Myalepta (Metreleptin)
Leptin analogue for the treatment of lipodystrophy complications
Myalepta (metreleptin) is a prescription-only injectable medicine used to treat the metabolic complications of leptin deficiency in patients with lipodystrophy. It is a recombinant analogue of human leptin that helps restore metabolic balance, improving blood sugar control and reducing dangerously high triglyceride levels. Myalepta is approved in the EU for generalized lipodystrophy in patients aged 2 years and older, and for partial lipodystrophy in patients aged 12 and older when other treatments have been insufficient.
Quick Facts
Key Takeaways
- Myalepta replaces the hormone leptin in patients with lipodystrophy, a rare condition where the body lacks sufficient fat tissue to produce adequate leptin.
- It is administered as a once-daily subcutaneous injection, with dosing based on body weight and sex. The powder must be reconstituted with sterile water before each injection.
- Treatment requires close medical supervision due to risks including lymphoma, severe infections from neutralizing antibodies, and hypoglycemia when used alongside insulin or diabetes medications.
- Never stop Myalepta abruptly — the dose must be gradually reduced over two weeks with a low-fat diet to prevent dangerous triglyceride spikes and pancreatitis.
- Women of childbearing potential must use effective non-hormonal contraception during treatment, as Myalepta may reduce the effectiveness of hormonal birth control and may increase fertility.
What Is Myalepta and What Is It Used For?
Myalepta contains the active substance metreleptin, a laboratory-produced version of the naturally occurring human hormone leptin. Leptin is normally produced by adipose (fat) tissue and plays a central role in regulating energy balance, appetite, glucose metabolism, and lipid homeostasis. In patients with lipodystrophy — a group of rare conditions characterized by partial or complete loss of body fat — the body cannot produce sufficient leptin, leading to severe metabolic derangements.
The consequences of leptin deficiency in lipodystrophy are significant. Without adequate leptin signaling, patients develop insulin resistance, severe diabetes mellitus, dangerously elevated blood triglyceride levels (hypertriglyceridemia), and non-alcoholic fatty liver disease (hepatic steatosis). These metabolic disturbances substantially increase the risk of acute pancreatitis, cardiovascular disease, and liver cirrhosis. Myalepta addresses the root cause by replacing the missing hormone.
Approved Indications
Myalepta is approved by the European Medicines Agency (EMA) and the U.S. Food and Drug Administration (FDA) for the following indications:
- Generalized lipodystrophy — In adults, adolescents, and children aged 2 years and older. Patients with generalized lipodystrophy have almost no body fat, resulting in severe leptin deficiency and major metabolic complications.
- Partial lipodystrophy — In adults and adolescents aged 12 years and older, when other treatments (such as dietary management and standard diabetes therapies) have not provided adequate metabolic control. Partial lipodystrophy can be congenital/familial (inherited) or acquired (developing later in life, sometimes triggered by autoimmune processes or viral infections).
How Myalepta Works
Metreleptin works by binding to and activating leptin receptors in the brain and peripheral tissues, mimicking the effects of endogenous leptin. This activation triggers several important metabolic pathways:
- Appetite regulation — Leptin signaling in the hypothalamus helps control hunger and energy expenditure, reducing the characteristic hyperphagia (excessive eating) seen in lipodystrophy.
- Insulin sensitivity — By restoring leptin signaling, metreleptin improves the body’s response to insulin, helping to normalize blood glucose levels and reducing the need for high doses of exogenous insulin.
- Lipid metabolism — Metreleptin reduces hepatic lipogenesis (fat production in the liver) and promotes fatty acid oxidation, leading to improved triglyceride levels and reduced hepatic steatosis.
- Metabolic homeostasis — Overall metabolic function improves, including reductions in HbA1c (a marker of long-term blood sugar control) and improvements in liver function tests.
Clinical trials have demonstrated that Myalepta treatment leads to clinically meaningful reductions in HbA1c and fasting triglyceride levels in patients with lipodystrophy, with sustained benefits observed over long-term treatment periods. The medication has been designated as an orphan medicine due to the rarity of lipodystrophy, and was approved under exceptional circumstances given the limited patient population.
What Should You Know Before Taking Myalepta?
Contraindications
Myalepta must not be used if you have a known hypersensitivity (allergy) to metreleptin or to any of the excipients in the formulation. Allergic reactions can range from mild skin reactions to severe anaphylaxis. If you have experienced any allergic reaction to a previous dose of Myalepta, you must inform your doctor immediately and the treatment should not be continued.
