Enzyme Replacement Therapy (Lysosomal Storage Disorder) Pregnancy: Data from postmarketing reports and published case reports in pregnant women have not identified a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes. Continuation of treatment for Pompe disease during pregnancy should be individualised, as untreated Pompe disease may worsen in pregnancy. A pregnancy exposure registry exists; pregnant women and women of reproductive potential should be encouraged to enrol in the Pompe patient registry.

Alglucosidase Alfa

Brand names: Myozyme

Alglucosidase alfa is a recombinant human acid alpha-glucosidase enzyme replacement therapy used to treat Pompe disease (acid maltase deficiency, a lysosomal storage disorder).

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 20 mg/kg body weight

Route: Intravenous infusion over approximately 4 hours, given through an in-line low protein binding 0.2-micron filter using an infusion pump (reconstitute and dilute before use; final concentration after dilution 0.5 to 4 mg/mL in 0.9% sodium chloride)

Frequency: Every 2 weeks

SOURCE: no UK SPC was fetched in this bundle — this draft is distilled from the US LUMIZYME prescribing information (label date 2025-01-10) and must be verified against the UK SPC. INFUSION RATE (step-wise, by infusion pump): the initial infusion rate should be no more than 1 mg/kg/hour; after patient tolerance to the rate is established the rate may be increased by 2 mg/kg/hour every 30 minutes until a maximum rate of 7 mg/kg/hour is reached; obtain vital signs at the end of each step and, if the patient is stable, continue at the maximum rate of 7 mg/kg/hour until the infusion is complete. Slow or temporarily stop the infusion for mild to moderate hypersensitivity reactions. SUPERVISION AND PREMEDICATION: administration should be supervised by a healthcare provider knowledgeable in the management of hypersensitivity reactions including anaphylaxis; initiate in a healthcare setting with appropriate monitoring and support including cardiopulmonary resuscitation equipment; consider pretreating with antihistamines, antipyretics and/or corticosteroids. MISSED DOSE: if one or more doses are missed, restart treatment as soon as possible, maintaining the 2-week interval between infusions thereafter. PREPARATION: determine the number of vials from actual body weight and the 20 mg/kg dose, rounding up to the next whole vial; reconstitute each vial with 10.3 mL Sterile Water for Injection to give 5 mg/mL (50 mg per 10 mL extractable); do not invert, swirl or shake. NOTE: the fetched section 2 was truncated at the source-fetch limit within section 2.5, so any further administration guidance was not retrieved.

Paediatric dose

Dose: 20 mg/kg

Route: Intravenous infusion over approximately 4 hours via an in-line 0.2-micron low protein binding filter

Frequency: Every 2 weeks

Max: Not stated — the label gives no maximum dose; the maximum INFUSION RATE is 7 mg/kg/hour, with an initial rate of no more than 1 mg/kg/hour

PROVENANCE: the US label states a single weight-based dosage of 20 mg/kg every 2 weeks with no age stratification, and section 8.4 states that safety and effectiveness have been ESTABLISHED in paediatric patients with Pompe disease (supported by a trial in 57 treatment-naive paediatric patients with infantile-onset Pompe disease aged 0.2 months to 3.5 years at first infusion, and by a late-onset trial including 2 patients 16 years of age or less). No separate paediatric regimen is given. Anaphylaxis, hypersensitivity reactions and acute cardiorespiratory failure have occurred in paediatric patients, and cardiac arrhythmia and sudden cardiac death have occurred during general anaesthesia for central venous catheter placement. Clinician to verify against the UK SPC.

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Paediatric weight-based calculator

Patient weight (kg)

Verify in a children's formulary

Contraindications

None stated — the US label section 4 Contraindications reads 'None'

Side effects

Hypersensitivity reactions including anaphylaxis (most frequently reported category, 5% or more)
Rash, urticaria, flushing/feeling hot, erythema, pallor and cyanosis
Pyrexia, rigors, hyperhidrosis and tremor
Cough, tachypnoea and decreased oxygen saturation; chest discomfort
Tachycardia and hypertension/increased blood pressure
Headache, dizziness, agitation, muscle twitching, nausea, vomiting, fatigue and myalgia
Labelled risks also include infusion-associated reactions, cardiac arrhythmia and sudden cardiac death during general anaesthesia for central venous catheter placement, and development of anti-alglucosidase alfa antibodies (CRIM assessment recommended early in infantile-onset disease)

Clinical monograph

How it works

It replaces deficient lysosomal acid alpha-glucosidase, enabling breakdown of accumulated lysosomal glycogen and thereby limiting glycogen-related damage to cardiac and skeletal muscle.

Prescribing in practice

Serious infusion-associated and hypersensitivity reactions, including anaphylaxis, can occur, so administer under supervision with resuscitation facilities available and consider premedication in at-risk patients.
Administered by intravenous infusion at a specialist centre, typically on a regular recurring schedule.
Infantile-onset patients, particularly those who are CRIM-negative, may develop anti-drug antibodies that can reduce efficacy.

Monitoring

Monitor for infusion-associated reactions during and after dosing, watch for cardiorespiratory compromise in infantile-onset disease, and consider periodic anti-drug antibody testing.

Counselling the patient

Report any rash, breathing difficulty, fever, or feeling unwell during or after the infusion immediately.
Treatment is long term and given by infusion in a specialist setting.

Evidence & guidelines

Enzyme replacement is the established disease-specific treatment for Pompe disease; consult the SPC and current prescribing references for administration and monitoring detail.

Reference: NICE TA321 (Alglucosidase alfa for late-onset Pompe disease, 2014); NHS England HST pathway for Pompe disease; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

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