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Combination anti-VEGF and PRP therapy can lower IOP, prevent further surgery
Patients in the combined treatment group had more rapid regression of neovascularization than those in PRP-only group, surgeon says.
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 Justis P. Ehlers |
PHILADELPHIA – Combination bevacizumab and panretinal photocoagulation proved more effective than panretinal photocoagulation alone in treating patients who have neovascular glaucoma, according to a surgeon speaking here at the Wills Eye Institute Annual Alumni Conference.
“Neovascular glaucoma is a devastating disease,” Justis P. Ehlers, MD, said. “It’s secondary to ocular ischemia and anterior segment neovascularization. Selected causes include central retinal vein occlusion, diabetes, ocular ischemic syndrome and central retinal artery occlusion.”
The study involved off-label use of Avastin (bevacizumab, Genentech), Dr. Ehlers said.
“[Neovascular glaucoma] is difficult to manage and often requires surgical intervention,” he said. “Currently, the gold standard is to use extensive panretinal photocoagulation (PRP) with initial medical management of intraocular pressure. It has many treatment challenges, including the fact that PRP takes several weeks for it to take full effect. During this time, progressive angle closure may occur.”
VEGF plays a key role
Dr. Ehlers cited literature showing that vascular endothelial growth factor (VEGF) plays an active role in neovascular glaucoma. For example, early animal studies showed that directly elevating VEGF levels resulted in neovascular glaucoma. Human studies showed that patients with neovascular glaucoma had significantly elevated VEGF levels in the aqueous, he said.
“From that, there have been multiple case reports and a few small case series that have looked at Avastin and neovascular glaucoma, and they’ve shown that regression of iris neovascularization occurs, as well as the observation that this takes place quite rapidly,” Dr. Ehlers said. “Additionally, there have been a couple of case reports that actually showed that intraocular pressure may decrease.”
Dr. Ehlers and colleagues hypothesized that combining PRP and anti-VEGF medication on the same day may help stabilize disease progression, speed control of anterior segment neovascularization and eliminate the need for subsequent surgery.
The retrospective case study included 23 patients. Of these, 11 patients received combined treatment with bevacizumab and PRP and 12 received PRP only.
Researchers studied changes in visual acuity, IOP, presence of anterior chamber neovascularization and need for surgical intervention, Dr. Ehlers said.
At baseline, IOP and visual acuity measurements were similar for both patient groups, he said.
Reduced neovascularization, IOP
After treatment, all patients in the combination group showed regression of neovascularization, Dr. Ehlers said.
“In fact, 100% of patients responded to treatment,” he said.
The combined treatment group had a more rapid regression of neovascularization compared with the PRP-only group, he noted.
At 4 months follow-up, investigators found that the combined treatment group had a mean IOP reduction of about 20 mm Hg, and the PRP-only group had a mean IOP decrease of about 7 mm Hg from initial diagnosis, Dr. Ehlers said.
No patients required surgical intervention in the combination group, he said.
Both groups showed similar visual outcomes. However, there was a trend toward a lower incidence of absolute glaucoma and a lower final IOP in patients treated with the combination therapy, he said.
“In general, combination therapy resulted in more rapid decrease in intraocular pressure with a more rapid rate and higher incidence of neovascular regression,” Dr. Ehlers said. “There were some trends that we observed that included decreased final IOP, decreased need for surgical intervention and possibly a decrease in absolute glaucoma.”
Other recent studies have shown similar findings.
“Recently, at the annual ASRS meeting, there were a couple of abstracts that were presented which supported these trends,” he said. “They didn’t quite achieve statistical significance in regard to visual outcome, but one showed that there was probably better visual outcome as well as decreased need for surgical intervention. Additionally, one study found that there was greater surgical success when Avastin was used preoperatively prior to a filtering procedure for [neovascular glaucoma].”
More definitive data needed
“Our study does have some significant limitations,” Dr. Ehlers said. “It is retrospective, short-term and has a relatively small study size. And importantly, we weren’t able to have comparative or serial gonioscopic data. However, we do feel that it provides a foundation for future research. It does support the critical role that VEGF plays in the pathogenesis of neovascular glaucoma.”
Dr. Ehlers invited colleagues to consider the combined treatment for patients with neovascular glaucoma.
“We urge you to consider using Avastin along with PRP for their initial treatment protocol for a neovascular glaucoma patient,” he said. “Further prospective research is probably needed to definitively document the changes in angle anatomy as well as the need for surgical intervention and the visual outcome in a larger study size.”
Some clinicians support using VEGF inhibitors alone for neovascular glaucoma, but some degree of controversy surrounds that trend, Dr. Ehlers said.
“There’s some suggestion in the community for considering possibly using VEGF inhibitors alone,” he said. “This is controversial because, obviously, the ischemic drive is long-lasting and would potentially expose the patient to repeated intravitreal injections, but it might avoid some of the quality-of-life issues that you can see with extensive PRP. If a prospective study is initiated, it may be worthwhile to include three arms to help answer this question: PRP only, bevacizumab only and combination therapy.”
For more information:
- Justis P. Ehlers, MD, can be reached at Wills Eye Institute, 840 Walnut St., Philadelphia, PA 19107; 215-440-3170; fax: 215-825-4732; e-mail: ehlersj1@yahoo.com. Dr. Ehlers has no direct financial interest in the products discussed in this article, nor is he a paid consultant for any companies mentioned.
- Matt Hasson is an OSN Staff Writer who covers all aspects of ophthalmology. He focuses on regulatory, legislative and practice management topics.