Drug Detail:Asfotase alfa (Asfotase alfa [ as-foe-tase-al-fa ])
Drug Class: Miscellaneous metabolic agents
Usual Adult Dose for Hypophosphatasia
2 mg/kg subcutaneously 3 times per week OR 1 mg/kg subcutaneously 6 times per week
Maximum dose: 9 mg/kg per week
Comments:
- For patients with perinatal/infantile-onset hypophosphatasia (HPP), an increase to 3 mg/kg three times per week may be necessary for insufficient efficacy (e.g., no improvement in respiratory status, growth, or radiographic findings).
- Injection site reactions may limit the tolerability of the 6 times per week dosing regimens.
Use: For the treatment of patients with perinatal/infantile and juvenile onset HPP.
Usual Pediatric Dose for Hypophosphatasia
2 mg/kg subcutaneously 3 times per week OR 1 mg/kg subcutaneously 6 times per week
Maximum dose: 9 mg/kg per week
Comments:
- For patients with perinatal/infantile-onset hypophosphatasia (HPP), an increase to 3 mg/kg three times per week may be necessary for insufficient efficacy (e.g., no improvement in respiratory status, growth, or radiographic findings).
- For patients weighing less than 40 kg: Do not use the 80 mg/0.8 mL vial because the systemic exposure is lower than that achieved with the lower strength vials and may not be adequate for these patients.
- Injection site reactions may limit the tolerability of the 6 times per week dosing regimens.
Use: For the treatment of patients with perinatal/infantile and juvenile onset HPP.
Renal Dose Adjustments
Data not available
Liver Dose Adjustments
Data not available
Precautions
CONTRAINDICATIONS:
- None
Clinical studies included patients from 1 day to 58 years of age.
Consult WARNINGS section for additional precautions.
Dialysis
Data not available
Other Comments
Administration advice:
- Administer subcutaneously into the abdominal area, thigh, or deltoid
- Always use a new syringe and needle; do not share syringes or needles
- Rotate injection sites to reduce risk of lipodystrophy; do not administer into reddened, inflamed, or swollen areas
Storage requirements:
- Store in the refrigerator [2C to 8C (36F to 46F)] in the original carton until time of use; protect from light
- Once removed from refrigerator, use within 1 hour
- Do not freeze or shake vial; single-use only
Reconstitution/preparation techniques:
- Administer dose within 1 hour of removing vial from the refrigerator.
- Do not use 80 mg/0.8 mL vial in patients weighing less than 40 kg.
- For injection volumes greater than 1 mL, split dose equally between 2 injections and use 2 separate injection sites.
- Vial should be clear, slightly opalescent or opalescent, colorless to slightly yellow aqueous solution; few small translucent or white particles may be present; discard vials not consistent with this description.
- Manufacturer product labeling should be consulted for weight-based dosing tables and more specific administration guidance.
General:
- Hypophosphatasia (HPP) Registry: A voluntary registry has been established to better understand the HPP population and to monitor and evaluate the long-term treatment effects of this drug; information can be found at www.hppregistry.com.
- In clinical trials, anti-drug antibodies were detected; no correlation between anti-drug antibody titer and percent inhibition was observed. The formation of anti-drug antibody resulted in a reduction in systemic exposure.
Monitoring:
- Signs and symptoms of hypersensitivity reactions
- Signs and symptoms of lipodystrophy
- Ophthalmologic exams and renal ultrasounds at baseline and periodically during treatment to monitor for ectopic calcifications
Patient advice:
- Patients or caregivers should be instructed on preparation, storage, and administration of this drug; proper injection technique and site rotation are necessary to avoid injection site reactions.
- Patients or caregivers should be instructed on proper disposal of needles and syringes; with each dose, a new syringe and needle should be used and needles and syringes should never be shared.
- If signs or symptoms of an allergic reaction occur, patients should seek immediate medical advice.
- Tell your health care provider if you notice skin thickening or pits at injection sites.