Abstract: Background: Follicular lymphoma (FL) remains an incurable disease for most patients (pts), characterized by a relapsing and remitting pattern. For pts with relapsed/refractory (r/r) FL, treatment outcomes typically worsen with each subsequent line of therapy, highlighting an unmet need. Tisagenlecleucel (tisa-cel) has demonstrated clinical benefits and manageable safety in pediatric and young adult pts with r/r B-cell acute lymphoblastic leukemia and adult pts with r/r diffuse large B-cell lymphoma. In a prior phase (Ph) 2a study of 14 pts with r/r FL, 71% achieved durable complete remission with tisa-cel (Chong et al. ICML 2019). Here we present a planned interim analysis of ELARA, a Ph 2, international trial of tisa-cel in adults with r/r FL. Methods: Adults with histologically confirmed FL (grades [Gr] 1-3A) being r/r within 6 mo after second-/later-line therapy (including an anti-CD20 monoclonal antibody with an alkylating agent) or relapsed after autologous hematopoietic stem cell transplant (autoHSCT), and with ECOG performance score of 0-1 were eligible. Pts wi th histologic transformation, prior allogeneic HSCT, or active CNS involvement were excluded. All pts received lymphodepleting chemotherapy followed by tisa-cel infusion of 0.6-6×108 CAR-T cells (bridging therapy prior to infusion was permitted). Disease was reassessed prior to infusion for all pts who received bridging therapy to establish a new baseline. After infusion, disease assessments were performed every 3 mo. The primary endpoint was complete response rate (CRR) based on best response by central review (Lugano 2014 criteria). Pts evaluable for efficacy had measurable disease at infusion and ≥6 mo follow-up from infusion or discontinued early. Secondary endpoints included overall response rate (ORR), duration of response (DOR), progression-free survival (PFS), overall survival (OS), and safety. Results: As of May 26, 2020, 122 pts were screened, 98 were enrolled, 97 received tisa-cel (median follow-up, 6.5 mo), and 52 were evaluable for efficacy (median follow-up, 9.9 mo). At study entry, median age among treated pts was 57 y (range, 29-73), 66% of pts were male, 84% had stage III-IV disease, and 60% had a FLIPI score ≥3. The median number of prior lines of therapy was 4 (range, 2-13), including prior autoHSCT in 36%; 77% were refractory to the last prior treatment (75% ≥2 prior regimens), and 60% had disease progression within 2 y of initial anti-CD20-containing treatment. Overall, 43% of pts received bridging therapy; 18% were treated as outpatient. Of the first 52 pts evaluable for efficacy, CRR was 65.4% (34/52; 99.5% CI, 45.1-82.4) in the intent-to-treat (ITT) population and 71.1% (33/46; 99.5% CI, 56.5-84.0) in the per-protocol (PP) population; ORR was 82.7% (43/52; 95% CI, 69.7-91.8) in the ITT population and 84.8% (39/46; 95% CI, 71.1-93.7) in the PP population. In pts with best response of CR, probability of response lasting ≥6 mo was 89.7% (84.4% for all responding pts [CR+PR]). CRR and ORR were consistent across key prognostic subgroups and per investigator assessment. Median DOR, PFS, OS, and time to next antilymphoma treatment were not reached. Of 97 pts evaluable for safety, 69% experienced Gr ≥3 adverse events, most commonly neutropenia (Gr 3, 13%; Gr 4, 15%); 48% of pts had cytokine release syndrome related to tisa-cel (CRS; Gr 1, 29%; Gr 2, 20%; Gr ≥3, 0%; per Lee scale). To treat CRS, 15% of pts required tocilizumab and 3% required steroids. Any grade serious neurologic events (NEs; per CTCAE v4.03) occurred in 10% of pts; 2% had Gr ≥3 and all recovered (1 pt developed Gr 4 immune-effector cell neurotoxicity syndrome related to tisa-cel concomitant with possible HHV6 encephalitis; 1 pt developed Gr 3 delirium unrelated to tisa-cel after progression of disease and start of salvage therapy). Median time to CRS and serious NEs onset were 4 and 8.5 d, respectively, with respective median time to resolution of 4 and 2 d. Three pts died from progressive disease; no deaths were treatment-related. Conclusions: Preliminary data from ELARA suggest that tisa-cel is effective in extensively treated r/r FL, resulting in high CRRs and ORRs, including in high-risk pts. The overall safety profile is favorable, with no severe CRS and very low NE reported, requiring