Innovator biologics such as ranibizumab (Lucentis®) and aflibercept (Eylea®) have been proven safe and effective for common conditions such as neovascular age-related macular degeneration (“wet” or nAMD), diabetic macular edema (DME), and macular edema from retinal vein occlusion (RVO).
Because the patents for these drugs have or will be expiring soon, the door is open for other pharmaceutical companies to develop and test biosimilar drugs in order to gain a share of this market.
The FDA has issued guidance to companies proposing biosimilar drugs regarding the modified approval process that must be completed for a biologic to be licensed for sale. Beyond analytic studies demonstrating chemical biosimilarity to the reference drug, sponsors must complete comparative clinical studies for at least one of the approved indications of the innovator drug.
Efficacy of a proposed biosimilar drug is judged by its ability to decrease the abnormal fluid into and under the retina, as evidenced by degree of retinal thickening measured on OCT images. While OCT technology provides the objective measurement of retinal thickening in the macular region, several technical challenges must be overcome for the resultant data to be considered reliable, and to be incorporated into a regulatory submission.