Making a Retina Surgeon.
For this issue’s verbatim excerpt from Making a Retina Surgeon, we have decided to highlight a post from Ehsan about the selection of anti-VEGF agents. Retina specialists’ reliance on head-to-head trials should continue—indeed, researchers in those studies produced excellent science—but we want to remind our colleagues that important differences in pharmacokinetics can sometimes become obfuscated when multiple drugs fall into a particular P value in a given study. Those differences, though often small, may be the difference between 20/20 and 20/200.
—Ehsan Rahimy, MD, and S.K. Steven Houston III, MD
But CATTs and Dogs Aren’t the Same…
We know from the Comparison of AMD Treatments Trial (CATT) that bevacizumab (Avastin, Genentech) and ranibizumab (Lucentis, Genentech) are more or less equivalent in the management of neovascular macular degeneration. Before you freak out, relax. This isn’t another CATT column. What it is, rather, is a worthwhile reminder that equivalent does not necessarily mean the same. Our patients are anything but the same. They often respond in unique and, as of yet, unpredictable ways to therapy with each of the three available anti-VEGF agents. This differential effect is perhaps most appreciable in retinovascular diseases where a significant ischemic burden may exist, such as in central retinal vein occlusion (CRVO). Compared with macular degeneration, the VEGF drive in CRVO is much greater, and subtle medication differences may be the deciding factor between observing a positive treatment effect versus a nonresponse.
I wanted to share a striking case of a patient I have taken care of. Briefly, a 33-year old male presented to me with CRVO and associated severe cystoid macular edema in the left eye. His visual acuity at presentation was counting fingers. After six monthly intravitreal bevacizumab injections (three were done on the outside prior to seeing me), he had persistent edema with a central macular thickness on SD-OCT imaging of >1,000 microns. Together, we elected for a trial of conversion to aflibercept. Four weeks after the first injection, his SD-OCT was completely dry and his visual acuity had recovered to 20/20 in this eye. From counting fingers to 20/20! We have since been able to successfully extend his aflibercept injections further and further apart (currently every 10 weeks apart) without any recurrence of fluid.
The ongoing SCORE2 trial (Study of COmparative Treatments for REtinal Vein Occlusion 2), which is prospectively comparing monthly bevacizumab to aflibercept for the treatment of macular edema secondary to CRVO, will go a long way towards elucidating whether these differences are clinically relevant over a much larger cohort of patients. n
WANT THE REST?
Drs. Rahimy and Houston have more to say—partially in meme form— at MakingARetinaSurgeon.com.