Crysvita

Generic name: burosumab
Drug class: Miscellaneous metabolic agents

Medically reviewed by  A Ras MD.

What is Crysvita?

Crysvita is a prescription medicine that is used to treat low phosphate levels

Description

Burosumab-twza is a human immunoglobulin G subclass 1 (IgG1), anti-human fibroblast growth factor 23 (FGF23) antibody produced by recombinant DNA technology using Chinese hamster ovary cells. Burosumab-twza is composed of two heavy chain (γ1-chain) molecules and two light chain (κ-chain) molecules. Each heavy chain has an N-linked carbohydrate moiety at asparagine 297 (Asn297). The molecular weight of burosumab-twza determined by mass spectrometry is approximately 147,000.

CRYSVITA (burosumab-twza) injection for subcutaneous administration is supplied as a sterile, preservative-free, clear to slightly opalescent and colorless to pale brown-yellow solution in a single-dose vial.

Each 1 mL of solution contains 10 mg, 20 mg or 30 mg of burosumab-twza, L-histidine (1.55 mg), L-methionine (1.49 mg), polysorbate 80 (0.5 mg), D-sorbitol (45.91 mg) in Water for Injection, USP. Hydrochloric acid may be used to adjust to a pH of 6.25.

Mechanism of Action

X-linked hypophosphatemia is caused by excess fibroblast growth factor 23 (FGF23) which suppresses renal tubular phosphate reabsorption and the renal production of 1,25 dihydroxy vitamin D. Burosumab-twza binds to and inhibits the biological activity of FGF23 restoring renal phosphate reabsorption and increasing the serum concentration of 1,25 dihydroxy vitamin D.

Before taking Crysvita, tell your doctor:

• If you are allergic to Crysvita; any part of this medicine; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.
• If you are taking any of these drugs: Vitamin D drugs like calcifediol, calcitriol, doxercalciferol, or paricalcitol; or oral phosphate.
• If you have a normal or high phosphorus level.
• If you have kidney problems.

This is not a list of all drugs or health problems that interact with this medicine.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take Crysvita with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take Crysvita?

• Tell all of your health care providers that you take Crysvita. This includes your doctors, nurses, pharmacists, and dentists.
• Have blood work checked as you have been told by the doctor. Talk with the doctor.
• Tell your doctor if you are pregnant, plan on getting pregnant, or are breast-feeding. You will need to talk about the benefits and risks to you and the baby.

How is Crysvita best taken?

Use Crysvita as ordered by your doctor. Read all information given to you. Follow all instructions closely.

• It is given as a shot into the fatty part of the skin in the upper arm, thigh, buttocks, or stomach area.

What do I do if I miss a dose?

• Call your doctor to find out what to do.

What are the side effects of Crysvita that I need to call my doctor about immediately?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
• Back pain, belly pain, or blood in the urine. May be signs of a kidney stone.
• This medicine may cause restless legs. It may also make restless legs worse in people who already have it. If this happens, call the doctor.

What are some other side effects of Crysvita?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Irritation where the shot is given.
• Dizziness or headache.
• Upset stomach or throwing up.
• Fever.
• Cough.
• Pain in arms or legs.
• Tooth pain.
• Muscle pain.
• Muscle spasm.
• Diarrhea or constipation.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.

If overdose is suspected:

If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

How do I store and/or throw out Crysvita?

• If you need to store Crysvita at home, talk with your doctor, nurse, or pharmacist about how to store it.

Label

PRINCIPAL DISPLAY PANEL – 30 MG/ML VIAL CARTON

• NDC 69794-304-01
• CRYSViTA®
  (burosumab-twza)
• Injection
• 30 mg/mL
• For Subcutaneous Use Only
• Single-Dose Vial
• Discard Unused Portion
• Rx only
  1 vial

PRINCIPAL DISPLAY PANEL – 20 MG/ML VIAL CARTON

• NDC 69794-203-01
• CRYSViTA®
  (burosumab-twza)
• Injection
• 20 mg/mL
• For Subcutaneous Use Only
• Single-Dose Vial
• Discard Unused Portion
• Rx only
  1 vial

SRC: NLM .