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Information about Aldurazyme

What is it and what is it used for?

Aldurazyme is used in patients with a confirmed diagnosis of mucopolysaccharidosis I (MPS I; α L iduronidase deficiency) to treat the non-neurological symptoms of the disease (symptoms that are not connected with the brain or nerves). MPS I is a rare, inherited disease, in which the level of α L iduronidase enzyme activity is much lower than normal. This means that substances called glycosaminoglycans (GAGs) are not broken down, so they build up in most of the organs in the body and damage them. The non-neurological symptoms of MPS I can be an enlarged liver, stiff joints that make moving more difficult, reduced lung volume, heart disease and eye disease.

How Aldurazyme works
The active substance in Aldurazyme, laronidase, is a copy of the human enzyme α L iduronidase. It is produced by a method known as ‘recombinant DNA technology’: the enzyme is made by cells into which a gene (DNA) has been introduced that makes them able to produce laronidase. Laronidase is used as ‘enzyme replacement therapy’, which means that it replaces the enzyme that is missing in patients with MPS I. This controls the symptoms of MPS I, improving the patient’s quality of life.

How Aldurazyme is used
Aldurazyme treatment should be supervised by a doctor who has experience in the management of patients with MPS I or other inherited metabolic diseases. Aldurazyme should be given in a hospital or clinic where resuscitation equipment is available, and patients may need to receive some medicines before the infusion to prevent an allergic reaction. Aldurazyme is given once a week as an infusion into a vein. It is intended for long-term use.

The medicine can only be obtained with a prescription.

What are the benefits?

The European Medicines Agency decided that Aldurazyme gives effective control of the symptoms of MPS I. The Agency decided that Aldurazyme’s benefits are greater than its risks and recommended that Aldurazyme be given marketing authorisation.

Aldurazyme was originally authorised under ‘exceptional circumstances’, because, as the disease is rare, limited information was available at the time of approval. As the company had supplied the additional information requested, the ‘exceptional circumstances’ ended on 16 December 2015.

What are main side effects?

Most of the side effects seen with Aldurazyme are reactions caused by the infusion procedure rather than the medicine itself. Some of these are severe, but the number of side effects tends to decrease with time.

The most common side effects in patients over the age of five years (seen in more than 1 patient in 10) are:
  • headache
  • nausea (feeling sick)
  • abdominal pain (stomach ache)
  • rash
  • arthropathy (damage to the joints)
  • arthralgia (joint pain)
  • back pain
  • pain in the extremities (hands and feet)
  • flushing
  • pyrexia (fever)
  • reactions at the site of the infusion
In patients under five years of age, the most common side effects (seen in more than 1 patient in 10) are:
  • increased blood pressure
  • decreased oxygen saturation (a measure of how well the lungs are working)
  • tachycardia (rapid heart rate)
  • pyrexia
  • chills
For the full list of all side effects reported with Aldurazyme, see the package leaflet.

Almost all patients who receive Aldurazyme develop antibodies (proteins that are produced in response to Aldurazyme). The effect of these on the safety and effectiveness of the medicine is not fully known.

Who should avoid taking it?

Aldurazyme must not be used in people who are severely allergic to laronidase or any of the other ingredients.

What studies have been done?

The study showed that Aldurazyme had improved both the FVC and the walking ability of patients at 26 weeks. This effect was maintained for up to four years.

In children under five years of age, Aldurazyme reduced the levels of GAGs in the urine by about 60%. Half of the children treated had a normal size liver at the end of the study.


Aldurazyme was first approved for use in the EU in 2003. It is manufactured by Genzyme.

European Medicines Agency website page for Aldurazyme (accessed 16/07/18)

Links available in External Resources

Reporting of suspected adverse reactions

Reporting suspected adverse reactions (side effects) after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals or patients are asked to report any suspected adverse reactions via the Yellow Card Scheme at or search for MHRA Yellow Card in the Google Play or Apple App Store.

Disclaimer: This site is designed to offer information for general educational purposes only. The health information furnished on this site and the interactive responses are not intended to be professional advice and are not intended to replace personal consultation with a qualified physician, pharmacist, or other healthcare professional. We cannot provide individual medical advice. You must always seek the advice of a professional for questions related to a disease, disease symptoms, and appropriate therapeutic treatments.

For the full list of side effects and restrictions, see the package leaflet (link to package leaflet available in External Resources).