limited anticytokine therapy. Updated safety and efficacy results on 97 pts (including dose and cellular kinetics data) will be presented at the meeting. Disclosures Fowler: TG Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Research Funding. Dickinson:Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Consultancy, Honoraria, Research Funding, Speakers Bureau; Merck Sharp & Dohme: Consultancy; Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau. Dreyling:Astra Zeneca: Consultancy; Abbvie: Research Funding; Roche: Consultancy, Research Funding, Speakers Bureau; Celgene: Consultancy, Research Funding, Speakers Bureau; Bayer: Consultancy, Speakers Bureau; Beigene: Consultancy; Gilead: Consultancy, Research Funding, Speakers Bureau; Janssen: Consultancy, Research Funding, Speakers Bureau; Novartis: Consultancy. Martinez-Lopez:Janssen: Consultancy, Honoraria; Novartis: Consultancy; Janssen-cilag: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Research Funding; Incyte: Consultancy, Research Funding. Kolstad:Merck: Research Funding; Nordic Nanovector: Membership on an entity's Board of Directors or advisory committees, Research Funding. Popplewell:Pfizer: Research Funding; Novartis: Research Funding; Roche: Research Funding. Chavez:Genentech: Speakers Bureau; Epizyme: Speakers Bureau; Gilead: Consultancy; Verastem: Consultancy; AbbVie: Consultancy; Karyopharm: Consultancy; BeiGene: Speakers Bureau; Novartis: Consultancy; Kite, a Gilead Company: Consultancy, Speakers Bureau; Pfizer: Consultancy; AstraZeneca: Speakers Bureau; Morphosys: Consultancy, Speakers Bureau; Merck: Research Funding; Bayer: Consultancy; Celgene: Consultancy. Bachy:Beigene: Membership on an entity's Board of Directors or advisory committees; Roche, Celgene, Amgen, Janssen, Gilead, Novartis, Sanofi: Honoraria; Amgen: Research Funding; Roche, Gilead: Consultancy. Kato:AbbVie, AstraZeneca, Celgene, Chugai, Eisai, Janssen, and Novartis: Consultancy; hugai, Takeda, Kyowa-Kirin, Abbvie, Novartis, Eisai, Janssen, Celgene, Ono: Research Funding; Chugai, Takeda, MSD, Kyowa-Kirin, Janssen, Celgene, Ono, Mundi, Dainippon-Sumitomo, Novartis: Honoraria. Harigae:Novartis, Chugai, BMS: Honoraria. Kersten:BMS: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Celgene: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Amgen: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Janssen/Cilag: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Miltenyi Biotech: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Takeda: Research Funding; Roche: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Kite/Gilead: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); MSD: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Novartis: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company). Andreadis:Novartis: Research Funding; Gilead/Kite: Consultancy; Merck: Research Funding; Incyte: Consultancy; Karyopharm: Honoraria; Jazz Pharmaceuticals: Honoraria; BMS/Celgene/Juno: Honoraria, Research Funding; Genentech: Consultancy, Current equity holder in publicly-traded company. Riedell:Bayer: Honoraria; Karyopharm Therapeutics: Honoraria; Morphosys: Research Funding; Celgene/Bristol-Myers Squibb Company: Honoraria, Research Funding; Verastem Oncology: Honoraria; Kite Pharmaceuticals/Gilead: Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding. Nastoupil:Karus Therapeutics: Research Funding; Gamida Cell: Honoraria; Gilead/KITE: Honoraria; Novartis: Honoraria, Research Funding; Merck: Research Funding; Celgene: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Bayer: Honoraria; Janssen: Honoraria, Research Funding; LAM Therapeutics: Research Funding; TG Therapeutics: Honoraria, Research Funding; Genentech, Inc.: Honoraria, Research Funding. von Tresckow:Takeda: Honoraria, Other: Travel support, Research Funding; Amgen: Honoraria; Pfizer: Honoraria; Kite/Gilead: Honoraria; Roche: Honoraria; MSD Sharp & Dohme: Honoraria, Research Funding; Takeda: Honoraria, Other: Travel support, Research Funding; Novartis: Other: Travel support, Research Funding. Ferreri:Morphosys: Research Funding; Hutchinson: Research Funding; BMS: Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding. Teshima:Sharp & Dohme Corp: Consultancy, Honoraria; Bristol-Myers Squibb: Honoraria; Pfizer Japan Inc.: Honoraria; Kyowa Kirin Co., Ltd.: Honoraria, Research Funding; TEIJIN PHARMA LIMITED: Honoraria; The Center of Innovation Program from Japan Science and Technology Agency: Other; Fuji Pharma Co., Ltd.: Honoraria; NIPPON SHINYAKU CO., LTD.: Honoraria; Janssen Pharmaceutical K.K.: Other; Japan Society for the Promotion of Science KAKENHI (17H04206): Other; Novartis Pharma K.K.: Consultancy, Other: Manuscript preparation, Research Funding; Takeda Pharmaceutical Company Limited: Consultancy, Honoraria; Chugai Pharmaceutical Co., Ltd.: Research Funding; Astellas Pharma Inc.: Research Funding; Merck: Consultancy, Honoraria; Sanofi K.K.: Research Funding. Patten:Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Honoraria; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria. McGuirk:Novartis: Research Funding; Fresenius Biotech: Research Funding; Astellas: Research Funding; Juno Therapeutics: Consultancy, Honoraria, Research Funding; Allo Vir: Consultancy, Honoraria, Research Funding; Kite Pharmaceuticals: Consultancy, Honoraria, Research Funding, Speakers Bureau; Pluristem Ltd: Research Funding; Gamida Cell: Research Funding; Bellicum Pharmaceutical: Research Funding. Petzer:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Kite-Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Viardot:Amgen: Honoraria, Other: advisory board; Novartis: Honoraria, Other: advisory board; Kite/Gilead: Honoraria, Other: advisory board; Roche: Honoraria, Other: advisory board. Zinzani:ADC Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Immune Design: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; EUSA Pharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Immune Design: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sandoz: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Portola: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Kyowa Kirin: Consultancy, Speakers Bureau; Eusapharma: Consultancy, Speakers Bureau; Verastem: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kirin Kyowa: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Servier: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; TG Therapeutics, Inc.: Honoraria, Speakers Bureau; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen-Cilag: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Celltrion: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Malladi:Novartis: Consultancy, Honoraria. Bubuteishvili Pacaud:Novartis: Current Employment. Forcina:Novartis: Current Employment. Zia:Novartis: Current Employment. Schuster:Novartis, Genentech, Inc./ F. Hoffmann-La Roche: Research Funding; AlloGene, AstraZeneca, BeiGene, Genentech, Inc./ F. Hoffmann-La Roche, Juno/Celgene, Loxo Oncology, Nordic Nanovector, Novartis, Tessa Therapeutics: Consultancy, Honoraria. Thieblemont:Cellectis: Speakers Bureau; Roche, Amgen, Kyte Gilead, Celgene, Abbvie, Novartis, Cellectis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support; Roche, Hospita: Research Funding.

Abstract: Background: Follicular lymphoma is an indolent disease with a continuous relapsing pattern and typically requires multiple lines of therapy. Novel therapies such as tisagenlecleucel are being investigated to improve outcomes. Primary analysis of the single-arm, multicenter, Phase II ELARA trial in r/r FL demonstrated that tisagenlecleucel resulted in high overall (ORR) and complete response rates (CRR), and prolonged progression-free survival (PFS) at a median follow-up of 11 months (mo). Here, we report updated efficacy results from the overall population at a median follow-up of 17 mo, and a subgroup analysis of pts with high-risk disease from the ELARA trial (NCT03568461). Methods: Eligible adult pts had histologically confirmed r/r FL (grades 1-3A) after ≥2 lines of therapy or had relapsed after autologous stem cell transplant. Bridging therapy was allowed and was followed by disease evaluation before tisagenlecleucel infusion. Pts received tisagenlecleucel (0.6-6×10 8 CAR+ viable T cells) after lymphodepleting chemotherapy (fludarabine [25 mg/m 2] + cyclophosphamide [250 mg/m 2] QD for 3 d or bendamustine [90 mg/m 2] QD for 2 d). Endpoints included ORR, CRR, PFS, and duration of response (DOR). Descriptiv e efficacy subanalyses were performed for 9 high-risk subgroups, including prior hematopoietic