Burosumab (Crysvita)

Key Messages

• Canada’s Drug Agency recommends that Crysvita be reimbursed by public drug plans for the treatment of X-linked hypophosphatemia (XLH) in adult patients if certain conditions are met. The previous recommendation for Crysvita when initiated in pediatric patients who are at least 1 year of age and in whom epiphyseal closure has not yet occurred, continues to apply to those patients.
• Crysvita should only be covered to treat patients aged 18 years or older who have a diagnosis of XLH supported by classic clinical features of adult XLH and a confirmed PHEX gene variant, and who have not previously received it. Patients should also have a specific threshold for kidney function or reduced kidney function if it is confirmed not to be due to nephrocalcinosis, bone pain that is caused by XLH or osteomalacia, and have not had a sufficient response to conventional therapy (therapy with active vitamin D and oral phosphate). If a PHEX gene variant is not confirmed, XLH diagnosis can be confirmed with a serum intact fibroblast growth factor 23 (FGF23) level by a Kainos assay.
• Crysvita should only be reimbursed if it is prescribed by a physician who works in a comprehensive team of health care providers experienced in the diagnosis and management of XLH and if the cost of Crysvita is reduced. Reimbursement may be renewed on an annual basis for patients who do not meet any of the discontinuation criteria, which are the development of hyperparathyroidism, nephrocalcinosis, fasting hypophosphatemia, or fractures or pseudofractures based on X-ray.