The pharmacokinetics of Lucentis (ranibizumab) and Avastin (bevacizumab) are dramatically different and may account for different treatment protocols.

The binding affinity of ranibizumab (Lucentis) is much more specific than bevacizumab (Avastin), but the half live of bevacizumab is quite longer than ranibizumab.

Lucentis/ranibizumab = Higher Binding Affinity

Dosing regimens vary differently across the country and the differences in the pharmacokinetic profile may be the reason.  Presently, dosing of either drug may be once a month, but patients treated with Lucentis (ranibizumab) may fare better with every 2 week dosing, at least in the induction phase.  Spacing of injections; however, after induction may be possible because of the longer half-life of bevacizumab.

Avastin/bevacizumab = Longer Half Life

Using Lucentis initially, with higher binding affinity, then maintenance with Avastin, due to a longer half-life, may be the perfect combination.

Head to head studies of the 2 drugs are anticipated.

Randall V. Wong, M.D.
www.RetinaEyeDoctor.com ^[1]
Retina Specialist