Background: In erythropoietic protoporphyria (EPP), an inherited disease of porphyrin-biosynthesis, the accumulation of protoporphyrin in the skin causes severely painful phototoxic reactions. Symptom prevention was impossible until recently when afamelanotide became available. Afamelanotide-induced skin pigmentation has statistically significantly improved light-tolerance, although the clinical significance of the statistical effect was unknown.

Objectives: To assess clinical effectiveness by recording compliance and safety during prolonged use.

Methods: We report longitudinal observations of 115 ambulatory patients with EPP, who were treated with a total of 1023 afamelanotide implants over a period of up to 8 years at two porphyria centres; one in Rome, Italy, and the other in Zurich, Switzerland.

Results: Since the treatment first became available in 2006, the number of patients treated with 16 mg afamelanotide implants rose continuously until June 2014, when 66% of all patients with EPP known to the porphyria centres were treated. Only three patients considered afamelanotide did not meet their expectations for symptom improvement; 23% discontinued the treatment for other, mostly compelling, reasons such as pregnancy or financial restrictions. The quality of life (QoL) scores, measured by an EPP-specific questionnaire, were 31 ± 24% of maximum prior to afamelanotide treatment, rose to 74% after starting afamelanotide and remained at this level during the entire observation period. Only minor adverse events attributable to afamelanotide, predominantly nausea, were recorded.

Conclusion: Based on the improved QoL scores, high compliance and low discontinuation rates, we conclude that afamelanotide exhibits good clinical effectiveness and good safety in EPP under long-term routine conditions.