Acucela announced that the FDA granted orphan drug designation to Acucela’s leading drug candidate emixustat hydrochloride for the treatment of Stargardt disease. The orphan drug designation does not apply to other indications emixustat is being developed.
The Orphan Drug Act (ODA) provides for granting special status to drugs and biologics intended for the safe and effective treatment, diagnosis or prevention of rare diseases and disorders that affect fewer than 200,000 people in the U.S.
The visual cycle is the process by which vitamin A is recycled in the eye; vitamin A is crucial to the visual process. Emixustat modulates the visual cycle by inhibiting a critical enzyme of this pathway, retinal pigment epithelium protein 65 (RPE65). Slowing the visual cycle reduces the availability of vitamin A derivatives (11-cis- and all-trans-retinal) to form precursors of A2E and related compounds. In animal models of Stargardt disease and retinal degeneration, emixustat was found to stop and reverse the accumulation of A2E and to preserve the integrity of the retina. Emixustat when delivered orally was found to be generally well tolerated in human clinical studies with delayed dark adaptation being the most common ocular adverse event. Acucela is planning to explore emixustat’s potential to stop or slow the progression of vision loss in patients diagnosed with Stargardt disease in future clinical studies.
Dr. Ryo Kubota, MD, PhD, and Chairman, President and CEO of Acucela, states, “We are very pleased to receive FDA’s orphan drug designation for emixustat to treat Stargardt disease. We are actively advancing the development of emixustat to address this unmet medical need.”