Intravitreal Bevacizumab Revolutionizing Treatment of Diabetic Retinopathy

Vascular endothelial growth factor (VEGF) is a major driving force in the development of diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR). Intravitreal injection of the anti-VEFG medication bevacizumab (Avastin) has revolutionized the treatment of diabetic eye disease, and has emerged as an important treatment modality, either as primary or adjuvant therapy for DME and PDR.

The reference Avastin was approved to treat cancer, as was its biosimilar (Mvasi), but its off-label use to treat diabetic retinopathy remains popular and widespread around the world, especially in low-income countries, given its lower cost, perceived effectiveness, and comparable safety profile.

Writing for the Pan-American Collaborative Retina Study Group (PACORES), J. Fernando Arevalo, MD, and T.Y. Alvin Liu, MD, reviewed 5 years of experience using intravitreal bevacizumab for diabetic retinopathy in Latin America and Spain, and conclude that it is an important tool in the armamentarium for treating the complications of diabetic retinopathy.

The researchers add that intravitreal bevacizumab can also be used as a preoperative, adjuvant therapy before vitrectromy for proliferative diabetic retinopathy. Their study provides one of the longest-term follow-up data sets on the efficacy of the anti-VEGF treatments in DME. The review is published in the December 2017 issue of Asia-Pacific Journal of Ophthalmology (Philadelphia).

Their study enrolled 201 patients (296 eyes) with center-involving DME and vision loss who were treated monthly with 1.25 mg of intravitreal bevacizumab until edema was stabilized, then returned to clinic and treated on an as-needed regimen, based on best corrected visual acuity (BCVA) and optical coherence tomography (OCT). The main outcome measures were changes in BCVA and central macular thickness (CMT) at the 60-month follow-up visit.

• Mean baseline BCVA compared with mean final BCVA at month 60 was not statistically different despite statistically significant vision gain during the first 3 years.
• Subgroup analysis showed that at month 60, BCVA improved by 2 or more lines, remained stable, and decreased by 2 or more lines in 29%, 43.6%, and 27.4% of eyes, respectively.
• Mean baseline CMT was 403.5 µm. Significant decrease in CMT was generally maintained throughout the remainder of the study period.
• At month 60, the mean CMT was 313.7 µm, significantly lower than baseline (P ≤.0001).

The group’s data on preoperative intravitreal bevacizumab suggest that it is beneficial before vitrectomy for PDR, as it tends to decrease intraoperative bleeding, facilitate intraoperative fibroproliferative membrane dissection, and decrease postoperative bleeding. The researchers believe intravitreal bevacizumab before vitrectomy is safe, especially with careful planning and patient selection.

“Based on our experience, we recognize intravitreal bevacizumab to be an important tool in our armamentarium for treating the complications of diabetic retinopathy,” they conclude. “For center-involving DME, our real-world data suggest that there is a roughly 70% chance of stabilized or improved vision with intravitreal bevacizumab treatments over a time course of 5 years,” they write, adding that for PDR, intravitreal bevacizumab is a good adjuvant therapy for patients who have already received prior panretinal photocoagulation treatment. Finally, they conclude that preoperative intravitreal bevacizumab before vitrectromy is safe, with a low incidence of development or progression of tractional retinal detachment.