Bevacizumab (Avastin) is frequently used off-label for intravitreal injection. Compared to ranibizumab (Lucentis), bevacizumab:
- A Is a Fab fragment with faster vitreous clearance and lower systemic VEGF suppression
- B Is a full-length IgG1 monoclonal antibody with larger molecular weight and potentially greater systemic bioavailability from the eye ✓
- C Has a higher intravitreal binding affinity for VEGF-A compared to ranibizumab
- D Is specifically approved by DCGI for intravitreal use in India
Correct answer: B. Is a full-length IgG1 monoclonal antibody with larger molecular weight and potentially greater systemic bioavailability from the eye
Explanation
Bevacizumab is a full-length IgG1 monoclonal antibody (molecular weight ~149 kDa), while ranibizumab is an affinity-matured Fab fragment (~48 kDa). The larger molecular weight of bevacizumab means it clears more slowly from the vitreous and has a longer intraocular half-life, but its larger size may also allow greater transcytosis across the RPE into systemic circulation, potentially suppressing systemic VEGF for longer. Ranibizumab has higher affinity for VEGF-A due to affinity maturation; bevacizumab is not approved for intravitreal use.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
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Written and medically reviewed by the StethoPrep medical team.