FDA approves Clinuvel drug for rare disease causing pain on exposure to sunlight

The agency approved Scenesse, a subcutaneous implant for treating the rare disorder erythropoietic protoporphyria. The drug is the first FDA-approved treatment for EPP.

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Shares of an Australian drugmaker skyrocketed Wednesday morning following the Food and Drug Administration’s approval of its drug to treat a rare condition that causes hypersensitivity to light.

Melbourne-based Clinuvel Pharmaceuticals said Wednesday that the FDA had approved Scenesse (afamelanotide) as the first drug for erythropoietic protoporphyria, or EPP, a condition that causes extreme pain when patients are exposed to light. Scenesse is a subcutaneous implant approved for increasing the amount of time patients can be exposed to light without experiencing pain.

Following the news Wednesday morning, shares of Clinuvel were up 60 percent on the Australian Stock Exchange and 30 percent on the over-the-counter market in the U.S. The company had suspended trading ahead of the announcement Tuesday.

An inherited metabolic disorder caused by deficiency of the enzyme ferrochelatase, EPP is estimated to affect one in every 75,000-200,000 people in Europe, though its incidence in the U.S. is unknown, according to the National Organization for Rare Disorders. The most common symptom of EPP is severe pain when patients are exposed to sunlight, starting with tingling, itching or burning. Blistering and redness of the skin can occur as well. In addition to sunlight, exposure to some forms of artificial light, such as fluorescent lighting, can also cause symptoms.

“Prior to today’s approval, there were no FDA-approved treatments to help erythropoietic protoporphyria patients increase their light exposure,” said Julie Beitz, director of the FDA’s Center for Drug Evaluation and Research Office of Drug Evaluation III, 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.”

The approval is based on two clinical trials that respectively enrolled 93 and 74 patients randomized to receive Scenesse or placebo. The first study’s 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; results showed that patients on Scenesse were able to spend 64 hours in direct sunlight without pain, compared with 41 hours for those on placebo. The second study measured the number of hours 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, over the course of 270 days. Patients on Scenesse in that study were able to spend six hours in direct sunlight, compared with three-quarters of an hour for those receiving placebo.

Nausea, pain in the area of the throat just behind the mouth, cough, fatigue, darkening of the skin, dizziness, moles, respiratory tract infection, drowsiness, skin irritation and buildup of molecules created during heme production were the most common side effects.

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