QLT PhotoTherapeutics Inc.

CIBA Vision
A Novartis Company

1. What is visudyne therapy?

Visudyne therapy involves the use of a light-activated compound called verteporfin combined with a non-thermal laser to produce a therapeutic effect.  QLT PhotoTherapeutics and CIBA Vision, the eye care unit of Novartis AG, are conducting research to investigate Visudyne therapy as a potential treatment for the more severe "wet" form of age-related macular degeneration.

2. What is wet AMD?

AMD is the leading cause of blindness in people over the age of 50 in the western world.  It s characterzed by two forms - the "dry" form and the more severe "wet" form.  Whle the wet form of AMD accounts for only about 15% of all MAD cases it is responsible for 90% of the severe vsion loss associated with this condition.  The wet form of AMD is caused by the growth of abnormal blood vessels, called "neovascularization", across the macula - the central part of the retina.  These abnormal vessels leak fluid and blood into the tissue at the back of the eye, causing a blister to form in the retina, which eventually leads to scar tssue and a loss of central vsoin.  Worldwide, approxmiately 500,000 new cases of wet AMD are diagnosed annually.  In North America, approximately 200,000 new cases of wet AMD are diagnosed annually.

3. How is Visudyne therapy different or better than the existing thermal laser therapy?

Visudyne therapy appears to stop the leakage of abnormal blood vessels associated with wet AMD without damaging the overlaying retina, thereby preserving vision.  This means that Visudyne therapy may have benefits for patients whose most central vision, the vision needed for reading, driving and other functional activities, is affected and for whom the current thermal laser therapy is inappropriate.  Early studies shwoed that Visudyne therapy may be able to selectively close the abnormal blood vessels without damaging normal vessels, even after multiple treatments.

4. Will Visudyne therapy prevent blindness?

Clinical studies have shown promising results, and both companies are optimistic that Visudyne therapy may offer the first effective treatment for stabilizing remaining vision in patients with wet AMD.  However, the therapy will not restore vision in eyes that have suffered longstanding vision loss or have already been significantly damaged by AMD.

5. How can patients and practitioners obtain more information about Visudyne therapy?

Patients and practitioners may call CIBA vision's Visudyne hotline at 1-800-821-2450.  Also, you may visit the Visudyne website.