM Therapeutics: Research Funding; Mayo Clinic Rochester: Employment; LAM Therapeutics: Research Funding; LAM Therapeutics: Research Funding; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; Mayo Clinic Rochester: Employment; Affimed: Research Funding; Regeneron: Research Funding; LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding; Trillium: Research Funding; Affimed: Research Funding; Trillium: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Mayo Clinic Rochester: Employment; Trillium: Research Funding; Regeneron: Research Funding; LAM Therapeutics: Research Funding; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding; Trillium: Research Funding; Trillium: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; Bristol-Myers Squibb: Research Funding; Seattle Genetics: Research Funding; LAM Therapeutics: Research Funding; Regeneron: Research Funding; Affimed: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Seattle Genetics: Research Funding; Affimed: Research Funding; Affimed: Research Funding. Bennani:Seattle Genetics: Other: Advisory board; Kite Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board; Adicet Bio: Other: Advisory board; Seattle Genetics: Other: Advisory board; Purdue Pharma: Other: Advisory board; Adicet Bio: Other: Advisory board; Purdue Pharma: Other: Advisory board; Purdue Pharma: Other: Advisory board; Adicet Bio: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Kite Pharma: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Kite Pharma: Other: Advisory board. Paludo:Verily Life Sciences: Research Funding; Celgene: Research Funding; Verily Life Sciences: Research Funding; Celgene: Research Funding. Tun:DTRM Biopharma: Research Funding; Mundi-pharma: Research Funding; BMS: Research Funding; Celgene: Research Funding; Curis: Research Funding; TG Therapeutics: Research Funding. Foran:Agios: Honoraria, Research Funding. Kharfan-Dabaja:Daiichi Sankyo: Consultancy; Pharmacyclics: Consultancy.

Introduction: Myelodysplastic syndromes (MDS) are a heterogenous group of blood disorders defined by peripheral cytopenia(s), bone marrow failure, morphological dysplasia, and risk of progression. To understand the genetic, epigenetic and biological factors associated with the initiation and progression of MDS, NHLBI created the National MDS Study (NCT02775383). This is a prospective cohort study conducted at 92 community hospitals and 29 academic centers enrolling patients undergoing diagnostic work up for suspected MDS or MDS/myeloproliferative neoplasm (MPN) overlap syndrome. Eligible patients have yet to receive any therapy directed at their cytopenias. Previously untreated cytopenic participants underwent centralized histopathology and data review at the time of enrollment for assignment into distinct subcategories: MDS, MDS/MPN overlap, AML, and Other. Targeted exon sequencing of 96 genes was performed using marrow specimens from the first 300 consecutive individuals in the study. Here we report the genetic mutations for this cohort. Methods: NovaSeq 6000 was used for deep sequencing at a mean coverage of 1,286X and mean breadth (bases covered at ≥100X) of 99.8%. Reads were aligned against build GRCh38 using BWA-MEM, and VarScan2 was used to detect SNVs and INDELS. Variants were filtered for those with an allele base quality of >25 in combination with rule-based and manual review criteria. Subjects in the Other category without an identified malignancy were considered clonal cytopenias of undetermined significance (CCUS) when a mutation or a clonal cytogenetic change was present. Fisher's exact and Wilcoxon rank sum tests in combination with Bonferroni correction were applied to compare groups. Results : A total of 350 putative nonsynonymous pathogenic variants in 36 genes with an allele frequency of >.05 were identified across 150 patients (50%). At least one variant was noted in the following proportion of individuals: 61/72 (85%) with