DOSING, ADMINISTRATION, AND STORAGE
CRYSVITA® (burosumab-twza)
has a simple dosing schedule
CRYSVITA dosing schedule
Every 2 weeks for pediatric patients (6 months to <18 years of age)1,*
* Effectiveness in patients aged 6 months to 1 year and adolescents is supported by evidence from the studies in pediatric patients aged 1 to <13 years with additional modeling and simulation of adult and pediatric pharmacokinetic (PK) and pharmacodynamic (PD) data to inform dosing.
All patients should discontinue oral phosphate and/or active vitamin D analogs (e.g., calcitriol, paricalcitol, doxercalciferol, calcifediol) 1 week prior to initiation of treatment.
Fasting serum phosphorus concentration should be below the reference range for age prior to initiation of treatment.
Recommended starting dose for children1:
For patients who weigh less than 10 kg,
starting dose regimen is 1 mg/kg of body
weight, rounded to the nearest 1 mg
For patients who weigh 10 kg or greater,
starting dose regimen is 0.8 mg/kg of body
weight, rounded to the nearest 10 mg.
The minimum starting dose is 10 mg up to
a maximum dose of 90 mg
After initiating CRYSVITA, measure fasting serum phosphorus every 4 weeks for the first 3 months of treatment and thereafter, as appropriate. If serum phosphorus is above the lower limit of the reference range for age and below 5 mg/dL, continue treatment with the same dose. To maintain serum phosphorus within the reference range for age, adjust the dose, as indicated in the full Prescribing Information.1
Dose adjustments in children
Reassess fasting serum phosphorus level 4 weeks after dose adjustment.1
Do not adjust CRYSVITA more frequently than every 4 weeks.1
Dose increase:
For patients who weigh less than 10 kg, if serum phosphorus is below the reference range for age, the dose may be increased to 1.5 mg/kg, rounded to the nearest 1 mg, administered every two weeks. If additional dose increases are needed, the dose may be increased to the maximum dose of 2.0 mg/kg, rounded to the nearest 1 mg, administered every two weeks.
For patients who weigh 10 kg or greater, if serum phosphorus is below the reference range for age, the dose may be increased stepwise up to approximately 2 mg/kg (maximum dose of 90 mg, administered every two weeks), according to the dosing schedule shown in Table 1.1
|
Table 1. Pediatric Dose Schedule for Stepwise Dose Increase for Patients Weighing 10 kg or More |
|||
|---|---|---|---|
| Body Weight (kg) | Starting Dose (mg) |
First Dose Increase to (mg) |
Second Dose Increase to (mg) |
| 10-14 | 10 | 15 | 20 |
| 15-18 | 10 | 20 | 30 |
| 19-31 | 20 | 30 | 40 |
| 32-43 | 30 | 40 | 60 |
| 44-56 | 40 | 60 | 80 |
| 57-68 | 50 | 70 | 90 |
| 69-80 | 60 | 90 | 90 |
| 81-93 | 70 | 90 | 90 |
| 94-105 | 80 | 90 | 90 |
| 106 and greater | 90 | 90 | 90 |
Dose decrease:
If serum phosphorus is above 5 mg/dL, withhold the next dose and reassess the serum phosphorus level in 4 weeks. The patient must have serum phosphorus below the reference range for age to reinitiate CRYSVITA. Once serum phosphorus is below the reference range for age, treatment may be restarted.
For patients who weigh less than 10 kg, restart CRYSVITA at 0.5 mg/kg of body weight, rounded to the nearest 1 mg, administered every two weeks. For patients who weigh 10 kg or more, restart CRYSVITA according to the dose schedule shown in Table 2. Reassess serum phosphorus level 4 weeks after dose adjustment. If the level remains below the reference range for age after the reinitiation dose, the dose can be adjusted according to Table 1.1
| Table 2. Pediatric Dose Schedule
for Reinitiation of Therapy for Patients Weighing 10 kg or More |
|||
|---|---|---|---|
| Previous Dose (mg) | Reinitiation Dose (mg) | ||
| 10 | 5 | ||
| 15 | 10 | ||
| 20 | 10 | ||
| 30 | 10 | ||
| 40 | 20 | ||
| 50 | 20 | ||
| 60 | 30 | ||
| 70 | 30 | ||
| 80 | 40 | ||
| 90 | 40 | ||
How CRYSVITA is supplied
CRYSVITA injection for subcutaneous administration is supplied as a sterile, preservative-free, clear to slightly opalescent and colorless to pale brown-yellow solution. The product is available as 1 single-dose vial per carton in the following strengths: 10 mg/mL, 20 mg/mL, and 30 mg/mL.1
Administration
CRYSVITA is administered by subcutaneous injection and should be administered by a healthcare provider.
Discontinue oral phosphate and active vitamin D analogs (e.g., calcitriol, paricalcitol, doxercalciferol, calcifediol) 1 week prior to initiation of treatment. Fasting serum phosphorus concentration should be below the reference range for age prior to initiation of treatment.
