Background:
Vascular endothelial growth factor (VEGF) has been shown to be capable of inducing Choroidal Neovascularization (CNV). CNV is the wet form of Macular Degeneration. Therefore, a strategy to treat the wet form of macular degeneration is to block the VEGF action by using anti-VEGF drugs.

Eyetech Pharmaceuticals has released the results of Phase II human clinical trial of an anti-VEGF drug. The results appear in the May 2003 issue of the Journal 'Ophthalmology' (Ophthalmology 2003 110: 979-986). The drug used in this clinical trial was Macugen (pegaptanib sodium). It is an anti-VEGF aptamer. Aptamers are chemically synthesized short strands of RNA (nucleic acid). The anti-VEGF aptamer prevents the binding of VEGF to its receptor.
The drugs was injected inside the eye cavity (injections into the vitreous) on three occasions at 28-day intervals. Patients who were treated had poor vision due to wet macular degeneration (best-corrected vision in the study eye was worse than 20/100 and CNV was active subfoveal).

Results of the study:
  ● 87.5% of patients who received the anti-VEGF drug alone showed stable or improved vision 3 months after treatment.
  ● Vision improved by 3 or more lines in 25% of eyes that received this drug alone.
  ● However when combined with photodynamic therapy, many more eyes (60% ) gained 3 or more lines of vision.

This study has reported short term (3 month) results, which look encouraging. As the authors conclude - "Further clinical trials are necessary to demonstrate the efficacy and long-term safety of anti-VEGF therapy for wet macular degeneration". No definitive conclusions regarding the efficacy of the drug can be deduced from this study because of the absence of a control group, small sample size, and short follow-up period. Phase II/III trials using this drug are presently underway to evaluate this potential treatment in more than a 1000 patients in more than 100 centers worldwide.

An accompanying editorial critique of this study is published in the same issue (Ophthalmology 2003;110: 879-881). The problem in wet macular degeneration is that there is a relentless loss of vision despite treatment (even with the recently introduced photodynamic therapy). As with Photodynamic therapy, this study showed a definite short term improvement in vision, but it is unclear whether this improvement was due to lessening of edema and blood in the macula or whether the degeneration process itself was halted or reversed. Long-term controlled studies will answer this important question.
Even so, given the paucity of other available treatments, any treatment that improves vision, even if it is for a short term deserves to be welcomed, albeit with tempered expectations. Wet macular degeneration results in more severe vision loss than any other disease in the elderly population. These patients demand our continued efforts to find safe and effective modalities to prevent this devastating disease.