MDS, 13/13 (100%) with MDS/MPN, 15/17 (88%) with AML, and 61/198 (31%) in the Other category, of which 48 were CCUS and 13 were other cancers. Two CCUS patients only had a cytogenetic abnormality. Table 1 shows the distribution of variants in each subcategory of patients for the most commonly mutated genes in our cohort of 300 subjects. Mutations in these genes were enriched in specific groups: SF3B1, STAG2,TP53, and ASXL1 in MDS; TET2 in MDS/MPN; and IDH2 and TP53 in AML (one-sided p<0.0012). None were enriched in the Other group. Within the CCUS subset, 21 genes were mutated, with 37 of 50 (74%) patients having a mutation in TET2, ASXL1, SRSF2, SF3B1, or DNMT3A. The heatmap presented in Figure 1 summarizes variants by subject and allele frequency. Pair-wise comparisons of baseline characteristics of subjects between MDS, MDS/MPN, AML, or CCUS groups revealed no significant differences for age or sex. The CCUS group had significantly higher hemoglobins than the MDS group with median hemoglobin levels of 11.35 and 9.40 g/dL, respectively (p<0.0084). AML had significantly lower platelets compared to all other groups (median of 53 vs. > 110x109/L , respectively, p<0.0084). All groups significantly differed in their median ANC with AML having the lowest (0.8x109/L), followed by MDS (1.5x109/L), CCUS (2.45x109/L), and MDS/MPN overlap (5.95x109/L) (p<0.0084). There was no difference in the median number of variants per patient between groups or correlation with age (rs=0.11, p=0.18). The maximum variant allele frequency (maxVAF) per patient was highest in the MDS/MPN group (median = 0.42, range = 0.38-0.91) and lowest in the CCUS group (median = 0.37, range =0.06-0.98) with the MDS/MPN group having a significantly higher maxVAF compared to the MDS and the CCUS groups (p<0.0084). The proportions of subjects with mutations was similar for those who had abnormal (92% [34/37]) and normal (91% [80/88]) cytogenetics. Conclusions: Incorporation of gene-panel sequencing in the comprehensive evaluation of 300 adult cytopenic patients identified half of the cohort with potentially pathogenic variants. Ultimately, a diagnosis of CCUS was possible in 48 of 183 subjects (26%) not diagnosed with MDS, MDS/MPN overlap syndrome, AML, other cancers or clonal cytogenetics. This study continues to serially bank samples from patients with CCUS, in addition to MDS, MDS/MPN, and ICUS, with the goal to better understand the natural history of these diseases and their progression. Disclosures Lindsley: Jazz Pharmaceuticals: Research Funding; Takeda Pharmaceuticals: Consultancy; Medlmmune: Research Funding. Bejar:Celgene: Consultancy; Takeda Pharmaceuticals: Research Funding; AbbVie/Genentech: Consultancy, Honoraria; Astex/Otsuka: Consultancy; Modus Outcomes: Consultancy; Daiichi-Sankyo: Consultancy. Al Baghdadi:Celgene: Consultancy, Honoraria; Heron: Consultancy, Honoraria; Tracon: Equity Ownership; Epizyme: Equity Ownership; Bristol Myer Squibb: Consultancy, Honoraria; Sunesis: Equity Ownership; Portola: Equity Ownership; Heron therapeutics: Equity Ownership; Cardinal health: Consultancy, Honoraria; Bristol Myer Squibb: Equity Ownership; Celgene: Equity Ownership; Spectrum pharmaceutical: Equity Ownership; Astrazeneca: Equity Ownership; Seattle genetics: Equity Ownership; Roche: Consultancy, Honoraria. DeZern:Astex Pharmaceuticals, Inc.: Consultancy; Celgene: Consultancy. Foran:Agios: Honoraria, Research Funding. Gore:Celgene Corporation: Consultancy, Research Funding. Komrokji:DSI: Consultancy; Agios: Consultancy; Novartis: Speakers Bureau; JAZZ: Speakers Bureau; pfizer: Consultancy; celgene: Consultancy; Incyte: Consultancy; JAZZ: Consultancy. Maciejewski:Alexion: Consultancy; Novartis: Consultancy. Starczynowski:Kurome Therapeutics: Consultancy. Sekeres:Millenium: Membership on an entity's Board of Directors or advisory committees; Syros: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees.

