burosumab

Burosumab is a human monoclonal antibody approved for the treatment of X-linked hypophosphatemia (XLH) and studied for tumor-induced osteomalacia (TIO). It targets fibroblast growth factor 23 (FGF23), a hormone that promotes renal phosphate wasting and suppresses production of active vitamin D.

By inhibiting FGF23, burosumab increases renal phosphate reabsorption and raises circulating levels of 1,25-dihydroxyvitamin D. This restores phosphate homeostasis and supports bone mineralization, addressing the underlying cause of XLH rather than only alleviating symptoms.

Clinical use: XLH is a hereditary phosphate-wasting disorder that causes rickets in children and osteomalacia in adults. Burosumab acts on the disease mechanism by correcting phosphate loss and improving bone health. The drug has been approved in several regions for XLH in both pediatric and adult patients; other regional approvals exist for certain indications such as TIO, with regulatory status varying by country.

Administration and dosing: Burosumab is given by subcutaneous injection, typically every two weeks. Dosing is individualized based on age, body weight, baseline phosphate levels, and clinical response, with adjustments made to maintain phosphate repletion and symptom improvement.

Safety and monitoring: Common adverse events include injection-site reactions and headaches; hyperphosphatemia can occur and requires monitoring. Ongoing safety data emphasize regular monitoring of serum phosphate, calcium, and vitamin D metabolism, along with assessment of renal function and bone health. Long-term effects continue to be evaluated in treated populations.