title: Low blood concentration of hydroxychloroquine in patients with refractory cutaneous lupus erythematosus: a French multicenter prospective study.
abstract: OBJECTIVE
  To study the relation between blood concentration of hydroxychloroquine and the clinical efficacy of hydroxychloroquine sulfate in a series of patients with cutaneous lupus erythematosus (CLE).
  
  
  METHODS
  Prospective multicenter study. A staff dermatologist blinded to blood hydroxychloroquine concentrations performed a standardized review of medical records and assessment of hydroxychloroquine efficacy in the following 3 categories: complete remission, partial remission (clearing of >50% of skin lesions), or treatment failure. Whole-blood samples were collected for measurement of blood hydroxychloroquine concentration.
  
  
  METHODS
  Fourteen French university hospitals.
  
  
  METHODS
  Three hundred consecutive patients with subacute or chronic CLE who had been treated with hydroxychloroquine for at least 3 months.
  
  
  METHODS
  The statistical significance of correlation between blood hydroxychloroquine concentration and efficacy of hydroxychloroquine and the statistical associations in univariate and multivariate analyses of complete remission with several variables.
  
  
  RESULTS
  The study included 300 patients with discoid lupus erythematosus (n = 160), subacute CLE (n = 86), lupus erythematosus tumidus (n = 52), chilblain lupus (n = 26), and lupus panniculitis (n = 16); 38 of these patients had 2 or more associated forms. Median blood hydroxychloroquine concentration was significantly higher in patients with complete remission (910 [range, <50 to 3057] ng/mL) compared with partial remission (692 [<50 to 2843] ng/mL) and treatment failure (569 [<50 to 2242] ng/mL) (P = .007). In the multivariate analysis, complete remission was associated with higher blood hydroxychloroquine concentrations (P = .005) and the absence of discoid lesions (P = .004). Thirty patients (10.0%) had very low blood hydroxychloroquine concentrations (<200 ng/mL) and may be considered nonadherent to the treatment regimen.
  
  
  CONCLUSIONS
  Monitoring hydroxychloroquine blood concentrations might improve the management of refractory CLE.
authors.affiliation: Department of Dermatology-Allergology, Assistance Publique-Hôpitaux de Paris, Université Pierre et Marie Curie, Hôpital Tenon, 4 rue de la Chine 75970 Paris Cedex 20, France. camille.frances@tnn.aphp.fr
authors.forename: Camille
authors.initials: C
authors.lastname: Francès
authors.forename: Anne
authors.initials: A
authors.lastname: Cosnes
authors.forename: Pierre
authors.initials: P
authors.lastname: Duhaut
authors.forename: Noël
authors.initials: N
authors.lastname: Zahr
authors.forename: Boutros
authors.initials: B
authors.lastname: Soutou
authors.forename: Saskia
authors.initials: S
authors.lastname: Ingen-Housz-Oro
authors.forename: Didier
authors.initials: D
authors.lastname: Bessis
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Chevrant-Breton
authors.forename: Nadège
authors.initials: N
authors.lastname: Cordel
authors.forename: Dan
authors.initials: D
authors.lastname: Lipsker
authors.forename: Nathalie
authors.initials: N
authors.lastname: Costedoat-Chalumeau
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000962:Antimalarials / Q000097:blood* / Q000627:therapeutic use; D002647:Chilblains / Q000188:drug therapy; D002648:Child; D005260:Female; D005602:France; D006801:Humans; D006886:Hydroxychloroquine / Q000097:blood* / Q000627:therapeutic use; D008178:Lupus Erythematosus, Cutaneous / Q000188:drug therapy*; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D015999:Multivariate Analysis; D015435:Panniculitis, Lupus Erythematosus / Q000188:drug therapy; D011446:Prospective Studies; D016037:Single-Blind Method; D018709:Statistics, Nonparametric; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000962:Antimalarials; D006886:Hydroxychloroquine