Introduction Novel high-risk groups have been identified in adult ALL, including secondary (sALL) and Philadelphia-like ALL (Ph-like, based on CRLF2, IgH, ABL2, JAK2 and other tyrosine kinase translocations), and those with minimal residual disease >0.1% (MRD+) after induction therapy. Novel targeted therapies are now routinely incorporated into 1st line regimens, including tyrosine kinase inhibitors (BCR-ABL1-pos), rituximab (CD20+) and blinatumomab (Blina) for MRD+. The impact of these novel high risk groups and therapies after alloHCT is unknown; therefore, we evaluated their impact on overall survival (OS), relapse rate (REL), non-relapse mortality (NRM) and acute and chronic GVHD. Methods We evaluated pts receiving 1st Allo-HCT for ALL at Mayo Clinic (Rochester, Phoenix, and Jacksonville) from 2008-2018 for outcomes of interest, specifically the impact of novel therapies and risk groups. Associations of patient factors with outcomes were examined using univariable (UVA) and multivariable (MVA) Cox proportional hazards regression models, where the cause-specific hazard of the given outcome was modeled to account for the competing risk of death. Results We identified 261 consecutive AlloHCT recipients during the study period. Median age at transplant was 48 years (18-72) and 147 (56.3%) were male. The median comorbidity (HCT-CI) score was 2 (0-8). 213 pts (81.6%) had B-lineage ALL, of which 85 (32.6%) were BCR-ABL-pos, 17 (6.5%) Ph-like (identified by FISH), 16 (6.1%) hypoploidy/near triploidy (Hy/Tri), and 67 (25.7%) pre-B ALL NOS. The remaining 48 (18.4%) had T-ALL. 30 pts (11.5%) had sALL (i.e. prior chemo/radiotherapy for another malignancy). HyperCVAD was the most common 1st line regimen (68.2%). 243 (93.1%) pts achieved Complete Remission (CR1) after induction therapy, and 203 (77.8%) were in CR1 at the time of alloHCT. Blina was administered for MRD+ in 14 pts (5.4%), and for relapsed/refractory ALL (R/R) in 13 (27% of R/R pts), 7 of whom received Blina as initial therapy for R/R. Donors were matched unrelated in 149 (57.1%), matched related in 98 (37.5%), and haploidentical in 14 (5.4%). Peripheral blood (PB) grafts were used in 233 (89.3%). 103 (54.5%) were donor:recipient (D:R) sex-matched, and 86 D:R mismatched [47 (24.9%) M:F; and 39 (20.6%) F:M]. Myeloablative conditioning was used for the majority (78.5%) mostly with Cy/TBI (60.5%). Standard GVHD prophylaxis regimens were used. Outcomes Median follow-up after transplant was 22.4 months (0.5-135), and 51 (19.5%) had REL. The 1, 2 and 5-year survival rates were 71.9%, 64.9%, and 54.1%, respectively (Figure 1). Acute GVHD developed in 144 (55.2%) and chronic GVHD in 100 (38.3%). Ph-like ALL, Blina for MRD+, Blina for R/R, sALL and CD20-pos had no independent impact on OS. In contrast, age>60, Hy/Tri, and >CR1 at alloHCT were associated with worse OS in UVA, however, in MVA only pre-B ALL NOS was associated with better OS. Female:male D:R status was associated with inferior OS. Blina for R/R disease was associated with increased risk of REL in UVA [HR 5.26 95% CI (1.33, 20.00), p=0.017], whereas other novel high risk groups had no impact on REL. In contrast, T-ALL, Hy/Tri and >CR1 at AlloHCT were associated with increased REL in UVA, but only T-ALL and Hy/Tri continued to predict for increased REL in MVA. Secondary ALL was associated with increased NRM in UVA [HR 1.96 95% CI (1.07, 3.57), p=0.028], whereas other novel high risk groups had no impact on NRM. In contrast, age>60, >CR1 at AlloHCT and D:R sex mismatch were associated with higher NRM in UVA, but only sex mismatch and >CR1 at AlloHCT were associated with higher NRM in MVA. TBI use was associated with higher risk of acute GvHD (p=0.008) and ATG use with lower risk chronic GVHD (p<0.001). Similarly non-PB grafts were associated with a lower risk of chronic GVHD (p=0.005). Results for OS, REL, NRM, acute and chronic GVHD analysis are shown in Table 1. Conclusion Novel high risk groups (CD20+, Ph-like and sALL) do not appear to adversely impact OS after alloHCT, although sALL was associated with increased risk of NRM. Interestingly, pre-B-ALL NOS appear to be associated with favorable OS. Novel targeted therapies also do not independently predict outcome, with the exception of Blina for R/R ALL which may be associated with REL after subsequent alloHCT (a subgroup for whom novel maintenance strategies should be explored). Our analysis highlights the importance of allo-HCT for novel high risk ALL subgroups. Disclosures Patnaik: Stem Line Pharmaceuticals.: Membership on an entity's Board of Directors or advisory committees. Kharfan-Dabaja:Daiichi Sankyo: Consultancy; Pharmacyclics: Consultancy. Foran:Agios: Honoraria, Research Funding.

