Verteporfin therapy reduces vision loss for patients with CNV in AMD

Almost twice as many patients may be eligible for verteporfin therapy as for standard laser coagulation.

Editor’s Note: During production of this issue we learned of the death of Raymond Margherio, MD, a source for this article, in October 2000. Ocular Surgery News would like to express condolences to the family and colleagues of Dr. Margherio.

ROYAL OAK, U.S.A. — Photodynamic therapy with verteporfin has been shown to be safe and effective in the treatment of classic subfoveal choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD). It may cause less damage to the retina than other treatments.

“It is hoped that it will be an effective form of treatment for many subfoveal lesions. This therapy will increase treatments for neovascular AMD and will have a considerable impact on retinal practices. Although the resources that will need to be expended are high, the potential benefit of verteporfin therapy in reducing vision loss will outweigh the costs,” said Raymond R. Margherio, MD, in practice here.

The Treatment of Age-Related Macular Degeneration with Photodynamic Therapy (TAP) investigation was conducted in 609 patients in 22 centers in Europe and North America. One-year follow-up data from that study showed that visual acuity, contrast sensitivity and angiographic outcomes are better in verteporfin-treated eyes than in eyes receiving placebo. At 1 year, 67% of verteporfin-treated eyes versus 37% of placebo-treated eyes lost less than three lines of vision. Verteporfin therapy can, therefore, safely reduce the risk of vision loss in eyes with predominantly classic CNV (where the area of classic CNV is 50% or more of the area of the entire lesion). In the absence of occult CNV, the benefits are of an even greater magnitude.

Verteporfin therapy is the first major advance in treatment of AMD since the introduction of the thermal laser, Dr. Margherio said. “Verteporfin therapy may be applied to a much larger proportion of cases presenting with neovascular AMD,” he said.

Repeated treatment

One important consideration is the need for repeated treatment over a 12-month period. However, retreatment does not appear to adversely affect vision. “Therefore, a major limiting factor with this form of treatment may be compliance with retreatment over a prolonged period. Ophthalmologists must be willing to establish guidelines, such as retreatment schedule and number of visits, for this treatment modality that differ from those for traditional laser photocoagulation,” Dr. Margherio said.

Exudative AMD is the leading cause of blindness in people over age 50 in the developed world. It is not known how many of these people may be eligible for verteporfin therapy. Dr. Margherio and colleagues at Associated Retinal Consultants (ARC) attempted to determine the number of patients with AMD who underwent thermal laser therapy in 1998 and to estimate how many might have been eligible for verteporfin therapy.

“ARC is a group referral practice in Michigan [U.S.A.] that is limited exclusively to the diagnosis and treatment of vitreoretinal diseases. The group is geographically diverse with 14 offices scattered over Michigan. Offices are located in small towns and large cities. Patients come from diverse backgrounds and socioeconomic strata,” he said.

To estimate the number of eyes treated with a thermal laser for AMD in 1998, Dr. Margherio assumed that most were Medicare patients and that most of these treatments were billed under CPT code 67210. However, this code also covers laser treatment for other conditions, such as diabetic macular edema. “A 1998 survey distributed to five large retinal practices across the United States determined the proportion of treatment charges under CPT code 67210 that were exclusively for AMD. The results from this survey indicated that AMD treatments accounted for approximately 20% of all treatment charges under CPT code 67210,” he said.

U.S. data showed that 209,304 Medicare-allowed services were charged under CPT code 67210 in 1998. “Assuming that 20% of these charges were for eyes treated for CNV secondary to AMD, approximately 42,000 eyes with AMD were treated by laser photocoagulation in 1998 in the United States,” he added.

Eligible for therapy

To determine how many cases of neovascular AMD might benefit from verteporfin, Dr. Margherio and colleagues conducted a retrospective review of 1,000 consecutive records of new patients with AMD referred to ARC during 1998. To be included in the sample, patients had to be at least 50 years old, have drusen present in the involved or fellow eye and not have any other causes of CNV.

“The number of eligible patients with each of the following features was determined: neovascular AMD or non-neovascular AMD, presence of subfoveal CNV, classic CNV on fluorescein angiography and classic component covering 50% or more of the entire area of the CNV,” he said.

Of these 1,000 patients, 526 (53%) had non-neovascular AMD. “Non-neovascular AMD included eyes with drusen or abnormalities of retinal pigment epithelium associated with AMD. Neovascular AMD included eyes presenting with CNV. The ratio of eyes with non-neovascular AMD in this sample was much lower than that estimated for the general population, but this might be expected in a referral retinal practice,” he said.

“Of the 474 patients with neovascular AMD in at least one eye, 82 had extrafoveal or juxtafoveal CNV, and 392 (83%) had lesions extending under the center of the foveal avascular zone (subfoveal). Among the 392 patients with subfoveal CNV, 256 eyes had a classic component whereas the other 136 were classified as occult only (occult CNV without classic CNV),” he said.

Assuming ARC’s patient population is representative of other practices, these data may be used to estimate the number of patients eligible for the therapy. “Based on the inclusion criteria of the 12-month TAP Investigation results, at least 171 of the patients with neovascular CNV in the ARC patient population are indicated for verteporfin therapy. This is almost twice as many as compared with laser photocoagulation — 171 compared with 99,” he said.

Socioeconomic impact

Another consideration of using verteporfin therapy is the potential socioeconomic impact on retinal practices. “Most patients who will benefit from this treatment will be from the [elderly] Medicare population. If our estimates prove to be accurate, the resources that will need to be expended will be high. However, the potential benefit of effectively reducing vision loss would far outweigh the costs of this form of clinical management,” he said.

For Your Information:

• Raymond R. Margherio, MD, practiced at Beaumont Eye Institute, Associated Retinal Consultants, PC, 3535 West 13 Mile Road, Royal Oak, MI 48073 U.S.A.; +(1) 248-288-2280; fax: +(1) 248-288-5644; e-mail: margherio@beaumont.edu. Dr. Margherio was a principal investigator for QLT/CIBA Vision for verteporfin.

Reference

• Margherio RR, Margherio AR, DeSantis ME. Laser treatments with verteporfin therapy and its potential impact on retinal practices. Retina. 2000;20:325-330.