Macugen may be useful in diabetic retinopathy treatment, study suggests

NEW YORK — Treatment with pegaptanib sodium was associated with regression of signs of diabetic retinopathy and improvement on a scale of retinopathy severity, results of a phase 2 study showed.

Imaging data from the phase 2 study of Macugen (pegaptanib sodium injection, Eyetech/Pfizer) for the treatment of diabetic macular edema showed a reversal of capillary microaneurysms, retinal ischemia and neovascularization, “all important signs of diabetic retinopathy,” according to a press release from Eyetech Pharmaceuticals.

These “preliminary observations” from the study were presented at last week’s Association for Research in Vision and Ophthalmology meeting.

Larry Singerman, MD, said data from the phase 2 trial showed “an improvement on the diabetic retinopathy severity scale, which suggests that Macugen may have helped slow or even reverse the progression of the disease,” according to the Eyetech release.

Dr. Singerman noted that final conclusions could not be drawn yet, but the findings “are consistent with our current understanding of the role of VEGF in diabetic retinopathy.”

In the phase 2 study, researchers reviewed the charts of 69 patients who had recognized and gradable diabetic retinopathy at both baseline and week 36. Patients received either Macugen 0.3 mg or usual care. In the two arms of the trial, patients receiving Macugen showed an improvement in the severity scale designed for the Early Treatment of Diabetic Retinopathy Study.

At week 36, 11 of 39 patients (28.2%) treated with Macugen showed improvement of at least one step on the scale, compared with four patients in the sham group (13.3%). In addition, a higher percentage of the patients receiving Macugen showed an improvement of more than two scale steps at week 36 compared with the sham group.

A secondary retrospective analysis from the two arms of the trial included 82 patients whose retinal ischemia data was available at both baseline and week 36. Of the 43 patients in this subgroup treated with Macugen 0.3 mg, 16% had less capillary loss at final follow-up, compared with 5% of the 39 patients receiving sham treatment.

In the double-masked, sham-controlled phase 2 study of 172 patients with DME, 73% of patients receiving Macugen 0.3 mg had stable or improved vision at week 36 compared with 51% of patients on sham treatment. Of those receiving Macugen, 59% reported visual acuity gain of at least one line, compared to 34% of those receiving sham treatment. In addition, 42% of patients treated with Macugen 0.3 mg showed a decrease in mean retinal thickness of at least 100 µm compared with 16% of those receiving sham treatment, according to the press release. Half as many patients on Macugen 0.3 mg (25%) needed additional laser therapy as those receiving usual care (48%).

Eyetech and Pfizer have previously announced their intention to begin a pivotal phase 2/3 diabetic macular edema trial on Macugen. The companies expect the trial to start during the second half of 2005, according to the release.