Intravitreal injections of pegaptanib will induce the regression of Proliferative Diabetic Retinopathy (PDR) and reduce the need for retinal photocoagulation.

Primary Objective:

To further establish the efficacy of intravitreal pegaptanib injections in the regression of retinal neovascularization secondary to high-risk PDR, as compared to standard panretinal photocoagulation (PRP)

Secondary Objective:

To maintain the regression of PDR after the induction phase with intravitreal pegaptanib injections administered at 12-week intervals, as compared to standard PRP

To maintain the regression of PDR after the induction phase with retinal photocoagulation applied to areas of ischemia (Selective Laser Photocoagulation), as compared to standard PRP

To evaluate the rate of recurrence of neovascularization after 6 intravitreal pegaptanib injections

To determine if intravitreal pegaptanib will reduce the area and/or volume of concomitant diabetic macular edema, as assessed by leakage on fluorescein angiography (FA) and/or optical coherence tomography (OCT)

To determine if intravitreal pegaptanib injections maintain or reduce the loss of best-corrected visual acuity

Inclusion Criteria:

1. Eligible eyes will have active PDR with high risk characteristics (HRC) as defined by the DRS. All eyes must meet at least one or both of the following criteria:

   • Mild neovascularization of the disc (NVD) of at least 1/4 to 1/3 disc area as shown in standard photograph 10A of the DRS.
   • Moderate neovascularization of the retina elsewhere (NVE) of at least 1/2 disc area as shown in standard photograph 7 of the DRS.

2. ETDRS visual acuity score greater than or equal to 24 letters (approximately 20/320) and less than or equal to 85 letters (approximately 20/20) by the ETDRS visual acuity protocol at the screening visit.

3. Eyes with mild pre-retinal hemorrhage (PRH) or mild vitreous hemorrhage (VH) that does not interfere with clear visualization of the macula and optic disc are eligible for this study.

4. Evaluating physician believes that PRP can be safely withheld for 3 weeks.

Exclusion Criteria:

1. Presence of moderate or dense PRH or VH that prevents clear visualization of the macula and/or optic disc.

2. Presence of either:

   • significant epiretinal membranes involving the macula, OR

   • proliferative diabetic membranes along the major retinal arcades that are extensive enough to cause either:

     • significant vitreomacular traction, OR
     • significant impairment in visual acuity.

3. Presence of any tractional retinal detachment.

4. Severe ischemia involving the foveal avascular zone as determined by fluorescein angiography performed at the initial screening visit.

5. Significant media opacity (due to cornea, anterior chamber, or lens) precluding clear visualization of the macula or optic disc.

6. Presence of neovascular glaucoma with or without hyphema.

7. Previous treatment with intravitreal steroid injections in the study eye within 6 months of baseline.

8. Previous treatment with peribulbar steroid injections in the study eye within 90 days of baseline

9. Previous PRP laser treatment in the study eye within 90 days of baseline visit.