Intravitreal therapy for venous occlusive disease is promising in the short term, however, multiple injections are needed, dosing schedules are presently unclear, and rebound has to be evaluated.
Intravitreal therapy for venous occlusive disease is promising in the short term, however, multiple injections are needed, dosing schedules are presently unclear, and rebound has to be evaluated, said Peter Kaiser, MD, of the Cole Eye Institute, Cleveland Clinic, Cleveland, OH.
"Venous occlusive disease is the second leading cause of decreased visual acuity in diabetic retinopathy, with 25% of patients having worse than 20/200 vision," Dr. Kaiser said. Laser treatment was not effective for these patients in two randomized studies and observation is the only therapy for central vein occlusion, he said. Laser has shown more improvement for branch vein occlusion but, in the long term, results in only a one-line increase in vision, he added.
Steroids are an obvious choice for vein occlusion since they decrease vascular permeability, stabilize the blood-retinal barrier, and address periphlebitis, according to Dr. Kaiser. In all studies, visual acuity improved. However, the drugs are associated with increased IOP and cataract, he said. The Standard Care versus Corticosteroids for Retinal Vein Occlusion Study is taking a close look at the drugs for retinal vein occlusion.
Anti-vascular endothelial growth factor (VEGF) drugs are also being evaluated. Two doses (1 and 0.3 mg) of pegaptanib sodium (Macugen, OSI/Eyetech/Pfizer) were evaluated in a phase II study. After every 6-week dosing (five injections), the visual acuity increased with both doses, but the end result was not much better than that achieved with laser, Dr. Kaiser reported.
One injection of bevacizumab (Avastin, Genentech) achieves "very nice" clinical features and optical coherence tomography findings, according to Dr. Kaiser. After 4 months, however, the edema returns, he said. Similar results were achieved with ranibizumab (Lucentis, Genentech). The BRAVO and Cruise studies are enrolling patients to evaluate the use of ranibizumab versus controls for branch and central retinal vein occlusion.