To explore how baseline lesion composition influenced vision outcomes in patients with age-related macular degeneration (AMD) undergoing photodynamic therapy with verteporfin (Visudyne) for subfoveal choroidal neovascularization(CNV) in the Treatment of Age-Related Macular Degeneration With Photodynamic Therapy Investigation.
Patients with subfoveal lesions secondary to AMD with evidence of classic CNV were categorized into 2 subgroups based on baseline color photographs and fluorescein angiograms assessed by graders at the Wilmer Photograph Reading Center (The Johns Hopkins University School of Medicine) before any outcome analyses as follows: (1) predominantly classic CNV (area of classic CNV ≥50% of the area of the entire lesion) or (2) minimally classic CNV (area of classic CNV <50% but >0% of the area of the entire lesion). Additional exploratory analyses were performed in the predominantly classic subgroup to investigate the effects of visual acuity, lesion size, prior laser photocoagulation, phakic status, micronutrient use, and presence of occult CNV on vision outcomes.
Main Outcome Measures
Subgroup analyses of vision and fluorescein angiographic outcomes at 1 and 2 years after study enrollment were examined in an intent-to-treat analysis from 2 multicenter, double-masked, placebo-controlled, randomized clinical trials.
Compared with patients who had minimally classic CNV, patients with predominantly classic CNV had a worse initial mean visual acuity and smaller lesions and were more likely to have lesions that included blood or blocked fluorescence. When evaluated by treatment assignment and lesion composition, 84% to 88% completed the month 24 examination. In the subgroup with predominantly classic lesions, visual acuity outcomes were consistently better in verteporfin-treated patients. Outcomes for patients with predominantly classic lesions without occult CNV tended to be better than outcomes for patients with predominantly classic lesions with occult CNV, although the former tended to have smaller lesions and lower levels of visual acuity at baseline. Contrast sensitivity and fluorescein angiographic outcomes (total lesion size, progression of classic CNV, and absence of classic CNV) were better in verteporfin-treated patients than in placebo-treated patients in the predominantly classic and the minimally classic CNV subgroups. In patients with predominantly classic CNV, no interaction of the treatment benefit by phakic status, micronutrient use, or prior laser photocoagulation therapy was noted.
Verteporfin therapy can safely reduce the risk of moderate and severe vision loss in patients with subfoveal lesions that are predominantly classic CNV secondary to AMD. While this benefit seemed to be even greater in the absence of occult CNV, the effect may be related to the smaller lesions and worse visual acuity associated with predominantly classic lesions without occult CNV and not solely to the lesion composition itself. These analyses support initial reports that verteporfin therapy should be used to treat patients with AMD who have predominantly classic CNV, with or without occult CNV, but suggest that further investigations should be performed to determine if lesions with a minimally classic composition might benefit when they are smaller and have lower levels of visual acuity.