Issue link: https://optometricmanagementsupplements.epubxp.com/i/531600
JUNE 2015 • 7 is a 48 KDa monovalent monoclonal antibody fragment, the antigen-binding Fab without the Fc domain. Afibercept is a 115 KDa Fc fusion protein that combines the binding domains of VEGF recep- tors 1 and 2 with an Fc antibody fragment. Bevaci- zumab, which was developed for use in oncology to treat solid tumors, is a 149 KDa full-length, biva- lent monoclonal antibody against VEGF-A. When used off-label in ophthalmology, bevacizumab must be prepared in a compounding pharmacy. DR. PIZZIMENTI: Tell us about the afibercept trials . DR. ALBINI: In my opinion, the major difference between the VIVID and VISTA trials of afiber- cept 13 and the RISE and RIDE trials of ranibi- zumab 12 was the dosing interval. In RISE/RIDE, eyes were treated monthly. In VIVID/VISTA, eyes in one arm were treated every 4 weeks (2q4), while eyes in the second arm were treated every 8 weeks after fve initial monthly doses (2q8). Because afibercept has a higher binding affnity for VEGF than ranibizumab, the researchers theorized they could achieve similar visual gains with less frequent injections, and that was demonstrated in the study. Mean BCVA gains from baseline to week 52 in the 2q4 and 2q8 groups versus laser photocoagulation were 12.5 and 10.7 versus 0.2 letters in VISTA and 10.5 and 10.7 versus 1.2 letters in VIVID. The researchers concluded that afibercept demonstrated signifcant superiority in functional and anatomic endpoints over laser, with similar effcacy in both groups, despite the extended dosing interval in the 2q8 group. DR. PIZZIMENTI: Have there been any head-to-head comparisons of these three anti-VEGF agents? DR. ALBINI: The DRCR.net's Protocol T study compared the safety and effcacy of afibercept, ranibizumab and bevacizumab. 17 In short, the trial showed all three agents worked well. Patients treated with afibercept achieved more substantial improvements in visual acuity in eyes with poor vision. The cut off used in the trial was 20/40, but carefully looking at the data, the worse the start- ing vision, the more pronounced the superiority of afibercept. [Editor's note: Protocol T data were re- leased after this roundtable discussion took place.] DR. PIZZIMENTI: Dr. Albini, where does bevaci- zumab ft into the treatment paradigm? DR. ALBINI: Bevacizumab is probably one of the more commonly used drugs, mainly because it costs a fraction of what the on-label drugs do, and it has similar effcacy. The CATT study, a large, multi- center, prospective study of macular degeneration demonstrated that bevacizumab is noninferior to ranibizumab in macular degeneration. 18 In diabe- tes, perhaps even more than in macular degenera- tion, patients often have a tough time paying for a $2,000-per-month treatment. One downside to bevacizumab is that it must be prepared in com- pounding pharmacies, and there have been small outbreaks of devastating eye infections, because multiple vials of the drug were contaminated. 19 Therefore, one needs to carefully choose a com- pounding pharmacy, and the compounding pharmacies need to be held to high standards. DR. DUNBAR: Dr. Albini, what factors do you consider when choosing an anti-VEGF agent? DR. ALBINI: When fnances aren't an issue, I think most patients are more comfortable with an FDA-approved drug, specifcally packaged and manufactured for this indication, so I choose either ranibizumab or afibercept. The worse the vision, the more strongly I suggest afibercept. Please take the post test and evaluation online by going to OptometricManagementDMECE.com