Crysvita
Crysvita (burosumab or burosumab-twza) is a monoclonal antibody. It helps keep phosphate levels in the blood from getting too low in people with tumor-induced osteomalacia (TIO) or a genetic condition called X-linked hypophosphatemia (XLH). This medication is given as an injection under the skin every 2 or every 4 weeks by a trained healthcare professional. Side effects can be different depending on your dose, but they generally include headache, pain, and injection-site reactions (e.g., itching, redness, swelling).
What is Crysvita (burosumab)?
What is Crysvita (burosumab) used for?
- X-linked hypophosphatemia (XLH) in people ages 6 months and older
- Tumor-induced osteomalacia (TIO) in certain people ages 2 years and older
How Crysvita (burosumab) works
Crysvita (burosumab) is a monoclonal antibody that's known as an FGF23-blocking antibody. It stops the actions of a protein called fibroblast growth factor 23 (FGF23), which normally tells your kidneys to get rid of phosphorous from the body.
By stopping FGF23 from working, Crysvita (burosumab) lessens the amount of phosphate that gets removed from the body. As a result, the medication helps keep your phosphate levels from getting too low. This is important for your bone health.
Drug facts
Side effects of Crysvita (burosumab)
The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.
Common Side Effects
Children with XLH:
- Fever (55%)
- Injection-site reaction (52%)
- Cough (52%)
- Vomiting (41%)
- Pain in arm or leg (38%)
- Headache (34%)
- Tooth infection or toothache (34%)
- Diarrhea (24%)
- Low vitamin D levels (24%)
Adults with XLH:
- Back pain (15%)
- Headache (13%)
- Tooth infection (13%)
- Injection-site reaction (12%)
- Restless leg syndrome (12%)
- Low vitamin D levels (12%)
- Dizziness (10%)
Adults with TIO:
- Tooth infection or toothache (19%)
- Muscle spasms (19%)
- Dizziness (15%)
- Constipation (15%)
- Injection-site reaction (15%)
- Rash (15%)
- Headache (11%)
Less Common Side Effects
- Dizziness
- Allergic reaction
- High blood phosphorus levels
Crysvita (burosumab) serious side effects
Contact your healthcare provider immediately if you experience any of the following.
- Serious allergic reaction: trouble breathing, tightness in the throat, hives, itching, fast heartbeat, nausea, stomach pain, dizziness, lightheadedness, swelling in the face or tongue
The following Crysvita (burosumab) side effects have also been reported
Side effects that you should report to your care team as soon as possible:
- Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
- High phosphorus level—muscle pain or cramps, bone or joint pain, numbness and tingling around the mouth
- Kidney stones—blood in the urine, pain or trouble passing urine, pain in the lower back or sides
- Restless leg syndrome—tingling, crawling, pulling, or other unusual feelings in the legs, restlessness, uncontrolled urge to move
Side effects that usually do not require medical attention (report these to your care team if they continue or are bothersome):
Pros and cons of Crysvita (burosumab)
Pros
- Works well to raise blood phosphorus levels in people with XLH or TIO
- Given every 2 weeks or every 4 weeks, depending on your age
- Can use in children as young as 6 months (for XLH) or as young as 2 years (for TIO)
Cons
- Must be give as an injection under the skin by a healthcare professional
- Doesn't cure XLH or TIO
- Not clear how safe the medication is during pregnancy or while breastfeeding
Pharmacist tips for Crysvita (burosumab)
- Mark your appointments on your calendar to get your Crysvita (burosumab) injections at the medical office. It's important to get your injections on time so you don't miss any doses. Be sure to follow up with your care team to discuss how treatment is going for you.
- Your care team will order blood tests to measure your phosphorus level. This helps check how well Crysvita (burosumab) is working for you.
- It's possible to get a reaction at the injection site within a day of your Crysvita (burosumab) injection. These reactions can include pain, swelling, redness, itchiness, rash, hives, bleeding, or bruising. They're typically mild, last a few days, and go away on their own.
- Don't take phosphate supplements, vitamin D supplements, or vitamin D analogues (e.g., calcitriol (Rocaltrol)) at least 1 week before you start Crysvita (burosumab). Also don't take these medications or products during treatment. They can cause your phosphate level to get dangerously high while you're taking Crysvita (burosumab).
- Discuss with your healthcare team about nutrition and your treatment with Crysvita (burosumab). Since Crysvita (burosumab) can raise your phosphorous levels, make sure to be mindful about how much foods that are high in phosphorous you eat. Having phosphorous levels that are too high can be harmful.
- Some people who take Crysvita (burosumab) might start to have restless leg syndrome, which is a condition that causes an irresistible urge to move your legs because of an uncomfortable sensation, typically when you're trying to sleep. Talk to your care team if you start to notice this while you're taking this medication.
- Talk with your healthcare team if you're pregnant or thinking about getting pregnant. Crysvita (burosumab) hasn't been studied during pregnancy, so it's not known how safe it is for unborn babies. Call 1-844-768-3544 to report to the manufacturer if you become pregnant while you're taking this medication.
