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KRN23

Kyowa Kirin Co., Ltd. · FDA-approved active Small molecule

KRN23 is a monoclonal antibody that inhibits fibroblast growth factor 23 (FGF23), restoring phosphate reabsorption and vitamin D metabolism in patients with X-linked hypophosphatemia.

KRN23 is a monoclonal antibody that inhibits fibroblast growth factor 23 (FGF23), restoring phosphate reabsorption and vitamin D metabolism in patients with X-linked hypophosphatemia. Used for X-linked hypophosphatemia (XLH) in children and adults.

At a glance

Generic nameKRN23
Also known asBurosumab, Crysvita, burosumab, Crysvita®
SponsorKyowa Kirin Co., Ltd.
Drug classFGF23 inhibitor (monoclonal antibody)
TargetFGF23 (Fibroblast Growth Factor 23)
ModalitySmall molecule
Therapeutic areaEndocrinology / Rare Metabolic Disorders
PhaseFDA-approved

Mechanism of action

KRN23 binds to and neutralizes FGF23, a hormone that suppresses renal phosphate reabsorption and 1,25-dihydroxyvitamin D production. By blocking FGF23 activity, the drug allows the kidneys to retain phosphate and increase active vitamin D synthesis, correcting the biochemical abnormalities underlying X-linked hypophosphatemia and improving bone mineralization and growth.

Approved indications

Common side effects

Key clinical trials

Primary sources

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SourceUsed for
ClinicalTrials.govTrial enrolment, design, endpoints, results