Bevacizumab is an anti-VEGF monoclonal antibody used in solid tumours. Its primary anti-tumour mechanism is:
- A Direct cytotoxicity to VEGFR-expressing tumour cells via antibody-dependent cellular cytotoxicity (ADCC)
- B Inhibition of tumour angiogenesis by binding circulating VEGF-A, preventing binding to VEGFR-1 and VEGFR-2 on vascular endothelium ✓
- C Competitive inhibition of VEGF at its receptor inducing tumour vessel maturation and normalisation
- D Activation of complement-mediated lysis of tumour vasculature
Correct answer: B. Inhibition of tumour angiogenesis by binding circulating VEGF-A, preventing binding to VEGFR-1 and VEGFR-2 on vascular endothelium
Explanation
Bevacizumab is a recombinant humanised monoclonal antibody that binds all isoforms of VEGF-A with high affinity in the circulation, preventing VEGF-A from binding and activating its receptors (VEGFR-1 and VEGFR-2) on vascular endothelial cells. This inhibits proliferation of new blood vessels (angiogenesis), reducing tumour blood supply, interstitial pressure, and delivery of oxygen/nutrients to the tumour. It does not directly kill tumour cells (no ADCC on tumour cells) and does not activate complement lysis of vasculature.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.