The Scottish Medicines Consortium (SMC) has enabled access to the first treatment addressing the underlying cause of X-linked hypophosphataemia (XLH), a rare and life-long genetic disease that causes abnormalities in the bones, muscles and joints.
Kyowa Kirin’s Crysvita (burosumab) will be made available via the ultra-orphan pathway, which will allow eligible adults with symptomatic XLH to access the treatment while the company collects additional data.
Prior to the SMC’s decision, access to Crysvita was provided in 2020, also via the ultra-orphan pathway, for children with radiographic evidence of bone disease and adolescents with growing skeletons.
Patients with XLH have a genetic defect that causes chronically low levels of phosphate – a key mineral needed for maintaining the body’s energy levels and muscle function, and forming healthy bones and teeth.
XLH typically presents in early childhood, causing bowed legs, stunted growth, and bone and joint pain.
Adults living with the disease continue to experience a wide range of progressively debilitating bone, joint and muscle symptoms affecting most areas of the body, resulting in pain, stiffness and fatigue that severely limit physical function and mobility.
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.
The SMC’s initial assessment is supported by data from a phase 3 study in which significantly more patients in the Crysvita treatment group than in the placebo group achieved mean serum phosphate concentrations above the lower limit of normal over the 24-week treatment period.
Stuart Ralston, professor of rheumatology at the University of Edinburgh, said: “Until now, treatment options for adults living with symptomatic XLH have been limited. This is why it is excellent news that these patients will now be able to access a treatment that not only tackles the symptoms of XLH, but also targets the underlying cause of this rare, debilitating disease.”
While Scotland is currently the first in the UK to enable access to Crysvita for adults with XLH, Kyowa Kirin has said it will continue to engage with health authorities across the remaining three nations, where Crysvita is already available to eligible children.
The company’s president, Jeremy Morgan, said: “Extending access to Crysvita for adults, following its use for children, will provide a paradigm shift in the management of people living in Scotland with XLH.
“We are committed to working with the community to collect more data on the efficacy and tolerability of the treatment over the next few years.”