Warnings and Precautions
Before starting Myalepta, speak with your prescribing physician if any of the following apply to you. These conditions require careful monitoring or may affect the decision to prescribe:
Patients with lipodystrophy have an inherently increased risk of developing lymphoma (a type of blood cancer), regardless of whether they receive Myalepta treatment. However, treatment with Myalepta may further increase this risk. Your physician will assess the benefit-risk ratio before initiating treatment and will monitor you throughout the course of therapy. Cases of T-cell lymphoma have been reported in patients receiving metreleptin.
During treatment, your body may produce antibodies that neutralize the effects of both metreleptin and your own endogenous leptin. This can paradoxically lead to a state of worse leptin deficiency than before treatment, resulting in severe infections and sepsis. Tell your doctor immediately if you develop fever accompanied by increasing fatigue or malaise, as this may indicate neutralizing antibody formation.
If you take insulin or other glucose-lowering medications, Myalepta’s insulin-sensitizing effects may cause dangerously low blood sugar (hypoglycemia). Your doctor will closely monitor your blood glucose and may need to reduce your insulin dose or other diabetes medication doses, particularly during the early weeks of treatment. Learn to recognize the signs of hypoglycemia: dizziness, excessive drowsiness, confusion, increased sweating, irritability, and increased hunger.
Paradoxically, some patients may experience worsening hyperglycemia (high blood sugar) or hypertriglyceridemia (high triglycerides) during treatment. This may indicate that the medication is not working effectively, possibly due to the development of neutralizing antibodies. Report these changes to your healthcare provider promptly, as the treatment regimen may need to be adjusted.
Additional precautions apply if you have:
- Autoimmune disease (including autoimmune hepatitis) — Myalepta may exacerbate autoimmune conditions. Your doctor may need to perform additional monitoring tests.
- History of pancreatitis — While Myalepta helps reduce triglycerides (a major pancreatitis risk factor), careful monitoring is still warranted, especially during dose adjustments and discontinuation.
- Blood disorders (low blood cell counts) — Pre-existing hematologic abnormalities require evaluation before starting treatment.
Pregnancy and Breastfeeding
Myalepta should not be used during pregnancy. The effects of metreleptin on fetal development have not been adequately studied, and the potential risks to the unborn child are unknown. Women of childbearing potential must use effective contraception during treatment. Importantly, because Myalepta may reduce the effectiveness of hormonal contraceptives (such as combined oral contraceptive pills, patches, or hormonal IUDs), a non-hormonal method of contraception must also be used. Barrier methods such as condoms are recommended.
It is not known whether metreleptin passes into breast milk. The decision to breastfeed while taking Myalepta should be made in consultation with your physician, weighing the benefits of breastfeeding for the infant against the benefits of continued treatment for the mother.
Notably, Myalepta may increase fertility in women with lipodystrophy by restoring normal hormonal signaling. Women who were previously infertile may become capable of conceiving while on treatment and should be counseled about appropriate contraception.
Driving and Operating Machinery
Myalepta may have a minor effect on the ability to drive and use machines. Some patients experience dizziness or fatigue during treatment. If you are affected, you should not drive or operate heavy machinery until these symptoms resolve. The risk of hypoglycemia (particularly in patients taking concurrent diabetes medications) should also be considered, as low blood sugar can impair concentration and reaction time.
Sodium Content
Myalepta contains less than 1 mmol (23 mg) sodium per dose, meaning it is essentially sodium-free. This is not a concern for patients on sodium-restricted diets.
How Does Myalepta Interact with Other Drugs?
Leptin, the hormone that Myalepta replaces, is known to influence the activity of cytochrome P450 (CYP) enzymes in the liver. Since many medications are metabolized by these enzymes, starting or stopping Myalepta may alter the blood levels and effectiveness of concomitant drugs. Your doctor may need to monitor drug levels and adjust doses accordingly.
Major Interactions
| Interacting Drug | Effect | Clinical Action |
|---|---|---|
| Insulin & other diabetes medications | Myalepta improves insulin sensitivity, increasing risk of severe hypoglycemia | Close glucose monitoring required; insulin dose reduction often necessary, especially in early weeks |
| Hormonal contraceptives (pills, patches, rings) | Myalepta may reduce the contraceptive efficacy of hormonal birth control methods | Must use additional non-hormonal contraception (e.g., condoms) throughout treatment |
| Warfarin / Phenprocoumon (anticoagulants) | Altered CYP enzyme activity may affect anticoagulant metabolism and INR levels | More frequent INR monitoring; dose adjustment as needed |
| Ciclosporin (immunosuppressant) | Myalepta may alter ciclosporin blood levels through CYP3A4 modulation | Monitor ciclosporin trough levels; adjust dose if needed |
| Theophylline | Altered CYP1A2 activity may change theophylline clearance | Monitor theophylline levels; dose adjustment may be required |
General Interaction Guidance
Because Myalepta affects CYP enzyme activity, it has the potential to interact with any medication metabolized by the liver’s cytochrome P450 system. Drugs with a narrow therapeutic index (where small changes in blood levels can lead to toxicity or loss of efficacy) are particularly vulnerable. Examples include certain antiepileptic drugs, some antiarrhythmics, and calcineurin inhibitors. Always provide your healthcare team with a complete list of all medications, supplements, and herbal products you are taking.
