CHMP Recommends Expanded Approval for XLH Drug
July 24, 2020
The Committee for Medicinal Products for Human Use of the European Medicines Agency recommended the expanded approval of Kyowa Kirin’s Crysvita to include older adolescents and adults living with the rare disease X-linked hypophosphataemia, the most common form of hereditary rickets.
The European Commission previously granted a conditional marketing authorization for Crysvita for the treatment of XLH with radiographic evidence of bone disease in children one year of age and older and adolescents with growing skeletons. The new recommendation calls for expansion of the approval to include all adolescents with radiographic evidence of bone disease, regardless of growth status, as well as adults with XLH.
X-linked hypophosphataemia (XLH) is a rare, genetic condition that causes abnormalities to bone, muscle, and joints. XLH is not life-threatening, but its burden is life-long and progressive, and it may reduce a person’s quality of life. People with XLH have a genetic defect on the X-chromosome, which causes an excessive loss of phosphate through the urine and poor absorption from the gut, resulting in chronically low levels of phosphate in the blood. Phosphate is a key mineral needed for maintaining the body’s energy levels, muscle function, and the formation of healthy bones and teeth. While there is no cure for XLH, therapies aimed at helping to restore phosphate to normal levels within the body may help to improve the symptoms of the disease.
Crysvita is a recombinant fully human monoclonal IgG1 antibody against the phosphaturic hormone fibroblast growth factor 23 (FGF23). FGF23 is a hormone that reduces serum levels of phosphate by regulating phosphate excretion and active vitamin D production by the kidney. Phosphate wasting and resulting hypophosphataemia in XLH is caused by excessive levels and activity of FGF23. Crysvita is designed to bind to, and thereby inhibit, the biological activity of FGF23. By blocking excess FGF23 in patients, Crysvita is intended to increase phosphate reabsorption from the kidney and increase the production of vitamin D, which enhances intestinal absorption of phosphate and calcium.
There is currently no approved therapy in Europe for older adolescents and adults with XLH that targets the underlying cause of this debilitating, progressive, and life-long disease.
The positive opinion from the CHMP was based on data from two phase 3 studies.
“Adult XLH patients’ response to conventional therapy, which includes phosphate and activated vitamin D, is variable and the evidence-base for its efficacy is limited,” said Karine Briot, Hôpital Cochin, Paris, France. “Having access to an efficacious treatment consistently from childhood through adulthood will be highly valuable to patients and to the physicians administering their care. Today’s recommendation is an important step forward for all people with XLH and those who care for and support them.”
Author: Rare Daily Staff
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