Ranibizumab differs from bevacizumab in its mechanism of anti-VEGF action primarily because ranibizumab is:
- A An antigen-binding fragment (Fab) with higher VEGF-A binding affinity and no Fc region ✓
- B A full-length monoclonal antibody that inhibits all VEGF isoforms
- C A VEGF receptor decoy (fusion protein) that binds VEGF-A, VEGF-B, and PlGF
- D An intravitreal implant that slowly releases VEGF-A aptamer
Correct answer: A. An antigen-binding fragment (Fab) with higher VEGF-A binding affinity and no Fc region
Explanation
Ranibizumab is a humanised recombinant Fab fragment of an anti-VEGF-A antibody; lacking the Fc region it has faster ocular clearance and no systemic complement activation. Bevacizumab is the full-length parent IgG antibody. Aflibercept is the VEGF trap/fusion protein that binds VEGF-A, VEGF-B, and PlGF with high affinity. Pegaptanib is the RNA aptamer against VEGF165 specifically. Ranibizumab's smaller size allows better retinal penetration.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.