MYALEPT
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MYALEPT (MYALEPT).
Metreleptin is a recombinant analog of human leptin. It binds to and activates the leptin receptor (OB-R), which is involved in regulating energy homeostasis, neuroendocrine function, and immune response. In patients with leptin deficiency, exogenous leptin reduces hyperphagia, improves glycemic control, and promotes weight loss.
| Metabolism | Metreleptin is metabolized via renal catabolism and proteolysis into small peptides and amino acids. No specific CYP enzyme involvement. |
| Excretion | Renal (primarily), with minimal biliary/fecal elimination; approximately 70% of the dose recovered in urine as unchanged drug and metabolites. |
| Half-life | Terminal elimination half-life is approximately 20–30 hours in healthy individuals, with prolongation in renal impairment. |
| Protein binding | Approximately 60% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | Approximately 0.4 L/kg, indicating distribution primarily into extracellular fluid. |
| Bioavailability | Subcutaneous: approximately 80%. |
| Onset of Action | Subcutaneous: Clinical effects (e.g., appetite reduction) typically observed within 2–4 weeks of daily administration. |
| Duration of Action | Duration of action is sustained with daily dosing; steady-state concentrations achieved after ~1 week, with continuous effect for as long as therapy is maintained. |
0.1 mg/kg (ideal body weight) subcutaneous injection once daily, titrated to a maximum of 0.2 mg/kg per day if needed.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment required for renal impairment; use with caution in severe renal disease. |
| Liver impairment | No specific dose adjustment for hepatic impairment; not studied in Child-Pugh classes. |
| Pediatric use | Safety and efficacy not established; no pediatric dosing available. |
| Geriatric use | No specific dose adjustment; limited data in patients >65 years, use with caution. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for MYALEPT (MYALEPT).
| Breastfeeding | It is not known whether metreleptin is excreted in human milk. No data on M/P ratio. Because many drugs are excreted in human milk, caution should be exercised when MYALEPT is administered to a nursing woman. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for MYALEPT and any potential adverse effects on the breastfed child from MYALEPT or from the underlying maternal condition. |
| Teratogenic Risk | No adequate and well-controlled studies in pregnant women. In animal reproduction studies, no evidence of fetal harm at doses up to 10 times the clinical exposure. However, because animal studies are not always predictive of human response, MYALEPT should be used during pregnancy only if clearly needed. There is no known teratogenic risk associated with first trimester exposure based on limited human data. |
■ FDA Black Box Warning
WARNING: RISK OF ANTI-METRELEPTIN ANTIBODIES WITH NEUTRALIZING ACTIVITY and RISK OF LYMPHOMA. Treatment with MYALEPT has been associated with the development of anti-metreleptin antibodies with neutralizing activity, which may result in loss of efficacy or endogenous leptin activity (resulting in severe metabolic abnormalities). MYALEPT is contraindicated in patients with general obesity not associated with congenital leptin deficiency. Additionally, cases of T-cell lymphomas have been reported in patients with acquired generalized lipodystrophy (AGL). The risk of developing lymphoma is unknown; monitor for signs and symptoms.
| Serious Effects |
General obesity not associated with congenital leptin deficiency (efficacy not established and may increase lymphoma risk), hypersensitivity to metreleptin or any excipients.
| Precautions | Hypoglycemia risk (especially with concomitant antidiabetic therapy), neutralizing antibodies (loss of efficacy or endogenous leptin activity), lymphoma (especially in AGL patients), severe allergic reactions, pancreatitis (in patients with severe hypertriglyceridemia), autoimmune disease exacerbation, and metabolic abnormalities upon discontinuation. |
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| Fetal Monitoring | Monitor for hypoglycemia, hypersensitivity reactions, and development of anti-drug antibodies affecting efficacy. During pregnancy, additional monitoring for fetal growth and well-being via ultrasound and non-stress testing as clinically indicated, along with maternal metabolic parameters including blood glucose and triglycerides. |
| Fertility Effects | In female animals, metreleptin at doses up to 10 times the clinical exposure did not impair fertility. In humans, the effect on fertility is unknown; however, due to the role of leptin in reproductive function, treatment may potentially affect fertility. Clinical trials have not systematically evaluated fertility endpoints. |