Announcement of Start of Phase 1 Joint Japanese-Korean Study of a Human Monoclonal Anti-FGF23 Antibody (KRN23) in X-linked Hypophosphatemic Rickets/Osteomalacia in Adults

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Tokyo, Japan, July 29, 2014 --- Kyowa Hakko Kirin Co., Ltd. (Tokyo; 4151, President and CEO: Nobuo Hanai, "Kyowa Hakko Kirin") announced the start of a phase 1 study of anti-fibroblast growth factor 23 (FGF23) *1 monoclonal antibody KRN23 in adult patients with X-linked hypophosphatemic rickets/osteomalacia (XLH) *2 that is presently under development. The study is to be conducted as an Asian clinical trial between Japan and South Korea.

KRN23 is an anti-FGF23 fully human monoclonal antibody produced by Kyowa Hakko Kirin. It is intended to increase the blood concentration of phosphorus by binding to FGF23, which is produced in excess in patients with XLH, and then inhibiting its action to increase reabsorption of phosphorus in renal tubules. Data from a phase 1 single-dose study and phase 1/2 repeated-dose studies of KRN23 in adult XLH patients have been presented at multiple medical conferences.

With this background, Kyowa Hakko Kirin has begun a phase 1 study in adult XLH patients in Japan and South Korea. This study is a multicenter, sequential dose-escalation, open-label, single-dose study that mainly investigates the safety and tolerability of KRN23, and the target number of subjects is 15.

The Kyowa Hakko Kirin Group is contributing to the health and prosperity of the world's people by pursuing advances in life sciences and technology and creating new value.


*1 Fibroblast growth factor 23 (FGF23)
FGF23 is a polypeptide consisting of 251 amino acids that is mainly produced in bone tissue. It acts upon the kidneys to inhibit the reabsorption of phosphorus in renal tubules. In recent years, there have been suggestions that FGF23 is involved in such diseases as hypophosphatemic rickets, neoplastic osteomalacia, and renal failure.

*2 X-linked hypophosphatemic rickets/osteomalacia (XLH)
XLH is a rare disease in which the patient develops hypophosphatemia when phosphorus is excreted by the body in excess because of a high concentration of FGF23 in the blood, and as a result, the growth and maintenance of bone is impeded.


Overview of this study

Target Disease/Population XLH patients (aged 18 or older)
Study Design Multicenter, sequential dose-escalation, open-label, single-dose study (Administration of single subcutaneous dose of KRN23 in the amount of 0.3, 0.6, or 1.0 mg/kg)
Planned Number of Subjects 15 patients
Location Japan, South Korea
Primary Objective Safety (adverse events, laboratory test values)
News Source : Announcement of Start of Phase 1 Joint Japanese-Korean Study of a Human Monoclonal Anti-FGF23 Antibody (KRN23) in X-linked Hypophosphatemic Rickets/Osteomalacia in Adults
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