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

Cytotherapy. 2009;11(5):653-68. doi: 10.1080/14653240902960411.


Background aims: 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.

Publication types

  • Clinical Trial, Phase I

MeSH terms

  • Adult
  • Aged
  • Cancer Vaccines / administration & dosage
  • Cell Count
  • Cell Differentiation
  • Cell Movement
  • Cell Separation
  • Cells, Cultured
  • Cryopreservation
  • Dendritic Cells / cytology*
  • Dendritic Cells / immunology
  • Dose-Response Relationship, Immunologic
  • Electroporation*
  • Female
  • Freezing
  • Humans
  • Immunophenotyping
  • Immunotherapy, Adoptive / adverse effects*
  • Immunotherapy, Adoptive / methods*
  • Injections
  • Leukemia, Myeloid, Acute / therapy*
  • Male
  • Middle Aged
  • RNA, Messenger / metabolism
  • Reproducibility of Results
  • T-Lymphocytes / immunology


  • Cancer Vaccines
  • RNA, Messenger