When Myalepta is initiated, stopped, or dose-adjusted in patients taking CYP-metabolized medications, additional monitoring may be necessary during the transition period (typically the first few weeks). This allows your doctor to detect and respond to any changes in drug levels promptly.
What Is the Correct Dosage of Myalepta?
Myalepta should always be used exactly as prescribed by your specialist physician. The medication is supplied as a lyophilized (freeze-dried) powder that must be reconstituted with 0.6 mL of water for injections immediately before use. After reconstitution, the resulting solution contains 5 mg of metreleptin per mL. The entire reconstitution and injection process takes approximately 20 minutes.
Adults and Adolescents
| Patient Group | Starting Dose | Volume to Inject | Maximum Dose |
|---|---|---|---|
| Weight ≤ 40 kg (any sex) | 0.06 mg per kg body weight | 0.012 mL per kg | As prescribed by physician |
| Males > 40 kg | 2.5 mg | 0.5 mL | 10 mg (2 mL) |
| Females > 40 kg | 5 mg | 1 mL | 10 mg (2 mL) |
Your physician will adjust your dose over time based on your metabolic response. Dose changes are guided by blood glucose levels, triglyceride levels, HbA1c, and overall clinical assessment. If a dose exceeds 1 mL, your doctor may instruct you to split it into two separate injections using a clean syringe and needle for each.
Children
For children aged 2 years and older with generalized lipodystrophy, the starting dose is 0.06 mg per kg of body weight per day. For children aged 12 years and older with partial lipodystrophy, dosing follows the same weight-based guidelines as adults. Myalepta should not be used in children under 2 years of age with generalized lipodystrophy or under 12 years with partial lipodystrophy, as safety and efficacy have not been established in these age groups.
Syringe Selection
The syringe used for injection depends on the prescribed dose volume:
- 0.3 mL syringe — For doses of 1.5 mg (0.30 mL) or less. This syringe displays volume in units (U) rather than mL.
- 1 mL syringe — For doses between 1.5 mg and 5 mg (0.30 mL to 1.0 mL).
- 3 mL syringe — For doses above 5 mg (more than 1.0 mL).
To convert your dose to the correct volume: divide your dose in milligrams by 5 to get the volume in milliliters. For example, a 5 mg dose equals 1 mL of reconstituted solution (5 ÷ 5 = 1 mL).
Administration Sites
Myalepta should be injected subcutaneously (under the skin) at a 45-degree angle into one of the following sites:
- The abdomen (avoiding 5 cm around the navel)
- The front of the thigh
- The back of the upper arm
Rotate injection sites to minimize the risk of injection site reactions. Do not inject into the same exact spot as the previous day, and avoid injecting Myalepta at the same site where other injectable medications are administered.
Missed Dose
If you forget a dose, inject it as soon as you remember. Take your normal dose the following day at the usual time. Do not take a double dose to make up for the missed one. If you inject less than your prescribed dose, contact your doctor as they may need to monitor you for potential side effects related to undertreating your condition.
Overdose
If you accidentally inject more Myalepta than prescribed, contact your doctor immediately or go to the nearest hospital emergency department. Bring the medicine packaging with you so the healthcare team knows exactly what you have taken. Your physician will monitor you for any adverse effects.
Stopping Treatment
Never stop taking Myalepta without consulting your physician. If treatment needs to be discontinued, your doctor will gradually reduce the dose over a period of two weeks. You will also be advised to follow a strict low-fat diet during this period. Abrupt discontinuation can cause a rapid and dangerous rebound increase in blood triglyceride levels, which may trigger acute pancreatitis — a potentially life-threatening condition.
What Are the Side Effects of Myalepta?
Like all medicines, Myalepta can cause side effects, although not everybody gets them. The following information summarizes the known adverse reactions reported in clinical trials and post-marketing surveillance. Side effects are categorized by frequency according to MedDRA convention.
