Canadian company, QLT PhotoTherapeutics, saw heavy trading in its stock and a share price slump yesterday after its unveiled two-year data showing its photodynamic therapy, Visudyne, had failed in a trial of patients with an eye condition known as age-related macular degeneration with occult choroidal neovascularisation. Shares in the company dropped from $8.31 to $7.22 on the Nasdaq stock exchange yesterday on the news – which is down significantly from the firm’s 52-week high of $18.10.

However, analysts seemed less than perturbed, calling QLT a good buy and significantly undervalued, with growing revenues and earnings, and an extremely healthy cash position. Visudyne is still widely prescribed for AMD, with worldwide sales for the second quarter of $129 million, an increase of 18% over the same period last year. Visudyne – which is sold by Novartis - is the only drug currently approved worldwide for the treatment of a form of wet AMD, the leading cause of legal blindness in people over the age of 50, and has been used in more than 500,000 patients worldwide.

The Occult VIO trial is part of a broader series of trials conducted with Visudyne in patients with predominantly occult CNV. Two earlier trials, VIP (Visudyne In Photodynamic Therapy) and VIM (Visudyne in Minimally Classic), did however previously demonstrate evidence of efficacy in this patient population and QLT says it is still conducting further analyses on relevant subgroups. The results of these analyses, alongside evidence from the earlier studies, will be discussed at a forthcoming meeting of an independent Data and Safety Monitoring Committee.