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Afamelanotide for Erythropoietic Protoporphyria
Janneke G Langendonk1, Manisha Balwani1, Karl E Anderson1
1The Department of Internal Medicine, Center of Lysosomal and Metabolic Diseases, Erasmus Medical Center, Rotterdam (J.G.L., F.P.J.K., E.J.G.S., F.W.M.R., J.H.P.W.), and the Department of Dermatology, Maastricht University Medical Center, Maastricht (J.F.) - both in the Netherlands; the Departments of Genetics and Genomic Sciences (M.B., H.N., R.J.D.) and Dermatology (M.L.), Icahn School of Medicine at Mount Sinai, New York; the Departments of Preventive Medicine and Community Health, and Internal Medicine and the Institute for Translational Sciences, University of Texas Medical Branch, Galveston (K.E.A.); the Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, NC (H.L.B.); Royal Gwent Hospital, Newport (A.V.A., C.E.), the Centre for Dermatology, University of Manchester, Salford Royal Hospital, Manchester (L.E.R.), and the Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, Oxford (C.R.G.) - all in the United Kingdom; the Department of Medicine, University of California, San Francisco, San Francisco (D.M.B.); the Department of Medicine, University of Alabama, Birmingham (J.B.); the Department of Dermatology, Heinrich Heine University, Duesseldorf, Germany (N.J.N., J.F.); the Department of Internal Medicine, University of Utah, Salt Lake City (C.P., J.D.P.); the Department of Dermatology, Henry Ford Hospital, Detroit (H.W.L., I.H.); Hôpital Louis-Mourier, Hôpitaux Universitaire Paris Nord Val de Seine, Assistance Publique-Hôpitaux de Paris, INSERM Unité 1149, Université Paris Diderot, Colombes, France (J.-C.D.); the Departments of Medicine and Dermatology, University Hospital of Helsinki, Helsinki (R.K.); and the Department of Dermatology, Beaumont Hospital, Dublin (G.M.M.).
Background:
Erythropoietic protoporphyria is a severe photodermatosis that is associated with acute phototoxicity. Patients with this condition have excruciating pain and a markedly reduced quality of life. We evaluated the safety and efficacy of an α-melanocyte-stimulating hormone analogue, afamelanotide, to decrease pain and improve quality of life.
Methods:
We conducted two multicenter, randomized, double-blind, placebo-controlled trials of subcutaneous implants containing 16 mg of afamelanotide. Patients in the European Union (74 patients) and the United States (94 patients) were randomly assigned, in a 1:1 ratio, to receive a subcutaneous implant containing either afamelanotide or placebo every 60 days (a total of five implants in the European Union study and three in the U.S study). The type and duration of sun exposure, number and severity of phototoxic reactions, and adverse events were recorded over the respective 180-day and 270-day study periods. Quality of life was assessed with the use of validated questionnaires. A subgroup of U.S. patients underwent photoprovocation testing. The primary efficacy end point was the number of hours of direct exposure to sunlight without pain.
Results:
In the U.S. study, the duration of pain-free time after 6 months was longer in the afamelanotide group (median, 69.4 hours, vs. 40.8 hours in the placebo group; P=0.04). In the European Union study, the duration of pain-free time after 9 months was also longer in the afamelanotide group than in the placebo group (median, 6.0 hours vs. 0.8 hours; P=0.005), and the number of phototoxic reactions was lower in the the afamelanotide group (77 vs. 146, P=0.04). In both trials, quality of life improved with afamelanotide therapy. Adverse events were mostly mild; serious adverse events were not thought to be related to the study drug.
Conclusions:
Afamelanotide had an acceptable side-effect and adverse-event profile and was associated with an increased duration of sun exposure without pain and improved quality of life in patients with erythropoietic protoporphyria. (Funded by Clinuvel Pharmaceuticals and others; ClinicalTrials.gov numbers, NCT01605136 and NCT00979745.).
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