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Frequently asked questions

Answers to your questions about CRYSVITA

See responses to frequently asked questions or explore the glossary of terms below.

What is CRYSVITA and how does it work?

CRYSVITA is the only FDA-approved treatment for XLH in adults and children 6 months of age or older. It is designed specifically to target the underlying cause of XLH.

With XLH, the body doesn’t keep the phosphorus it needs. Phosphorus is a mineral that’s important for healthy bones. This can cause bones to weaken over time—a condition called osteomalacia that occurs in both adults and children. CRYSVITA can help the body hold onto more phosphorus.

Watch a video that shows how CRYSVITA works in the body.

Who should not take CRYSVITA?

You should not take CRYSVITA if:

  • You take an oral phosphate supplement and/or a specific form of vitamin D supplement (such as calcitriol, paricalcitol, doxercalciferol, calcifediol)
  • Your phosphorus levels from a blood sample are within or above the normal range for age
  • You have kidney problems
How is CRYSVITA given in children?

CRYSVITA is given as an injection under the skin by a healthcare provider. They will inject your child in one of 4 places (upper arm, upper thigh, buttocks, stomach) with the location being rotated at each visit.

  • When starting CRYSVITA, the recommended dose is once every 2 weeks
  • The dosage (the amount of CRYSVITA your child takes) is based on your child's body weight and will be determined by the doctor. In some cases, this may require more than 1 injection
  • After initial treatment, your child’s doctor may have to adjust their dose
How is CRYSVITA given in adults?

CRYSVITA is given as an injection under the skin by a healthcare provider. They will inject you in one of 4 places (upper arm, upper thigh, buttocks, stomach) with the location being rotated at each visit.

  • When starting CRYSVITA, the recommended dose is once every 4 weeks
  • The dosage (the amount of CRYSVITA you take) is based on body weight and will be determined by your doctor. In some cases, this may require more than 1 injection
  • After initial treatment, your doctor may have to adjust your dose
What happens if I (or my child) miss a CRYSVITA dose?

If you miss a dose, be sure to receive your next CRYSVITA dose as soon as possible. To avoid missed doses, CRYSVITA may be given up to 3 days before or after the scheduled treatment date.

How can CRYSVITA treatment help children with XLH?

Three clinical studies of children with XLH have shown that CRYSVITA can help by:

  • Helping to heal rickets and improve leg abnormalities
  • Increasing and maintaining phosphorus levels in the blood
  • Improving growth
How can CRYSVITA treatment help adults with XLH?

Two clinical studies of adults with XLH have shown that CRYSVITA can help by:

  • Increasing and maintaining phosphorus levels in the blood
  • Healing fractures and pseudofractures (a kind of fracture where the bone thickens at the site of an injury but is not completely broken)
  • Helping to heal osteomalacia
What is the most important information I should know about CRYSVITA?
  • Some patients developed allergic reactions (eg, rash and hives) while taking CRYSVITA
  • High levels of phosphorus in the blood have been reported in some patients taking CRYSVITA. This may be related to a risk of high calcium levels in the kidneys
  • 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 (ie, hematoma)

Learn more about CRYSVITA safety.

What are the possible side effects of CRYSVITA in children?

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

  • Fever
  • Injection site reaction
  • Cough
  • Vomiting
  • Pain in arm and legs
  • Headache
  • Tooth abscess
  • Dental cavities
  • Diarrhea
  • Decreased vitamin D levels
  • Toothache
  • Constipation
  • Muscle pain
  • Rash
  • Dizziness
  • Nausea
What are the possible side effects of CRYSVITA in adults?

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

  • Back pain
  • Headache
  • Tooth abscess
  • Restless leg syndrome
  • Decreased vitamin D levels
  • Dizziness
  • Constipation
  • Muscle spasms
  • Phosphorus levels increased in the blood
What should I do if I (or my child) experience any side effects while receiving CRYSVITA?

CRYSVITA may cause side effects including headaches, dizziness, and muscle pain. These are not all the possible side effects of CRYSVITA. Call your doctor for medical advice about side effects.

You are encouraged to report suspected adverse reactions to Kyowa Kirin, Inc. at 1-844-768-3544 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

How is CRYSVITA stored?

