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CRYSVITA® (burosumab-twza) logo

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Treatment initiation

Starting your patients on CRYSVITA

Initiate treatment with the recommended starting dose for patients based on the Prescribing Information (PI)

Dosing for pediatric patients

CRYSVITA

dosed every 2 weeks1

CRYSVITA is administered by an HCP every 2
weeks and its dose is based on the patient’s body weight.1

Recommended starting dose

(6 months to
<18 years of age)1

Patients who weigh <10 kg 

Starting dose regimen is 1 mg/kg of body weight, rounded to the nearest 1 mg, administered every 2 weeks.

Patients who weigh ≥10 kg

Starting dose regimen is 0.8 mg/kg of body weight, rounded to the nearest 10 mg, administered every 2 weeks. The minimum starting dose is 10 mg up to a maximum dose of 90 mg.

The maximum volume of CRYSVITA per injection is 1.5 mL. If multiple injections are required, administer at different injection sites.

CRYSVITA may be available for administration at a site of care and dispensed through a specialty pharmacy. Talk to a rep to learn more.

REP CONTACT

Testing fasting serum phosphorus levels throughout treatment is necessary to determine if dose adjustment is needed to maintain levels within the reference range.1

Assessment schedule

Measuring fasting serum phosphorus during CRYSVITA treatment

For the first 3 months of treatment, follow these time intervals to assess fasting serum phosphorus levels in patients:

Pediatric assessment schedule1

An icon of a syringe, with a transparent orange circle in the top corner

Dose 1

Day 1
An icon of a syringe, with a transparent orange circle in the top corne

Dose 2

Day 14
An icon of the phosphorus elemental symbol, with a transparent orange circle in the top corne

Assesment

Day 28

After 3 months, continue to assess serum phosphorus levels as appropriate.1

Dosing adjustments

Adjust CRYSVITA dosing to help maintain serum phosphorus within the reference range1

Directions for dose adjustments and monitoring in pediatric patients with CRYSVITA

Illustration of a calender with a star in the middle, and transparent

When making dose adjustments for your patients, take note of the following:1

  • Reassess fasting serum phosphorus level 4 weeks after dose adjustment
  • Do not adjust CRYSVITA more frequently than every 4 weeks

Increasing doses

For patients who weigh <10 kg1

If fasting serum phosphorus is below the reference range for age:

  • The dose may be increased to 1.5 mg/kg, rounded to the nearest 1 mg, administered every 2 weeks

If additional dose increases are needed:

  • The dose may be increased to the maximum dose of 2 mg/kg, rounded to the nearest 1 mg, administered every 2 weeks

For patients who weigh ≥10 kg1

If fasting serum phosphorus is below the reference range for age:

  • The dose may be increased stepwise up to approximately 2 mg/kg, administered every 2 weeks (maximum dose of 90 mg) according to the dose schedule shown to the right

XLH pediatric dose schedule for stepwise dose increase for patients ≥10 kg1

Body weight (kg) Starting dose (mg) First dose increase to (mg) Second dose increase to (mg)
10–14101520
15–18102030
19–31203040
32–43304060
44–56406080
57–68507090
69–80609090
81–93709090
94–105809090
≥106909090
Body weight (kg)
10-14
Starting dose (mg)
10
First dose increase to (mg)
10
Second dose increase to (mg)
20
15-18
Starting dose (mg)
10
First dose increase to (mg)
20
Second dose increase to (mg)
30
19-31
Starting dose (mg)
20
First dose increase to (mg)
30
Second dose increase to (mg)
40
32-43
Starting dose (mg)
30
First dose increase to (mg)
40
Second dose increase to (mg)
60
44-56
Starting dose (mg)
40
First dose increase to (mg)
60
Second dose increase to (mg)
80
57-68
Starting dose (mg)
50
First dose increase to (mg)
70
Second dose increase to (mg)
90
69-80
Starting dose (mg)
60
First dose increase to (mg)
90
Second dose increase to (mg)
90
81-93
Starting dose (mg)
70
First dose increase to (mg)
90
Second dose increase to (mg)
90
94-105
Starting dose (mg)
80
First dose increase to (mg)
90
Second dose increase to (mg)
90
≥106
Starting dose (mg)
90
First dose increase to (mg)
90
Second dose increase to (mg)
90

Decreasing doses

If fasting serum phosphorus is >5 mg/dL:1

  • Withhold the next dose and reassess the serum phosphorus level in 4 weeks. The patient must have serum phosphorus below the reference range for age to reinitiate CRYSVITA
  • Once serum phosphorus is below the reference range for age, treatment may be restarted

For patients who weigh <10 kg1

Restart CRYSVITA at 0.5 mg/kg of body weight, rounded to the nearest 1 mg, administered every 2 weeks.

