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

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XLH is a hereditary, progressive, and lifelong disease1

XLH is a chronic and rare disease—up to 1 in 20,000 people have it—characterized by hypophosphatemia that impacts the skeletal and muscular health of children and adults.1,2 It is often misperceived exclusively as a childhood disease; however, it can impact adults. Symptoms may persist and can worsen over time.1

XLH can be inherited or occur spontaneously

XLH is an X-linked dominant genetic disease caused by pathogenic variants in the PHEX gene. Although the majority of XLH cases are inherited, 20% to 30% of XLH cases occur spontaneously with no family history.2-4

A person only needs one pathogenic variant in the PHEX gene to be affected. Screening family members of patients with XLH may help identify previously undiagnosed individuals.3-5

PHEX=phosphate regulating endopeptidase X-linked.

XLH can be misdiagnosed and should be distinguished from6-9:

A bent knee joint with surrounding tissue

Nutritional rickets or osteomalacia

An arrow pointing down with the letters 'ALP' next to it

Hypophosphatasia

Two bones showing abnormalities

Other hereditary rickets

Two bones

Physiologic bowing

The vertebral column

Ankylosing
spondylitis

A silhouette of a person with bowed legs

Metaphyseal
dysplasia
(Pyle disease)

ALP=alkaline phosphatase.

In XLH, increased FGF23 is the source of chronic hypophosphatemia10

Three abstract shapes in a stylized protein shape labeled FGF23, which is a hormone in the bone

Excess FGF23

FGF23 is a protein hormone produced by osteocytes in the bones to regulate serum phosphorus levels.

PHEX gene variants cause excess FGF23 levels.5

The kidneys removing too much phosphate from the body due to excess FGF23

Reduced renal phosphate reabsorption

Excess FGF23 results in excess phosphate excretion.5

Decreased intestinal phosphate absorption due to excess FGF23

Decreased intestinal phosphate absorption

Reduced active vitamin D results in decreased phosphate absorption in the small intestine.5

Osteomalacia in the bone

Chronic hypophosphatemia

Due to loss of phosphate, bones become weakened.10

FGF23=fibroblast growth factor 23.

Restoring phosphate homeostasis

Historically, the treatment of chronic hypophosphatemia involved administering multiple daily doses of phosphate supplements to replete serum phosphorus along with active forms of vitamin D to prevent decreases in serum calcium and increases in parathyroid hormone.5,11,12 This approach aimed to counteract the downstream consequences of excess FGF23 but did not address the underlying disease mechanism.5

In 2018, CRYSVITA, an FGF23-blocking monoclonal antibody, became available as the first and only treatment that targets the cause of FGF23-related hypophosphatemia in XLH for patients 1 year of age and older. In 2019, the indication expanded to include children 6 months of age and older.5,13,14

Antibodies binding to FGF23 proteins to help reduce phosphate loss and increase phosphorus levels in the body for people with XLH

Help restore and maintain serum phosphorus levels with CRYSVITA13

How it works

Explore real-life cases of adult and pediatric patients with XLH

Case studies
A doctor and another person looking at a tablet together

Actor portrayal

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.

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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.

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.

References:

  • 1. Hamilton AA, Faitos S, Jones G, Kinsley A, Gupta RN, Lewiecki EM. Whole body, whole life, whole family: patients' perspectives on X-linked hypophosphatemia. J Endocr Soc. 2022;6(8):bvac086. doi:10.1210/jendso/bvac086 2. Trombetti A, Al-Daghri N, Brandi ML, et al. Interdisciplinary management of FGF23-related phosphate wasting syndromes: a Consensus Statement on the evaluation, diagnosis and care of patients with X-linked hypophosphataemia. Nat Rev Endocrinol. 2022;18(6):366-384. doi:10.1038/s41574-022-00662-x 3. Aljuraibah F, Al Amiri E, Al Dubayee M, et al. Diagnosis and management of X-linked hypophosphatemia in children and adolescent in the Gulf Cooperation Council countries. Arch Osteoporos. 2021;16(1):52. doi:10.1007/s11657-021-00879-9 4. National Cancer Institute. X-linked dominant inheritance. National Cancer Institute. Published 2023. Accessed February 26, 2025. 5. Dahir K, Roberts MS, Krolczyk S, Simmons JH. X-linked hypophosphatemia: a new era in management. J Endocr Soc. 2020;4(12):bvaa151. doi:10.1210/jendso/bvaa151 6. Carpenter TO, Imel EA, Holm IA, Jan de Beur SM, Insogna KL. A clinician's guide to X-linked hypophosphatemia. J Bone Miner Res. 2011;26(7):1381-1388. doi:10.1002/jbmr.340 7. Arboleya L, Braña I, Pardo E, Loredo M, Queiro R. Osteomalacia in adults: a practical insight for clinicians. J Clin Med. 2023;12(7):2714. doi:10.3390/jcm12072714 8. Charles JF, Malabanan AO, Krolczyk S, Dahir KM. Rare causes of musculoskeletal pain: thinking beyond common rheumatologic diseases. Case Rep Rheumatol. 2024;2024:6540026. doi:10.1155/2024/6540026 9. Aljuraibah F, Alalwan I, Habeb A. Diagnostic and new therapeutic approaches to two challenging pediatric metabolic bone disorders: hypophosphatasia and X-linked hypophosphatemic rickets. Curr Pediatr Rev. 2024;20(4):395-404.
    doi:10.2174/0115733963206838231031102750 10. Glorieux FH, Bonewald LF, Harvey NC, van der Meulen M. Potential influences on optimizing long-term musculoskeletal health in children and adolescents with X-linked hypophosphatemia (XLH). Orphanet J Rare Dis. 2022;17(1):30. doi:10.1186/s13023-021-02156-x 11. Aljuraibah F, Bacchetta J, Brandi ML, et al. An expert perspective on phosphate dysregulation with a focus on chronic hypophosphatemia. J Bone Miner Res. 2022;37(1):12-20. doi:10.1002/jbmr.4486 12. Linglart A, Biosse-Duplan M, Briot K, et al. Therapeutic management of hypophosphatemic rickets from infancy to adulthood. Endocr Connect. 2014;3(1):R13-R30. doi:10.1530/EC-13-0103 13. CRYSVITA (burosumab-twza). US Prescribing Information. Kyowa Kirin, Inc.; April 2026. 14. Kyowa Kirin Co., Ltd. FDA approves label expansion for Crysvita® (burosumab-twza) to include infants as young as 6 months of age. Published September 30, 2019. Accessed March 26, 2026. https://www.kyowakirin.com/media_center/news_releases/2019/e20190930_01.html.

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COMM-US-CRY-0776 June 2026