PRESENTATIONS FROM THE RETINA SOCIETY

Study Seeks to Prove Safety and Efficacy of 2.5-mg Bevacizumab

Higher dosing may offer trend toward improved VA, less frequent injections.

As the debate over vascular endothelial growth factor (VEGF) inhibitors goes on, Pradeepa Yoganathan, MD, a vitreoretinal fellow at the University of Toronto, presented the results of a study she undertook with David M. Fastenberg, MD, and Philip J. Ferrone, MD, of North Shore-Long Island Jewish Health System and Long Island Vitreoretinal Consultants. The safety/efficacy study of bevacizumab (Avastin, Genentech) in wet age-related macular degeneration (AMD) found that 2.5-mg prn dosing over an 8-month follow-up period required a statistically significant decrease in number of injections and a trend toward improved visual acuity (VA), compared to 1.25-mg prn dosing.

STUDY DETAILS

Dr. Yoganathan et al. performed a retrospective review of 88 eyes, 42 of which were injected with 2.5 mg bevacizumab and 46 of which were injected with 1.25 mg bevacizumab. Follow-up was monthly and consisted of visual acuity (VA) testing, screening for hypertension and thromboembolic events, and, when available, optical coherence tomography (OCT). The mean follow-up time was 7.9 months in the 2.5-mg cohort and 7.7 months in the 1.25-mg cohort. For 4 groupings (total 2.5 mg, total 1.25 mg, treatment-naïve 2.5 mg, and treatment naïve 1.25 mg), the best mean VA improvement was in the 2.5-mg treatment-naïve cohort, which improved from an overage VA of 20/120 to 20/63 over 8 months. The least improvement was in the total 1.25-mg group, improving from 20/160 to 20/130 in the same period of time.

Foveal thickness in the treatment-naïve group fell from nearly 375 μm to around 230 μm over 8 months, with the previously treated patients dropping from a mean of approximately 275 μm to around 200 μm. The 8-month mean improvement for all 42 patients was a drop in foveal thickness from approximately 330 μm to around 220 μm. The foveal thickness of the 2.5-mg group as a whole decreased only slightly more than that of the 1.25 mg.

The percentage of patients receiving reinjections over the 8-month period was statistically lower in the 2.5-mg cohort. Eighty-seven percent of 1.25-mg patients required reinjection at 1-month follow-up, whereas only 26% of 2.5-mg patients were retreated. This difference persisted every month until month 6.

FEW SIDE EFFECTS

Adverse effects among the patients were low, with no cases of severe vision loss, endophthalmitis, thromboembolisms, addition of antihypertensive medicine, or rises in mean blood pressure. Out of 88 eyes, there was 1 eye from the 1.25-mg group that experienced a tear in the retinal pigment epithelium. However, this patient's VA was not affected by the tear, and there were no additional safety concerns in the other patients.

The study provides additional evidence that off-label use of bevacizumab still plays a role in wet AMD management, depending on issues such as safety, economics, and individual drug response. RP