Japan Grants Orphan Drug Designations to Gildeuretinol, QRX003, and E2086

Japan's Ministry of Health, Labour and Welfare (MHLW) has granted Orphan Drug Designation to three investigational therapies: oral gildeuretinol for Stargardt disease, QRX003 for Netherton Syndrome, and E2086 for narcolepsy. The designations provide benefits including potential market exclusivity for up to 10 years if approved.

Alkeus Pharmaceuticals announced that the MHLW granted Orphan Drug Designation for oral gildeuretinol for the treatment of Stargardt disease, an inherited retinal disease that often begins in childhood or adolescence and progressively and irreversibly damages central vision. In Japan, Orphan Drug Designation is granted to drugs intended for the treatment of rare diseases affecting fewer than 50,000 patients in the country and for which there is a high medical need. Benefits include eligibility for subsidies for development costs and potential market exclusivity for up to 10 years if approved. Gildeuretinol is currently being evaluated in the global Phase 3 NORTHSTAR Study, a randomized, placebo-controlled, double-masked 24-month trial designed to evaluate its efficacy and safety in people living with advanced Stargardt disease. The primary endpoint is the rate of growth of atrophic lesions from months 6 to 24 comparing gildeuretinol to placebo, and the key secondary endpoint is the preservation of visual acuity as measured by low luminance visual acuity. Alkeus aims to enroll approximately 230 participants globally between the ages of 8 and 45, building on previously observed findings across more than 400 patients treated with gildeuretinol to date. Gildeuretinol has received Breakthrough Therapy, Rare Pediatric Disease, Fast Track and Orphan Drug designations for Stargardt disease from the U.S. Food and Drug Administration, and the European Medicines Agency has designated it as an orphan medicinal product for the treatment of non-syndromic inherited retinal dystrophies due to defects in the ABCA4 gene. Stargardt disease is the most common form of inherited juvenile macular degeneration and is estimated to affect approximately 1 in 8,000 to 10,000 individuals worldwide. There are currently no FDA-approved therapies for Stargardt disease.

Quoin Pharmaceuticals announced that Japan's Ministry of Health granted Orphan Drug Designation to QRX003, a once daily, topical lotion comprised of a broad-spectrum serine protease inhibitor formulated with the proprietary Invisicare technology, for the treatment of Netherton Syndrome. The designation allows for up to 10 years of market exclusivity upon approval. QRX003 is currently undergoing Phase 2 whole-body clinical trials for Netherton Syndrome, with a pivotal Phase 3 study expected to initiate in the second half of 2026, potentially leading to an NDA filing in 2027 if successful. QRX003 has also received Orphan Drug Designation and Fast Track Designation from the U.S. FDA and the European Medicines Agency. Quoin plans to self-commercialize the drug and other pipeline products post-approval in Japan.

Eisai Co Ltd announced that the MHLW granted orphan drug designation to its investigational compound E2086 for the prospective indication of narcolepsy. E2086 is a novel selective orexin 2 receptor agonist discovered and developed in-house by Eisai. Orexin is a neurotransmitter central to regulating sleep and wakefulness. While inhibiting orexinergic neurons promotes the transition to sleep—the mechanism behind Eisai's insomnia treatment DAYVIGO (lemborexant)—activating these neurons helps maintain stable wakefulness. E2086 is designed to improve symptoms by enhancing orexin receptor activity, directly acting on the pathophysiology of narcolepsy. Nonclinical studies have demonstrated statistically significant increases in time spent awake and significant reductions in rates of cataplexy. Data from a Phase 1b clinical study involving patients with narcolepsy type 1, presented at the World Sleep 2025 congress, suggested that E2086 demonstrated a statistically significant reduction in excessive daytime sleepiness compared to placebo or the existing drug modafinil.