Chen, Andy

Background: Autologous T cells engineered to express a chimeric antigen receptor (CAR) targeting the B-cell lineage antigen CD19 (CAR19) in patients with relapsed/refractory (r/r) aggressive B-cell lymphomas (BCL) and pre-B acute lymphoblastic leukemia (B-ALL) have resulted in transformative improvements in clinical outcomes. However, there remain significant limitations concerning autologous CAR19 T cell manufacturing, including dysfunctional starting material, lack of product consistency and purity following genetic engineering, manufacturing timelines that necessitate the administration of bridging therapy in patients with aggressive disease, and insufficient quantities of CAR19 T cells, especially in severely cytopenic patients, to allow for more than single-dose administration routinely. The ability to consistently administer more than a single dose of CAR19 T cells enables dosing schedules that may reduce the risk of potentially life-threatening toxicities such as cytokine release syndrome and neurotoxicity, while maintaining or improving the depth and durability of anti-tumor responses. FT819 is a first-of-kind, off-the-shelf CAR19 T cell product candidate derived from a clonal master engineered induced pluripotent stem cell (iPSC) line, which can be used as a renewable source for the mass production of off-the-shelf CAR T cells for broad patient access. FT819 is engineered with the following features designed to improve the safety and efficacy of CAR T cell therapy: a novel 1XX CAR signaling domain, which has been shown to extend T cell effector function without eliciting exhaustion; integration of the CAR transgene directly into the T cell receptor alpha constant (TRAC) locus, which has been shown to promote uniform CAR expression and enhanced T cell potency; and complete bi-allelic disruption of T cell receptor (TCR) expression for the prevention of graft-versus-host disease (GVHD). FT819 has demonstrated antigen-specific cytolytic activity in vitro against CD19-expressing leukemia and lymphoma cell lines comparable to that of donor-derived CAR T cells, and persists and maintains tumor clearance in the bone marrow in an in vivo disseminated xenograft model of lymphoblastic leukemia (Mandal et al. 2020). The properties of FT819 and its ability to improve outcomes of patients with B-cell malignancies warrants further clinical investigation. Study Design and Methods: This study is a multicenter, Phase I clinical trial of FT819 in patients with r/r B-cell malignancies, including BCL, chronic lymphocytic leukemia (CLL), and B-ALL. The primary objective of the trial is to determine the recommended Phase II dose of FT819. Key secondary objectives include evaluation of FT819 safety and tolerability, anti-tumor activity, and pharmacokinetics (PK). Exploratory objectives include characterization of FT819 pharmacodynamics as assessed by peripheral blood biomarkers, and by phenotypic and genetic characterization of the tumor microenvironment from paired pre- and post-treatment tumor biopsies. The dose-escalation part of the trial utilizes a 3+3 dose-escalation design to identify the maximum tolerated dose for BCL, CLL, and B-ALL. The dose-expansion part of the trial is designed to further characterize the safety, efficacy, and PK of FT819 in multiple indications. Up to a maximum of 300 patients will be enrolled. The trial will test up to four FT819 dose levels ranging from 30 to 900 million cells. Three FT819 dosing regimens each will be tested for BCL, CLL, and B-ALL: Regimen A, FT819 administered as a single dose; Regimen A1, FT819 administered as a single dose in combination with interleukin (IL)-2; and Regimen B, FT819 administered as fractionated doses on Days 1, 3, and 5. Lympho-conditioning will consist of three consecutive days of fludarabine and cyclophosphamide administered prior to the first dose of FT819. Key inclusion criteria include r/r disease after standard approved therapies, documented CD19 expression, and adequate organ function. Key exclusion criteria include ongoing immunosuppression such as systemic GVHD therapy, prior allograft organ transplant, active central nervous system involvement of disease, and known allergy to FT819 components. The trial is expected to begin patient recruitment in 2020. Disclosures Park: Novartis: Consultancy; Fate Therapeutics: Research Funding; Amgen: Consultancy, Research Funding; Genentech/Roche: Research Funding; Kite: Consultancy, Research Funding; Incyte: Consultancy, Research Funding; GSK: Consultancy; Autolus: Consultancy, Research Funding; Intellia: Consultancy; Minverva: Consultancy; Takeda: Consultancy, Research Funding; AstraZeneca: Consultancy; Servier: Consultancy, Research Funding; Allogene: Consultancy; Juno Therapeutics: Research Funding; Artiva: Membership on an entity's Board of Directors or advisory committees. Jain:Pfizer: Research Funding; ADC Therapeutics: Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Research Funding; Servier: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Research Funding; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive Biotechnologies: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; TG Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Aprea Therapeutics: Research Funding; BeiGene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Genentech: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Precision Bioscienes: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Fate Therapeutics: Research Funding; Verastem: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Cellectis: Research Funding; Pharmacyclics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. McGuirk:Bellicum Pharmaceutical: Research Funding; Gamida Cell: Research Funding; Astellas: Research Funding; Pluristem Ltd: Research Funding; Novartis: Research Funding; Juno Therapeutics: Consultancy, Honoraria, Research Funding; Kite Pharmaceuticals: Consultancy, Honoraria, Research Funding, Speakers Bureau; Fresenius Biotech: Research Funding; Allo Vir: Consultancy, Honoraria, Research Funding. Diaz:Fate Therapeutics, Inc.: Current Employment. Valamehr:Fate Therapeutics, Inc: Current Employment, Current equity holder in publicly-traded company. Chu:Fate Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company; Roche Holding AG: Current equity holder in publicly-traded company. Castro:Kite Pharma: Research Funding; Pharmacyclics: Research Funding; Fate Therapeutics: Research Funding. OffLabel Disclosure: Cyclophosphamide and fludarabine will be used as lympho-conditioning therapy prior to FT819 administration. IL-2 will be administered in order to promote the expansion and function of FT819 as a T-cell product.

