Production and quality control assessment of a GLP-grade immunotoxin, D2C7-(scdsFv)-PE38KDEL, for a phase I/II clinical trial

Appl Microbiol Biotechnol. 2017 Apr;101(7):2747-2766. doi: 10.1007/s00253-016-8063-x. Epub 2016 Dec 24.


D2C7-(scdsFv)-PE38KDEL (D2C7-IT) is a novel recombinant Pseudomonas exotoxin A-based immunotoxin (IT), targeting both wild-type epidermal growth factor receptor (EGFRwt) and mutant EGFR variant III (EGFRvIII) proteins overexpressed in glioblastomas. Initial pre-clinical testing demonstrated the anti-tumor efficacy of D2C7-IT against orthotopic glioblastoma xenograft models expressing EGFRwt, EGFRvIII, or both EGFRwt and EGFRvIII. A good laboratory practice (GLP) manufacturing process was developed to produce sufficient material for a phase I/II clinical trial. D2C7-IT was expressed under the control of the T7 promoter in Escherichia coli BLR (λ DE3). D2C7-IT was produced by a 10-L batch fermentation process and was then purified from inclusion bodies using anion exchange, size exclusion, and an endotoxin removal process that achieved a yield of over 300 mg of purified protein. The final vialed batch of D2C7-IT for clinical testing was at a concentration of 0.12 ± 0.1 mg/mL, the pH was at 7.4 ± 0.4, and endotoxin levels were below the detection limit of 10 EU/mL (1.26 EU/mL). The stability of the vialed D2C7-IT has been monitored over a period of 42 months through protein concentration, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), isoelectric focusing, size exclusion chromatography, cytotoxicity, sterility, and pH measurements. The vialed D2C7-IT is currently being tested in a phase I/II clinical trial by intratumoral convection-enhanced delivery for 72 h in patients with recurrent glioblastoma (NCT02303678, D2C7 for Adult Patients with Recurrent Malignant Glioma; ).

Keywords: Epidermal growth factor receptor; Good laboratory practice; Malignant glioma; Mutant EGFR variant III; Recombinant immunotoxin.

MeSH terms

  • ADP Ribose Transferases / genetics
  • Adult
  • Bacterial Toxins / genetics
  • Cell Line, Tumor
  • Clinical Trials, Phase I as Topic
  • Clinical Trials, Phase II as Topic
  • Drug Stability
  • Electrophoresis, Polyacrylamide Gel
  • ErbB Receptors / genetics
  • ErbB Receptors / metabolism
  • Escherichia coli / genetics
  • Exotoxins / genetics
  • Fermentation
  • Glioblastoma / drug therapy
  • Humans
  • Immunotoxins / chemistry
  • Immunotoxins / genetics
  • Immunotoxins / metabolism*
  • Immunotoxins / therapeutic use
  • Quality Control
  • Virulence Factors / genetics


  • Bacterial Toxins
  • Exotoxins
  • Immunotoxins
  • Virulence Factors
  • ADP Ribose Transferases
  • toxA protein, Pseudomonas aeruginosa
  • EGFR protein, human
  • ErbB Receptors

Associated data