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Vascular Endothelial Growth Factor Inhibition Shows Long-Lasting Efficacy in Treating Neovascular Age-Related Macular Degeneration: Presented at AAO

By Emma Hitt, PhD

ATLANTA -- November 12, 2008 – An experimental vascular endothelial growth factor (VEGF) inhibition treatment called VEGF Trap-Eye produces at least similar results to that of the standard of care in the treatment of neovascular age-related macular degeneration (AMD), according to trial results presented here at the American Academy of Ophthalmology (AAO) annual meeting.

VEGF Trap-Eye has a high binding affinity for VEGF-A and placental growth factor and penetrates all layers of the retina, noted David S. Boyer, MD, Retina-Vitreous Associates Medical Group, Beverly Hills, California, presenting findings here at an Original Paper Session on November 11 from a 1-year interim analysis of a dose- and interval-ranging study.

The results of the phase 2 trial, called CLEAR-IT 2, highlight the efficacy of intravitreal VEGF Trap-Eye. The CLEAR-IT 2 study was designed to assess the responses at 12 weeks to a range of VEGF Trap-Eye doses administered monthly and quarterly. Durability of the response to as-needed dosing was also measured out to 1 year.

Subjects (n = 159) were equally randomised to 5 groups who received either 0.5 or 2 mg VEGF Trap-Eye every 4 weeks or 0.5, 2, or 4 mg every 12 weeks.

"The 12-week results were very encouraging, indicating a significant improvement in mean visual acuity of 5.7 letters for all groups combined [P < .0001]," noted Dr. Boyer. "Central retinal thickness was also significantly reduced, [by] 119 mcm for all groups combined [P < .0001]," he added

In addition, groups dosed only quarterly (ie, at baseline and at week 12) demonstrated improved visual acuity and retinal thickness, although the effect was not as robust as with monthly dosing Notably, visual acuity was maintained with a single dose for up to 8 weeks.

Patients were re-treated starting at week 16 if they met one of several criteria, including persistent fluid on optical coherence tomography (OCT), a loss of at least 5 letters with recurrent fluid on OCT, new macular haemorrhage, or new-onset classic neovascularisation.

Patients received, on average, about 2 additional injections over the 40-week, as-needed dosing phase following a 12-week fixed dosing period. Nineteen percent of patients received no additional injections after week 12.

A total of 84% of patients completed the study at week 52. Reasons for discontinuation were varied, with no single reason warranting concern, Dr. Boyer said. At week 52, up to 9.0 mean letters were gained, and central retinal lesion thickness was decreased by 161 mcm as measured by OCT.

"These findings were very encouraging and exciting, because they suggest that VEGF Trap-Eye produces at least similar results to that of the standard of care," said Quan Dong Nguyen, MD, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, who presented OCT and fluorescein angiographic outcomes from CLEAR-IT 2. "We are also very encouraged by the long duration of action of the drug," he said in an interview.

Treatment was generally well tolerated, with no serious treatment-related adverse events. Adverse events were mostly typical of intravitreal injection. Those occurring in at least 10% of patients included 38% with conjunctival haemorrhage, 18.5% with increased intraocular pressure (transient postinjection), 15.9% with refraction disorder, 14.6% with retinal haemorrhage, 13.4% with reduction in visual acuity, and 11.5% with vitreous detachment.

Funding for this study was provided by Regeneron.


[Presentation titles: One-Year Results of a Phase 2 Study of Intravitreal VEGF Trap-Eye in Patients With Neovascular AMD. Abstract PA080. OCT and Fluorescein Angiographic Outcomes Through 1 Year for the Phase 2 Study of Intravitreal VEGF Trap-Eye in Neovascular AMD. Abstract PO571]

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