4D-110

4D-110 is an investigational gene therapy developed for the treatment of choroideremia, a rare X-linked monogenic retinal disorder caused by mutations in the REP-1 gene. The therapy uses an adeno-associated virus (AAV) vector—specifically, the proprietary vector 4D-R100—to deliver a functional CHM transgene via intravitreal injection. This approach is designed to achieve widespread expression of the Rab escort protein-1 (REP-1) protein throughout all layers of the retina and potentially treat patients at all stages of choroideremia. Unlike other AAV-based therapies for this condition that require subretinal surgical injection, 4D-110 aims to provide less invasive administration and broader retinal coverage[1][3][5]. The drug was granted orphan drug designation by the FDA for choroideremia but its development was discontinued after Phase I trials[3][8].