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Myalept Side Effects

Generic name: metreleptin

Medically reviewed by Last updated on Dec 11, 2023.

Note: This document contains side effect information about metreleptin. Some dosage forms listed on this page may not apply to the brand name Myalept.

Applies to metreleptin: subcutaneous powder for solution.


Subcutaneous route (Powder for Solution)

Anti-metreleptin antibodies with neutralizing activity have been identified in patients treated with metreleptin. The consequences of these neutralizing antibodies are not well characterized but could include inhibition of endogenous leptin action and/or loss of metreleptin efficacy. Severe infection and/or worsening metabolic control have been reported. Test for anti-metreleptin antibodies with neutralizing activity in patients who develop severe infections or show signs suspicious for loss of metreleptin efficacy during treatment. Contact Amryt Pharmaceuticals DAC at 1-866-216-1526 for neutralizing antibody testing of clinical samples.T-cell lymphoma has been reported in patients with acquired generalized lipodystrophy, both treated and not treated with metreleptin. Carefully consider the benefits and risks of treatment with metreleptin in patients with significant hematologic abnormalities and/or acquired generalized lipodystrophy.Because of these risks associated with the development of anti-metreleptin antibodies that neutralize endogenous leptin and/or metreleptin and the risk for lymphoma, metreleptin is available only through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS) called the Myalept(TM) REMS Program.

Serious side effects of Myalept

Along with its needed effects, metreleptin (the active ingredient contained in Myalept) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking metreleptin:

More common

Less common

Other side effects of Myalept

Some side effects of metreleptin may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

For Healthcare Professionals

Applies to metreleptin: subcutaneous powder for injection.


The most frequently reported side effects were headache, hypoglycemia, decreased weight, and abdominal pain.[Ref]


Very common (10% or more): Hypoglycemia (13%), decreased weight (13%)[Ref]

Nervous system

Very common (10% or more): Headache (13%)

Common (1% to 10%): Dizziness, paresthesia[Ref]


Very common (10% or more): Abdominal pain (10%)

Common (1% to 10%): Nausea, diarrhea, pancreatitis[Ref]

It has been reported that two patients (4%) had symptoms of pancreatitis. Both had a medical history of pancreatitis.[Ref]


Frequency not reported: Autoimmune disorder, immunogenicity[Ref]

In vitro neutralizing activity anti-metreleptin antibodies were identified in 2 patients (n=33) with generalized lipodystrophy who showed severe infections and worsening metabolic control (increases in HbA1c and/or triglycerides). Three patients with anti-metreleptin antibodies without lipodystrophy showed excessive weight gain, and/or development of glucose intolerance or diabetes.

In clinical trials, anti-metreleptin antibodies were detected in 36 of 43 generalized lipodystrophy patients, with titers ranging from 1:5 to 1:1,953, 125; however, these numbers may be misleading as detection of antibody formation is highly dependent on the sensitivity and specificity of the assay (the assays utilized in clinical trials lacked sensitivity), handling of the sample, concomitant drugs, and underlying disease. Due to incompleteness of the immunogenicity data, the clinical significance and the magnitude and persistence of the anti-drug responses are not well characterized.[Ref]


Common (1% to 10%): Ovarian cyst


Common (1% to 10%): Anemia[Ref]


Common (1% to 10%): Injection-site erythema, urticaria

Frequency not reported: Generalized rash[Ref]


Common (1% to 10%): Arthralgia, back pain[Ref]


Common (1% to 10%): Pyrexia, ear infection, fatigue[Ref]


Common (1% to 10%): Proteinuria[Ref]


Common (1% to 10%): Upper respiratory tract infection[Ref]


Frequency not reported: T-cell lymphoma, anaplastic large cell lymphoma

Three cases of T-cell lymphoma were reported among patients with acquired generalized lipodystrophy; 2 patients diagnosed with peripheral T-cell lymphoma during treatment had immunodeficiency and significant hematologic abnormalities including severe bone marrow abnormalities prior to starting treatment. Anaplastic large cell lymphoma was reported in 1 patient receiving this drug who did not have hematologic abnormalities before treatment.


1. Product Information. Myalept (metreleptin). Bristol-Myers Squibb. 2014.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.