Afamelanotide (Scenesse, Clinuvel) activates the synthesis of eumelanin mediated by the melanocortin 1 receptor. Eumelanin contributes to photoprotection by:
strongly absorbing UV and visible light (acting as a filter)
inactivating the superoxide anion and increasing the availability of superoxide dismutase to reduce oxidative stress.
Afamelanotide has a marketing authorisation in the UK under 'exceptional circumstances' for the 'prevention of phototoxicity in adult patients with erythropoietic protoporphyria (EPP)'. It is administered as a subcutaneous dissolving implant. One implant is administered every 2 months before expected and during increased sunlight exposure, for example, from spring to early autumn. The marketing authorisation recommends 3 implants per year, depending on the length of protection needed. The maximum number of implants recommended in the marketing authorisation is 4 per year. The marketing authorisation stipulates that afamelanotide should only be prescribed by specialist clinicians in recognised porphyria centres, and that it should only be given by a clinician trained and accredited by the marketing authorisation holder to insert the implants.