The Cryopyrin Associated Periodic Syndrome (CAPS) National Treatment Service at the NAC is the only UK centre specialising in diagnosis and treatment of patients with CAPS. It has been commissioned by the NHS National Commissioning Group to provide the CAPS Treatment Service for the entire UK.
The consultants’ expertise in diagnosis, genetic analysis and clinical management of this extremely rare disorder is recognised internationally. Patients can now be offered highly effective treatment for this debilitating disorder.
CAPS is an extremely rare genetic disease. There are currently about 50 patients in England with confirmed CAPS, all of whom have been diagnosed at the NAC. There may be about 20 further cases as yet undiagnosed. It is estimated that a child is born with CAPS about once every 2 years in England.
Patients with this condition experience flu-like symptoms including severe fatigue, fever and muscle pains on a daily basis, often starting in early infancy. There are also several other associated complaints that may affect the skin, eyes, joints and brain. Patients may develop severe long term disabilities such as blindness, deafness and, in about 1 in 4 cases, amyloidosis.
The physicians at the NAC have been managing patients with CAPS for over 14 years. In 2001 they discovered that CAPS is caused by mutations in the gene for a newly discovered protein called cryopyrin. This leads to excessive production of an inflammatory messenger called interleukin 1β (IL-1β). IL-1β is also responsible for many of the symptoms healthy people experience when they have flu.
The role of IL-1β production in causing the symptoms of CAPS was discovered at the NAC. Over the last 10 years the NAC team have been involved in the development of a new and profoundly effective treatment for CAPS called canakinumab. Canakinumab is the only licensed treatment for CAPS.
Canakinumab is a type of drug called a monoclonal antibody. When administered by injection under the skin every 8 weeks it leads to complete resolution of the symptoms and signs of CAPS. Since they began receiving this treatment, patients with CAPS have experienced a remarkable turnaround in their lives. Canakinumab blocks the activity of IL-1β and thereby simply “switches off” the excessive inflammation that is the hallmark of CAPS. Canakinumab has only become standard treatment for CAPS relatively recently, so information is not yet available regarding the long term. But it is hoped that prolonged treatment with canakinumab will completely prevent the long term deformities and complications that were previously seen in patients with CAPS.
If patients are referred to the NAC because of suspected CAPS, the following services are offered:
- expert clinical assessment
- genetic testing to confirm or rule out CAPS, or other hereditary fever syndromes if relevant
After diagnosis of CAPS, the following services are offered:
- expert clinical evaluation of disease
- assessment of suitability for canakinumab therapy (in almost all patients aged over 4 years, this treatment is deemed suitable)
Baseline assessment before starting canakinumab includes:
- audiometric hearing test
- ophthalmic assessment by ophthalmologist
- brain MRI and neurological assessment if there is neurological disease
- quality of life assessment
- entry of details into CAPS registry
- SAP scan in selected individuals
Subsequent management includes:
- prescription and administration of canakinumab at the NAC
- every 8 weeks:
- administration of canakinumab by injection under the skin
- blood tests
- quality of life assessment
- monthly measurements of SAA protein in blood samples sent to the NAC by post (SAA is the most sensitive marker of disease activity in CAPS, and predictor of development of amyloidosis)
- annual assessment:
- ophthalmic assessment
- follow up brain MRI in selected cases
- long term surveillance and follow up at the NAC
It may become possible to reduce frequency of visits to the NAC to four monthly. This depends on the availability of adequate local arrangements to formulate and deliver canakinumab and to perform the necessary monitoring.
Children with CAPS under age 4
There are no licensed drugs for children under age 4 with CAPS at present, although there is an ongoing trial of canakinumab.
Children in this age group may be prescribed off label canakinumab or anakinra, another drug of the same class.