Bone disorders:

Indications for CRYSVITA:

Treatment of X-linked hypophosphatemia.

Adult:

Discontinue oral phosphate and/or active vitamin D analogs 1 week prior to treatment start. Give as SC inj (eg, upper arms, upper thighs, buttocks, abdomen quadrant); rotate sites. Round to nearest 10mg; max 1.5mL per inj site. ≥18yrs: 1mg/kg every 4 weeks; max 90mg. Assess fasting serum phosphorus every 4 weeks, measured 2 weeks post-dose, for the first 3 months, 2 weeks after a dose adjustment, then thereafter as needed. Dose adjustment: see full labeling.

Children:

<6mos: not established. Discontinue oral phosphate and/or active vitamin D analogs 1 week prior to treatment start. Give as SC inj (eg, upper arms, upper thighs, buttocks, abdomen quadrant); rotate sites. Round to nearest 1mg (<10kg) or 10mg (≥10kg); max 1.5mL per inj site. 6mos–<18yrs (<10kg): initially 1mg/kg every 2 weeks; (≥10kg): initially 0.8mg/kg every 2 weeks, max 90mg. Assess fasting serum phosphorus every 4 weeks for the first 3 months, 4 weeks after a dose adjustment, then thereafter as needed. Dose adjustment: see full labeling.

Contraindications:

Concomitant oral phosphate and/or active vitamin D analogs (eg, calcitriol, paricalcitol, doxercalciferol, calcifediol). Serum phosphorus within or above normal range for age. Severe renal impairment or ESRD.

Warnings/Precautions:

Prior to initiation, confirm fasting serum phosphorus concentration below reference range for age. Monitor 25-hydroxy vitamin D levels; supplement with cholecalciferol or ergocalciferol to maintain normal range for age. Discontinue if serious hypersensitivity or severe inj site reactions occur. Elderly. Pregnancy. Nursing mothers.

Pharmacologic Class:

Fibroblast growth factor 23 (FGF23) blocking antibody.

Interactions:

Risk of hyperphosphatemia when concomitant with oral phosphate and/or active vitamin D analogs.

Adverse Reactions:

Back pain, headache, tooth infection, restless leg syndrome, vitamin D decreased, dizziness, constipation, muscle spasms, blood phosphorus increased; hypersensitivity, hyperphosphatemia, nephrocalcinosis. In children: pyrexia, inj site reaction, cough, vomiting, pain in extremity, headache, tooth abscess, dental carries.

Generic Availability:

NO

How Supplied:

Single-dose vial—1