Skip to main content

Safety

CRYSVITA clinical safety profile in adult patients with TIO1

Adverse reactions reported in adult patients with TIO, based on Study 6 and 7 (N=27)1

The safety of CRYSVITA in patients with TIO was demonstrated in 2 single-arm clinical studies (Study 6 and Study 7) that enrolled a total of 27 patients. Fourteen patients were male, and patients ranged from 33 to 73 years of age. The mean dose of CRYSVITA was 0.77 mg/kg every 4 weeks and the mean duration of exposure was 121 weeks.1

There were no significant changes in frequency, type, or severity of adverse reactions reported through 144 weeks, compared with prior clinical studies in patients receiving CRYSVITA (N=162).1

*Tooth abscess includes: tooth abscess and toothache.

†Injection site reaction includes: injection site reaction, injection site pain, and injection site swelling.

‡Rash includes: rash and rash papular.

Hypersensitivity reactions1

In the phase 2 studies, 22% of patients experienced a hypersensitivity reaction, which were mild or moderate in severity. The most frequent hypersensitivity reactions were eczema (11%) and rash (11%).

Hyperphosphatemia1

In the phase 2 studies, 7% of patients experienced hyperphosphatemia, which was managed with dose reduction.

Injection site reaction1

The frequency of injection site reactions was 15% (injection site reaction, injection site pain, and injection site swelling). Injection site reactions were generally mild in severity, required no treatment, and resolved in all cases.

Restless legs syndrome1-4

In the phase 2 studies, 7% (2/27) of patients experienced symptoms of restless legs syndrome, which were mild and did not require treatment interruption.

Postmarketing experience

Hypercalcemia, urticaria, and increased blood parathyroid hormone have been identified during postapproval use of CRYSVITA. Because these adverse reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Ready to start your patients on CRYSVITA?

Take the first step by filling out the enrollment form.

Enrollment Form

Stay connected

Set up time with a representative to talk more about CRYSVITA.

Rep contact

Indication

CRYSVITA® (burosumab-twza) is a fibroblast growth factor 23 (FGF23) blocking antibody indicated for the treatment of FGF23-related hypophosphatemia in tumor-induced osteomalacia (TIO) associated with phosphaturic mesenchymal tumors that cannot be curatively resected or localized in adult and pediatric patients 2 years of age and older.

Indication

CRYSVITA® (burosumab-twza) is a fibroblast growth factor 23 (FGF23) blocking antibody indicated for the treatment of FGF23-related hypophosphatemia in tumor-induced osteomalacia (TIO) associated with phosphaturic mesenchymal tumors that cannot be curatively resected or localized in adult and pediatric patients 2 years 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.
  • Patients who undergo treatment of the underlying tumor should have dosing interrupted and adjusted to prevent hyperphosphatemia.

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

Adult Patients

  • Adverse reactions reported in more than 10% of CRYSVITA-treated adult TIO patients in two studies are: tooth abscess (19%), muscle spasms (19%), dizziness (15%), constipation (15%), injection site reaction (15%), rash (15%), and headache (11%).

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 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 FGF23-related hypophosphatemia in tumor-induced osteomalacia (TIO) associated with phosphaturic mesenchymal tumors that cannot be curatively resected or localized in adult and pediatric patients 2 years 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.
  • Patients who undergo treatment of the underlying tumor should have dosing interrupted and adjusted to prevent hyperphosphatemia.

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

Adult Patients

  • Adverse reactions reported in more than 10% of CRYSVITA-treated adult TIO patients in two studies are: tooth abscess (19%), muscle spasms (19%), dizziness (15%), constipation (15%), injection site reaction (15%), rash (15%), and headache (11%).

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 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. CRYSVITA (burosumab-twza). US Prescribing Information. Kyowa Kirin, Inc.; August 2025. 2. Jan de Beur SM, Miller PD, Weber TJ, et al. Burosumab for the treatment of tumor-induced osteomalacia. J Bone Miner Res. 2021;36(4):627-635. doi:10.1002/jbmr.4233 3. Imanishi Y, Ito N, Rhee Y, et al. Interim analysis of a phase 2 open-label trial assessing burosumab efficacy and safety in patients with tumor-induced osteomalacia. J Bone Miner Res. 2021;36(2):262-270. doi:10.1002/jbmr.4184 4. Data on file. 201 CSR. Ultragenyx Pharmaceutical Inc.; 2019. 5. Brandi ML, Clunie GPR, Houillier P, et al. Challenges in the management of tumor-induced osteomalacia (TIO). Bone. 2021;152:116064. doi:10.1016/j.bone.2021.116064