Background: Mutations in isocitrate dehydrogenase 1 (IDH1) occur in ~3% of individuals with myelodysplastic syndrome (MDS) and have been associated with increased transformation to acute myeloid leukemia (AML). Ivosidenib (AG-120) is an oral, potent, targeted inhibitor of the mutant isocitrate dehydrogenase 1 enzyme (mIDH1) and is approved in the US for the treatment of newly diagnosed AML with a susceptible IDH1 mutation in patients ≥75 years of age or who have comorbidities that preclude the use of intensive induction chemotherapy, and in adult patients with relapsed or refractory (R/R) AML. The first-in-human, phase 1 dose escalation and expansion study of ivosidenib (NCT02074839) enrolled adults with mIDH1 advanced hematologic malignancies, including R/R MDS, and the study is ongoing. In the initial phase of the study (DiNardo et al. N Engl J Med 2018), the 12 patients with R/R MDS received 500 mg ivosidenib once daily and were characterized as follows: 75% were male, median age was 72.5 years (range 52-78), and 42% were ≥75 years of age; median number of prior therapies was 1 (range 1-3). Adverse events (AEs) of any grade, irrespective of causality, occurring in ≥20% of the 12 patients were diarrhea, fatigue, back pain, rash (n=4 each, 33.3%), anemia, urinary tract infection, decreased appetite, hypokalemia, arthralgia, dyspnea, pruritus, and hypotension (n=3 each, 25.0%). No AEs led to permanent discontinuation of treatment. Response was assessed according to International Working Group 2006 criteria for MDS. According to investigators, five of 12 patients achieved complete remission (CR) (41.7%; 95% CI 15.2%, 72.3%); median duration of CR was not estimable for these patients (95% CI 2.8 months, not estimable). Nine of 12 patients were transfusion independent for at least 56 days during study treatment. Mutation clearance was observed in one of the 5 CR patients. Here we report the design of a new sub-study of this trial, which is being undertaken to further assess the safety, tolerability, and clinical activity of treatment with ivosidenib in patients with R/R MDS. Methods: This sub-study is evaluating the safety, tolerability, pharmacokinetics, pharmacodynamics, and clinical activity of ivosidenib. Adults with R/R MDS with an IDH1 mutation will be enrolled in the MDS sub-study. These individuals must have R/R disease after treatment with standard agents indicated for MDS. Eligible patients must have a platelet count of ≥20,000/μL, and adequate hepatic function (total bilirubin ≤1.5 × upper limit of normal [ULN]; aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase ≤3.0 × ULN) and renal function (serum creatinine ≤2.0 × ULN or creatinine clearance >40 mL/min). Additional key inclusion criteria are bone marrow blasts >5% and/or transfusion dependence. Ivosidenib is to be administered at a dose of 500 mg once daily orally on Days 1 to 28 of 28-day cycles. The addition of the MDS sub-study to this phase 1 clinical study in patients with hematological malignancies will provide additional insights into the use of ivosidenib for the treatment of mIDH1 R/R MDS. Disclosures Foran: Agios: Honoraria, Research Funding. DiNardo:notable labs: Membership on an entity's Board of Directors or advisory committees; medimmune: Honoraria; daiichi sankyo: Honoraria; abbvie: Consultancy, Honoraria; agios: Consultancy, Honoraria; jazz: Honoraria; celgene: Consultancy, Honoraria; syros: Honoraria. Watts:Takeda: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Stein:Agios: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astellas Pharma US, Inc: Membership on an entity's Board of Directors or advisory committees; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo, Inc.: Membership on an entity's Board of Directors or advisory