Very Common
Affects more than 1 in 10 patients
- Weight loss
Common
Affects up to 1 in 10 patients
- Decreased appetite
- Headache
- Hair loss (alopecia)
- Unusually heavy or prolonged menstrual bleeding
- Fatigue
- Injection site reactions (bruising, redness, itching, hives)
- Development of anti-metreleptin antibodies (may increase risk of severe infections)
Reported (Frequency Not Established)
Reported in post-marketing use; exact frequency unknown
- Influenza and respiratory infections
- Diabetes mellitus
- Increased appetite or overeating
- Faster heart rate (tachycardia)
- Cough and shortness of breath
- Muscle pain (myalgia) and joint pain (arthralgia)
- Swollen hands and feet (peripheral edema)
- Increased body fat
- Injection site swelling or bleeding
- General malaise
- Increased blood triglycerides
- Increased HbA1c
- Weight gain
- High blood sugar (hyperglycemia)
Serious Side Effects (Seek Immediate Medical Attention)
May be life-threatening; require urgent care
- Severe hypoglycemia (low blood sugar) — dizziness, confusion, sweating, tremor
- Severe hyperglycemia (high blood sugar) — excessive thirst, frequent urination, nausea
- Deep vein thrombosis (DVT) — leg pain, swelling, warmth, redness
- Pulmonary edema — difficulty breathing, persistent cough
- Severe allergic reaction (anaphylaxis) — breathing difficulty, facial swelling, hives
- Acute pancreatitis — sudden severe abdominal pain, nausea, vomiting
- Lymphoma — T-cell lymphoma has been reported in treated patients
Signs of High and Low Blood Sugar
Dizziness, excessive drowsiness or confusion, clumsiness and dropping things, increased hunger, increased sweating, and increased irritability or nervousness. Contact your doctor immediately if you experience these symptoms, as your medication doses may need adjustment.
Excessive thirst or hunger, increased urination, drowsiness, nausea or vomiting, blurred vision, chest or back pain, and shortness of breath. These symptoms may indicate that Myalepta is not working optimally or that neutralizing antibodies have developed.
Chest pain, pain below the ribs resembling heartburn or indigestion, nausea or vomiting. Elevated triglycerides can trigger pancreatitis and require prompt medical evaluation.
If you experience any of the side effects listed above, or any unusual symptoms not mentioned here, report them to your healthcare provider. In the European Union, patients and healthcare professionals can also report suspected adverse reactions to their national medicines regulatory authority.
How Should You Store Myalepta?
Proper storage of Myalepta is essential to ensure the medication remains safe and effective. The following guidelines should be followed:
- Unopened vials: Store in a refrigerator at 2–8°C (36–46°F). Keep the vial in the original carton to protect it from light.
- Before reconstitution: Allow the vial to reach room temperature for approximately 10 minutes before preparing the injection. Do not use other methods to warm the vial.
- After reconstitution: The solution must be administered immediately. Do not store the reconstituted solution for later use. Any unused portion must be discarded.
- Visual inspection: Do not use the solution if it is not clear, appears discolored, or contains visible particles or clumps. Discard such preparations and start with a new vial.
- Expiry date: Do not use after the expiry date printed on the vial and carton. The expiry date refers to the last day of the stated month.
- Disposal: Do not dispose of Myalepta via wastewater or household waste. Return unused medicine to your pharmacy for proper disposal to protect the environment.
Keep all medicines, including Myalepta, out of the sight and reach of children. Used syringes, needles, vials, and ampules should be placed immediately in a sharps disposal container. When the container is full, consult your pharmacist or local waste authority for proper disposal procedures.
What Does Myalepta Contain?
Myalepta is supplied as a white lyophilized (freeze-dried) powder in a glass vial sealed with a rubber stopper and aluminum seal with a red plastic flip-off cap. It is available in packs of 1 or 30 vials (not all pack sizes may be marketed in every country).
Active Ingredient
Each vial contains 3 mg of metreleptin. After reconstitution with 0.6 mL of water for injections, each milliliter of the resulting solution contains 5 mg of metreleptin.
Inactive Ingredients (Excipients)
- Glycine — An amino acid used as a stabilizer and buffering agent
- Sucrose — A sugar used as a lyoprotectant to protect the protein during freeze-drying
- Polysorbate 20 — A surfactant that prevents protein aggregation
- Glutamic acid — An amino acid used as a stabilizer
- Sodium hydroxide — Used for pH adjustment (the medicine is essentially sodium-free at <1 mmol per dose)
The water for injections used for reconstitution is supplied separately by your pharmacist or healthcare provider and may come in plastic ampules, glass ampules, or glass vials. Always use a fresh container of water for injections for each dose — never reuse leftover water from a previous preparation.