stem cell transplant (HSCT), ≥5 prior lines of therapy, progression of disease within 24 mo from first immunochemotherapy (POD24), double-refractory disease, high Follicular Lymphoma International Prognostic Index (FLIPI) at study entry, high lactate dehydrogenase at baseline, high C-reactive protein (CRP) prior to infusion, radiological bulky disease (by GELF criteria), and high total metabolic tumor volume (TMTV; & gt;510 cm 3) at baseline (median 155.32 cm 3; range 0.1-2470.4 cm 3). Descriptive subgroup analysis was supported by multivariate analysis to identify factors predictive of worse outcomes. Results: As of March 29, 2021, 97 pts received tisagenlecleucel and 94 were evaluable for primary efficacy analysis (median follow-up 17 mo). High and durable responses were seen in the overall ELARA population (ORR 86.2%, CRR 69.1%, 9-mo DOR 76.0%, and 12-mo PFS 67.0%). In CR pts at 9 mo, PFS was 85.5% and estimated probability of remaining in response was 86.5%. Safety reflected known tisagenlecleucel profile; 48% of pts had CRS (majority were grade 1/2) and 11.3% had neurological events (3% grade ≥3). In the subgroup analysis, pts were stratified into risk groups. Efficacy (ORR, CRR) and durability of response were well maintained in all high-risk subgroups, except for POD24 (n=35), high TMTV (n=20), and ≥5 prior lines of therapy (n=27). Compared with corresponding low-risk subgroups, there was a numerical reduction in CRR for high-risk subgroups (POD24 59.0% vs 87.9%; high TMTV 40.0% vs 76.4%; ≥5 prior lines of therapy 59.3% vs 73.1%) (Figure). A reduction in 12-mo PFS was also identified for pts in these subgroups: POD24 (60.8% vs 77.9%), high baseline TMTV (54.5% vs 68.5%), and ≥5 prior lines of therapy (59.6% vs 69.7%). Evaluating the disease characteristics of the high TMTV subgroup compared with low TMTV, high TMTV was associated with a higher incidence of bulky disease (58.3% vs 90.0%), high FLIPI (54.2% vs 85.0%), and high CRP (45.8% vs 70.0%). In the multivariate analysis of high-risk factors, only POD24 (hazard ratio [HR] 2.34; 95% CI, 1.02- 5.34) and high TMTV (HR 2.53; 95% CI, 1.14-5.65) were associated with shorter PFS. For pts with both POD24 and high TMTV (n=12), the CRR was 16.7% with a 12-mo PFS of 36.0%. These analyses of high-risk subgroups are exploratory in nature and should be validated in a larger study cohort. Conclusions : With 17-mo median follow-up, tisagenlecleucel produced high ORR and CRR and was associated with durable response and promising 12-mo PFS in pts with r/r FL and 2+ prior lines of therapy. Safety was consistent with known tisagenlecleucel profile. POD24 and high TMTV were independently associated with PFS. These results suggest that tisagenlecleucel can induce high rates of durable response, including most pts in the high-risk disease subgroups, who have poor prognosis with current non-CAR-T cell therapies. Figure 1 Figure 1. Disclosures Thieblemont: Bristol Myers Squibb/Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses ; Gilead Sciences: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses ; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses ; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses , Research Funding; Kyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses ; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses ; Cellectis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses ; Hospira: Research Funding; Bayer: Honoraria; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses . Dickinson: Amgen: Honoraria; Gilead Sciences: Consultancy, Honoraria, Speakers Bureau; MSD: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Takeda: Research Funding; Celgene: Research Funding; Roche: Consultancy, Honoraria, Other: travel, accommodation, expenses, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau. Martinez-Lopez: Incyte: Consultancy, Research Funding, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; BMS: Consultancy, Research Funding, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Roche: Consultancy, Research Funding, Speakers Bureau; Astellas: Research Funding, Speakers Bureau. Kolstad: Nordic Nanovector: Membership on an entity's Board of Directors or advisory committees, Research Funding. Popplewell: Pfizer: Other: Travel; Novartis: Other: