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Burosumab Pregnancy and Breastfeeding Warnings

Medically reviewed by Last updated on Apr 24, 2023.

Burosumab is also known as: Crysvita

Burosumab Pregnancy Warnings

Benefit should outweigh risk

AU TGA pregnancy category: B3
US FDA pregnancy category: Not assigned

Risk Summary: There is no available human data to inform a drug-associated risk of developmental outcomes; in utero exposure in cynomolgus monkeys did not show teratogenic effects; adverse effects including late fetal loss and preterm birth were observed with exposures estimated to be 15-fold higher than human exposure and accompanied by maternal hyperphosphatemia and placental mineralization.

-Serum phosphate levels should be monitored throughout pregnancy.
-Some authorities advise against use in women of childbearing potential not using contraception.
-Pregnancies should be reported to the manufacturer's (Kyowa Kirin, Inc) adverse event reporting line (US; 1-888-756-8657).

Studies in cynomolgus monkeys found no evidence of teratogenic effects in fetuses or offspring when dosed at 0.2, 2 and 15-fold the expected human exposure. Maternal hyperphosphatemia and placental mineralization were observed along with increased late fetal loss, a shortened gestation period, and an increased incidence of preterm births at doses 15-fold the expected human exposure. This drug has been detected in the serum of fetuses indicating transport across the placenta. There are no controlled data in human pregnancy.

AU TGA pregnancy category B3: Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals have shown evidence of an increased occurrence of fetal damage, the significance of which is considered uncertain in humans.

US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.

See references

Burosumab Breastfeeding Warnings

There is no information on the effects of this drug on milk production or on the breastfed infant. This drug is a large protein molecule and therefore the amount excreted into human milk is likely to be very low and absorption unlikely because it will probably be destroyed in the infants gastrointestinal tract. Due to lack of clinical data, the developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for this drug and any potential adverse effects on the breastfed infant from the drug or from the underlying maternal condition.

Safety has not been established

Excreted into human milk: Unknown
Excreted into animal milk: Data not available

-The effects in the nursing infant are unknown.

See references

References for pregnancy information

  1. Cerner Multum, Inc. Australian Product Information.
  2. Product Information. Crysvita (burosumab). Ultragenyx Pharmaceutical. 2018.

References for breastfeeding information

  1. Cerner Multum, Inc. Australian Product Information.
  2. United States National Library of Medicine. Toxnet. Toxicology Data Network. 2013.
  3. Product Information. Crysvita (burosumab). Ultragenyx Pharmaceutical. 2018.
  4. National Library of Medicine (US). Drugs and Lactation Database (LactMed) 2019.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.