Frequently Asked Questions About Myalepta
Myalepta (metreleptin) is used to treat the metabolic complications of leptin deficiency in patients with lipodystrophy. Lipodystrophy is a rare condition where the body lacks sufficient fat tissue, leading to inadequate production of the hormone leptin. This causes severe metabolic problems including insulin-resistant diabetes, dangerously high triglyceride levels, and fatty liver disease. Myalepta replaces the missing leptin to help restore normal metabolic function. It is approved for generalized lipodystrophy in patients aged 2 years and older, and for partial lipodystrophy (inherited or acquired) in patients aged 12 and older when standard treatments have been insufficient.
Myalepta is given as a once-daily subcutaneous injection (under the skin). The powder in the vial must first be reconstituted with 0.6 mL of water for injections. After gentle swirling (not shaking), the clear solution is drawn into an injection syringe and injected into the abdomen (avoiding the area around the navel), thigh, or back of the upper arm at a 45-degree angle. The entire preparation and injection process takes about 20 minutes. Patients can self-inject after receiving proper training from their healthcare team. Injection sites should be rotated daily.
The most common side effect is weight loss, which occurs in more than 1 in 10 patients. Common side effects (affecting up to 1 in 10 patients) include decreased appetite, headache, hair loss, unusually heavy menstrual bleeding, fatigue, and injection site reactions such as bruising, redness, or itching. The body may also develop antibodies against metreleptin, which in some cases can increase the risk of serious infections. Serious but less common side effects include severe hypoglycemia (low blood sugar, particularly in patients also taking insulin), deep vein thrombosis, and pancreatitis.
No, Myalepta should not be used during pregnancy because the effects on fetal development are unknown. Women of childbearing potential must use effective contraception while on treatment. An important consideration is that Myalepta can reduce the effectiveness of hormonal contraceptives, so a non-hormonal method (such as condoms) must also be used. Additionally, Myalepta may increase fertility in women with lipodystrophy, meaning women who were previously unable to conceive may become fertile during treatment. Discuss family planning with your doctor before starting therapy.
Unopened vials of Myalepta must be stored in a refrigerator at 2–8°C, kept in the original carton to protect from light. Before use, allow the vial to reach room temperature for about 10 minutes. Once the powder has been reconstituted with water for injections, the solution must be used immediately — it cannot be stored or refrigerated for later use. Any unused reconstituted solution should be discarded. Used syringes, needles, and vials should be disposed of in a proper sharps container.
Stopping Myalepta abruptly is dangerous and must be avoided. Without gradual dose reduction, blood triglyceride levels can spike rapidly, potentially triggering acute pancreatitis — a severe and potentially life-threatening inflammation of the pancreas. If treatment needs to be discontinued, your physician will taper the dose gradually over a two-week period. During this time, you will also need to follow a strict low-fat diet to help prevent triglyceride rebound. Never stop or change your Myalepta dose without first consulting your prescribing physician.
References
- European Medicines Agency (EMA). Myalepta (metreleptin) – Summary of Product Characteristics. Last updated 2025. Available at: EMA – Myalepta EPAR.
- U.S. Food and Drug Administration (FDA). Myalepta (metreleptin) Prescribing Information. Approved February 2019, updated 2024.
- Brown RJ, Araujo-Vilar D, Cheung PT, et al. The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline. J Clin Endocrinol Metab. 2016;101(12):4500-4511. doi:10.1210/jc.2016-2466.
- Oral EA, Simha V, Ruiz E, et al. Leptin-replacement therapy for lipodystrophy. N Engl J Med. 2002;346(8):570-578. doi:10.1056/NEJMoa012437.
- Diker-Cohen T, Cochran E, Gorden P, Brown RJ. Partial and generalized lipodystrophy: comparison of baseline characteristics and response to metreleptin. J Clin Endocrinol Metab. 2015;100(5):1802-1810. doi:10.1210/jc.2014-4491.
- World Health Organization (WHO). Model List of Essential Medicines. 23rd edition, 2023.
- Akinci B, Meral R, Oral EA. Phenotypic and Genetic Characteristics of Lipodystrophy: Pathophysiology, Metabolic Abnormalities, and Comorbidities. Curr Diab Rep. 2018;18(12):143. doi:10.1007/s11892-018-1099-z.
- British National Formulary (BNF). Metreleptin monograph. Available at: bnf.nice.org.uk.
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