title: Vemurafenib: an unusual UVA-induced photosensitivity.
abstract: Vemurafenib is a new-targeted therapy approved for the treatment of patients with V600E BRAF-mutant metastatic melanoma. Among the cutaneous adverse events reported, the photosensitivity is frequently experienced. We aimed to characterize more deeply the mechanism leading to this photosensitivity as well as the corresponding UV spectrum. Phototests showed that the phototoxicity was UVA-dependent since from normal value prior to vemurafenib treatment, the UVA-minimal erythema dose decreased in 17 of 18 patients (94.4%) while the minimal erythema dose remained unchanged. Furthermore, a vemurafenib-induced erythema appeared quickly during the UVA exposure contrarily to what is observed with a conventional drug-induced phototoxicity showing an erythema 12-24 h after the phototesting. Vitamin PP concentration decreased, and porphyrin level significantly increased after 2 months of vemurafenib. Our study confirms the high risk of vemurafenib-induced photosensitivity and indicates that it is possibly vitamin PP- and porphyrin dependent.
authors.forename: Pauline
authors.initials: P
authors.lastname: Gelot
authors.forename: Hervé
authors.initials: H
authors.lastname: Dutartre
authors.forename: Amir
authors.initials: A
authors.lastname: Khammari
authors.forename: Aurélie
authors.initials: A
authors.lastname: Boisrobert
authors.forename: Caroline
authors.initials: C
authors.lastname: Schmitt
authors.forename: Jean-Charles
authors.initials: JC
authors.lastname: Deybach
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Nguyen
authors.forename: Sophie
authors.initials: S
authors.lastname: Seité
authors.forename: Brigitte
authors.initials: B
authors.lastname: Dréno
mesh_terms: D000970:Antineoplastic Agents / Q000009:adverse effects*; D017484:Dermatitis, Phototoxic / Q000097:blood / Q000209:etiology*; D006801:Humans; D007211:Indoles / Q000009:adverse effects*; D008545:Melanoma / Q000188:drug therapy* / Q000235:genetics; D009154:Mutation; D011166:Porphyrins / Q000097:blood; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics; D013449:Sulfonamides / Q000009:adverse effects*; D014466:Ultraviolet Rays / Q000009:adverse effects; D000077484:Vemurafenib
chemical_list: D000970:Antineoplastic Agents; D007211:Indoles; D011166:Porphyrins; D013449:Sulfonamides; D000077484:Vemurafenib; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf