Frequently asked questions about CRYSVITA for XLH

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 which can cause rickets in children and osteomalacia (softening of the bones) in adults. CRYSVITA can help the body hold onto more phosphorus.

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

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

CRYSVITA is given as an injection under the skin by a healthcare provider. They will inject your child in 1 of 4 places (upper arm, upper thigh, buttocks, stomach) with the location being rotated at each visit.

When starting CRYSVITA, the recommended dose schedule is once every 2 weeks. The starting dose (the amount of CRYSVITA your child receives) 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.

Your child’s doctor will check their phosphorus levels every 4 weeks for the first 3 months of treatment, and then as needed. They may adjust your child’s dose if their phosphorus levels are not in the normal range.

CRYSVITA is given as an injection under the skin by a healthcare provider. They will inject you in 1 of 4 places (upper arm, upper thigh, buttocks, stomach) with the location being rotated at each visit.

When starting CRYSVITA, the recommended dose schedule is once every 4 weeks. The starting dose (the amount of CRYSVITA you receive) is based on body weight and will be determined by your doctor. In some cases, this may require more than 1 injection.

Your doctor will check your phosphorus levels 2 weeks after you start CRYSVITA, then each month for the first 3 months, and as needed after that. They may adjust your dosage (the amount and how often you receive CRYSVITA) if your phosphorus levels are not in the normal range.

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.

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

• Healing rickets and helping to improve leg abnormalities
• Increasing and maintaining phosphorus levels in the blood
• Improving growth

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)
• Healing osteomalacia

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.

High levels of calcium in the blood have been reported in patients taking CRYSVITA. The risk is greater in patients with pre-existing hyperparathyroidism (overactive parathyroid glands), for those who are unable to move for extended periods of time, become dehydrated, have high vitamin D levels, or have kidney issues.

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.

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

• 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

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

• Back pain
• Headache
• Tooth infection
• Restless legs syndrome
• Decreased vitamin D levels
• Dizziness
• Constipation
• Muscle spasms
• Phosphorus levels increased in the blood

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.

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 them
• 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

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

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.