General considerations for administration
Injection sites should be rotated with each injection administered at a different anatomic location (upper arms, upper thighs, buttocks, or any quadrant of abdomen) than the previous injection. Do not inject into moles, scars, or areas where the skin is tender, bruised, red, hard, or not intact.
If a given dose on a dosing day requires multiple vials of CRYSVITA, contents from 2 vials can be combined for injection. The maximum volume of CRYSVITA per injection site is 1.5 mL. If multiple injections are required on a given dosing day, administer at different injection sites. Monitor for signs of reactions.
Visually inspect CRYSVITA for particulate matter and discoloration prior to administration. Do not use if the solution is discolored or cloudy or if the solution contains any particles or foreign particulate matter.
Storage
Store in original carton to protect from light and under refrigerated conditions at 36°F to 46°F (2°C to 8°C) until time of use.1
Do not freeze or shake. Do not use CRYSVITA beyond the expiration date stamped on the carton. CRYSVITA vials are single-dose only. Discard any unused product.1
Reference
-
CRYSVITA (burosumab-twza) US Prescribing Information; June 2020.
DOSING, ADMINISTRATION, AND STORAGE
CRYSVITA® (burosumab-twza)
has a simple dosing schedule
CRYSVITA dosing schedule
Every 4 weeks for adults (≥18 years of age)1
Recommended starting dose for adults:
1 mg/kg body weight, rounded to the nearest 10 mg up to a maximum dose of 90 mg1
After initiating CRYSVITA, assess fasting serum phosphorus on a monthly basis, measured 2 weeks postdose, for the first 3 months of treatment and thereafter, as appropriate. If serum phosphorus is within the normal range, continue with the same dose. To maintain serum phosphorus within the normal range, adjust the dose, as indicated in the full Prescribing Information.1
Dose adjustments in adults
Dose decrease: Reassess fasting serum phosphorus level 2 weeks after dose adjustment.1
Do not adjust CRYSVITA more frequently than every 4 weeks.1
If serum phosphorus is above the normal range, withhold the next dose and reassess the serum phosphorus level after 4 weeks. The patient must have serum phosphorus below the normal range to be able to reinitiate CRYSVITA. Once serum phosphorus is below the normal range, treatment may be restarted at approximately half the initial starting dose up to a maximum dose of 40 mg every 4 weeks, according to the dose schedule shown in Table 3. Reassess serum phosphorus 2 weeks after any change in dose.1
| Table 3. Adult Dose Schedule for Reinitiation of Therapy |
|||
|---|---|---|---|
| Previous Dose (mg) | Reinitiation Dose (mg) | ||
| 40 | 20 | ||
| 50 | 20 | ||
| 60 | 30 | ||
| 70 | 30 | ||
| 80 and greater | 40 | ||
Missed Dose
If a patient misses a dose, resume CRYSVITA as soon as possible at the prescribed dose. To avoid missed doses, treatments may be administered 3 days either side of the scheduled treatment date.1
25-Hydroxy vitamin D supplementation
Monitor 25-hydroxy vitamin D levels. Supplement with cholecalciferol or ergocalciferol to maintain 25-hydroxy vitamin D levels in the normal range for adults. Do not administer active vitamin D analogs during CRYSVITA treatment.1
How CRYSVITA is supplied
CRYSVITA injection for subcutaneous administration is supplied as a sterile, preservative-free, clear to slightly opalescent and colorless to pale brown-yellow solution. The product is available as 1 single-dose vial per carton in the following strengths: 10 mg/mL, 20 mg/mL, and 30 mg/mL.1
Crysvita Administration
CRYSVITA is administered by subcutaneous injection and should be administered by a healthcare provider.
Discontinue oral phosphate and active vitamin D analogs (e.g., calcitriol, paricalcitol, doxercalciferol, calcifediol) 1 week prior to initiation of treatment. Fasting serum phosphorus concentration should be below the reference range for age prior to initiation of treatment.
General considerations for administration
Injection sites should be rotated with each injection administered at a different anatomic location (upper arms, upper thighs, buttocks, or any quadrant of abdomen) than the previous injection. Do not inject into moles, scars, or areas where the skin is tender, bruised, red, hard, or not intact.
If a given dose on a dosing day requires multiple vials of CRYSVITA, contents from 2 vials can be combined for injection. The maximum volume of CRYSVITA per injection site is 1.5 mL. If multiple injections are required on a given dosing day, administer at different injection sites. Monitor for signs of reactions.
Visually inspect CRYSVITA for particulate matter and discoloration prior to administration. Do not use if the solution is discolored or cloudy or if the solution contains any particles or foreign particulate matter.
CRYSVITA Storage
Store in original carton to protect from light and under refrigerated conditions at 36°F to 46°F (2°C to 8°C) until time of use.1
Do not freeze or shake. Do not use CRYSVITA beyond the expiration date stamped on the carton. CRYSVITA vials are single-dose only. Discard any unused product.1
Reference
-
CRYSVITA (burosumab-twza) US Prescribing Information; June 2020.
