By Fred Gebhart
SAN FRANCISCO -- October 28, 2009 -- The inhibition of vascular endothelial growth factor (VEGF), inhibiting angiogenesis, and decreasing vascular permeability can be a highly effective treatment for a variety of ocular diseases, including exudative age-related macular degeneration (AMD) and diabetic macular oedema (DME).
Fernando Arevalo, MD, Clinica Oftalmologica Centro Caracas, Caracas, Venezuela, presented detailed 24-month data from the Pan-American Collaborative Retina Study Group (PACORES) here on October 26 at the 2009 Joint Meeting of the American Academy of Ophthalmology and Pan-American Association of Ophthalmology (AAO-PAAO).
The initial 12-month results of the study (published in 2008), which examined the effects of bevacizumab in AMD, were largely positive. Longer-term data were also positive, Dr. Arevalo said.
The most important distinction between the 1- and 2-year results was the finding that the higher 2.5-mg dose of bevacizumab produced clinical results similar to the 1.25-mg dose but had significantly higher rates of adverse events.
The trial was a retrospective review of 180 consecutive patients (207 eyes) with subfoveal neovascularisation in AMD who were treated with intravitreous bevacizumab and followed for 24 months. Of the 207 eyes, 83 (40.1%) were treated with the 2.5-mg dose and 124 (59.9%) were treated with 1.25 mg.
At baseline, the mean best corrected visual acuity was 20/257. Two years later, the mean best corrected visual acuity had improved significantly to 20/184 (P < .0001). The mean baseline central macular thickness was 349.6 microns compared with 251.5 microns 24 months later (P < .0001).
The higher 2.5-mg dose showed greater numerical improvement than the 1.25-mg dose, but the differences were not statistically significant. Patients in the 1.25-mg dose required a mean of 4.04 injections compared with 6.61 injections for the 2.5-mg dose, again not statistically significant.
More important differences between the 2 doses appeared with adverse events. Researchers noted a transient increase in intraocular pressure in 1 eye in the 1.25-mg group and retinal pigment epithelial tearing in 1 eye in the 2.5-mg group. There were no systemic adverse events in the 1.25-mg group and 4 adverse events (5.2%) in the 2.5-mg group, including arterial hypertension (2.6%), stroke (1.3%), and death (1.3%).
"There appears to be no difference in clinical outcomes between the 2 doses and a somewhat higher rate of adverse events with the 2.5-mg dose," Dr. Arevalo said. "Given these findings, the lower 1.25-mg dose should be preferred."
The researchers also reviewed records of 115 consecutive patients (139 eyes) with DME who had been treated with intravitreal bevacizumab and followed for 24 months. In the DME group, 62 eyes (44.6%) remained stable, 72 eyes (51.8%) improved by >=2 ETDRS lines, and 5 eyes (3.6%) decreased by >=2 ETDRS lines.
One month after treatment, baseline best corrected visual acuity had improved from a minimum angle of resolution (logMAR) 0.90 to logMAR 0.76. The improvement was maintained during the entire 24-month follow up period and there were no statistically significant differences between the 2 dosage groups.
[Presentation title: Emerging Pharmacotherapies for the Treatment of Posterior Segment Diseases, Bevacizumab (Avastin) in AMD & DDME. Abstract SYM 44]
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