Travel; Hoffman La Roche: Other: Food. Chavez: AstraZeneca: Research Funding; Novartis: Consultancy; MorphoSys: Speakers Bureau; Karyopharm Therapeutics: Consultancy; Adaptive: Research Funding; Kite/Gilead: Consultancy; Abbvie: Consultancy; Merck: Research Funding; BeiGene: Speakers Bureau; ADC Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Myers Squibb: Speakers Bureau; Epizyme: Speakers Bureau. Bachy: Roche: Consultancy; Takeda: Consultancy; Kite, a Gilead Company: Honoraria; Novartis: Honoraria; Daiishi: Research Funding; Incyte: Consultancy. Kato: Kyowa Kirin: Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Eisai: Consultancy, Research Funding; Dainippon-Sumitomo: Honoraria; Daiichi Sankyo: Consultancy, Research Funding; Chugai: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; AstraZeneca: Consultancy; Abbvie: Consultancy, Research Funding; MSD: Honoraria; Mundi: Honoraria; Novartis: Consultancy, Research Funding; Ono: Honoraria, Research Funding. Harigae: Novartis Pharma: Honoraria, Research Funding; Chugai Pharma: Honoraria; Janssen Pharma: Honoraria; Ono pharma: Honoraria, Other: Subsidies or Donations; Astellas Pharma: Other: Subsidies or Donations; Kyowakirin: Other: Subsidies or Donations; Bristol Myers Squibb: Honoraria. Kersten: Kite/Gilead: Honoraria, Research Funding; Novartis: Honoraria; Miltenyi Biotech: Honoraria; BMS/Celgene: Honoraria, Research Funding; Roche: Honoraria; Takeda: Honoraria. Andreadis: GenMAB: Research Funding; Karyopharm: Honoraria; Incyte: Honoraria; BMS/Celgene: Research Funding; Epizyme: Honoraria; Crispr Therapeutics: Research Funding; Atara: Consultancy, Honoraria; Novartis: Research Funding; Kite: Honoraria; Merck: Research Funding; Roche: Current equity holder in publicly-traded company, Ended employment in the past 24 months; TG Therapeutics: Honoraria. Riedell: Kite/Gilead: Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; MorphoSys: Research Funding; BeiGene: Consultancy; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene/BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees; Tessa Therapeutics: Research Funding; Bayer: Membership on an entity's Board of Directors or advisory committees; Xencor: Research Funding; Karyopharm: Consultancy, Membership on an entity's Board of Directors or advisory committees; Calibr: Research Funding. Pérez-Simón: Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Chen: Mesolbast: Honoraria; Morphosys: Honoraria. Nastoupil: MorphoSys: Honoraria; Bayer: Honoraria; Genentech: Honoraria, Research Funding; Takeda: Honoraria, Other: DSMC, Research Funding; IGM Biosciences: Research Funding; Denovo Pharma: Other: DSMC; Bristol Myers Squibb/Celgene: Honoraria, Research Funding; Caribou Biosciences: Research Funding; Novartis: Honoraria, Research Funding; Gilead/Kite: Honoraria, Research Funding; TG Therapeutics: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; ADC Therapeutics: Honoraria; Epizyme: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding. Von Tresckow: Pentixafarm: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Other: Congress and travel support, Research Funding; MSD: Consultancy, Honoraria, Other: Congress and travel support, Research Funding; Kite-Gilead: Consultancy, Honoraria; BMS-Celgene: Consultancy, Honoraria, Other: Congress and travel support; AstraZeneca: Honoraria, Other: Congress and travel support; Amgen: Consultancy, Honoraria; AbbVie: Other: Congress and travel support; Pfizer: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Other, Research Funding. Ferreri: Gilead, Novartis, Juno, PletixaPharm, Roche, Incyte: Membership on an entity's Board of Directors or advisory committees; BMS, Beigene, Pharmacyclics, Hutchison Medipharma, Amgen, Genmab, ADC Therapeutics, Gilead, Novartis, Pfizer: Research Funding. Teshima: Fuji pharma CO.,Ltd: Research Funding; Astellas Pharma Inc.: Research Funding; TEIJIN PHARMA Limited: Research Funding; CHUGAI PHARMACEUTICAL CO., LTD.: Research Funding; Pfizer Inc.: Honoraria; Merck Sharp & Dohme: Membership on an entity's Board of Directors or advisory committees; Kyowa Kirin Co.,Ltd.: Honoraria, Research Funding; Takeda Pharmaceutical Company: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis International AG: Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; Janssen