Duration of action of intravitreal ranibizumab and bevacizumab in exudative AMD eyes based on macular volume measurements

Background/aims: Sequential macular volume and central foveal point thickness (CFPT) measurements on optical coherence tomography (OCT) were used to determine the efficacy and duration of action of ranibizumab versus bevacizumab in wet age-related macular degeneration (AMD). Methods: Retrospective chart review of patients who received their first treatment of intravitreal ranibizumab or bevacizumab for exudative AMD. 316 patients (202 ranibizumab;114 bevacizumab) who received 823 injections (313 ranibizumab;510 bevacizumab) were identified. 74 patients had pre- and post-treatment OCTs performed to determine CFPT and macular volume changes. Results: Ranibizumab caused a significant reduction in CFPT (278 (SD 84) before treatment vs 227 (80) μm after treatment; p=0.001) and macular volume (7.22 (0.96) vs 6.69 (0.74) mm ³; p=0.002). Intravitreal bevacizumab caused a similar reduction in CFPT (288 (94) vs 220 (55) μm; p=0.008) and macular volume (7.36 (1.08) vs 6.50 (0.42) mm³; p<0.001). The mean duration of action was 74.0 (19.1) days for ranibizumab compared with 101.8 (16.6) days for bevacizumab (p=0.036; t test). The ratio of the relative duration of action of bevacizumab versus ranibizumab was 1.40 (0.19). Conclusions: Both drugs are equally effective at reducing CFPT or macular volume. Bevacizumab appears to take longer to achieve the minimum macular volume, and its effects take longer to wear off, suggesting it can be given less often.