A Cost-per-Number Needed to Treat Analysis Assessing the Efficiency of Biologic Drugs in Moderate to Severe Plaque Psoriasis.

Background And Objectives: Psoriasis is a chronic inflammatory skin disease with an estimated prevalence in Spain of 2.3% of the population. Approximately 30% of patients have moderate-to-severe forms. Treatment with biologic agents is proving to be a step forward in the management of the disease, although these treatments are very expensive. The objective of this study was to determine the efficiency, in terms of cost per number needed to treat (NNT), of the biologic drugs available in Spain for the treatment of moderate to severe plaque psoriasis.

Methods: NNT data were obtained from a network meta-analysis that included all randomized clinical trials of biologic drugs sold in Spain. The cost of each treatment was calculated based on the approved dosage for the first year of treatment, as indicated in the Summary of Product Characteristics. These data were used to calculate the cost per NNT of the drugs for various PASI scores (75, 90, and 100). A sensitivity analysis was performed taking into consideration only the PASI-response measurement time (after 10, 12, or 16 weeks, depending on the drug).

Results: The order of efficiency, from most to least efficient, in the case of a PASI 75 response was ixekizumab > ustekinumab 45mg > ustekinumab 90mg > secukinumab > infliximab > etanercept > adalimumab. The order for PASI 90 was ixekizumab >secukinumab >ustekinumab 45mg > ustekinumab 90mg > infliximab > adalimumab > etanercept. The order for PASI 100 was ixekizumab > secukinumab > infliximab > ustekinumab 90mg > ustekinumab 45mg > adalimumab > etanercept. The sensitivity analysis showed some changes in the order, depending on the response-assessment period.

Conclusions: The findings show a link between the efficacy of the biologic therapies available in Spain for the treatment of moderate-to-severe plaque psoriasis and their efficiency. Ixekizumab had the lowest cost per NNT for all PASI-response scores (75, 90, and 100) during the first year of treatment.