FDA Approves First Treatment to Increase Pain-Free Light Exposure in Rare Disorder

The U.S. Food and Drug Administration granted approval to Scenesse, Clinuvel’s therapy to increase pain-free light exposure in adult patients with a history of damage to their skin from erythropoietic protoporphyria.

Erythropoietic protoporphyria is a rare disorder in which exposure to light may be extremely painful. It is caused by mutations leading to impaired activity of ferrochelatase, an enzyme involved in heme production. Heme is an important component in hemoglobin, the oxygen carrying molecule in red blood cells. 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, such as redness and thickening.

Scenesse, a melanocortin-1 receptor agonist, increases the production of eumelanin in the skin independent of exposure to sunlight or artificial light sources. It is an implant that is inserted under the skin.

The efficacy of Scenesse was established in two parallel group clinical trials with patients with erythropoietic protoporphyria who received Scenesse or placebo form of the implant subcutaneously every two months.

The first clinical trial enrolled 93 subjects, of whom 48 received Scenesse, and who were followed for 180 days. The primary endpoint was the total number of hours over 180 days spent in direct sunlight between 10 a.m. and 6 p.m. on days with no pain. The median total number of hours over 180 days spent in direct sunlight between 10 a.m. and 6 p.m. on days with no pain was 64 hours for patients receiving Scenesse and 41 hours for patients taking placebo.

The second clinical trial enrolled 74 patients, of whom 38 received Scenesse, and were followed for 270 days. The primary endpoint was the total number of hours over 270 days spent outdoors between 10 a.m. and 3 p.m. on days with no pain for which “most of the day” was spent in direct sunlight.

The analysis did not include sun exposure on days patients reported spending time in a combination of both direct sunlight and shade. The median total number of hours over 270 days spent outdoors between 10 a.m. and 3 p.m. on days with no pain for which “most of the day” was spent in direct sunlight was six hours for patients receiving Scenesse and 0.75 hours for patients receiving placebo.

Scenesse’s most common side effects are implant site reaction, nausea, oropharyngeal (part of the throat just behind the mouth, where the oral cavity starts) pain, cough, fatigue, skin hyperpigmentation, dizziness, moles, respiratory tract infection, drowsiness, build-up of normally occurring molecules created during heme production, and skin irritation.

The FDA granted the application Priority Review designation. Scenesse also received Orphan Drug designation, which provides incentives to assist and encourage the development of drugs for rare diseases.

Author: Rare Daily Staff