Public health agency The US Food and Drug Administration Tuesday authorised the marketing of Scenesse to increase pain-free light exposure in adult patients with phototoxic reactions from erythropoietic protoporphyria under its priority review and orphan drug designations.

The approval of Scenesse (afamelanotide) was granted by the agency to Clinuvel.

Erythropoietic protoporphyria is reportedly a rare disorder caused by mutations leading to impaired activity of ferrochelatase, an enzyme involved in heme production. The decrease in ferrochelatase activity leads to an accumulation of protoporphyrin IX (PPIX) in the body. Light reaching the skin can react with PPIX causing intense skin pain and skin changes, including redness and thickening.

According to the agency. Scenesse (afamelanotide), a melanocortin-1 receptor (MC1-R) agonist, increases the production of eumelanin in the skin independent of exposure to sunlight or artificial light sources. It is an implant administered subcutaneously under the skin.

In addition, the efficacy of the company's Scenesse was established in two parallel group clinical trials in patients with erythropoietic protoporphyria who received Scenesse or a placebo form of the implant subcutaneously every two months. The first primary endpoint was the total number of hours over 180 days spent in direct sunlight between 10:00 and 18:00 on days with no pain. The second primary endpoint was the total number of hours over 270 days spent outdoors between 10:00 and 15:00 on days with no pain in direct sunlight.