Setmelanotide (Imcivree): Uses, Evidence, and Side Effects

For people with rare genetic forms of obesity, standard weight management approaches often fall short. Setmelanotide, sold under the brand name Imcivree, was developed specifically to target the biological pathway involved in some of these conditions.

Key takeaways

• Setmelanotide is approved as Imcivree for chronic weight management in specific genetic and syndromic obesity conditions.
• It works as a melanocortin 4 (MC4) receptor agonist, targeting a brain pathway tied to hunger and energy use.
• Across 27 registered trials, studies have spanned early safety work through a completed Phase 3 open-label extension.
• The most frequently reported reactions involve gastrointestinal symptoms and skin pigmentation changes.
• Setmelanotide does not carry a boxed warning.

What Setmelanotide Is

Setmelanotide belongs to a drug class called MC4 receptor agonists. It acts on melanocortin 4 receptors in the brain, which help regulate hunger, fullness, and how the body uses energy. The drug has about 20 times less activity at related melanocortin 3 and melanocortin 1 receptors. By acting on this pathway, setmelanotide is thought to reduce food intake and increase energy expenditure in people with certain forms of obesity.

What Setmelanotide Is Approved For

Marketed as Imcivree, setmelanotide is indicated to reduce excess body weight and help maintain that reduction long term. Approved uses include adults and children aged 4 years and older with acquired hypothalamic obesity, and adults and children aged 2 years and older with syndromic or monogenic obesity linked to Bardet-Biedl syndrome. It is also approved for obesity caused by confirmed genetic variants in the POMC, PCSK1, or LEPR genes, including variants classified as pathogenic, likely pathogenic, or of uncertain significance. The label does not carry a boxed warning.

What the Evidence Shows

Setmelanotide has been studied across 27 registered clinical trials. An early Phase 1b/2a study evaluated its safety and efficacy in patients with obesity and has been completed. More recently, a Phase 3 open-label extension study of setmelanotide has also been completed, reflecting longer-term follow-up on the drug's use.

Reported Side Effects

Reported reactions associated with setmelanotide are led by gastrointestinal symptoms, including nausea (81 reports), vomiting (43), and diarrhoea (38). Skin-related changes are also commonly reported, with skin hyperpigmentation (64) and skin discolouration (35) noted. Headache (42) and fatigue (36) appear as well, alongside a notable number of reports coded as off-label use (79). These figures reflect counts of submitted reports, not confirmed incidence rates or proof that the drug caused the reaction.