For patients who weigh ≥10 kg1

Restart CRYSVITA according to the dose schedule shown in the table to the right.

XLH pediatric dose schedule for reinitiation of therapy for patients ≥10 kg1

Previous dose (mg) Reinitiation dose (mg)
105
1510
2010
3010
4020
5020
6030
7030
8040
9040
Previous dose (mg)
10
Reinitiation dose (mg)
5
15
Reinitiation dose (mg)
10
20
Reinitiation dose (mg)
10
30
Reinitiation dose (mg)
10
40
Reinitiation dose (mg)
20
50
Reinitiation dose (mg)
20
60
Reinitiation dose (mg)
30
70
Reinitiation dose (mg)
30
80
Reinitiation dose (mg)
40
90
Reinitiation dose (mg)
40

After a dose decrease, reassess serum phosphorus level 4 weeks after the dose adjustment. If the level remains below the reference range for age after the reinitiation dose, the dose can be adjusted as outlined in the “Increasing doses” section above.1

Additional considerations

Additional considerations for dosing and administration of CRYSVITA

When treating your patients with CRYSVITA, consider the following:1

  • Patients should fast before serum phosphorus tests when specified in the PI
  • If a patient misses a dose, resume CRYSVITA as soon as possible at the prescribed dose. To avoid missed doses, treatments may be administered 3 days on either side of the scheduled treatment date
  • CRYSVITA should be administered by an HCP and via subcutaneous injection only
Two side-by-side outlines showing the front and back of a person, with transparent blue circles on the injection sites.

Injection sites should be rotated with each injection, administered at a different anatomic location than the previous injection. Injection site locations include1

  • Upper arms
  • Upper thighs
  • Buttocks
  • Any quadrant of the abdomen

Do not inject into moles, scars, or areas where the skin is tender, bruised, red, hard, or not intact.1

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Indication

CRYSVITA® (burosumab-twza) is a fibroblast growth factor 23 (FGF23) blocking antibody indicated for the treatment of X-linked hypophosphatemia (XLH) in adult and pediatric patients 6 months of age and older.

Important Safety Information

CONTRAINDICATIONS

CRYSVITA is contraindicated:

  • In concomitant use with oral phosphate and/or active vitamin D analogs (e.g., calcitriol, paricalcitol, doxercalciferol, calcifediol) due to the risk of hyperphosphatemia.
  • When serum phosphorus is within or above the normal range for age.
  • In patients with severe renal impairment or end stage renal disease because these conditions are associated with abnormal mineral metabolism.

WARNINGS AND PRECAUTIONS

Hypersensitivity

  • Hypersensitivity reactions (e.g., rash, urticaria) have been reported in patients with CRYSVITA. Discontinue CRYSVITA if serious hypersensitivity reactions occur and initiate appropriate medical treatment.

Hyperphosphatemia and Risk of Nephrocalcinosis

  • Increases in serum phosphorus to above the upper limit of normal may be associated with an increased risk of nephrocalcinosis. For patients already taking CRYSVITA, dose interruption and/or dose reduction may be required based on a patient’s serum phosphorus levels.

Injection Site Reactions

  • Administration of CRYSVITA may result in local injection site reactions. Discontinue CRYSVITA if severe injection site reactions occur and administer appropriate medical treatment.

ADVERSE REACTIONS

Pediatric Patients

  • Adverse reactions reported in 10% or more of CRYSVITA-treated pediatric XLH patients across three studies are: pyrexia (55%, 44%, and 62%), injection site reaction (52%, 67%, and 23%), cough (52%), vomiting (41%, 48%, and 46%), pain in extremity (38%, 46%, and 23%), headache (34% and 73%), tooth abscess (34%, 15%, and 23%), dental caries (31%), diarrhea (24%), vitamin D decreased (24%, 37%, and 15%), toothache (23% and 15%), constipation (17%), myalgia (17%), rash (14% and 27%), dizziness (15%), and nausea (10%).
  • Postmarketing experience reported in CRYSVITA-treated pediatric XLH patients: blood phosphorus increased.

Adult Patients

  • Adverse reactions reported in more than 5% of CRYSVITA-treated adult XLH patients and in at least 2 patients more than placebo in one study are: back pain (15%), headache (13%), tooth infection (13%), restless legs syndrome (12%), vitamin D decreased (12%), dizziness (10%), constipation (9%), muscle spasms (7%), and blood phosphorus increased (6%).
  • Spinal stenosis is prevalent in adults with XLH, and spinal cord compression has been reported. It is unknown if CRYSVITA therapy exacerbates spinal stenosis or spinal cord compression.

