Sepofarsen aims to restore vision loss in people with Leber congenital amaurosis due to a specific mutation in the CEP290 gene. This p.Cys998X mutation, also known as c.2991+1655A>G, is the most common mutation causing LCA10. The p.Cys998X mutation causes a mistake in the CEP290 RNA and therefore a process called splicing is not done properly. The cell can therefore not use the RNA to produce a working CEP290 protein that is essential for vision.
Sepofarsen works by binding to the mutated CEP290 RNA to enable correct splicing. The cells in the retina can then produce the CEP290 protein again.