Important safety information related to taking CRYSVITA® (burosumab-twza)

Learn about the potential side effects related to taking CRYSVITA

Learn about the potential side effects related to taking CRYSVITA

You should not take CRYSVITA if:

  • You take an oral phosphate supplement and a specific form of vitamin D supplement
  • Your phosphorus levels from a blood sample are within or above the normal range for age
  • You have kidney problems

What is the most important information I should know about CRYSVITA?

  • Some patients developed allergic reactions (rash and hives) while taking CRYSVITA. Your doctor will monitor you for symptoms of an allergic reaction while you are taking CRYSVITA
  • A high level of phosphorus in the blood has been reported in some adult patients receiving CRYSVITA. This may be related to a risk of high calcium levels in the kidneys. Your doctor will collect samples to monitor your levels
  • Administration of CRYSVITA may result in reactions at the injection site, such as hives, reddening of the skin, rash, swelling, bruising, pain, severe itching of the skin, and collection of blood outside of a blood vessel (hematoma)
Potential side effects of CRYSVITA in children

What are the possible side effects of CRYSVITA in children?

The following side effects were observed in more than 10% of children who received CRYSVITA every 2 weeks in Studies 1 and 2.

The most common side effects reported in children with XLH who were treated with CRYSVITA were:

  • Headache
  • Injection site reaction
  • Vomiting
  • Fever
  • Pain in arms and legs
  • Decreased vitamin D levels
  • Rash
  • Toothache
  • Muscle pain
  • Tooth infection
  • Dizziness
Potential side effects of CRYSVITA in adults

What are the possible side effects of CRYSVITA in adults?

The following side effects were observed in more than 5% of adults who were treated with CRYSVITA every 4 weeks and in at least 2 patients more than with placebo in Study 3.

The most common side effects reported in adults with XLH who were treated with CRYSVITA were:

  • Back pain
  • Headache
  • Tooth infection
  • Restless leg syndrome
  • Decreased vitamin D levels
  • Dizziness
  • Constipation
  • Phosphorus levels increased in the blood
  • Narrowing of the spaces within the spine is common in adults with XLH, and pressure on the spinal cord has been reported in adults taking CRYSVITA. It is not known if taking CRYSVITA worsens the narrowing of the spaces within the spine or the pressure on the spinal cord.

Before taking CRYSVITA, tell your doctor about all of your medical conditions, including if you:

  • are pregnant, think you may be pregnant, or plan to become pregnant. There is not enough experience to know if CRYSVITA may harm your unborn baby. Report pregnancies to the Ultragenyx Adverse Event reporting line at 1-888-756-8657.
  • are breastfeeding or plan to breastfeed. There is not enough experience to know if CRYSVITA passes into your breast milk. Talk with your doctor about the best way to feed your baby while you receive CRYSVITA.