FDA Panel Recommends Macular Degeneration Drug
Nov. 17, 1999 (Washington) -- Without taking a formal vote, an advisory
panel to the FDA recommended laser therapy with the light-sensitive agent
called Visudyne (verteporfin) to treat a particularly aggressive form of
macular degeneration that can result in blindness. "The treatment is
effective, but the treatment effect is very modest ... it's not
penicillin," Donald Fong, MD, chair of the Ophthalmic Drugs Subcommittee,
In the wet form of age-related macular degeneration (AMD), leaky blood
vessels grow across the central portion of the retina, or macula, for unknown
reasons and cause scarring. Laser therapy selectively destroys the abnormal
blood vessels, leaving the normal vessels and tissue alone. About 200,000 cases
occur in the U.S. annually, and the ability of current treatments to preserve
useful vision is limited to about 20% of new cases.
Fong says about half of those treated with Visudyne still lost vision, but
he termed it "a step in the right direction." Since the drug is under a
priority review, it could be available in the spring, pending FDA action. If
ultimately approved, Visudyne would be a new approach to treating patients with
the wet form of AMD, a small percentage of people who develop AMD.
Trials for Visudyne focused on those who have the 'classical' form of the
disease, which is considered the most aggressive. In two studies involving more
than 600 patients, researchers compared Visudyne to placebo in patients at
least 50 years old with a variety of macular-related lesions.
The treatment involves a 30-minute drug infusion, and then, 15 minutes
later, a jolt of laser energy aimed into the eye 'turns on' the Visudyne. The
drug then inhibits the growth of abnormal blood vessels, apparently without
damaging normal tissue. According to the manufacturer, 15% more of those
treated with this therapy either stabilized or showed a small loss of vision at
the 12-month follow-up compared with those on placebo.
The improvement could mean the difference between 20/100 and 20/200 vision,
according to drug investigator Neil Bressler, MD, ophthalmologist at Johns
Hopkins University School of Medicine. This is described as clinically
significant for those who have the classic type of AMD.
Among the safety problems associated with Visudyne were severe vision loss
in a dozen cases, most of which got better over time, and skin sensitivity to
light in patients shortly after treatment. The makers of the drug say they plan
to conduct training courses for doctors across the country to apprise them of
the risk and how to minimize it.
"We're basically putting this systemically administered photo-toxic drug
into the body, and we don't know what the long-term effects of these drugs
are," says Fong.
Wiley Chambers, MD, who reviewed the drug for the FDA, says there are
concerns about the lack of data on the drug's safety and effectiveness. These
studies have been done but haven't yet been fully evaluated. Chambers also said
most of the patients need another treatment after three months, thus exposing
this elderly population to more potential side effects.
Still, panelist Jack Cioffi, MD, of the Devers Eye Institute in Portland,
Ore., says Visudyne could stave off vision loss for 6-18 months. For many
patients, this could be important in maintaining vision and, therefore,