Dispensing Patterns of Ranibizumab and Aflibercept for the Treatment of Neovascular Age-Related Macular Degeneration: A Retrospective Cohort Study in Australia

INTRODUCTION: Anti-vascular endothelial growth factor therapy is the standard of care for neovascular age-related macular degeneration (nAMD). The dosage of two licensed agents, ranibizumab and aflibercept, was established through clinical trials; however, it is unclear if either agent is administered as recommended in routine clinical practice. Using pharmacy claims data, we investigated if the dispensing patterns of ranibizumab differ from those of aflibercept 6 and 12 months after treatment initiation. METHODS: Prescription data retrieved from the Australian IMS(®) AUS LRx database were used to identify nAMD patients with one or more claims for ranibizumab or aflibercept between December 1, 2012, and March 31, 2015, with follow-up of at least 6 months. The number of ranibizumab and aflibercept units dispensed was adjusted for baseline patient Medication-Based Disease Burden Index (MBDBI) scores. No difference in the number of ranibizumab versus aflibercept units dispensed was concluded if the 95% confidence interval (CI) limits of the adjusted mean difference between the study cohorts were 1.00 unit or less. RESULTS: Baseline patient MBDBI scores were similar for the ranibizumab (N = 1235) and aflibercept (N = 959) cohorts. The adjusted mean (standard deviation) number of units dispensed was 5.3 (1.3) versus 5.1 (1.4) at month 6 and 8.9 (2.2) versus 8.9 (2.3) at month 12. The 95% CI limits of the adjusted mean difference did not exceed 1.00 unit dispensed at either time point: 95% CI of 0.09 to 0.32 for an adjusted mean difference of 0.20 at month 6 and −0.23 to 0.30 for an adjusted mean difference of 0.04 at month 12. Mean (standard deviation) dispensing intervals were comparable for both cohorts: 35.3 (19.2) days versus 36.8 (20.0) days at month 6 (adjusted mean difference −1.59 days; 95% CI –2.51 to −0.67 days) and 41.2 (20.9) days versus 41.6 (20.4) days at month 12 (adjusted mean difference −0.40 days; 95% CI −1.70 to 0.91 days). CONCLUSIONS: Ranibizumab and aflibercept are dispensed in a similar manner by Australian pharmacies during the first year of treatment. FUNDING: Novartis Pharma AG.