Instructions for storing and handling CRYSVITA:

  • CRYSVITA vials must be kept refrigerated at 36ºF to 46ºF (2ºC to 8ºC) in the original carton until it’s time to use it
  • Keep the CRYSVITA vial in the original carton to protect it from light until time of use
  • Do not freeze or shake CRYSVITA
  • Do not use CRYSVITA after the expiration date stamped on the carton
  • CRYSVITA vials are single dose only. Discard any unused product

Can I take CRYSVITA if I am pregnant?

Currently there are no studies that measured the risk and benefits of CRYSVITA in pregnant women. Talk to your doctor if you are considering CRYSVITA treatment and are, or plan to be, pregnant.

Is CRYSVITA an option for adults whose growth plates have closed?

CRYSVITA is approved for the treatment of XLH in adults and children 6 months of age or older. Talk to your doctor to find out if CRYSVITA is right for you.

Glossary

These are some important terms that you might need to know about XLH and CRYSVITA.

Antibody

A protein that is made by the immune system to recognize and block a target.

Baseline

The beginning of a study before patients are given any treatment.

Conventional therapy

A therapeutic approach for XLH that consists of oral phosphate and a type of vitamin D called active vitamin D.

Fibroblast growth factor 23 (FGF23)

A protein that plays a role balancing the amount of phosphorus in the body; in XLH, the activity of FGF23 is abnormally increased, causing the body to release excess phosphorus in the urine.

Fractures

Broken bones.

Hypophosphatemia

A condition in which your blood has a low level of phosphorus.

Mineralization

A process in which minerals like phosphorus are deposited in the bone, causing the bone to harden.

Monoclonal antibody

A type of antibody that is made in the laboratory and can bind to certain proteins in the body.

Osteoid volume to bone volume (OV/BV)

A ratio of unmineralized bone to mineralized bone.

Osteomalacia

A softening and weakening of the bones in children and adults caused by deficiencies in vitamin D, calcium, or phosphorus.

Phosphorus

A mineral that is important for proper bone healing and growth.

Placebo

A harmless pill, medicine, or procedure that has no therapeutic effect.

Pseudofracture

A kind of fracture where the bone thickens at the site of an injury but is not completely broken.

Radiographic Global Impression of Change (RGI-C)

A way to measure the extent of the healing of rickets. This score uses a 7-point scale to rank the healing of rickets and can range from -3=severe worsening to 0=no change to +3=near/complete healing. An RGI-C global score of ≥+2.0 means a substantial healing of rickets was achieved after treatment.

Rickets

A softening and weakening of the bones in children caused by deficiencies in vitamin D, calcium, or phosphorus before the growth plate closes, leading to bone abnormalities in the limbs.

Serum phosphorus

Amount of phosphorus in the blood.

Thacher Rickets Severity Score (RSS)

A way to measure changes in the severity of rickets. This score uses a 10-point scale to rank the severity of rickets from 0 (normal) to 10 points (severe). A lower score means reduced severity of rickets. This score is complementary to RGI-C.

Discover more about CRYSVITA

Learn how CRYSVITA works

See how CRYSVITA targets the underlying cause of XLH

Hear from people taking CRYSVITA

Experience real stories of people with XLH and their journeys with CRYSVITA

Find helpful CRYSVITA resources

Tools that can support your CRYSVITA journey

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What is CRYSVITA?

CRYSVITA is a prescription medicine used to treat adults and children 6 months of age and older with X-linked hypophosphatemia (XLH).

What is CRYSVITA?

CRYSVITA is a prescription medicine used to treat adults and children 6 months of age and older with X-linked hypophosphatemia (XLH).

Important Safety Information

You should not take CRYSVITA if:

  • You take an oral phosphate supplement and/or a specific form of vitamin D supplement (such as calcitriol, paricalcitol, doxercalciferol, calcifediol).
  • 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 you should know about CRYSVITA?

  • Some patients developed allergic reactions (e.g., rash and hives) while taking CRYSVITA. Your doctor will monitor you for symptoms of an allergic reaction while you are taking CRYSVITA. Your treatment may need to be discontinued for serious allergic reactions.
  • High levels of phosphorus in the blood have been reported in some patients taking CRYSVITA. This may be related to a risk of high calcium levels in the kidneys. Your doctor will collect blood samples to monitor your levels. If you are already taking CRYSVITA, dose interruption and/or dose reduction may be required based on your serum phosphorus 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 (i.e., hematoma). Call your doctor if you develop an injection site reaction. CRYSVITA may be discontinued if severe injection site reactions occur.

