Recombinant leptin analogue Pregnancy: US label 8.1: Available pharmacovigilance reports in pregnant women are insufficient to evaluate a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes. In mice, no adverse developmental effects during organogenesis at 7- and 15-fold the maximum recommended clinical dose, but pre- and post-natal studies showed prolonged gestation and dystocia with maternal death during parturition and lower offspring survival at around the maximum recommended clinical dose. A pregnancy exposure registry exists. Product reconstituted with Bacteriostatic Water for Injection contains benzyl alcohol.

Metreleptin

Brand names: Myalepta

Metreleptin is a recombinant analogue of human leptin used as an adjunct to diet to treat the metabolic complications of leptin deficiency in patients with congenital or acquired generalised lipodystrophy (and certain forms of partial lipodystrophy).

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: Body weight greater than 40 kg - males: 2.5 mg once daily (starting dose); females: 5 mg once daily (starting dose). Body weight 40 kg or less (males and females): 0.06 mg/kg once daily (starting dose)

Route: Subcutaneous injection (lyophilised cake reconstituted with 2.2 mL Bacteriostatic Water for Injection or preservative-free sterile Water for Injection; delivers 5 mg per mL)

Frequency: Once daily, at the same time every day; may be given at any time of day without regard to the timing of meals

Max: Greater than 40 kg: 10 mg per day. 40 kg or less: 0.13 mg/kg per day

US label 2.1, Table 1. Dose adjustments: greater than 40 kg - increase or decrease by 1.25 mg (0.25 mL) to 2.5 mg (0.5 mL) per day; 40 kg or less - increase or decrease by 0.02 mg/kg (0.004 mL/kg). Adjust based on clinical response (e.g. inadequate metabolic control) or other considerations (e.g. tolerability, excessive weight loss, especially in paediatric patients). Missed dose: administer as soon as noticed and resume the normal schedule the next day. Reconstituted in Bacteriostatic Water for Injection the solution may be used within 3 days if refrigerated at 2-8 degrees C and protected from light; reconstituted in sterile Water for Injection it must be administered immediately and any unused solution discarded. Do not mix with, or transfer into, another MYALEPT vial; do not add other medications including insulin (use a separate syringe for insulin). Hypoglycaemia: a dose adjustment, including possible large reductions, of insulin or an insulin secretagogue may be necessary - monitor blood glucose closely. US labelling - verify against UK labelling.

Paediatric dose

Dose: 0.06 mg/kg

Route: Subcutaneous injection

Frequency: Once daily

Max: 0.13 mg/kg per day

The US label band is defined by body weight (40 kg or less), applying to males and females of any age, not by age itself: starting dose 0.06 mg/kg (0.012 mL/kg) once daily, adjusted up or down in 0.02 mg/kg (0.004 mL/kg) steps, to a maximum daily dose of 0.13 mg/kg (0.026 mL/kg). In paediatric patients, small administration volumes can result in medication errors when measured incorrectly - the label gives an example chart, e.g. 5 kg: start 0.30 mg (0.06 mL / 6 Units), max 0.65 mg; 10 kg: start 0.60 mg (0.12 mL / 12 Units), max 1.3 mg; 20 kg: start 1.2 mg (0.24 mL / 24 Units), max 2.6 mg; 40 kg: start 2.4 mg (0.48 mL / 48 Units), max 5.2 mg (insulin syringe conversion 100 Units/mL). Reconstitute with preservative-free sterile Water for Injection for neonates and infants - the benzyl alcohol preservative in Bacteriostatic Water for Injection has been associated with serious adverse events, death and 'gasping syndrome' in neonates and low-birth-weight infants. Trial population was 35 paediatric patients aged 1 to 17 years, with no clinically meaningful efficacy or safety differences from adults. US labelling - verify against UK labelling and a children's formulary before use.

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

General obesity not associated with congenital leptin deficiency (not shown to be effective, and anti-metreleptin antibodies with neutralising activity have been reported in obese patients)
Prior severe hypersensitivity reactions to metreleptin or any product component (reported reactions have included anaphylaxis, urticaria and generalised rash)

Side effects

Headache
Hypoglycaemia
Decreased weight
Abdominal pain
Anti-metreleptin antibodies with neutralising activity (may inhibit endogenous leptin action and/or cause loss of efficacy)
Hypersensitivity reactions including anaphylaxis, urticaria or generalised rash; T-cell lymphoma; progression of autoimmune disorders

Interactions

No formal drug interaction studies were performed. Leptin is a cytokine and may alter the formation of cytochrome P450 enzymes - take this into account when prescribing concomitant drugs metabolised by CYP450 (e.g. oral contraceptives and narrow-therapeutic-index drugs)
On starting or stopping metreleptin in patients on narrow-therapeutic-index CYP450 substrates, monitor effect (e.g. warfarin) or drug concentration (e.g. ciclosporin, theophylline) and adjust the individual dose as needed
Insulin or insulin secretagogues - dose reduction, possibly large, may be required because of hypoglycaemia

Clinical monograph

How it works

It is a leptin receptor agonist that replaces deficient leptin signalling, helping to regulate appetite, energy balance, insulin sensitivity and lipid metabolism.

Prescribing in practice

Anti-metreleptin antibodies with neutralising activity can develop and may reduce efficacy or be associated with severe infections, so it must be used under specialist supervision with awareness of this risk.
There is a recognised risk of T-cell lymphoma reported in acquired generalised lipodystrophy, so the benefit-risk balance must be assessed by a specialist.
Improved insulin sensitivity may cause hypoglycaemia, so concomitant insulin or insulin secretagogues may need dose reduction.

Monitoring

Monitor metabolic response (glycaemic control, triglycerides), blood glucose for hypoglycaemia and for signs of infection or lymphoproliferative disease.

Counselling the patient

This is a specialist medicine used alongside a structured diet to control metabolic complications.
Report any signs of infection or unexplained illness promptly.
Diabetes treatments may need adjusting, so be alert to symptoms of low blood sugar.

Evidence & guidelines

Metreleptin is approved for leptin replacement in generalised lipodystrophy on the basis of improvements in metabolic parameters in this rare population.

Reference: NICE HST14; 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).

Curated clinical cross-links plus same-class fallbacks.

Pathways