Skip to main content

This website is intended for use by US residents only.

Prescribing Information location icon US patients website
CRYSVITA® (burosumab-twza) injection 10, 20, 30 mg/mL

Choose indication

Enrollment form Request a rep
Dosage and administration

Pediatric dosing schedule and administration for CRYSVITA® (burosumab-twza)

How to initiate treatment using the recommended starting dosage for children with XLH.

Recommended starting dosage for pediatric patients (6 months to <18 years of age)*

Patients who weigh less than 10 kg:

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

Patients who weigh 10 kg or greater:

Starting dosage 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.1

CRYSVITA
dosed every

2

weeks1

CRYSVITA should be administered by a healthcare professional.1

Ready-to-use subcutaneous injection that comes in 3 strengths1:

CRYSVITA® (burosumab-twza) injection 10, 20, 30 mg/mL

The maximum volume of CRYSVITA per injection is 1.5 mL. If multiple injections are required, administer at different injection sites.1

A silhouette of a person indicating areas for injection in the front and back of the body

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

*Safety and effectiveness in patients aged 6 months to 1 year and adolescents are supported by evidence from the studies in pediatric patients aged 1 to <13 years with additional modeling and simulation of adult and pediatric pharmacokinetic and pharmacodynamic data to inform dosing.1

Before initiating treatment

Preparing your pediatric patients for CRYSVITA

Before initiating CRYSVITA1

  • Have your patient discontinue oral phosphate and/or active vitamin D analogs (eg, calcitriol, paricalcitol, doxercalciferol, calcifediol) 1 week prior
  • Fasting serum phosphorus concentration should be below the reference range for age
  • In patients at high risk for hypercalcemia (eg, pre-existing hyperparathyroidism, prolonged immobilization, dehydration, hypervitaminosis D, or renal impairment), assess serum calcium and parathyroid hormone levels
CRYSVITA® (burosumab-twza) injection 10, 20, 30 mg/mL vials
After initiating treatment

Measuring fasting serum phosphorus during CRYSVITA treatment for children with XLH

CRYSVITA is administered once EVERY 2 WEEKS.1

After initiation of CRYSVITA, measure fasting serum phosphorus EVERY 4 WEEKS for the first 3 months of treatment, and thereafter as appropriate.1

Monitor and adjust dose based on serum phosphorus levels1

If serum phosphorus is above the lower limit of the reference range for age and below 5 mg/dL, continue treatment with the same dose. Follow the Dose adjustment schedule below to maintain serum phosphorus within the reference range for age.

Dose adjustments

Adjust CRYSVITA dose for children with XLH to help maintain serum phosphorus within the reference range1

A calendar date with a star in the middle

When making dose adjustments for your patients, take note of the following1:

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

Increasing CRYSVITA dosing

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 rightbelow
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)
10–14 10 15 20
15–18 10 20 30
19–31 20 30 40
32–43 30 40 60
44–56 40 60 80
57–68 50 70 90
69–80 60 90 90
81–93 70 90 90
94–105 80 90 90
≥106 90 90 90
XLH pediatric dose schedule for stepwise dose increase for patients ≥10 kg1
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 CRYSVITA dosing

If fasting serum phosphorus is >5 mg/dL1:

  • 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.below.

XLH pediatric dose schedule for reinitiation of therapy for patients ≥10 kg1
Previous dose (mg) Reinitiation dose (mg)
10 5
15 10
20 10
30 10
40 20
50 20
60 30
70 30
80 40
90 40
XLH pediatric dose schedule for reinitiation of therapy for patients ≥10 kg1
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 section above on increasing dosing.1

Additional considerations

Additional considerations for dosage and administration of CRYSVITA for children with XLH

When treating your patients with CRYSVITA, consider the following1:

  • CRYSVITA should be administered via subcutaneous injection only
  • Visually inspect CRYSVITA for particulate matter and discoloration prior to administration. Do not use if the solution is discolored or cloudy or if the solution contains any particles or foreign particulate matter
  • If a patient misses a dose, have the patient 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
  • Monitor serum calcium and parathyroid hormone levels in patients at high risk for hypercalcemia before and during treatment

Have questions about biochemical reference ranges?

Check with the testing laboratory for specific definitions, parameters, and normal ranges. Your CRYSVITA representative can also provide resources on biochemical markers in XLH, including serum phosphorus.

Contact a rep

Connect with Kyowa Kirin Cares to help your pediatric patients prescribed CRYSVITA with their treatment journey

Patient access & support
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.

read more
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.

Hypercalcemia

  • Increases in serum calcium have been reported in patients treated with CRYSVITA. Patients with risk factors such as pre-existing hyperparathyroidism, prolonged immobilization, dehydration, hypervitaminosis D, or renal impairment, are at higher risk of hypercalcemia. Monitor these patients for serum calcium and parathyroid hormone levels before and during CRYSVITA treatment for moderate to severe hypercalcemia. In patients with moderate to severe hypercalcemia, CRYSVITA should not be administered until hypercalcemia is adequately managed.

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%).

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 COUNSELING 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.

Hypercalcemia

  • Increases in serum calcium have been reported in patients treated with CRYSVITA. Patients with risk factors such as pre-existing hyperparathyroidism, prolonged immobilization, dehydration, hypervitaminosis D, or renal impairment, are at higher risk of hypercalcemia. Monitor these patients for serum calcium and parathyroid hormone levels before and during CRYSVITA treatment for moderate to severe hypercalcemia. In patients with moderate to severe hypercalcemia, CRYSVITA should not be administered until hypercalcemia is adequately managed.

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%).

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 COUNSELING 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.; April 2026.

Back to top

COMM-US-CRY-0778 June 2026