Background: Acute myeloid leukemia (AML) is the most common form of acute leukemia in adults, with an incidence that increases with age, and a generally poor prognosis. The prognosis remains especially grim for those who are older, have secondary AML, or relapsed or refractory (R/R) disease, in which 5-year OS is 5-10%. Therefore, novel therapeutic approaches are needed. CD123(IL3Rα) is a cell surface target that is expressed on normal, committed hematopoietic progenitor cells, and a variety of hematological neoplasms, including AML, myelodysplastic syndrome (MDS), and blastic plasmacytoid dendritic cell neoplasm (BPDCN). UCART123 is genetically modified, allogeneic ("off-the-shelf"), anti-CD123 CAR T cell product candidate in which the TCR alpha constant gene is disrupted to reduce the risk of GvHD, and the CD52 gene is disrupted to permit the use of alemtuzumab for selective and prolonged host lymphodepletion. Also, the CAR is co-expressed with a suicide mechanism (RQR8), which can be activated by using rituximab. In vitro data have demonstrated that UCART123 efficiently targets primary AML cells, with minimal effect on normal progenitors. Also, in PDX mouse models of AML, UCART123 cells can eliminate tumor cells in vivo, prevent relapse, and improve survival; in a competitive BM/AML PDX model, UCART123 cells demonstrated preferential targeting of AML blasts (Guzman; Blood 2016).

Methods: AMELI-01 is a phase 1, multi-center clinical trial of UCART123 that employs an mTPI design to evaluate the safety, tolerability and preliminary anti-leukemia activity of UCART123 in patients (pts) with R/R AML. Additional objectives include determination of the MTD; characterization of the expansion, trafficking and persistence of UCART123; assessment of cytokine, chemokine and CRP levels after UCART123 infusion; and assessment of immune cell depletion, reconstitution and immune response. Dose escalation will include up to 28 pts. The dose expansion portion follows a Simon 2-stage design and will enroll up to an additional 37 pts. Eligible pts must be ≤ 65 years of age with R/R AML, adequate organ function, a confirmed donor for potential back-up stem cell transplantation, and no ongoing > G1 toxicity from prior treatment. Pts with APL, prior gene or cellular therapy, > 1 allogeneic SCT, or those with a clinically relevant CNS disorder (including CNS leukemia) are not eligible. Pts receive a lymphodepletion (LD) regimen of either fludarabine and cyclophosphamide (FC) or fludarabine, cyclophosphamide plus alemtuzumab (FCA) starting on Day -5, followed by an infusion of UCART123 at one of 5 dose levels on Day 0. Pts are evaluated for the presence of dose-limiting toxicities (DLT) during a 28-day observation period, which extends to 42 days in the setting of marrow aplasia and/or persistent clinically significant cytopenias without residual AML. DL1 has cleared safety without DLT, and enrollment at the next dose levels are proceeding.

ClinicalTrials.gov Identifier: NCT03190278

Monica L. Guzman, et al; Allogeneic TCRα/β Deficient CAR T-Cells Targeting CD123 Prolong Overall Survival of AML Patient-Derived Xenografts. Blood 2016; 128 (22): 765. doi: https://doi.org/10.1182/blood.V128.22.765.765

Disclosures

Roboz:Orsenix: Consultancy; Otsuka: Consultancy; Takeda: Consultancy; Trovagene: Consultancy; Cellectis: Research Funding; Jasper Therapeutics: Consultancy; Epizyme: Consultancy; Helsinn: Consultancy; MEI Pharma: Consultancy; Novartis: Consultancy; Janssen: Consultancy; Pfizer: Consultancy; Agios: Consultancy; Celgene: Consultancy; Astex: Consultancy; Amphivena: Consultancy; Abbvie: Consultancy; Array BioPharma: Consultancy; Bayer: Consultancy; Celltrion: Consultancy; Eisai: Consultancy; Jazz: Consultancy; Roche/Genentech: Consultancy; Sandoz: Consultancy; Actinium: Consultancy; Argenx: Consultancy; Astellas: Consultancy; Daiichi Sankyo: Consultancy; AstraZeneca: Consultancy. DeAngelo:Blueprint Medicines Corporation: Consultancy, Research Funding; Forty-Seven: Consultancy; Amgen: Consultancy; Abbvie: Research Funding; Glycomimetics: Research Funding; Shire: Consultancy; Takeda: Consultancy; Pfizer: Consultancy; Novartis: Consultancy, Research Funding; Jazz: Consultancy; Autolos: Consultancy; Incyte Corporation: Consultancy; Agios: Consultancy. Sallman:Agios, Bristol Myers Squibb, Celyad Oncology, Incyte, Intellia Therapeutics, Kite Pharma, Novartis, Syndax: Consultancy; Celgene, Jazz Pharma: Research Funding. Guzman:SeqRx: Honoraria; Cellectis: Research Funding. Kantarjian:Delta Fly: Honoraria; Novartis: Honoraria, Research Funding; Adaptive biotechnologies: Honoraria; Ascentage: Research Funding; Amgen: Honoraria, Research Funding; BMS: Research Funding; Daiichi-Sankyo: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; Jazz: Research Funding; Actinium: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Research Funding; BioAscend: Honoraria; Janssen: Honoraria; Oxford Biomedical: Honoraria; Immunogen: Research Funding; Aptitute Health: Honoraria. Konopleva:Genentech: Consultancy, Research Funding; Rafael Pharmaceutical: Research Funding; Ascentage: Research Funding; AstraZeneca: Research Funding; Agios: Research Funding; Amgen: Consultancy; Sanofi: Research Funding; F. Hoffmann La-Roche: Consultancy, Research Funding; Stemline Therapeutics: Consultancy, Research Funding; Forty-Seven: Consultancy, Research Funding; Eli Lilly: Research Funding; Kisoji: Consultancy; Ablynx: Research Funding; AbbVie: Consultancy, Research Funding; Reata Pharmaceutical Inc.;: Patents & Royalties: patents and royalties with patent US 7,795,305 B2 on CDDO-compounds and combination therapies, licensed to Reata Pharmaceutical; Calithera: Research Funding; Cellectis: Research Funding. Bejanyan:Kiadis Pharma: Membership on an entity's Board of Directors or advisory committees. Esteva:Cellectis: Current Employment. Garton:Cellectis: Current Employment. Backhouse:Cellectis: Current Employment. Galetto:Cellectis: Current Employment. Brownstein:Cellectis: Current Employment. Pemmaraju:Blueprint Medicines: Honoraria; Roche Diagnostics: Honoraria; MustangBio: Honoraria; AbbVie: Honoraria, Research Funding; SagerStrong Foundation: Other: Grant Support; Plexxikon: Research Funding; Novartis: Honoraria, Research Funding; LFB Biotechnologies: Honoraria; Stemline Therapeutics: Honoraria, Research Funding; Celgene: Honoraria; Affymetrix: Other: Grant Support, Research Funding; Incyte Corporation: Honoraria; DAVA Oncology: Honoraria; Samus Therapeutics: Research Funding; Cellectis: Research Funding; Daiichi Sankyo: Research Funding; Pacylex Pharmaceuticals: Consultancy.

Author notes

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Asterisk with author names denotes non-ASH members.

© 2020 by The American Society of Hematology
2020
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