Burosumab is a fully human monoclonal antibody that represents a breakthrough therapy for X-linked hypophosphatemia, a rare genetic disorder characterized by excessive production of fibroblast growth factor 23 (FGF23). This condition leads to renal phosphate wasting, hypophosphatemia, and subsequent bone abnormalities including rickets in children and osteomalacia in adults. Prior to the approval of Burosumab, treatment options were limited to frequent oral phosphate and active vitamin D supplementation, which provided incomplete correction of the underlying pathophysiology and was associated with substantial treatment burden and adverse effects.In addition to immunogenicity testing, reliable quantification of Burosumab concentrations in biological matrices is critical for pharmacokinetic characterization and therapeutic drug monitoring. Understanding the relationship between drug exposure and clinical response enables dose optimization and supports regulatory submissions. This page provides a comprehensive overview of Burosumab as an FGF23-targeting antibody, the importance of bioanalytical monitoring, and validated ELISA-based detection solutions including the Anti-Burosumab ELISA Kit for anti-drug antibody detection and the Free Anti-FGF23 (Burosumab) ELISA Kit for drug quantification.
Figure 1Anti-Burosumab ADA ELISA Kit Burosumab Drug Level Testing.
Fibroblast growth factor 23 is a hormone produced primarily by osteocytes in bone that plays a central role in the regulation of phosphate homeostasis. FGF23 acts on the kidney to inhibit phosphate reabsorption by downregulating expression of the sodium-phosphate co-transporters NPT2a and NPT2c. Additionally, FGF23 suppresses production of 1,25-dihydroxyvitamin D by inhibiting the enzyme 1-alpha-hydroxylase, further reducing intestinal phosphate absorption. Under normal physiological conditions, FGF23 levels are regulated by serum phosphate and vitamin D concentrations. When serum phosphate levels rise, FGF23 increases to promote phosphate excretion. Conversely, when phosphate levels fall, FGF23 decreases to conserve phosphate. This feedback loop maintains serum phosphate within a narrow physiological range.
Burosumab is a fully human IgG1 monoclonal antibody that binds to FGF23 with high affinity, blocking its interaction with FGF receptors. By neutralizing FGF23 activity, Burosumab restores renal phosphate reabsorption. Serum phosphate levels increase toward the normal range, and the hormonal signals that would otherwise compensate for hypophosphatemia normalize. Clinical trials have demonstrated the efficacy of Burosumab in both pediatric and adult patients with X-linked hypophosphatemia. In children, Burosumab treatment improved serum phosphate levels, healing of rickets as measured by radiographic scores, linear growth, and physical function. In adults, Burosumab increased serum phosphate levels, improved osteomalacia assessed by bone biopsy, reduced bone pain, and improved fracture healing. The safety profile of Burosumab is generally favorable. The most common adverse events include injection site reactions, headache, and arthralgia. Hyperphosphatemia can occur, particularly in younger children, requiring dose adjustment. Serious hypersensitivity reactions are rare.
| Key Molecular Targets | Details |
| Importance of Drug Quantification | Pharmacokinetic characterization describes the time course of Burosumab concentrations in the body following administration. Reliable quantification of drug concentrations in serum is essential for understanding the relationship between dose and exposure, evaluating the impact of patient characteristics on drug levels, and supporting dosing regimen optimization. Burosumab exhibits target-mediated drug disposition due to binding to FGF23. As FGF23 levels vary across patients and over the course of treatment, pharmacokinetic variability is observed. The half-life of Burosumab supports dosing every two to four weeks depending on patient age and weight. |
| Therapeutic Drug Monitoring Considerations | Therapeutic drug monitoring involves measuring drug concentrations in individual patients to guide dosing decisions. For Burosumab, serum phosphate levels serve as the primary pharmacodynamic biomarker for dose adjustment. However, measurement of drug concentrations may provide additional information in patients with suboptimal responses or suspected immunogenicity. |
The Anti-Burosumab ELISA Kit is designed for the detection and semi-quantitative determination of anti-Burosumab antibodies in human serum, plasma, or other biological fluids. This kit is optimized for immunogenicity assessment in clinical research and regulatory-compliant environments.
The Free Anti-FGF23 (Burosumab) ELISA Kit is designed for the quantitative determination of functional Burosumab concentrations in human serum, plasma, or other biological matrices. This kit is optimized for pharmacokinetic studies and therapeutic monitoring applications.
Burosumab represents a breakthrough therapy for X-linked hypophosphatemia, addressing the underlying pathophysiology of this rare bone disease by neutralizing excessive FGF23 activity. Reliable bioanalytical methods are essential for supporting the clinical development and optimal use of this important therapeutic antibody. The Anti-Burosumab ELISA Kit provides a validated, sensitive, and specific solution for detecting anti-Burosumab antibodies, supporting immunogenicity assessment that meets regulatory expectations. The Free Anti-FGF23 (Burosumab) ELISA Kit enables accurate quantification of functional drug concentrations, facilitating pharmacokinetic characterization and therapeutic drug monitoring. Together, these kits provide a comprehensive bioanalytical toolkit for researchers and clinicians working with Burosumab across all stages of development and clinical use.
| Cat. No. | Product Name | Species Reactivity | Detection Method | |
| DEIA-JY25238 | Anti-Burosumab ELISA Kit | Human | sELISA | Inquiry |
| DEIA-JY25258 | Free Anti-FGF23 (Burosumab) ELISA Kit | Human | sELISA | Inquiry |