- Make sure to ask your healthcare team whether it's safe for you to breastfeed while you're taking Crysvita (burosumab). There haven't been any studies done to know whether it's safe to nurse while you're taking this medication.
Common questions about Crysvita (burosumab)
In a small clinical study of 61 children with X-linked hypophosphatemia who had rickets (vitamin D deficiency), those who took Crysvita (burosumab) for a little more than a year had a significant improvement in bone healing and reduced severity of rickets compared to those who took phosphate and vitamin D supplementation. Children who took Crysvita (burosumab) also had improved blood phosphate levels. Another clinical study also found that Crysvita (burosumab) might help improve phosphorus levels and healing of fractures in adults with XLH.
A very small study of Japanese and Korean adults with tumor-induced osteomalacia showed that almost 70% of those who took Crysvita (burosumab) had improved blood phosphorus levels after about 5.5 months of treatment. There was also some evidence that Crysvita (burosumab) could potentially lessen bone damage caused by osteomalacia (brittle bones due to low phosphorus levels). More research is needed to get a better understanding of how well Crysvita (burosumab) works for TIO.
Based on clinical studies, it takes about a week or two for Crysvita (burosumab) to start raising the phosphorus levels in your blood. But how long it takes for the medication to help with bone problems caused by having low phosphorus levels isn't completely clear. It'll probably depend on the severity of your condition and your bone health. Follow up with your healthcare team to find out what to expect from your treatment with Crysvita (burosumab).
Yes, Crysvita (burosumab) is a type of biologic. Biologics are medications that are made from living sources, like cells or proteins, in the lab. Crysvita (burosumab) is a monoclonal antibody, which is a lab-made protein. This monoclonal antibody works by specifically stopping a protein called FGF23 from telling your kidneys to get rid of phosphorous from the body.
Hair loss wasn't a side effect that people who took Crysvita (burosumab) reported during clinical studies. Contact your healthcare team if you notice hair loss, hair shedding, or hair thinning while you're taking Crysvita (burosumab). Your care team can help figure out possible causes of the hair loss you're experiencing.
Crysvita (burosumab) injections are currently FDA approved to be administered by a trained healthcare professional at a clinic or infusion center only. Speak with your healthcare team if this is inconvenient for you to see whether there are other options for you.
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Risks and warnings for Crysvita (burosumab)
Crysvita (burosumab) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Allergic reactions
Allergic reactions to Crysvita (burosumab) are possible. The most common allergic reactions that people reported during clinical studies were rash and hives. Get medical attention right away if you notice trouble breathing; a choking sensation; dizziness; sweating; nausea; rash; or swelling around your eyes, lips, or tongue at any time during treatment with Crysvita (burosumab).
Injection-site reactions
Crysvita (burosumab) can cause injection-site reactions, such as pain, swelling, redness, itchiness, rash, hives, bleeding, and bruising. These reactions are typically mild, last about 1 to 3 days, and usually go away on their own. Contact your healthcare team if you have a more severe reaction.
High phosphorous levels, leading to calcium buildup in the kidneys
- Risk factors: High blood phosphorus levels | Eating foods or taking other medications that raise phosphorus levels
Crysvita (burosumab) raises your blood phosphorus levels. When the phosphorous levels get too high, there's a risk for calcium to build up in your kidneys. Your healthcare team will monitor for this risk throughout treatment by checking your blood phosphorous levels.
Your risk for this problem might be higher if you take medications that raise phosphorus levels (phosphate supplements or vitamin D analogues) or eat too much food that contains phosphorus. Make sure to tell your healthcare team about all of the medications, vitamins, and supplements that you're taking or planning to take during treatment with Crysvita (burosumab).
Contact your healthcare team if you notice blood in the urine. Also speak with your care team if you have fever; chills; nausea; or severe pain in the belly, back, or groin area. These might be signs of calcium buildup in the kidneys.
Crysvita (burosumab) dosage
Typical dosage for Crysvita (burosumab)
Crysvita (burosumab) is given as an injection under the skin in the upper arm, upper thigh, buttock, or stomach. The injection is given by a trained healthcare professional.
The dose depends on the medical condition you have and is calculated based on your age and weight. And how often you need to get Crysvita (burosumab) injections depends on your age.
- Children younger than 18 years old: Crysvita (burosumab) is typically given every 2 weeks.
- Adults: Crysvita (burosumab) is typically given every 4 weeks.
Your healthcare team will adjust your dose based on how your blood phosphate levels are responding to the medication and whether you're having side effects.
Crysvita (burosumab) contraindications
Contraindications are specific health conditions or situations in which a person should not take a medication due to safety concerns. If you have any of the following conditions or if any of the following apply to you, let your healthcare provider know because Crysvita (burosumab) will not be safe for you to take.
- Take vitamin D analogues or medications with phosphate in them
- Normal or high blood phosphorus levels
- Severe kidney problems
Crysvita (burosumab) images
