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Enzyme Replacement Therapy (Hypophosphatasia — Tissue Non-specific Alkaline Phosphatase)

Asfotase Alfa

Brand names: Strensiq

Asfotase alfa is a recombinant tissue-non-specific alkaline phosphatase enzyme replacement therapy used for paediatric-onset hypophosphatasia.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It is a bone-targeted enzyme that restores alkaline phosphatase activity, reducing accumulation of inorganic pyrophosphate and promoting normal bone mineralisation.

Prescribing in practice

  • Hypersensitivity reactions, including anaphylaxis, can occur, so administer with appropriate supervision and counsel on recognising reactions.
  • Given by subcutaneous injection on a regular recurring schedule; injection-site reactions and lipodystrophy at injection sites are common.
  • Ectopic calcification, including ophthalmic and renal, has been reported and warrants monitoring.

Monitoring

Monitor for hypersensitivity and injection-site reactions, and arrange ophthalmological and renal assessment for ectopic calcification.

Counselling the patient

  • Report rash, swelling, or breathing difficulty after injection.
  • Rotate injection sites to reduce skin and fat changes.
  • Attend scheduled eye and kidney checks; for children, dosing follows a children's formulary and specialist guidance.

Evidence & guidelines

Asfotase alfa is the established enzyme replacement therapy for paediatric-onset hypophosphatasia; consult the SPC and current prescribing references.

Reference: NICE TA467 (Asfotase alfa for treating paediatric-onset hypophosphatasia, 2017); NHS England HST10; ESPE Hypophosphatasia Guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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