committees; Bioline: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; PTC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Syros: Membership on an entity's Board of Directors or advisory committees. De Botton:Daiichi Sankyo: Consultancy; Astellas: Consultancy; Bayer: Consultancy; AbbVie: Consultancy; Syros: Consultancy; Forma: Consultancy, Research Funding; Janssen: Consultancy; Novartis: Consultancy; Pfizer: Consultancy; Servier: Consultancy; Pierre Fabre: Consultancy; Celgene: Consultancy, Speakers Bureau; Agios: Consultancy, Research Funding. Fathi:Amphivena, Kite, Jazz, NewLink Genetics,: Honoraria; Agios, Astellas, Celgene, Daiichi Sankyo, Novartis, Takeda, Amphivena, Kite, Forty Seven,Trovagene, NewLink genetics, Jazz, Abbvie, and PTC Therapeutics: Consultancy. Stein:Stemline: Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Celgene: Speakers Bureau. Stone:AbbVie, Actinium, Agios, Argenx, Arog, Astellas, AstraZeneca, Biolinerx, Celgene, Cornerstone Biopharma, Fujifilm, Jazz Pharmaceuticals, Amgen, Ono, Orsenix, Otsuka, Merck, Novartis, Pfizer, Sumitomo, Trovagene: Consultancy; Argenx, Celgene, Takeda Oncology: Other: Data and Safety Monitoring Board/Committee: ; Novartis, Agios, Arog: Research Funding. Patel:France Foundation: Honoraria; Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Dava Oncology: Honoraria. Tallman:UpToDate: Patents & Royalties; Daiichi-Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees; BioLineRx: Consultancy, Membership on an entity's Board of Directors or advisory committees; Rigel: Consultancy, Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Cellerant: Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Delta Fly Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Nohla: Consultancy, Membership on an entity's Board of Directors or advisory committees; ADC Therapeutics: Research Funding; Tetraphase: Consultancy, Membership on an entity's Board of Directors or advisory committees; Orsenix: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Biosight: Research Funding; Oncolyze: Consultancy, Membership on an entity's Board of Directors or advisory committees; KAHR: Consultancy, Membership on an entity's Board of Directors or advisory committees. Choe:Agios: Employment, Equity Ownership; Agios: Employment, Equity Ownership. Wang:Agios: Employment, Equity Ownership. Zhang:Agios: Employment, Equity Ownership; Agios: Employment, Equity Ownership. Fan:Agios: Employment, Equity Ownership. Yen:Agios: Employment, Equity Ownership. Oluyadi:Agios: Employment, Equity Ownership. Winkler:Agios: Employment. Hickman:Agios: Employment, Equity Ownership. Agresta:Agios: Employment, Equity Ownership. Liu:Agios: Employment, Equity Ownership. Wu:Agios: Employment, Equity Ownership. Attar:Aprea Therapeutics: Employment; Agios: Employment, Equity Ownership. Kantarjian:Astex: Research Funding; Takeda: Honoraria; Actinium: Honoraria, Membership on an entity's Board of Directors or advisory committees; Immunogen: Research Funding; AbbVie: Honoraria, Research Funding; Jazz Pharma: Research Funding; Agios: Honoraria, Research Funding; Ariad: Research Funding; Amgen: Honoraria, Research Funding; Cyclacel: Research Funding; BMS: Research Funding; Daiichi-Sankyo: Research Funding; Novartis: Research Funding; Pfizer: Honoraria, Research Funding. OffLabel Disclosure: Ivosidenib (AG-120) is an IDH1 inhibitor indicated for the treatment of AML with a susceptible IDH1 mutation as detected by an FDA-approved test in: 1) adult patients with newly-diagnosed AML who are more than 75 years old or who have comorbidities that preclude use of intensive induction chemotherapy and 2) adult patients with relapsed or refractory AML. It is being evaluated in clinical trials for mutant IDH1 advanced hematologic malignancies.

