FDA Approves New Treatment for Erythropoietic Protoporphyria

Officials with the FDA have granted approval to afamelanotide (Scenesse, Clinuvel) for the treatment of erythropoietic protoporphyria, a rare, inherited metabolic disorder where exposure to light may be extremely painful for affected individuals, according to the agency.¹

The FDA previously granted priority review and orphan drug designations to afamelanotide.

Afamelanotide, an injectable implant, is indicated to increase pain-free light exposure in adults with a history of phototoxic reactions, or damage to skin, from erythropoietic protoporphyria. Erythropoietic protoporphyria is caused by mutations leading to impaired activity of ferrochelatase, an enzyme involved in heme production. This decreased ferrochelatase activity causes an accumulation of protoporphyrin IX in the body, which can lead to intense skin pain and skin changes from light exposure.

“For patients suffering from erythropoietic protoporphyria, a rare disorder, exposure to light may be extremely painful. Prior to today’s approval, there were no FDA-approved treatments to help erythropoietic protoporphyria patients increase their light exposure,” Julie Beitz, MD, director of FDA’s Center for Drug Evaluation and Research Office of Drug Evaluation III, said in a statement. “Today’s approval is one example of the FDA’s ongoing commitment to encourage industry innovation of therapies to treat rare diseases, and work with drug developers to make promising new therapies available to patients as safely and efficiently as possible.”

A melanocortin-1 receptor agonist, afamelanotide works by increasing the production of eumelanin in the skin independent of exposure to sunlight or artificial exposures.

The approval is based on data from 2 parallel group clinical trials involving patients with erythropoietic protoporphyria who received eitehr afamelanotide or placebo of the implant subcutaneously every 2 months. In the first trial, 93 patients, of whom 48 received afamelanotide, were followed for 180 days. Overall, the results showed that the median total number of hours over 180 days spent in direct sunlight between 10 am and 6 pm on days with no pain was 64 hours for patients receiving afamelanotide compared with 41 hours for patients taking a placebo.

For the second study, 74 patients, of whom 38 received afamelanotide, were followed for 270 days. The median total number of hours over 270 days spent outdoors between 10 am and 3 pm on days with no pain for which “most of the day” was spent in direct sunlight was 6 hours for patients receiving afamelanotide and 0.75 hours for patients receiving a placebo, according to the results.

In terms of safety, the most common adverse effects for afamelanotide are implant site reactions, nausea, oropharyngeal pain, cough, fatigue, skin hyperpigmentation, dizziness, melanocytic nevus, respiratory tract infection, somnolence, non-acute porphyra, and skin irritation. Afamelanotide must be administered by a health care professional, according to the FDA.

References

• FDA approves first treatment to increase pain-free light exposure in patients with a rare disorder [news release]. FDA website. https://www.fda.gov/news-events/press-announcements/fda-approves-first-treatment-increase-pain-free-light-exposure-patients-rare-disorder. Accessed October 8, 2019.