In many chronic indications, the advantage of drug versus placebo tends to blur over time. Thus QLT Inc. was pleasantly surprised when Phase IIIb data for its Visudyne verteporfin photodynamic therapy in age-related macular degeneration showed greater benefit at two years than at one year.

The trial was in patients with AMD caused by occult subfoveal choroidal neovascularization (CNV) without classic components. These data, along with Phase IIIb data for patients with CNV due to pathologic myopia, could more than double the target patient population for Visudyne, which is approved in the U.S. and Europe to treat predominantly classic subfoveal CNV caused by AMD.