title: Clinical-grade manufacturing of autologous mature mRNA-electroporated dendritic cells and safety testing in acute myeloid leukemia patients in a phase I dose-escalation clinical trial.
abstract: OBJECTIVE
  RNA-electroporated dendritic cell (DC)-based vaccines are rapidly gaining interest as therapeutic cancer vaccines. We report on a phase I dose-escalation trial using clinical-grade manufactured mature RNA-electroporated DC in acute myeloid leukemia (AML) patients.
  
  
  METHODS
  CD14(+) cells were isolated from leukapheresis products by immunomagnetic CliniMACS separation and differentiated into mature DC (mDC). mDC were electroporated with clinical-grade mRNA encoding the Wilm's tumor (WT1) antigen, and tested for viability, phenotype, sterility and recovery. To test product safety, increasing doses of DC were administered intradermally four times at 2-week intervals in 10 AML patients.
  
  
  RESULTS
  In a pre-clinical phase, immunomagnetic monocyte isolation proved superior over plastic adherence in terms of DC purity and lymphocyte contamination. We also validated a simplified DC maturation protocol yielding a consistent phenotype, migration and allogeneic T-cell stimulatory capacity in AML patients in remission. In the clinical trial, highly purified CD14(+) cells (94.5+/-3.4%) were obtained from all patients. A monocyte-to-mDC conversion factor of 25+/-10% was reached. All DC preparations exhibited high expression of mDC markers. Despite a decreased cell recovery of mDC after a combination of mRNA electroporation and cryopreservation, successful vaccine preparations were obtained in all AML patients. DC injections were well tolerated by all patients.
  
  
  CONCLUSIONS
  Our method yields a standardized, simplified and reproducible preparation of multiple doses of clinical-grade mRNA-transfected DC vaccines from a single apheresis with consistent mature phenotype, recovery, sterility and viability. Intradermal injection of such DC vaccines in AML patients is safe.
authors.affiliation: Vaccine and Infectious Disease Institute (VIDI), Laboratory of Experimental Hematology, Faculty of Medicine, University of Antwerp, Antwerp, Belgium.
authors.forename: Ann
authors.initials: A
authors.lastname: Van Driessche
authors.forename: Ann L R
authors.initials: AL
authors.lastname: Van de Velde
authors.forename: Griet
authors.initials: G
authors.lastname: Nijs
authors.forename: Tessa
authors.initials: T
authors.lastname: Braeckman
authors.forename: Barbara
authors.initials: B
authors.lastname: Stein
authors.forename: Jolanda M
authors.initials: JM
authors.lastname: De Vries
authors.forename: Zwi N
authors.initials: ZN
authors.lastname: Berneman
authors.forename: Viggo F I
authors.initials: VF
authors.lastname: Van Tendeloo
mesh_terms: D000328:Adult; D000368:Aged; D019496:Cancer Vaccines / Q000008:administration & dosage; D002452:Cell Count; D002454:Cell Differentiation; D002465:Cell Movement; D002469:Cell Separation; D002478:Cells, Cultured; D015925:Cryopreservation; D003713:Dendritic Cells / Q000166:cytology* / Q000276:immunology; D004306:Dose-Response Relationship, Immunologic; D018274:Electroporation; D005260:Female; D005615:Freezing; D006801:Humans; D016130:Immunophenotyping; D016219:Immunotherapy, Adoptive / Q000009:adverse effects* / Q000379:methods*; D007267:Injections; D015470:Leukemia, Myeloid, Acute / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism; D015203:Reproducibility of Results; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D019496:Cancer Vaccines; D012333:RNA, Messenger