Asfotase alfa

What is Asfotase alfa?

Asfotase alfa (STRENSIQ) is a tissue nonspecific alkaline phosphatase used to treat perinatal, infantile and juvenile-onset hypophosphatasia(HPP).

What are the uses of this medicine?

• This medicine is used to treat people with perinatal, infantile, and juvenile onset hypophosphatasia (HPP).

How does this medicine work?

• HPP is caused by a deficiency in TNSALP enzyme activity, which leads to elevations in several TNSALP substrates, including inorganic pyrophosphate (PPi).
• TNSALP is a metallo-enzyme that catalyzes the hydrolysis of phosphomonoesters with release of inorganic phosphate and alcohol.
• Elevated extracellular levels of PPi block hydroxyapatite crystal growth which inhibits bone mineralization and causes an accumulation of unmineralized bone matrix which manifests as rickets and bone deformation in infants and children and as osteomalacia (softening of bones) once growth plates close, along with muscle weakness.
• Replacement of the TNSALP enzyme upon STRENSIQ treatment reduces the enzyme substrate levels.

Who Should Not Use this medicine ?

• This medicine have no usage limitations.

What drug interactions can this medicine cause?

• Alkaline Phosphatase (ALP) is used as a detection reagent in many laboratory tests and the presence of asfotase alfa in clinical laboratory samples could result in erroneous test results. Inform laboratory personnel and discuss use of an alternative testing platform for patients on treatment.
• High serum ALP measurements detected through clinical laboratory testing are expected in patients receiving STRENSIQ and reflect circulating concentrations of asfotase alfa.

Is this medicine FDA approved?

• It was approved for use in the United States in 2015.

How should this medicine be used?

• Administer dexamethasone 20 mg intravenously 30 minutes prior to each dose of YONDELIS.

Recommended Dosage: Perinatal/Infantile-Onset HPP

• Recommended dosage regimen is 2 mg/kg administered subcutaneously three times per week, or 1 mg/kg administered six times per week. Injection site reactions may limit the tolerability of the six times per week regimen.
• The dose may be increased to 3 mg/kg three times per week for insufficient efficacy.

Juvenile-Onset HPP The recommended dosage regimen of STRENSIQ for the treatment of juvenile-onset HPP is 6 mg/kg per week administered subcutaneously as either:

• 2 mg/kg three times per week, or
• 1 mg/kg six times per week.
• Injection site reactions may limit the tolerability of the six times per week regimen.

Preparation and Weight-Based Dosing Determine the total weekly volume needed for the prescribed dosage based on the patient's weight and recommended dosage. Follow these steps to determine the patient dose. Total weekly dose (mg) = patient's weight (kg) × prescribed dose (mg/kg/week)

• Total injection volume (mL) per week = Total dose (mg/week) divided by the STRENSIQ concentration (40 mg/mL or 100 mg/mL).
• Note product concentrations are: 40 mg/mL (vial strengths 18 mg/0.45 mL, 28 mg/0.7 mL, 40 mg/mL) or 100 mg/mL (vial strength 80 mg/0.8 mL).
• Round total injection volume to the nearest hundredth of a mL
• Total number of vials per week = Total injection volume divided by vial volume (mL)
• Determine the number of injection days per week (three or six per week).
• Determine dose per injection day. Patient weights should be rounded to the nearest kilogram when determining dose. Use the following tables for guidance, for patients administering 2 mg/kg three times per week (Table 1), 1 mg/kg six times per week (Table 2) and for dose escalations to 3 mg/kg three times per week, recommended only for patients with perinatal/infantile-onset HPP

Administration

• Use STRENSIQ exactly as your healthcare provider tells you to.
• Your healthcare provider will tell you how much STRENSIQ to use and when to use it.
• Your healthcare provider may change your dose if needed.
• Change (rotate) your injection site with each injection. Do not use the same injection site for each injection.

What are the dosage forms and brand names of this medicine?

This medicine is available in fallowing doasage form:

• As Injection: 18 mg/0.45 mL, 28 mg/0.7 mL, 40 mg/mL, or 80 mg/0.8 mL solution in single-dose vials.

This medicine is available in fallowing brand namesː

• STRENSIQ

What side effects can this medication cause?

The most common side effects of this medicine include:

• local skin injection site reactions (including skin red patches, bruising, color change, pain, itching, thinning, swelling, pits, and bumps)
• calcium build up in your eyes and kidneys

STRENSIQ may cause serious side effects, including:

• serious allergic (hypersensitivity) reactions
• skin thickening or pits at the injection site (lipodystrophy)
• calcium build up in your eyes and kidneys

What special precautions should I follow?

• Hypersensitivity reactions, including anaphylaxis, have been reported in STRENSIQ-treated patients. Monitor and if a severe reaction occurs, discontinue treatment and initiate appropriate medical treatment.
• Localized lipodystrophy, including lipoatrophy and lipohypertrophy, has been reported at injection sites after several months in patients treated with STRENSIQ in clinical trials. Advise patients to follow proper injection technique and to rotate injection sites.
• Ectopic Calcifications (eye and kidneys) may. Monitor using ophthalmologic examinations and renal ultrasounds at baseline and periodically during treatment.
• In clinical trials, most STRENSIQ-treated patients developed anti-asfotase alfa antibodies and neutralizing antibodies which resulted in reduced systemic exposure of asfotase alfa. Evaluate patients for antibody formation if clinically indicated.

What to do in case of emergency/overdose?

• In case of overdose, call the poison control helpline of your country. In the United States, call 1-800-222-1222.

• Overdose related information is also available online at poisonhelp.org/help.
• In the event that the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services. In the United States, call 911.

Can this medicine be used in pregnancy?

• There are no available data on STRENSIQ use in pregnant women to inform a drug associated risk.

Can this medicine be used in children?

• The safety and effectiveness of STRENSIQ for the treatment of perinatal/infantile- and juvenile-onset HPP have been established in pediatric patients.

What are the active and inactive ingredients in this medicine?

• Active ingredient: asfotase alfa.
• Inactive ingredients: dibasic sodium phosphate, heptahydrate; monobasic sodium phosphate, monohydrate and sodium chloride.

Who manufactures and distributes this medicine?

• Manufactured by: Alexion Pharmaceuticals, Inc., Boston, MA 02210 USA

What should I know about storage and disposal of this medication?

• STRENSIQ vials must be stored in the original carton until the time of use under refrigerated conditions at 2°C to 8°C (36°F to 46°F) and protected from light.
• Once removed from refrigeration, STRENSIQ should be administered within 3 hours.
• Do not use beyond the expiration date stamped on the carton.
• DO NOT FREEZE OR SHAKE.
• Vials are for one time use only.
• Discard any unused product.

• Dailymed label info on Asfotase alfa
• FDA Asfotase alfa

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