Pharmaceutical K.K.: Other; Nippon Shinyaku Co., Ltd.: Research Funding; Bristol Myers Squibb: Honoraria; Sanofi S.A.: Research Funding; Gentium/Jazz Pharmaceuticals: Consultancy. Patten: ASTRA ZENECA: Honoraria; ABBVIE: Honoraria; NOVARTIS: Honoraria; GILEAD SCIENCES: Honoraria, Research Funding; ROCHE: Research Funding; JANSSEN: Honoraria. McGuirk: Kite/ Gilead: Consultancy, Honoraria, Other: travel accommodations, expense, Kite a Gilead company, Research Funding, Speakers Bureau; Novartis: Research Funding; Gamida Cell: Research Funding; Fresenius Biotech: Research Funding; Novartis: Research Funding; EcoR1 Capital: Consultancy; Magenta Therapeutics: Consultancy, Honoraria, Research Funding; Allovir: Consultancy, Honoraria, Research Funding; Juno Therapeutics: Consultancy, Honoraria, Research Funding; Astelllas Pharma: Research Funding; Bellicum Pharmaceuticals: Research Funding; Pluristem Therapeutics: Research Funding. Petzer: AppVie: Honoraria; Astra Zeneca: Honoraria; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria; Amgen: Honoraria; Janssen: Honoraria; Sanofi: Honoraria; Takeda: Honoraria; Sandoz: Honoraria. Viardot: University Hospital of Ulm: Current Employment; F. Hoffmann-La Roche Ltd: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Kite/Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees. Zinzani: JANSSEN-CILAG: Other: Advisory board, Speakers Bureau; NOVARTIS: Consultancy, Other, Speakers Bureau; EUSAPHARMA: Consultancy, Other, Speakers Bureau; SANDOZ: Other: Advisory board; MSD: Consultancy, Other: Advisory board, Speakers Bureau; TAKEDA: Other: Advisory board, Speakers Bureau; BMS: Other: Advisory board, Speakers Bureau; TG Therapeutics: Other: Advisory board, Speakers Bureau; ROCHE: Other, Speakers Bureau; SERVIER: Other: Advisory board, Speakers Bureau; KYOWA KIRIN: Other, Speakers Bureau; Incyte: Other, Speakers Bureau; CELLTRION: Other: Advisory board, Speakers Bureau; ADC Therap.: Other; GILEAD: Other: Advisory board, Speakers Bureau; Beigene: Other, Speakers Bureau; VERASTEM: Consultancy, Other: Advisory board, Speakers Bureau. Malladi: Gilead Science: Consultancy; Gilead: Honoraria, Other: Travel support. Lobetti Bodoni: Spouse: Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Spouse: Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Spouse: Celgene: Honoraria; Spouse: Harlcok Healthcare: Current holder of individual stocks in a privately-held company; Spouse: Takeda: Consultancy, Honoraria, Speakers Bureau; Spouse: Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees; Spouse: NHS: Ended employment in the past 24 months; Spouse: F. Hoffmann-La Roche: Current Employment, Current equity holder in publicly-traded company; Gilead: Other: Travel sponsorship in June 2019; Novartis: Current Employment, Current equity holder in publicly-traded company. Masood: Novartis: Current Employment, Current holder of stock options in a privately-held company. Schuster: Genentech/Roche: Consultancy, Research Funding; Tessa Theraputics: Consultancy; Loxo Oncology: Consultancy; BeiGene: Consultancy; Juno Theraputics: Consultancy, Research Funding; Alimera Sciences: Consultancy; Merck: Research Funding; Incyte: Research Funding; Acerta Pharma/AstraZeneca: Consultancy; Abbvie: Consultancy, Research Funding; Novartis: Consultancy, Honoraria, Patents & Royalties, Research Funding; TG Theraputics: Research Funding; Pharmacyclics: Research Funding; Adaptive Biotechnologies: Research Funding; Nordic Nanovector: Consultancy; Celgene: Consultancy, Honoraria, Research Funding. Fowler: Bristol Myers Squibb, F. Hoffmann-La Roche Ltd, TG Therapeutics and Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; BostonGene, Corp: Current Employment, Current holder of stock options in a privately-held company. Dreyling: Bayer HealthCare Pharmaceuticals: Consultancy, Research Funding, Speakers Bureau; Astra Zeneca: Consultancy, Speakers Bureau; BeiGene: Consultancy; Celgene: Consultancy, Research Funding, Speakers Bureau; Genmab: Consultancy; Amgen: Speakers Bureau; Incyte: Consultancy, Speakers Bureau; Gilead/Kite: Consultancy, Research Funding, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Janssen: Consultancy, Research Funding, Speakers Bureau; Roche: Consultancy, Research Funding, Speakers Bureau; Abbvie: Research Funding.

