Recombinant α-mannosidase
Pregnancy: May cause embryo-foetal harm based on animal reproduction studies — major visceral malformations were observed in rats (at the highest dose, approximately 7-fold the recommended 1 mg/kg human dose) and at all dose levels in rabbits (highest exposure approximately 2.5-fold the recommended dose). No available human data in pregnancy. Verify that females of reproductive potential are not pregnant before initiating treatment, and advise effective contraception during treatment and for 14 days after the last dose if treatment is discontinued. Advise the pregnant female of the potential risk to the foetus; the decision to continue or discontinue in pregnancy should weigh the need for treatment, the potential drug-related risks to the foetus, and the potential adverse outcomes of untreated maternal disease.
Velmanase alfa
Brand names: Lamzede
Velmanase alfa is a recombinant human alpha-mannosidase enzyme replacement therapy for the non-neurological manifestations of alpha-mannosidosis.
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:1 mg/kg (actual body weight)
Route: Intravenous infusion
Frequency: Once every week
Alpha-mannosidosis (LAMZEDE, velmanase alfa-tycv). Prior to administration, consider pre-treating with antihistamines, antipyretics and/or corticosteroids. For females of reproductive potential, verify that the patient is not pregnant before initiating treatment. Administration: the total infusion volume is determined by the patient's actual body weight and should be given over a MINIMUM of 60 minutes for patients weighing up to 49 kg; patients weighing 50 kg and greater should be infused at a MAXIMUM infusion rate of 25 mL/hour to control the protein load. Use an infusion set with a pump and a low-protein-binding 0.2 micron in-line filter. Each reconstituted vial yields 2 mg/mL. Missed doses: if one or more doses are missed, restart treatment as soon as possible provided it is at least 3 days from the next scheduled dose; if within 3 days of the next scheduled dose, give only the next dose per schedule. Hypersensitivity / infusion-associated reactions (IARs): for severe reactions (including anaphylaxis) immediately discontinue and treat; for mild to moderate reactions consider holding the infusion for 15 to 30 minutes, slowing the rate to 25% to 50% of the recommended rate and treating — if symptoms subside, resume at 25% to 50% of the recommended rate and, if tolerated, increase in 25% increments back to the recommended rate; if symptoms persist, stop the infusion and consider re-initiating within 7 to 14 days at 25% to 50% of the recommended rate with appropriate pretreatment. Geriatric: alpha-mannosidosis is largely a disease of paediatric and young adult patients — clinical trials did not include patients 65 years and older. Source: US FDA prescribing information (DailyMed, Chiesi USA, label date 2023-02-21); NO UK SPC was available in the fetched bundle — verify against UK/EMA labelling before use.
Paediatric dose
Dose:1 mg/kg
Route: Intravenous infusion
Frequency: Once every week
Max: Not stated in the source label
The US label states a single weight-based dosage of 1 mg/kg (actual body weight) once every week for all patients; safety and effectiveness for alpha-mannosidosis have been established in paediatric patients, supported by an adequate and well-controlled trial in adult and paediatric patients and an open-label trial in 5 paediatric patients younger than 6 years. Trial 1 included paediatric patients aged 6–17 years who received 1 mg/kg weekly for 52 weeks. Paediatric patients reported a HIGHER incidence of hypersensitivity reactions than adults (14 of the 19 patients with hypersensitivity reactions were paediatric). Infusion duration is weight-based, not age-based (minimum 60 minutes up to 49 kg; maximum 25 mL/hour at 50 kg and above). Verify all paediatric dosing against a children's formulary and against UK labelling — this figure is from US prescribing information only.
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
The US label states a single weight-based dosage of 1 mg/kg (actual body weight) once every week for all patients; safety and effectiveness for alpha-mannosidosis have been established in paediatric patients, supported by an adequate and well-controlled trial in adult and paediatric patients and an open-label trial in 5 paediatric patients younger than 6 years. Trial 1 included paediatric patients aged 6–17 years who received 1 mg/kg weekly for 52 weeks. Paediatric patients reported a HIGHER incidence of hypersensitivity reactions than adults (14 of the 19 patients with hypersensitivity reactions were paediatric). Infusion duration is weight-based, not age-based (minimum 60 minutes up to 49 kg; maximum 25 mL/hour at 50 kg and above). Verify all paediatric dosing against a children's formulary and against UK labelling — this figure is from US prescribing information only.
Hypersensitivity reactions including anaphylaxis (incidence >20%) — signs and symptoms have included cyanosis, hypotension, emesis, urticaria, erythema, facial swelling, pyrexia and tremor
Infusion-associated reactions (IARs)
Nasopharyngitis (incidence >20%)
Pyrexia and headache (incidence >20%)
Arthralgia (incidence >20%)
Acute renal failure — serious adverse reaction reported in 1 (7%) treated patient in Trial 1
Clinical monograph
How it works
It replaces deficient alpha-mannosidase, enabling lysosomal breakdown of accumulated mannose-rich oligosaccharides.
Prescribing in practice
Hypersensitivity and infusion-associated reactions, including anaphylaxis, can occur; administer under supervision with resuscitation facilities available.
It does not cross the blood–brain barrier and is not expected to affect the central neurological features of the disease.
It is given by intravenous infusion at regular intervals; refer to the SPC for administration guidance.
Monitoring
Patients are monitored during and after infusions for hypersensitivity, with periodic assessment of disease-related outcomes and antibody status as indicated.
Counselling the patient
This treatment is given as a regular drip and is a long-term therapy.
Report any rash, breathing difficulty, flushing or feeling unwell during or after an infusion.
Attend scheduled appointments so your response can be monitored.
Evidence & guidelines
Approval was based on clinical trials in alpha-mannosidosis evaluating functional and biochemical outcomes.
Reference: NICE HST15; SmPC; 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).
Related
Curated clinical cross-links plus same-class fallbacks.