The largest series of long-term outcomes of anti-VEGF agents in patients with wet AMD shows notably better visual acuity results than previous long-term reports, which the authors attribute to more frequent injections.
Gillies and colleagues collected data on 1,212 eyes followed for a mean of 4.5 years; including 131 eyes (11%) followed through 7 years. Mean visual acuity (VA) improved from 55.1 letters to 61.4 letters after 6 months and remained above mean presenting VA for 6 years. However at 7 years, the authors found an overall mean decline of 2.6 letters, a modest loss compared with the SEVEN UP study, the only other study to follow patients for 7 years, which found a mean loss of 8.6 letters. The present study also found that 40% achieved 20/40 or better vision at 7 years compared with just 23% in the SEVEN UP study. Additionally, Gillies found that geographic atrophy at the center of the fovea was the most common cause of visual loss (37%), followed by subretinal fibrosis (31%).
Gillies writes that the difference in outcomes is likely due to the difference in dosing regimens, and it is important for clinicians to take this into account when applying this data to patients.
In the current study, a median of 6 injections were administered the first year, decreasing to 5 treatments per year thereafter. Physicians in this study favored a treat-and-extend protocol. In contrast, patients in the SEVEN UP study received monthly injections the first 2 years, followed by about 2 injections per year in years 4 through the 7. Physicians in the SEVEN UP study favored PRN dosing. A subgroup of patients in the SEVEN UP study who received 11 or more anti-VEGF injections during this later time period had a significantly better mean gain in letter score.
Although recent data from the CATT clinical trial (Comparison of AMD Treatments Trials, 2011) has shown higher rates of geographic atrophy and vision loss with monthly dosing compared to PRN dosing, it is possible that a treat-and-extend protocol may mitigate the adverse effects of frequent anti-VEGF suppression while still maintaining longer term visual benefit.
Even though the outcomes reported in this study were reasonably good, 40% of eyes that had 20/40 or better vision at baseline fell below this level after 7 years. Further research is warranted to determine if more eyes with good presenting vision can be induced to retain it.