Abstract: Aims: To review the outcome of allogeneic stem cell transplantation (SCT) in imatinib refractory chronic myeloid leukaemia (CML). Methods: Outcomes of all allogeneic transplants performed after January 2001 for CML at our institution were retrospectively reviewed. Imatinib-refractory CML was defined as either lack of any cytogenetic response (CGR) after at least 6mths of imatinib, loss of CGR or progression to a more advanced disease stage (accelerated or blast phase) during imatinib therapy. Using the EBMT risk score (Lancet1998; 352: 1087), transplant outcomes for imatinib refractory CML were compared with all other CML transplants performed during the same time period. Survival analysis was performed using the Kaplan-Meier product-limit and comparison of survival data via the log-rank test. Results: Of 31 allogeneic transplants (19M; 12F) performed for CML, 12 had been performed for imatinib refractory CML (no CGR to imatinib n=3; loss of CGR n=3; progression to AP n=3; progression to BC n=3), 5 in patients with imatinib responsive CML, and 14 in patients never exposed to imatinib. Median age at SCT was 40yrs (range 19–63yrs). Donor source included HLA-matched unrelated donors in 14 cases, HLA-identical siblings in 16 and other matched family donors in 1. Conditioning regimens included Cy/TBI (20 cases), Bu/Cy (8 cases), Flu/Mel (2 cases) and Flu/Cy (1 case); CsA + MTX was used as standard GVHD prophylaxis. EBMT risk scores were 1 (4 cases), 2 (6 cases), 3 (8 cases), 4 (5 cases), 5 (3 cases) and 6 (5 cases). At median follow-up post-SCT of 37mths (range 6–64mths), median PFS and OS are not reached; at 2yrs PFS, EFS and OS are 81%, 58% and 61% respectively. For patients with EBMT risk scores of 1–2 versus 3–4 versus 5–6, OS at 2 yrs post-SCT is 80%, 62% and 38% respectively (p=0.03). Based on EBMT risk score, no significant differences in PFS, EFS or OS were observed when comparing SCT for imatinib-refractory versus imatinib-responsive / imatinib-naïve CML. Conclusion: Our experience suggests that survival post-SCT for imatinib-refractory CML is similar to SCT for imatinib-responsive / imatinib-naïve CML. The EBMT risk score appears to remain useful in predicting survival post-SCT in imatinib-refractory CML.

Abstract: Introduction: The optimal treatment approach for newly diagnosed patients with AML remains uncertain. HiDAC is widely considered to increase the proportion of patients cured compared to standard-dose cytarabine. However, it remains uncertain whether HiDAC is best given during induction or consolidation, and how many cycles of HiDAC are optimal. Many centres in Australia treat younger patients (age ≤60 yrs) with newly diagnosed AML with one of two approaches: either 7+3 induction followed by HiDAC-2 consolidation for 2 cycles; or a single course of HiDAC-3±7 induction followed by 2 cycles of lower dose cytarabine-based therapy (eg 5+2±5). Our retrospective study compared the outcomes of these 2 approaches in a large cohort of Australian patients treated at 5 centres. Methods: Consecutive patients aged ≤60 yrs with a new diagnosis of AML (de novo or secondary) were included in the study if they were planned for treatment with either: 1) cytarabine 100 mg/m2 for 7 days plus idarubicin 12 mg/m2 for 3 days (7+3) induction followed by 2 cycles of HiDAC 3 g/m2 days 1,3,5,7 plus idarubicin 12 mg/m2 for 2 days (HiDAC consolidation cohort); or 2) HiDAC 3 g/m2 days 1,3,5,7 plus idarubicin 9-12 mg/m2 for 3 days ± etoposide 75-100 mg/m2 for 7 days as induction followed mostly by cytarabine 100 mg/m2 for 5 days plus idarubicin 9-12 mg/m2 for 2 days ± etoposide 75-100 mg/m2 for 5 days as consolidation (HiDAC induction cohort). Patients were diagnosed from 1999 to June 2013, and were followed for at least 12 months with data cut off June 2014. Results: 486 patients were included: HiDAC consolidation cohort n=251; HiDAC induction cohort n=235. The HiDAC consolidation cohort had a