Biologic medicines have changed the way psoriasis and other chronic inflammatory disorders are treated. Many tumour necrosis factor-alpha ‘biosimilar’ agents have been developed in recent years. These biosimilars are structurally and functionally comparable to their original compounds, but they are not identical. Given that the original biologic’s safety and efficacy have already been established, biosimilars must simply demonstrate bioequivalence, or non-inferiority, to the reference biologic in order to be authorised. Biosimilars may be authorised for all indications of the originator biologic based on extrapolation of these non-inferiority results, even without being specifically investigated in these numerous diseases. These biosimilar medicines have been promoted as a means of lowering the prices of biologic treatments, therefore boosting access to these medications and, as a result, improving the treatment of psoriasis globally. Biosimilars of adalimumab, etanercept, and infliximab for the treatment of psoriasis have been authorised by the US Food and Drug Administration and/or the European Medicines Agency, and others are being evaluated.

Many phase III results demonstrating the bioequivalence of these anti-tumour necrosis factor-alpha biosimilar medicines in the treatment of psoriasis and rheumatologic illness are addressed here. In general, these biosimilar medicines have been demonstrated to have equal effectiveness, tolerability, and immunogenicity profiles in patients with rheumatologic illness compared to their originators, however, trials in patients with psoriasis are lacking. To test the interchangeability of biosimilar medicines with their reference drugs, further switching trials and post-marketing safety evaluations are required.