Notice of New Release of Urea Cycle Disorder Treatment Drug 'Ravicti® Oral Solution 1.1 g/mL'

OrphanPacific Co., Ltd. (Headquarters: Minato-ku, Tokyo; President and CEO: Ai Hara; hereinafter "OrphanPacific") announced today that "Ravicti® Oral Solution 1.1 g/mL" (generic name: glycerol phenylbutyrate; hereinafter "Ravicti®"), a drug indicated for urea cycle disorder (UCD), has been listed on the drug price standard and its sales have commenced.

Ravicti® is a prodrug formulation of phenylbutyrate that obtained manufacturing and marketing approval in Japan on December 22, 2025. It is an oral liquid formulation with almost no taste or odor, and compared to existing sodium phenylbutyrate formulations (Buphenyl® Tablets 500mg and Granules 94%), it has the characteristic of allowing patients to take a smaller volume of liquid even when the same amount of active ingredient is required. Furthermore, since it does not contain sodium, it can be used by patients who require sodium restriction.

Due to these formulation characteristics, Ravicti® is expected to provide stable blood ammonia control, contribute to reducing the treatment burden for UCD patients and their families, and offer a new treatment option.

Through the launch of Ravicti®, OrphanPacific will contribute to resolving unmet medical needs in UCD treatment and actively provide appropriate use information to medical professionals. We will continue to strive to improve the quality of life for patients and their families by developing and providing medicines in the rare disease area.

Overview of Drug Price Listing and Launch

Product Name: Ravicti® Oral Solution 1.1 g/mL Generic Name: Glycerol Phenylbutyrate Indications: Urea Cycle Disorder Date of Drug Price Listing: April 15, 2026 Drug Price: 41,455.40 yen Launch Date: April 15, 2026 Manufacturer and Distributor: OrphanPacific Co., Ltd.

About Urea Cycle Disorder (UCD) The urea cycle is a metabolic pathway mainly in the liver that converts toxic ammonia produced in the body into non-toxic urea. Urea cycle disorder is a group of diseases characterized by congenital abnormalities in enzymes involved in the urea cycle, leading to hyperammonemia. Symptoms include vomiting, poor feeding, tachypnea, convulsions, altered consciousness, behavioral abnormalities, and developmental delays, sometimes leading to life-threatening severe conditions. It often develops in infancy, but some cases are diagnosed for the first time in adulthood. It occurs in 1 in 8,000 to 44,000 people and is designated as an intractable disease. Reference: Intractable Disease Information Center, Urea Cycle Disorder (Designated Intractable Disease 251) https://www.nanbyou.or.jp/entry/4732

About OrphanPacific Co., Ltd. OrphanPacific is a Japanese pharmaceutical company that provides new therapeutic drugs to patients with rare diseases through the development, manufacturing, and sales of orphan drugs. With the mission of "Delivering smiles and happiness to patients with rare diseases and their families" and the determination of "Leave No One Behind," we are actively engaged in the development and provision of therapeutic drugs for rare diseases with very small patient populations. OrphanPacific is a wholly-owned subsidiary of CMIC Holdings (https://www.cmicgroup.com/), a pioneer and leading company in Japanese CRO (Contract Research Organization), and aims to maximize the experience and know-how of the CMIC Group in drug development, manufacturing, and sales to ensure that as many patients with rare diseases as possible have access to therapeutic drugs. https://www.orphanpacific.com/