What are the possible side effects of CRYSVITA?

  • Adverse reactions that were seen in children with XLH are:

    • Fever
    • Injection site reaction
    • Cough
    • Vomiting
    • Pain in arms and legs
    • Headache
    • Tooth abscess
    • Dental cavities
    • Diarrhea
    • Decreased vitamin D levels
    • Toothache
    • Constipation
    • Muscle pain
    • Rash
    • Dizziness
    • Nausea

  • Adverse reactions that were seen in adults with XLH are:

    • Back pain
    • Headache
    • Tooth infection
    • Restless legs syndrome
    • Decreased vitamin D levels
    • Dizziness
    • Constipation
    • Muscle spasms
    • 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 medications (including supplements) and medical conditions, including if you:

  • Are taking oral phosphate and/or active vitamin D (such as calcitriol, paricalcitol, doxercalciferol, calcifediol).
  • 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 Kyowa Kirin, Inc. Adverse Event reporting line at 1-844-768-3544.
  • 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.

While taking CRYSVITA, tell your doctor if you experience:

  • An allergic reaction such as rash or hives
  • A rash, swelling, bruising, or other reaction at the injection site
  • New or worsening restless legs syndrome

These are not all the possible side effects of CRYSVITA. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at (800) FDA-1088 or www.fda.gov/medwatch. You may also report side effects to Kyowa Kirin, Inc. at 1-844-768-3544.

For important risk and use information, please see the full Prescribing Information.

What is CRYSVITA?

CRYSVITA is a prescription medicine used to treat adults and children 6 months of age and older with X-linked hypophosphatemia (XLH).

Important Safety Information

You should not take CRYSVITA if:

  • You take an oral phosphate supplement and/or a specific form of vitamin D supplement (such as calcitriol, paricalcitol, doxercalciferol, calcifediol).
  • 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 you should know about CRYSVITA?

  • Some patients developed allergic reactions (e.g., rash and hives) while taking CRYSVITA. Your doctor will monitor you for symptoms of an allergic reaction while you are taking CRYSVITA. Your treatment may need to be discontinued for serious allergic reactions.
  • High levels of phosphorus in the blood have been reported in some patients taking CRYSVITA. This may be related to a risk of high calcium levels in the kidneys. Your doctor will collect blood samples to monitor your levels. If you are already taking CRYSVITA, dose interruption and/or dose reduction may be required based on your serum phosphorus 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 (i.e., hematoma). Call your doctor if you develop an injection site reaction. CRYSVITA may be discontinued if severe injection site reactions occur.

What are the possible side effects of CRYSVITA?

  • Adverse reactions that were seen in children with XLH are:

    • Fever
    • Injection site reaction
    • Cough
    • Vomiting
    • Pain in arms and legs
    • Headache
    • Tooth abscess
    • Dental cavities
    • Diarrhea
    • Decreased vitamin D levels
    • Toothache
    • Constipation
    • Muscle pain
    • Rash
    • Dizziness
    • Nausea

  • Adverse reactions that were seen in adults with XLH are:

    • Back pain
    • Headache
    • Tooth infection
    • Restless legs syndrome
    • Decreased vitamin D levels
    • Dizziness
    • Constipation
    • Muscle spasms
    • 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 medications (including supplements) and medical conditions, including if you:

  • Are taking oral phosphate and/or active vitamin D (such as calcitriol, paricalcitol, doxercalciferol, calcifediol).
  • 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 Kyowa Kirin, Inc. Adverse Event reporting line at 1-844-768-3544.
  • 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.

While taking CRYSVITA, tell your doctor if you experience:

  • An allergic reaction such as rash or hives
  • A rash, swelling, bruising, or other reaction at the injection site
  • New or worsening restless legs syndrome

These are not all the possible side effects of CRYSVITA. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at (800) FDA-1088 or www.fda.gov/medwatch. You may also report side effects to Kyowa Kirin, Inc. at 1-844-768-3544.

For important risk and use information, please see the full Prescribing Information.