Background Biological drugs are effective treatments for chronic plaque psoriasis. The doses tend to be reduced when the drug has demonstrated sustained effectiveness.

Purpose The main objective was to assess the average cost per patient of each anti-TNF drug based on its prescribed doses. The secondary objective was two-fold: to estimate the annual costs per responder and the incremental cost.

Material and methods A cross-sectional observational study was conducted from January to June 2014. Patients with psoriasis who had received biological treatment for at least six months were included. The effectiveness endpoint was the proportion of patients with at least 75% improvement in the psoriasis area-and-severity index (PASI75). Mean prescribed doses of each anti-TNF drug were calculated and translated into a percentage of the label doses. The average cost per patient for each drug was assessed with the mean prescribed doses (real costs, RC) and the theoretical costs (TC) were estimated based on the label doses of the drugs. The incremental cost (IC) was calculated by comparing the theoretical vs. real costs. For the purpose of calculating the annual costs, the real costs of six months of treatment were extrapolated. This study was performed from the pharmacoeconomic perspective of the hospital.

Results We included 143 patients.

Conclusion The average RC of each biological drug was lower than TC, except for infliximab. Both the annual RC and the IC of adalimumab were better than the other drugs, followed by etanercept and ustekinumab. Infliximab did not allow dose reduction. Reducing doses of biological treatments permits cost minimisation while maintaining clinical effectiveness.

References and/or Acknowledgements No conflict of interest.