Burosumab is a recombinant human immunoglobulin G1 (IgG1) monoclonal antibody that specifically binds to and inhibits the biological activity of fibroblast growth factor 23 (FGF23). It is produced using recombinant DNA technology in Chinese hamster ovary (CHO) mammalian cell culture.
Burosumab is a biotechnology-derived therapeutic protein used in the development and manufacture of pharmaceutical products targeting FGF23-mediated disorders. The molecule has an approximate molecular mass of 147 kDa.
Burosumab is an anti-FGF23 monoclonal antibody designed to bind FGF23 and inhibit its interaction with the Klotho-FGF receptor complex. By inhibiting FGF23 activity, burosumab promotes renal phosphate reabsorption and increases serum concentrations of 1,25-dihydroxy vitamin D.
Burosumab is associated with pharmaceutical development for FGF23-mediated hypophosphatemic disorders, including X-linked hypophosphatemia (XLH) and tumor-induced osteomalacia (TIO). Current U.S. labeling includes XLH in patients 6 months and older and FGF23-related hypophosphatemia associated with certain phosphaturic mesenchymal tumors in patients 2 years and older.
Burosumab drug substance requires biologics-specific quality controls covering identity, purity, product-related and process-related impurities, protein content, potency/biological activity, endotoxin and microbial quality. Public regulatory information describes methods including ELISA/peptide mapping for identification, chromatographic and electrophoretic methods for purity, and an FGF23-neutralizing activity assay for biological activity.
| Parameter | Specification |
|---|---|
| Appearance | White to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | NLT 98.0% |
| Loss on Drying | NMT 0.5% |
| pH (1% Solution) | 2.0 – 4.0 |
| Individual Impurity | ≤ 0.5% |
| Melting Point | 168°C – 172°C |