Recently Published Studies
The afamelanotide implant trials counted pain-free sunlight, in two different studies
Langendonk, Balwani, and colleagues reported two randomized trials of a 16 mg afamelanotide implant in erythropoietic protoporphyria. The hour counts are not interchangeable.
Erythropoietic protoporphyria makes ordinary sunlight painful. The New England Journal of Medicine paper on afamelanotide, an analogue of alpha-melanocyte-stimulating hormone, reports two multicenter, randomized, placebo-controlled trials of a subcutaneous implant containing 16 mg, given every 60 days. The European Union study enrolled 74 patients and used five implants. The United States study enrolled 94 patients and used three.
Two hour counts, two windows
In the United States study, median pain-free time in direct sun after 6 months was 69.4 hours with afamelanotide and 40.8 hours with placebo. In the European Union study, the median after 9 months was 6.0 hours against 0.8 hours. Phototoxic reactions in that European count were 77 against 146. Those pairs answer different durations. They are not two measurements of the same afternoon.
What the paper is not
The implant is not a tanning injection, and it is not melanotan II. The registries are NCT01605136 and NCT00979745. A later prescribing label, where one exists, states the approved implant and the approved condition. This paper is the trial record behind that distinction.