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Anti-VEGF injection improves PRP results in diabetic retinopathy
Administering intravitreal bevacizumab before panretinal photocoagulation enhanced leakage reduction while preserving vision.
NEW ORLEANS, U.S.A. – Treating severe proliferative diabetic retinopathy with a combination of panretinal photocoagulation and bevacizumab appears more effective than treating with panretinal photocoagulation alone, according to a speaker here.
“Avastin (bevacizumab, Genentech) combined with [panretinal photocoagulation] … was effective on the regression of the new vessels and resolution of macular edema in patients with diabetic retinopathy,” Murat Oncel, MD, said at the annual meeting of the American Academy of Ophthalmology.
“In the future, pharmacologic, nondestructive therapy may substitute for laser photocoagulation when better methods of sustained delivery become available,” he said.
In a prospective study, Dr. Oncel evaluated the effects of administering an anti-VEGF injection in patients with diabetic retinopathy before treating with panretinal photocoagulation (PRP).
“It takes some time for PRP to cause neovascular regression and places the patient at risk for vitreous hemorrhage and tractional retinal detachment, and in one-third of the cases, new vessels continue to grow,” Dr. Oncel said.
Additionally, “PRP is a destructive therapy,” he said, citing loss of peripheral visual field and night vision, exacerbated macular edema, subsequent reduction of central vision and patient discomfort as possible side effects.
The study
Dr. Oncel evaluated the efficacy of using bevacizumab as an adjunctive therapy to PRP in 46 eyes of 23 patients with mild to high-risk diabetic retinopathy. Specifically, one eye of each patient received a 1.25-mg injection of bevacizumab 5 to 7 days before PRP, and the fellow control eye received PRP alone. The injected eyes were randomly chosen.
PRP was performed with a 532-nm laser during three sessions scheduled about 1 week apart. The injected eyes received 1,300 spots, with an average laser power of 295 mW, whereas the control eyes received 1,500 spots, with an average power of 389 mW.
Patients’ ages averaged 55 years and ranged from 35 to 67 years. Follow-up evaluations were conducted 1 week after bevacizumab injection and at 3, 6, 9 and 12 months from baseline. All patients were followed for at least 10 months.
“Patients with a history of uncontrolled hypertension and recent thromboembolic events were not included in the study,” Dr. Oncel said.
Improved results
“All patients with neovascularization had complete or at least partial reduction in leakage of the neovascularization within 1 week after the injection,” Dr. Oncel said.
“The leakage was reduced as early as 24 hours after injection,” he added.
The investigator observed a consistent but much slower decrease in leakage in the control eyes throughout follow-up.
“The speed and degree of neovascular regression in combination treatment is much faster than PRP alone,” he said.
In addition, macular thickening significantly decreased in the combined treatment group but increased in the control eye group. Specifically, central macular thickness decreased by 40% at 3 months, 35% at 6 months, 33% at 9 months and 15% at 12 months in injected eyes. In control eyes, central macular thickness increased by 18% at 3 months, 20% at 6 months, 14% at 9 months and 12% at 12 months.
Vision also increased in the injected eye group but was lost in the control group. The injected eyes gained an average of 1.7 lines at 3 months, 1.5 lines at 6 months, 1 line at 9 months and 0.8 lines at 12 months. In contrast, the control eyes lost an average of 2.2 lines of vision at 3 months, 1.5 lines at 6 months, 1.3 lines at 9 months and 1.8 lines at 12 months.
No systemic or ocular adverse events were observed in any patients, and no IOP increase or cataract progression was observed in any of the injected eyes.
“The very rapid, dramatic effect seen with Avastin can be maintained long term with a proven effect of PRP,” Dr. Oncel said.
“Intravitreal Avastin seems a promising adjuvant treatment to PRP, while minimizing the risk for exudative complications such as macular edema, progression of diabetic retinopathy, vitreous hemorrhage, tractional detachment and decreased vision,” he said.
For more information:
- Murat Oncel, MD, can be reached at Istanbul Retina Center, Kodaman sok. No. 10-11, Nisantasi, Istanbul 34363 Turkey; +90-212-2248471; e-mail: muratoncel@superonline.com. Dr. Oncel has no direct financial interest in the products discussed in this article, nor is he a paid consultant for any companies mentioned.
- Jessica Loughery is an OSN Staff Writer who covers all aspects of ophthalmology.