Kissei Pharmaceutical Co., Ltd. (Head Office: Matsumoto-city, Nagano, Japan; President & CEO: Mutsuo Kanzawa) is pleased to announce that it concluded an agreement with Pfizer Inc. granting exclusive rights to Pfizer to develop and commercialize the investigational therapy KUX-1151 for gout and hyperuricemia. KUX-1151 was discovered by Kissei.

Under this agreement, Kissei grants Pfizer exclusive worldwide rights to KUX-1151 excluding Japan. Kissei will receive an upfront payment and will be eligible to receive milestone payments and royalties on any product sales in accordance with the terms of the agreement.

KUX-1151 is currently in a Phase I clinical trial in Japan, and is under investigation as a new approach in the treatment of gout and hyperuricemia. KUX-1151 reduces serum uric acid levels through inhibiting both xanthine oxidase, which regulates uric acid production, and uric acid transporter (URAT1), which is responsible for the reabsorption of uric acid. Moving forward, the KUX-1151 program will be progressed by Pfizer’s Neusentis Research Unit, which is advancing a growing portfolio focused on pain and associated conditions.

Kissei focuses on research and development of new drugs, and supporting international expansion of our original products. The company’s therapy Silodosin (brand name in Japan: Urief®) for the treatment of dysuria associated with benign prostatic hyperplasia has been launched in 29 countries around the world to date and is anticipated to continue worldwide growth. Kissei will continue to contribute to the health of people around the world, through developing and launching new drugs and supporting international expansion via strategic partnership with other companies.

-About Xanthine Oxidase-

Xanthine oxidase is an enzyme existing mainly in the liver and acts in the final step of the production of uric acid in the metabolism of purine. Purine plays an important role as a component of nucleic acids (such as DNA) and energy substances (such as ATP). The amount of uric acid (uric acid pool) in the body is kept at a certain level by the balance of the production of uric acid, the end product of purine, and the excretion into outside the body from the kidney and intestinal tract. It is presumed that gout and hyperuricemia are caused through the uric acid pool increasing due to the impairment of the balance. It is believed that the production of uric acid is suppressed by inhibiting xanthine oxidase, resulting in reducing the uric acid pool

About URAT1 (Urate Transporter 1)-

URAT1 is a uric acid transporter present in the renal proximal tubule and responsible for the reabsorption of uric acid. Uric acid filtered through the renal glomeruli is re-absorbed by the URAT1. It is believed that excretion of uric acid is promoted by inhibiting URAT1, resulting in reducing the amount of uric acid in the bod