Comparison of two doses of intravitreal bevacizumab (Avastin) for treatment of macular edema secondary to branch retinal vein occlusion: Results from the Pan-American collaborative retina study group at 6 months of follow-up

Purpose: To report the 6-month anatomical and visual outcomes after injecting two different doses of intravitreal bevacizumab in patients with macular edema secondary to branch retinal vein occlusion (BRVO). Methods: An interventional, retrospective multicenter study of 45 eyes that were treated with at least one intravitreal injection (24 eyes, 1.25 mg; 21 eyes, 2.5 mg) of bevacizumab is reported. The main outcome measures were the central 1-mm macular thickness (CMT) and the change in ETDRS lines of best-corrected visual acuity (BCVA) at 6 months. Results: Forty-five eyes were injected on average 26.1 months (range, 3-86 months) after the diagnosis. The average follow-up was 35.2 weeks (range, 24-52 weeks). All patients completed at least 6 months of follow-up. In the 1.25-mg dose group, at 1 month, there was an average gain of 4.5 lines of BCVA; at 3 months, 5.1 lines of BCVA; and at 6 months, 5.1 lines of BCVA (P < 0.005). In the 2.5-mg dose group, at 1 month, there was an average gain of 2.3 lines of BCVA; at 3 months, 3.8 lines of BCVA; and at 6 months, 4.8 lines of BCVA (P = 0.05). In the 1.25-mg dose group, the mean CMT +/- SD decreased from 461 +/- 211 mu m at baseline to 321 +/- 152 mu m at 1 month, 273 +/- 99 mu m at 3 months, and 277 +/- 114 mu m at 6 months (P = 0.0002). In the 2.5-mg group, the mean CMT +/- SD decreased from 385 +/- 168 mu m at baseline to 279 +/- 111 mu m at 1 month, 249 +/- 97 mu m at 3 months, and 240 +/- 93 mu m at 6 months (P = 0.011). Conclusion: There were no statistically significant differences between the two dose groups with regard to the number of injections and anatomical and functional outcomes. Intravitreal injection of bevacizumab at doses up to 2.5 mg appears to be effective in improving BCVA and reducing CMT in BRVO in the short term. Multiple injections are needed in a large number of eyes for continued control of macular edema and preservation of visual acuity in the short term. Longer studies are needed to determine what role if any intravitreal injection of bevacizumab may play in the long-term treatment of this condition.