Asfotase Alfa

Asfotase Alfa is used for the treatment of patients with perinatal/infantile-and juvenile-onset hypophosphatasia (HPP).

• Asfotase Alfa is available under the following different brand names: Strensiq

Common side effects of Asfotase Alfa include:

• injection site reactions (redness, discoloration, pain, tenderness, itching, swelling, bruising, or a hard lump)
• body fat redistribution (lipodystrophy)
• calcification of soft tissues
• allergic reactions (difficulty breathing, nausea, puffy eyes, dizziness, vomiting, fever, headache, flushing, irritability, chills, skin redness, rash, itching, and changes in the sense of taste)

Serious side effects of Asfotase Alfa include:

• hives
• difficulty breathing
• swelling of the face, lips, tongue, or throat
• dizziness
• nausea
• vomiting
• choking sensation
• vision changes
• urinating more or less than usual
• painful or difficult urination
• pink, red, or brown urine
• severe pain in your side or lower back

Rare side effects of Asfotase Alfa include:

• none 

Seek medical care or call 911 at once if you have the following serious side effects:

• Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, coordination loss, unsteady, very stiff muscles, high fever, profuse sweating, or tremors.
• Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights.
• Serious heart symptoms include fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheadedness, or passing out.

This is not a complete list of side effects and other serious side effects or health problems that may occur because of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

Adult and pediatric dosage

SC injectable solution

• 18 mg/0.45 mL
• 28 mg/0.7 mL
• 40 mg/mL
• 80 mg/0.8 mL (used for patients who weigh above 40 kg)

Hypophosphatasia

Adult and pediatric dosage

• 6 mg/kg/week SC administered as 2 mg/kg given 3 × per week or 1 mg/kg given 6 × per week
• Injection site reactions may limit the tolerability of the 6 × per week regimen
• Note: For perinatal/infantile-onset HPP, the dose may be increased for lack of efficacy (. eg, no improvement in respiratory status, growth, or radiographic findings) up to 9 mg/kg per week administered SC as 3 mg/kg 3 × per week.

Dosage Considerations – Should be Given as Follows: 

• See “Dosages”

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, healthcare provider, or pharmacist first.

• Asfotase Alfa has no noted severe interactions with any other drugs.
• Asfotase Alfa has no noted serious interactions with any other drugs.
• Asfotase Alfa has no noted moderate interactions with any other drugs.
• Asfotase Alfa has no noted minor interactions with any other drugs.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all the products you use. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your healthcare professional or doctor for additional medical advice, health questions, or concerns.

Contraindications

• None

Effects of drug abuse

• None

Short-Term Effects

• See “What Are Side Effects Associated with Using Asfotase Alfa?”

Long-Term Effects

• See “What Are Side Effects Associated with Using Asfotase Alfa?”

Cautions

• Hypersensitivity reactions (rare) reported in clinical trials; reactions occurred within minutes after subcutaneous administration and were observed more than 1 year after treatment initiation; monitor and discontinue treatment and initiate appropriate medical treatment if a severe reaction occurs
• Localized lipodystrophy, including lipoatrophy and lip hypertrophy, has been reported at injection sites after several months; monitor for proper injection technique and injection site rotation
• Patients with HPP are at increased risk for developing ectopic calcifications; in clinical trials, 14 cases (14%) reported ectopic calcification of the eye, including the cornea and conjunctiva, and the kidneys (nephrocalcinosis); there was insufficient information to determine whether or not the reported events were consistent with the disease or associated with Asfotase Alfa; ophthalmology examinations and renal ultrasounds are recommended at baseline and periodically during treatment
• Studies have shown that there is analytical interference between Asfotase Alfa and laboratory tests that utilize an alkaline phosphatase (ALP)-conjugated test system, rendering erroneous test results in patients treated; it is recommended that laboratory assays that do not have ALP-conjugate technology be used when testing samples from patients; inform laboratory personnel that patient is being treated with the drug and discuss the use of testing platform which does not utilize an ALP-conjugated test system

Pregnancy and Lactation

• There are no available human data on the use of AAsfotase Alfa in pregnant women to inform a drug-associated risk
• In animal reproduction studies, Asfotase Alfa administered IV to pregnant rats and rabbits during the period of organogenesis showed no evidence of fetotoxicity, embryo lethality, or teratogenicity at doses causing plasma exposures up to 21 and 24 times, respectively, the disclosure at the recommended human dose
• Lactation
  • Unknown if it is distributed in human breast milk