USE IN SPECIFIC POPULATIONS

  • There are no available data on CRYSVITA use in pregnant women to inform a drug-associated risk of adverse developmental outcomes. Serum phosphorus levels should be monitored throughout pregnancy. Report pregnancies to the Kyowa Kirin, Inc. Adverse Event reporting line at 1-844-768-3544.
  • There is no information regarding the presence of CRYSVITA in human milk or the effects of CRYSVITA on milk production or the breastfed infant. Therefore, the developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for CRYSVITA and any potential adverse effects on the breastfed infant from CRYSVITA or from the underlying maternal condition.

PATIENT COUNSELLING INFORMATION

  • Advise patients not to use any oral phosphate and/or active vitamin D analog products.
  • Instruct patients to contact their physician if hypersensitivity reactions, injection site reactions, and restless legs syndrome induction or worsening of symptoms occur.

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 for CRYSVITA.

Indication

CRYSVITA® (burosumab-twza) is a fibroblast growth factor 23 (FGF23) blocking antibody indicated for the treatment of X-linked hypophosphatemia (XLH) in adult and pediatric patients 6 months of age and older.

Important Safety Information

CONTRAINDICATIONS

CRYSVITA is contraindicated:

  • In concomitant use with oral phosphate and/or active vitamin D analogs (e.g., calcitriol, paricalcitol, doxercalciferol, calcifediol) due to the risk of hyperphosphatemia.
  • When serum phosphorus is within or above the normal range for age.
  • In patients with severe renal impairment or end stage renal disease because these conditions are associated with abnormal mineral metabolism.

WARNINGS AND PRECAUTIONS

Hypersensitivity

  • Hypersensitivity reactions (e.g., rash, urticaria) have been reported in patients with CRYSVITA. Discontinue CRYSVITA if serious hypersensitivity reactions occur and initiate appropriate medical treatment.

Hyperphosphatemia and Risk of Nephrocalcinosis

  • Increases in serum phosphorus to above the upper limit of normal may be associated with an increased risk of nephrocalcinosis. For patients already taking CRYSVITA, dose interruption and/or dose reduction may be required based on a patient’s serum phosphorus levels.

Injection Site Reactions

  • Administration of CRYSVITA may result in local injection site reactions. Discontinue CRYSVITA if severe injection site reactions occur and administer appropriate medical treatment.

ADVERSE REACTIONS

Pediatric Patients

  • Adverse reactions reported in 10% or more of CRYSVITA-treated pediatric XLH patients across three studies are: pyrexia (55%, 44%, and 62%), injection site reaction (52%, 67%, and 23%), cough (52%), vomiting (41%, 48%, and 46%), pain in extremity (38%, 46%, and 23%), headache (34% and 73%), tooth abscess (34%, 15%, and 23%), dental caries (31%), diarrhea (24%), vitamin D decreased (24%, 37%, and 15%), toothache (23% and 15%), constipation (17%), myalgia (17%), rash (14% and 27%), dizziness (15%), and nausea (10%).
  • Postmarketing experience reported in CRYSVITA-treated pediatric XLH patients: blood phosphorus increased.

Adult Patients

  • Adverse reactions reported in more than 5% of CRYSVITA-treated adult XLH patients and in at least 2 patients more than placebo in one study are: back pain (15%), headache (13%), tooth infection (13%), restless legs syndrome (12%), vitamin D decreased (12%), dizziness (10%), constipation (9%), muscle spasms (7%), and blood phosphorus increased (6%).
  • Spinal stenosis is prevalent in adults with XLH, and spinal cord compression has been reported. It is unknown if CRYSVITA therapy exacerbates spinal stenosis or spinal cord compression.

USE IN SPECIFIC POPULATIONS

  • There are no available data on CRYSVITA use in pregnant women to inform a drug-associated risk of adverse developmental outcomes. Serum phosphorus levels should be monitored throughout pregnancy. Report pregnancies to the Kyowa Kirin, Inc. Adverse Event reporting line at 1-844-768-3544.
  • There is no information regarding the presence of CRYSVITA in human milk or the effects of CRYSVITA on milk production or the breastfed infant. Therefore, the developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for CRYSVITA and any potential adverse effects on the breastfed infant from CRYSVITA or from the underlying maternal condition.

PATIENT COUNSELLING INFORMATION

  • Advise patients not to use any oral phosphate and/or active vitamin D analog products.
  • Instruct patients to contact their physician if hypersensitivity reactions, injection site reactions, and restless legs syndrome induction or worsening of symptoms occur.

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 for CRYSVITA.

Reference:

  • 1. CRYSVITA (burosumab-twza). US Prescribing Information. Kyowa Kirin, Inc.; March 2023.

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COMM-US-CRY-0076 | March 2025