Learn more about Strensiq® (asfotase alfa) and HPP.

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By replacing alkaline phosphatase, Strensiq® treats the underlying cause of hypophosphatasia (HPP).1

The underlying cause of hypophosphatasia is deficient tissue-nonspecific alkaline phosphatase (TNSALP) activity.1

Hypophosphatasia is a lifelong disease caused by loss-of-function mutations in the ALPL gene, which encodes the tissue-nonspecific form of alkaline phosphatase (TNSALP).3-5 Deficient TNSALP leads to elevations in several TNSALP substrates (eg, inorganic pyrophosphate), causing rickets and bone deformation in infants and children and osteomalacia (softening of bones) once growth plates close, along with muscle weakness.1

Patients with hypophosphatasia suffer from a variety of skeletal manifestations.3 In a historical cohort of untreated patients with life-threatening perinatal/infantile-onset hypophosphatasia, >50% of patients died by the first year of life. The primary cause of death in the cohort was respiratory complications and/or failure.6 Patients with hypophosphatasia who survive into childhood and adolescence can suffer from skeletal issues, growth delays, and limited mobility.1,3,4,7,8


Strensiq® replaces the deficient TNSALP enzyme and reduces the enzyme substrate levels.1


In Strensiq clinical trials, mean alkaline phosphatase levels varied across populations studied and increased typically well above the upper limit of normal9

  • The levels remained elevated during the treatment period, reflecting ongoing treatment with Strensiq9


Treatment with Strensiq lowered plasma levels of the alkaline phosphatase substrates inorganic pyrophosphate (PPi) and pyridoxal 5’-phosphate (PLP) within 6 to 12 weeks of treatment1

  • Reductions in PPi and PLP did not correlate with clinical outcomes1

Strensiq® improved bone mineralization in patients with perinatal/infantile- and juvenile-onset hypophosphatasia.1

Bone biopsy data indicated that both osteoid volume and thickness decreased during treatment with Strensiq.1

Strensiq® Product Video



STRENSIQ® is indicated for the treatment of patients with perinatal/infantile- and juvenile-onset hypophosphatasia (HPP)

Important Safety Information

  • Hypersensitivity reactions, including anaphylaxis, have been reported in STRENSIQ-treated patients. Signs and symptoms consistent with anaphylaxis included difficulty breathing, choking sensation, nausea, periorbital edema, and dizziness. These reactions have occurred within minutes after subcutaneous administration of STRENSIQ and can occur in patients on treatment for more than one year. Other hypersensitivity reactions have also been reported in STRENSIQ-treated patients, including vomiting, fever, headache, flushing, irritability, chills, skin erythema, rash, pruritus and oral hypoesthesia. If a severe hypersensitivity reaction occurs, discontinue STRENSIQ treatment and initiate appropriate medical treatment. Consider the risks and benefits of re-administering STRENSIQ to individual patients following a severe reaction. If the decision is made to re-administer the product, monitor patients for a reoccurrence of signs and symptoms of a severe hypersensitivity reaction.
  • Localized lipodystrophy, including lipoatrophy and lipohypertrophy, has been reported at injection sites after several months in patients treated with STRENSIQ. Advise patients to follow proper injection technique and to rotate injection sites.
  • Patients with HPP are at increased risk for developing ectopic calcifications. In clinical trials, 14 cases (14%) of ectopic calcification of the eye including the cornea and conjunctiva, and the kidneys (nephrocalcinosis) were reported. There was insufficient information to determine whether or not the reported events were consistent with the disease or due to STRENSIQ. No visual changes or changes in renal function were reported. Ophthalmology examinations and renal ultrasounds are recommended at baseline and periodically during treatment with STRENSIQ to monitor for signs and symptoms of ophthalmic and renal ectopic calcifications and for changes in vision or renal function.
  • The most common adverse reactions (≥ 10%) are injection site reactions, lipodystrophy, ectopic calcifications and hypersensitivity reactions.

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