FDA Approves SCENESSE (Afamelanotide) Implant to Increase Pain Free Light Exposure in Adult Patients with a History of Phototoxic Reactions from Erythropoietic Protoporphyria
On October 8, 2019, the U.S. Food and Drug Administration (FDA) approved SCENESSE (afamelanotide) implant to increase pain free light exposure in adult patients with a history of phototoxic reactions from erythropoietic protoporphyria (EPP). SCENESSE should be administered by a healthcare professional who is proficient in the subcutaneous implantation procedure and has completed training prior to administration. The approved recommended dosage of SCENESSE is a single implant, containing 16 mg of afamelanotide, inserted subcutaneously above the anterior supra-iliac crest every 2 months. SCENESSE may induce skin darkening, and a full body skin examination is recommended for patients twice a year. In addition, patients are encouraged to maintain sun protection measures during treatment with SCENESSE to prevent phototoxic reactions related to erythropoietic protoporphyria.
Additional information regarding dosage and administration and important warnings and precautions about monitoring pre-existing and new skin pigmentary lesions can be found in the full prescribing information linked below.
Mechanism of Action (MOA), Pharmacokinetics (PK), and Pharmacodynamics (PD)
- MOA: Afamelanotide is a melanocortin receptor agonist and binds predominantly to MC1-R.
- General PK: Following administration of a single subcutaneous implant of SCENESSE, the mean ± SD Cmax and AUC0-inf of afamelanotide were 3.7 ± 1.3 ng/mL and 138.9 ± 42.6 hr*ng/mL, respectively. High variability was observed in the plasma concentrations of afamelanotide. The last measurable afamelanotide concentration is at 96 hours post-dose in most subjects studied.
- Absorption: The median Tmax is 36 hours.
- Elimination: The apparent half-life of afamelanotide is approximately 15 hours when administered subcutaneously in a controlled release implant.
- Metabolism: Afamelanotide may undergo hydrolysis. However, its metabolic profile has not been fully characterized.
- PD: Afamelanotide increases production of eumelanin in the skin independently of exposure to sunlight or artificial UV light sources.
No drug interaction studies were conducted with afamelanotide.
Use in Specific Populations
The effect of renal or hepatic impairment on the pharmacokinetics of afamelanotide is unknown.
Efficacy and Safety
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. Additional information regarding efficacy trials can be found in the full prescribing information linked below.
The most common adverse reactions (incidence > 2%) are implant site reaction, nausea, oropharyngeal pain, cough, fatigue, dizziness, skin hyperpigmentation, somnolence, melanocytic nevus, respiratory tract infection, non-acute porphyria, and skin irritation.
Full prescribing information is available at https://go.usa.gov/xVtCv.
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This communication was prepared by Office of Clinical Pharmacology, Office of Translational Sciences, CDER, FDA.