JAN 13, 2009
This small prospective study compared outcomes in two consecutive cohorts of 25 patients with choroidal neovascularization secondary to exudative AMD treated with either a loading dose of three monthly Avastin (bevacizumab) injections followed by monthly injections as needed or simply monthly injections (PRN). The treating physician determined if reinjection was necessary based on whether fluid was seen on OCT scans. The study's results are of particular interest because the loading dose group had much better outcomes than the PRN group after six months.
Mean improvement in Early Treatment Diabetic Retinopathy Study (ETDRS) BCVA was 13.7 letters in the loading dose group compared with 4.6 letters in the PRN group. Both results were statistically significant, although the difference between them was not. Thirty-six percent of the loading dose group gained 15 or more letters compared with 12 percent of the PRN group, a difference that did reach statistical significance. Mean foveal thickness decreased by 91.3 µm in the loading dose group and 48.2 µm in the PRN group, significant changes that were not significantly different from each other.
Interestingly, out of a total of seven possible injections during the six month study, the loading dose group received 4.1 injections compared with the PRN group's 4.3, which was not significantly difference. Thus, eyes treated with either approach will likely require the same number of treatments, but visual acuity results appear to be better if more injections are given up front.
Although this study is limited by its small size and single-center nonrandomized design, it is part of the growing literature suggesting that PRN anti-VEGF injections given as determined by the treating physician are not as effective at improving or preserving vision as following a pre-set protocol of monthly injections. Physicians treating patients with anti-VEGF therapy for exudative AMD will want to take note of these results.
Dr. Holekamp is a consultant to Alcon Laboratories, Inc., Genentech, Inc., Pfizer Ophthalmics and OSI Eyetech, and receives lecture fees from Genentech.