A novel AML-selective TRAIL fusion protein that is superior to Gemtuzumab Ozogamicin in terms of in vitro selectivity, activity and stability

Leukemia. 2009 Aug;23(8):1389-97. doi: 10.1038/leu.2009.34. Epub 2009 Mar 5.


Gemtuzumab ozogamicin (GO, Mylotarg) is a targeted therapeutic agent in which an anti-CD33 antibody is chemically coupled to a highly cytotoxic calicheamicin derivative through a hydrolysable linker. GO has improved the treatment outcome for a subgroup of acute myeloid leukemia (AML) patients, but its use is associated with severe myelosuppression and hepatotoxicity. Here, we report on a novel anti-leukemia agent, designated scFvCD33:sTRAIL, in which an anti-CD33 single chain fragment of variable regions (scFv) antibody fragment is genetically linked to soluble tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL). Normal CD33-positive monocytes were fully resistant to prolonged treatment with scFvCD33:sTRAIL, whereas treatment with GO resulted in substantial cytotoxicity. The activity of scFvCD33:sTRAIL towards AML cells was up to 30-fold higher than GO. The CD33-restricted anti-leukemia activity of scFvCD33:sTRAIL remained stable during prolonged storage at 37 degrees C, whereas GO showed a rapid increase in CD33-independent cytotoxicity. Moreover, scFvCD33:sTRAIL showed potent anti-leukemia activity towards CD33+ CML cells when treatment was combined with the Bcr-Abl tyrosine kinase inhibitor, Gleevec. Importantly, ex vivo treatment of patient-derived CD33+ AML tumor cells with scFvCD33:sTRAIL resulted in potent apoptosis induction that was enhanced by valproic acid, mitoxantrone and 17-(Allylamino)-17-demethoxygeldanamycin (17-AAG). Taken together, scFvCD33:sTRAIL is superior to GO in terms of tumor selectivity, activity and stability, warranting its further development for the treatment of CD33-positive leukemias.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Disease
  • Aminoglycosides / pharmacology
  • Antibodies, Monoclonal / pharmacology
  • Antibodies, Monoclonal, Humanized
  • Antigens, CD / metabolism
  • Antigens, Differentiation, Myelomonocytic / metabolism
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects
  • Bystander Effect
  • Cells, Cultured / drug effects
  • Drug Delivery Systems
  • Drug Screening Assays, Antitumor
  • Drug Stability
  • Enzyme Activation / drug effects
  • Gemtuzumab
  • Humans
  • Leukemia, Myeloid / pathology
  • Leukocytes, Mononuclear / drug effects
  • Neoplasm Proteins / metabolism
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / pharmacology*
  • Sialic Acid Binding Ig-like Lectin 3
  • Single-Chain Antibodies
  • Tumor Cells, Cultured / drug effects


  • Aminoglycosides
  • Antibodies, Monoclonal
  • Antibodies, Monoclonal, Humanized
  • Antigens, CD
  • Antigens, Differentiation, Myelomonocytic
  • Antineoplastic Agents
  • CD33 protein, human
  • Neoplasm Proteins
  • Recombinant Fusion Proteins
  • Sialic Acid Binding Ig-like Lectin 3
  • Single-Chain Antibodies
  • scFvCD33-sTRAIL protein
  • Gemtuzumab