Ocular Photodynamic Therapy and Intravitreal Drug Therapy for Wet Age-Related Macular Degeneration

Over the last several years there have been remarkable advances in the treatment of wet age-related macular degeneration (AMD). In 2004 I began using Visudyne/OPT (ocular photodynamic therapy) to treat patients with subretinal neovascularization from wet AMD. This was used in conjunction with "off-label" (FDA approved for other conditions) intravitreal Kenalog. It has been gratifying to see that 61 % of patients treated in this office have had stable or improved vision. Usually, 80 % of these patients will have the subfoveal neovascular membrane inactivated with one treatment. Complications include a 30-40 % incidence of cataract and/or glaucoma, and a 1/2 % infection rate.

Intravitreal Macugen became available in February, 2005. Macugen is an inhibitor of a biochemical under the retina that stimulates the growth of new vessels. Macugen has often been used to treat patients whose subretinal neovascular membranes remain active after Kenalog/Visudyne treatments or who did not qualify for Visudyne treatment under existing guidelines. Intravitreal Macugen reduces the rate of significant vision loss compared to Visudyne / OPT used alone and occasionally allows better vision. However, Macugen requires an intraocular injection every six weeks. Even with regular use, the vision usually slowly deteriorates after several months of treatment. There are rare ocular side effects.

In June, 2006 a new drug, Lucentis, was approved for wet AMD only. It is an antibody to the same biochemical that causes vessel growth beneath the retina. Clinical trials suggest that approximately 30 % of patients gain vision. Lucentis' excessively high cost and the manufacturer's recommendation for monthly intravitreal injections for years are decided drawbacks. There are rare ocular side effects.

Avastin Therapy for Subretinal Neovascularization and Macular Edema

I have been using Lucentis' parent drug, Avastin, since October, 2005 with great success. It is a larger molecule and has a longer half-life within the eye. It can be used to treat both subretinal neovascularization (from wet AMD or other causes) and macular edema (from diabetic retinopathy or other causes) in select patients. Intravitreal Avastin is felt to be as effective inside the eye as Lucentis. Both require monthly injections initially. Avastin requires at least a series of three injections. Ninety to 95 % of patients treated with Avastin experience stabilized vision, with approximately one-third gaining vision. This may be used alone as monotherapy or in combination with additional therapy, i.e. Visudyne. Avastin use in the eye is presently "off-label", though approved by Medicare and most other insurance carriers. Avastin is FDA approved to treat patients with colon cancer, using frequent high-dose intravenous infusions. In that cancer group there was a two-fold increase in the incidence of heart attack and stroke, as well as increased rates of hypertension. However, there have been no similar adverse events noted with eye patients receiving intravitreal injections. The dose used in the eye is only approximately 1/400 of the FDA approved intravenous dose. On-going monitoring and more experience may show some systemic risk but, to date, this risk is hypothetical.

David V. Poer, MD, FACS