Pegaptanib sodium shows promise in treatment of CRVO

Treatment of macular edema secondary to central retinal vein occlusion (CRVO) with pegaptanib sodium (Macugen, OSI/Eyetech, Pfizer Ophthalmics) was associated with improved visual acuity in a comparison with patients receiving sham injections. This finding suggests that pegaptanib, which inhibits vascular endothelial growth factor (VEGF), may provide functional benefits to patients with CRVO, said John A. Wells III, MD, a private practitioner at the Palmetto Retina Center, Columbia, SC.

Dr. Wells presented results of the phase II study on behalf of the Pegaptanib in CRVO Study, a trial performed to assess the safety and efficacy of the drug in treating macular edema secondary to CRVO. Since pegaptanib slows vision loss in age-related macular degeneration and reduces diabetic macular edema, investigators wanted to study the drug's effect in CRVO, a condition involving overexpression of VEGF. However, because of damage to the retinal vasculature and neurosensory retina present in CRVO, selective inhibition of (VEGF) might be more beneficial than nonselective inhibition, Dr. Wells said.

The trial included 98 subjects enrolled at 36 centers internationally who were randomized to 0.3 mg (n = 33) of pegaptanib, 1 mg (n = 33), or sham (n = 32). They received intravitreous injections every six weeks for 24 weeks; follow-up continued through 52 weeks. Rescue therapy was permitted after week 30; eight patients in the 0.3-mg group, seven in the 1-mg group, and two in the sham group received this treatment.

Baseline vision was about 48 letters in all three groups, visual acuity was about 20/100, and the mean central retinal thickness was also similar, Dr. Wells said.

An early and sustained treatment effect was shown in the active treatment groups. At week 30, there was almost a 10-letter gain in the 1-mg arm, a seven-letter gain in the 0.3-mg group, and a three-letter loss in the sham group.

The primary endpoint of the trial was the proportion of patients who gained 15 letters or more (3 lines) at week 30.

"While there was a trend favoring the Macugen eyes, it failed to meet that endpoint," Dr. Wells said. The proportion of patients gaining 15 letters or more was 36% in the 0.3-mg group and 39% in the 1-mg group, compared to 28% in the controls.

At week 52, the mean change in baseline was a gain of 7.5 letters for the 0.3-mg group and 6.3 letters in the 1-mg group compared with a loss of 2.4 letters in the sham group. The difference was not statistically significant. Fewer subjects treated with 0.3-mg of pegaptanib lost ≥15 letters than those in the sham group at 52 weeks (6% versus 31%, p p p