Treatment Sequencing After Failure of the First Biologic in Cost-Effectiveness Models of Psoriasis: A Systematic Review of Published Models and Clinical Practice Guidelines

OBJECTIVES To analyse the treatment sequencing assumptions after failure on a first-line biologic in cost-effectiveness models of treatment of moderate to severe plaque psoriasis, and to compare them with the most recent treatment guidelines. METHODS A systematic search of MEDLINE, Embase, EconLit and the Cochrane Library databases used free text and Medical Subject Headings terms including psoriasis, biologic therapies indicated for psoriasis, and all types of economic evaluations. Two researchers performed 2-level abstract screening for articles meeting pre-specified inclusion criteria. Assumptions about treatment pathways after first-line biologic failure in the cost-effectiveness models were analysed. A second systematic search was performed for psoriasis clinical practice guidelines. Sequence assumptions were compared with treatment guideline recommendations. RESULTS Of 25 cost-effectiveness modelling studies identified, ten estimated the incremental cost per responder; time horizons varied (12 weeks-18 months) and treatment sequencing was not considered. In 15 studies where treatment sequencing was considered, with time horizons up to 10 years, five studies included only a switch to nonsystemic therapy or best supportive care after first-line biologic failure. Another five of the 15 treatment-pathway studies were available only as abstracts with no details of the sequence assumptions. In five of the 15 studies, first-line biologic failure was followed by second-line biologic monotherapy, one of the recommendations in current treatment guidelines. In only one of these five studies was the efficacy of the second-line biologic adjusted downwards, compared with first-line treatment. Only one of these studies considered dose titration with a first-line biologic and none combination therapy (biologic plus methotrexate or phototherapy) after first-line biologic failure, as recommended in some treatment guidelines. CONCLUSIONS Cost-effectiveness models of first-line biologics for moderate to severe plaque psoriasis either do not include subsequent treatment regimens or include only some of the regimens recommended in current treatment guidelines. Results may be sensitive to assumptions about treatment sequencing and the choice and efficacy of subsequent treatment regimens.