title: Improving clinical trial design in psoriasis: Perspectives from the global dermatology community.
abstract: BACKGROUND
  Clinical trials to test investigational drugs for the treatment of chronic plaque psoriasis currently lack standards for comparison of efficacy and safety data.The majority of studies do not address the important need for long-term treatment.
  
  
  METHODS
  The International Psoriasis Council (IPC) conducted two surveys of its members to assess the need for gold standards, active comparators, and long-term therapy in clinical trials. In Survey 1, 30 participants delivered viewpoints on active comparators for topical therapy (six questions), systemic therapy (nine questions), and continuous versus intermittent therapy (six questions). In Survey 2, 31 participants provided input on gold standards for treatment (five questions), appropriate comparators (four questions), and continuous versus intermittent therapy (six questions). The IPC leadership interpreted the results after each survey.
  
  
  RESULTS
  The majority of participants (77% in Survey 1 and 89% in Survey 2) agreed that studies of investigative treatments should include an active comparator. Participants described the most important feature of a gold standard as a treatment that: is widely used and generally accepted (45%); has the best efficacy (42%); and is well tolerated (13%). The majority agreed that gold standards should be dependent on: patient subgroup; location/extent of psoriasis; and psoriasis subtype/morphology. It was also agreed that continuous therapy for more than 3 years is needed for patients with moderate-to-severe plaque psoriasis. We have provided an expert opinion regarding the definition of a gold standard in psoriasis and have also established that no single treatment can be the gold standard across all subgroups and types of the disease.
  
  
  CONCLUSIONS
  A single gold standard for the treatment of psoriasis does not exist. The complexity and heterogeneity of psoriasis requires different gold standards for the various manifestations of psoriasis and for subgroups of patients reconciling comorbidities. Of note, 17 experts out of 30 selected methotrexate as the most nominated gold standard amongst systemic agents. The experts support the election of an active comparator as one that is most efficacious over just the best in a particular class. In concordance, 87% of respondents agreed that good tolerability is therefore not the lead criterion for selection of an active comparator in favor of effectiveness and broad use. Patients with moderate-to-severe plaque psoriasis require continuous therapy; this statement was supported by 93% of the experts. Reasons for considering long-term therapy included appearance of comorbidities, impairment of quality of life, possibility of relapse, and subjective complaints such as itch, pain, and joint disease.
authors.affiliation: Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. P.vandeKerkhof@derma.umcn.nl
authors.forename: Peter
authors.initials: P
authors.lastname: van de Kerkhof
authors.forename: Jonathan
authors.initials: J
authors.lastname: Barker
authors.forename: Christopher E M
authors.initials: CE
authors.lastname: Griffiths
authors.forename: Alan
authors.initials: A
authors.lastname: Menter
authors.forename: Craig
authors.initials: C
authors.lastname: Leonardi
authors.forename: Melodie
authors.initials: M
authors.lastname: Young
authors.forename: Lajos
authors.initials: L
authors.lastname: Kemeny
authors.forename: Carlo
authors.initials: C
authors.lastname: Pincelli
authors.forename: Hervé
authors.initials: H
authors.lastname: Bachelez
authors.forename: Andreas
authors.initials: A
authors.lastname: Katsambas
authors.forename: Mona
authors.initials: M
authors.lastname: Ståhle
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Horn
authors.forename: Wolfram
authors.initials: W
authors.lastname: Sterry
mesh_terms: D035061:Control Groups; D006801:Humans; D011565:Psoriasis / Q000188:drug therapy*; D016032:Randomized Controlled Trials as Topic / Q000592:standards; D012107:Research Design; D011795:Surveys and Questionnaires