Alkeus Pharma's lead compound, ALK-001, is an oral compound with a well-understood mechanism of action. ALK-001 was specifically designed to prevent the formation of these toxic vitamin A dimers in the eye. ALK-001 is a chemically-modified vitamin A, in which 3 hydrogen atoms have been replaced by 3 deuterium atoms at carbon number 20. Replacing the retina's vitamin A with ALK-001 slows the formation of toxic vitamin A dimers. ALK-001 is in phase II clinical trials for the treatment of Stargardt's disease. The compound was co-developed by Alkeus Pharmaceuticals and Columbia University.