greater median age (49 vs 47 yrs, p=0.02) and more patients with good risk cytogenetics (16% vs 8%, p= 〈 0.005). Other baseline demographics were well matched. For the HiDAC consolidation cohort and the HiDAC induction cohort, respectively, CR1 rate was 80% vs 91% (p=0.001); TRM 8% vs 5% (p=0.14); OS (5 yrs) 49% vs 50% (p=0.7); DFS (5 yrs) 47% vs 41% (p=0.24) and the cumulative incidence of relapse (CIR) 41% vs 50% (p=0.1). The CIR was greater in the HiDAC induction cohort despite a higher allogeneic hematopoietic stem cell transplantation (alloHSCT) in CR1 rate (18% vs 29%, p=0.002) in this cohort. For the 301 patients who achieved CR1 and did not undergoing alloHSCT in CR1, CIR was greater in the HiDAC induction cohort (49% vs 60%, p=0.059) leading to a reduced DFS (58% vs 46%, p=0.058), and OS (59% vs 49%, p=0.13) in that subset of patients. Excluding patients with good risk cytogenetics from the analyses did not change the results significantly. Conclusions: OS and PFS using HiDAC as induction or consolidation therapy were similar, and compared favourably to published data. Interestingly, the better CR rate and a greater use of alloHSCT in CR1 in the HiDAC induction cohort did not lead to a better PFS or OS - because of a greater relapse rate in this cohort - primarily seen in those patients not undergoing alloHSCT in CR1. In the absence of mutational prognostic information, these data may suggest that HiDAC as induction therapy can achieve CR in patients with biologically higher risk disease who have a higher relapse rate, and that including 2 cycles of HiDAC in consolidation in the absence of alloHSCT in CR1 is a more effective therapy than a single cycle of HiDAC administered during induction therapy. Disclosures Mollee: Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Nilelse: Research Funding.

Abstract: Acquired Severe Aplastic Anaemia (SAA) is a rare bone marrow failure syndrome, for which allogeneic haematopoietic stem cell transplant (HSCT) is a proven curative therapy. Despite excellent outcomes for matched sibling SAA recipients in terms of engraftment and survival, HSCT remains highly challenging in older matched-unrelated-donor (MUD) recipients, due to increased non-relapse mortality (NRM) from causes such as graft versus host disease (GVHD), organ failure and infection. We sought to evaluate our local HSCT outcomes for SAA, determine factors that predict for inferior outcomes, and benchmark local outcomes against international cohorts. To define outcomes for sibling and MUD HSCT in adults ≥17 years of age with SAA at a single Australian institution between 2002 and 2018 and compare these outcomes to internationally published cohorts. The primary outcome was 1-year overall survival (OS). Secondary outcomes included the incidences of engraftment, response, secondary graft failure, GVHD, and moderate to severe organ dysfunction. All 21 patients comprising 10 sibling and 11 MUD HSCTs, with a median age of 30 (range 17-64), received bone marrow grafts. At a median follow up of 3.5 years, 17 (81%) of 21 patients remained alive and in remission from SAA. 1-year OS, non-relapse mortality (NRM), and GVHD incidence were 85%, 15%, and 48% respectively. Two patients died prior to engraftment at Day+27 and Day+33. When comparing sibling and MUD HSCT recipients, incidences of survival, engraftment and post-HSCT complications were similar; however, MUD HSCT survivors experienced a higher incidence of chronic GVHD (67% vs. 11%; p=0.04). Age 〉 40 years, AKI by Day+28, infection by Day+100 and deviation from intended GVHD prophylaxis predicted for worse OS. Our outcomes following HSCT for SAA are comparable to international cohorts with age 〉 40 years, early onset infection, AKI and deviation from intended GVHD prophylaxis protocol negatively impacting OS. Further research is warranted to optimise MUD HSCT conditioning and GVHD prophylaxis protocols for SAA, particularly in older patients.