Afamelanotide

Pharmaceutical-Grade

Afamelanotide is a 13-amino-acid synthetic peptide (Ac-Ser-Tyr-Ser-Nle-Glu-His-D-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH2) and a structural analog of α-MSH. According to the FDA label, it is a melanocortin receptor agonist that binds predominantly to the melanocortin 1 receptor (MC1R) and increases production of eumelanin in the skin independently of exposure to sunlight or artificial UV light. It is supplied as a bioresorbable rod about 1.7 cm long and 1.45 mm in diameter that contains 16 mg of afamelanotide in a poly(DL-lactide-co-glycolide) matrix. Erythropoietic protoporphyrias are ultra-rare inherited disorders of heme biosynthesis in which protoporphyrin IX accumulates in red blood cells. Affected people usually develop episodes of severe phototoxic pain in skin exposed to visible light from early childhood, and complications can include liver failure, gallstones, mild anaemia and vitamin D deficiency. Management centres on avoiding light and treating complications; afamelanotide is described in a 2025 review as the only approved specific treatment that increases pain-free sunlight exposure and quality of life. Two randomized, double-blind, placebo-controlled trials published in the New England Journal of Medicine tested a 16 mg implant every 60 days. In the U.S. study (94 patients, 6 months), median pain-free time in direct sunlight was 69.4 hours with afamelanotide vs 40.8 hours with placebo; in the EU study (74 patients, 9 months) it was 6.0 vs 0.8 hours, with fewer phototoxic reactions (77 vs 146). Quality of life improved and adverse events were mostly mild. The EMA authorised Scenesse under 'exceptional circumstances' because complete data could not be obtained for such a rare disease, and its committee considered the additional time in sunlight small. In routine practice, a Dutch cohort of 117 patients and a German post-authorisation safety study of 200 patients reported sustained use, better quality of life and no new safety concerns. The FDA label lists implant-site reactions, nausea, oropharyngeal pain, cough and fatigue as the most common adverse reactions, recommends twice-yearly full-body skin examinations, and since 2024 warns of serious hypersensitivity reactions, including anaphylaxis, reported after marketing.