Introduction There have been few recent therapeutic advances in T-acute lymphoblastic leukemia/lymphoma (T-ALL/LBL), a rare and aggressive malignancy. Intensive chemotherapy +/- allogeneic transplantation (AlloHCT) can effect cure, realized by only a minority of adults. In distinction to B-ALL, there have been no safe/effective targeted therapies developed in T-ALL/LBL. We therefore performed a focused tissue array to identify novel tumor proteins, including CCR4; evaluated together with established immunophenotypic (IP) T-ALL/LBL subtypes [early-T-precursor (ETP), early non-ETP (Pre/Pro-T), common & late thymocyte]. We evaluated the clinical phenotype and outcome together with clinical and epidemiologic data in patients diagnosed at the 3-site Mayo Clinic Cancer Center (MCCC: Rochester, MN; Phoenix, AZ; and Jacksonville, FL). Methods Following IRB approval, we identified 50 consecutive T-ALL/LBL patients from 1997 -2019 diagnosed at the 3-site MCCC. Available remnant leukemia/lymphoma paraffin blocks were identified (n=28). Using immunohistochemistry (IHC) we evaluated expression of leukemic antigens of interest (CCR4, CD47, BCL2, BCL6, PD-L1, CD38 and CD123); these were selected based on clinical availability of novel targeted agents, approved or in development for other indications. Tissue array studies were performed and interpreted by a single hematopathologist (L.J) blinded to clinical data, using positive and negative controls, according to standard techniques. We also evaluated the clinical and epidemiological parameters, including different IP subtypes [ETP: CD1a-, sCD3- & CD8-, Pre/Pro-T: CD1a-, sCD3- & CD8+ or CD8- (11 marker T-ALL IP score was used to distinguish CD8- ETP vs. Pre/Pro-T), thymic: CD1a+ and mature: CD1a- & sCD3+] (Khogeer et al., Br J Haematol., 2019) & the presence of the unique MLLT10-PICALM fusion (n=6), as well as therapy and outcome. Comparisons of characteristics and outcomes of interest were made using a Wilcoxon rank sum test (continuous characteristics) or Fisher's exact test (categorical characteristics), unadjusted Cox proportional hazards regression models (overall survival), or unadjusted logistic regression models (complete remission after first line treatment). Results We identified the expression of novel targetable tissue proteins in all adult T-ALL/LBL cases [Table 1]. BCL2, CD38 & CD47 were expressed in majority of the cases, and CCR4 [Fig. 1] was expressed in 11/28 (39.3%) cases. CCR4 expression was significantly more common in the Pre/Pro-T (75%) vs. other IP subtypes (19%) (p=0.011); there was no other association of CCR4 expression with clinical characteristics/outcomes. We also observed differences in T-ALL vs. T-LBL, specifically T-ALL patients were more likely to be male (71% vs. LBL 38.9%, p=0.038). Surprisingly, T-LBL patients were more likely to have a family history of leukemia/lymphoma (41.2% vs. T-ALL 0%, p<0.001). In addition, a significantly different distribution of IP subtype in T-LBL was noted [Table 2]. Not surprisingly, T-LBL patients were more likely to receive 1st line Hyper-CVAD therapy (88.2% v. T-ALL 43.3%, p=0.005), & had a longer delay from diagnosis to initiation of therapy (median 14 vs. 4 days, p=0.012), however this did not appear to impact clinical outcome. In contrast, we observed an important association of IP subtype with outcome after therapy, including complete remission (p=0.035), & a trend suggesting differences in survival (p=0.069) [Table 3]. However, MLLT10-PICALM was not associated with any unique clinical features or with outcome (death, p=0.85; CR, p=0.98), although 4/6 patients underwent AlloHCT, suggesting an important role of AlloHCT in this subgroup. No other significant association of epidemiologic risk factors with phenotype or outcome was noted. Conclusion Using focused tissue array we have identified expression of tumor associated proteins in T-ALL/LBL including CCR4 (Pre/Pro-T IP) & others, which may be targets of therapeutic agents like mogamulizumab. Furthermore, our analysis demonstrates an important clinical impact of IP subtype in T-ALL/LBL, as well as important clinical & therapeutic differences in T-ALL vs. LBL. This study will help guide development of targeted clinical trials in T-ALL/LBL (CCR4 trial already in development). Further analyses are planned to determine the clinical & epidemiologic association of genetic lesions in this cohort. Disclosures Foran: Agios: Honoraria, Research Funding.