About Avastin: Proposed Mechanism of Action

As demonstrated in preclinical models: Avastin directly binds vascular endothelial growth factor (VEGF) to inhibit angiogenesis

  • While expressed in normal tissues, VEGF is also present at physiologically relevant levels in tumors[28,29]
  • A VEGF ligand binds to receptors on endothelial cells to help drive angiogenesis[30-32]

The mechanism of action of Avastin has been elucidated in preclinical models. Its clinical significance is unknown.

  • Avastin is designed to directly bind to VEGF extracellularly to prevent interaction with VEGF receptors (VEGFRs) on the surface of endothelial cells, and thereby may inhibit VEGF's angiogenic activity[1]
    • The VEGFR family is primarily responsible for pro-angiogenic VEGF signaling[28,34,35]

As demonstrated in preclinical models: Avastin may exert certain effects to inhibit tumor growth and development[36-47]

Proposed effects Potential effect on vessels Potential impact on tumor
Anti-vascular Regression of existing tumor vasculature[36-41] Reduction of tumor size[37,42]
Anti-angiogenesis Inhibition of new and recurrent tumor vessel growth[37,43,44] Inhibition of tumor growth[44-47]
  • The impact of the individual effects of VEGF inhibition may vary over time[37,48]
  • Early effects of inhibiting VEGF with Avastin may lead to a reduction in tumor size[36,37,42]
  • Sustained VEGF inhibition may be an important strategy to maintain tumor regression[45,47-50]

The mechanism of action of Avastin has been elucidated in preclinical models. Its clinical significance is unknown.