Key Points There was no difference in overall survival after allogeneic transplant between patients aged 55-64 years and patients ≥65 years. Age alone should not be a determinant for allogeneic transplant eligibility among older non-Hodgkin lymphoma patients.

BACKGROUNDEarly treatment failure (ETF) in follicular lymphoma (FL), defined as relapse or progression within 2 years of frontline chemoimmunotherapy, is a newly recognized marker of poor survival and identifies a high‐risk group of patients with an expected 5‐year overall survival (OS) rate of approximately 50%. Transplantation is an established option for relapsed FL, but its efficacy in this specific ETF FL population has not been previously evaluated.METHODSThis study compared autologous hematopoietic stem cell transplantation (auto‐HCT) with either matched sibling donor (MSD) or matched unrelated donor (MUD) allogeneic hematopoietic cell transplantation (allo‐HCT) as the first transplantation approach for patients with ETF FL (age ≥ 18 years) undergoing auto‐HCT or allo‐HCT between 2002 and 2014. The primary endpoint was OS. The secondary endpoints were progression‐free survival, relapse, and nonrelapse mortality (NRM).RESULTSFour hundred forty FL patients had ETF (auto‐HCT, 240; MSD hematopoietic stem cell transplantation [HCT], 105; and MUD HCT, 95). With a median follow‐up of 69 to 73 months, the adjusted probability of 5‐year OS was significantly higher after auto‐HCT (70%) or MSD HCT (73%) versus MUD HCT (49%; P = .0008). The 5‐year adjusted probability of NRM was significantly lower for auto‐HCT (5%) versus MSD (17%) or MUD HCT (33%; P < .0001). The 5‐year adjusted probability of disease relapse was lower with MSD (31%) or MUD HCT (23%) versus auto‐HCT (58%; P < .0001).CONCLUSIONSPatients with high‐risk FL, as defined by ETF, undergoing auto‐HCT for FL have low NRM and a promising 5‐year OS rate (70%). MSD HCT has lower relapse rates than auto‐HCT but similar OS. Cancer 2018;124:2541‐51. © 2018 American Cancer Society.

Summary For diffuse large B‐cell lymphoma ( DLBCL ) patients progressing after autologous haematopoietic cell transplantation (auto HCT ), allogeneic HCT (allo HCT ) is often considered, although limited information is available to guide patient selection. Using the Center for International Blood and Marrow Transplant Research ( CIBMTR ) database, we identified 503 patients who underwent allo HCT after disease progression/relapse following a prior auto HCT . The 3‐year probabilities of non‐relapse mortality, progression/relapse, progression‐free survival ( PFS ) and overall survival ( OS ) were 30, 38, 31 and 37% respectively. Factors associated with inferior PFS on multivariate analysis included Karnofsky performance status ( KPS ) <80, chemoresistance, auto HCT to allo HCT interval <1‐year and myeloablative conditioning. Factors associated with worse OS on multivariate analysis included KPS <80, chemoresistance and myeloablative conditioning. Three adverse prognostic factors were used to construct a prognostic model for PFS , including KPS <80 (4 points), auto HCT to allo HCT interval <1‐year (2 points) and chemoresistant disease at allo HCT (5 points). This CIBMTR prognostic model classified patients into four groups: low‐risk (0 points), intermediate‐risk (2‐5 points), high‐risk (6‐9 points) or very high‐risk (11 points), predicting 3‐year PFS of 40, 32, 11 and 6%, respectively, with 3‐year OS probabilities of 43, 39, 19 and 11% respectively. In conclusion, the CIBMTR prognostic model identifies a subgroup of DLBCL patients experiencing long‐term survival with allo HCT after a failed prior auto HCT .

SummaryPre‐existing central nervous system (CNS) involvement may influence referral for autologous haematopoietic cell transplantation (AHCT) for patients with non‐Hodgkin lymphoma (NHL). The outcomes of 151 adult patients with NHL with prior secondary CNS involvement (CNS+) receiving an AHCT were compared to 4688 patients without prior CNS lymphoma (CNS−). There were significant baseline differences between the cohorts. CNS+ patients were more likely to be younger, have lower performance scores, higher age‐adjusted international prognostic index scores, more advanced disease stage at diagnosis, more aggressive histology, more sites of extranodal disease, and a shorter interval between diagnosis and AHCT. However, no statistically significant differences were identified between the two groups by analysis of progression‐free survival (PFS) and overall survival (OS) at 5 years. A matched pair comparison of the CNS+ group with a subset of CNS− patients matched on propensity score also showed no differences in outcomes. Patients with active CNS lymphoma at the time of AHCT (n = 55) had a higher relapse rate and diminished PFS and OS compared with patients whose CNS lymphoma was in remission (n = 96) at the time of AHCT. CNS+ patients can achieve excellent long‐term outcomes with AHCT. Active CNS lymphoma at transplant confers a worse prognosis.