Dersimelagon (MT-7117)

The Food and Drug Administration accepted the dersimelagon New Drug Application for filing with Priority Review, with a Prescription Drug User Fee Act action date by the end of February 2027. The product is not approved in any jurisdiction. If approved, it would be the first oral therapy for these disorders and the first available to patients aged 12 to 17 years. The application rests on one positive phase 3 trial, INSPIRE, for which no registry results, protocol, statistical analysis plan, confidence intervals, disposition table, or baseline characteristics have been published, and which is preceded by a larger and longer phase 3 trial that did not meet the same primary endpoint. The measured effect in INSPIRE, 23.19 minutes of additional daily sunlight exposure before the first prodromal symptom over weeks 12 to 16, is smaller than the 53.8 to 62.5 minutes observed in the phase 2 trial and was not significant at the registered week 16 timepoint. Because the drug produces visible pigmentation, blinding was incomplete in the phase 2 trial, where 97% to 100% of actively treated participants correctly identified their assignment. Two safety observations warrant attention for a chronic therapy in this class: a 20.7% rate of melanocytic nevi compared with 1.2% on placebo in INSPIRE with one malignant melanoma in situ, and the hepatobiliary signal from the earlier phase 3 trial, which included one fatal cholestasis. No United States price, budget impact model, or head-to-head comparison against afamelanotide exists.