The TGA has approved the photoprotective drug afamelanotide for prevention of phototoxicity in adult patients with erythropoietic protoporphyria (EPP).
The subcutaneous implant under the brand name Scenesse is used to increase pain-free light exposure in people affected by the rare inherited metabolic disorder of haem molecule synthesis resulting from overproduction of protoporphyrin IX (PPIX).
Afamelanotide is a melanocortin receptor agonist that stimulates the synthesis of eumelanin in melanocytes. Light reaching the skin can react with PPIX causing intense skin pain and skin changes, such as redness and thickening.
According to the TGA decision statement, eumelanin contributes to photoprotection by acting as a filter to provide strong broadband absorption of UV and visible light; antioxidant activity; and inactivation of the superoxide anion and increased availability of superoxide dismutase to reduce oxidative stress.
Clinical trials in patients with EPP have shown that those who had an afamelanotide implant every two months. Were able to tolerate significantly more hours in sunlight without pain compared to those who received placebo.
The product is marketed by Clinuvel and comes in the form of a 16 mg implant is inserted subcutaneously above the anterior supra-iliac crest.