Uptake of tumour necrosis factor-alpha inhibitor biosimilars for psoriasis: a drug utilization study from the British Association of Dermatologists Biologic and Immunomodulators Register (BADBIR).

BACKGROUND

Tumour necrosis factor-alpha inhibitors (TNFi) have revolutionized the treatment of moderate-to-severe psoriasis. Following patent expiry of the originator biologics, TNFi biosimilars became available, presenting the opportunity for significant reductions in drug costs.

OBJECTIVES

To describe the uptake of TNFi biosimilars for psoriasis treatment in the UK and Ireland.

METHODS

This observational cohort study utilizes data from the British Association of Dermatologists Biologic and Immunomodulators Register (BADBIR), a national pharmacovigilance study register for patients with psoriasis on systemic treatments. We analysed biosimilar uptake trends over time in nine geographical regions of England along with Wales, Scotland, Northern Ireland and the Republic of Ireland. We assessed the incidence of switching to biosimilars in an originator-user cohort (switchers). Patients on originators infliximab, etanercept and adalimumab at the time originator patents expired, entered the cohort on 1 February 2015, August 2015 and October 2018, respectively, and were followed up until 31 October 2021. Trends in biosimilar initiations were assessed in an adalimumab-naïve cohort who started adalimumab between 1 October 2018 and 31 July 2019 (starters). We assessed the associations between patient factors and originator-to-biosimilar switching and biosimilar initiation using a multivariable Cox regression model and a multivariable logistic regression model, respectively.

RESULTS

Included in the originator-user cohort were 4202 patients (209 on infliximab, 742 on etanercept and 3251 on adalimumab). For infliximab, etanercept and adalimumab, respectively, the cumulative incidence of originator-to-biosimilar switching increased with time to 14.8%, 23.6% and 66.6% after 3 years. Across geographical regions, 3-year switching rates varied from 0% to 43.7% for infliximab; from 0% to 40.4% for etanercept; and from 12.5% to 84.3% for adalimumab. Out of the 528 patients included in the adalimumab-naïve cohort, 67.8% started on biosimilars. Originator-to-biosimilar switching and biosimilar initiation were more common in men and in patients who had lower Psoriasis Area and Severity Index at cohort entry.

CONCLUSIONS

The uptake of biosimilars increased over time and varied considerably across the UK and Ireland; adalimumab had the highest biosimilar uptake rate compared with that of other TNFi drugs.

Informations de copyright

© The Author(s) 2023. Published by Oxford University Press on behalf of British Association of Dermatologists. All rights reserved. For permissions, please e-mail: [e-mail].

Déclaration de conflit d'intérêts

Conflicts of interest A.P.B. reported receiving honoraria and consulting fees from AbbVie, Almirall, Galderma, Janssen, LEO Pharma, Eli Lilly, Novartis, Pfizer, Sanofi and UCB; he is also President of the European Society for Dermatology and Psychiatry. C.H.S. reported receiving grants from a Medical Research Council-funded stratified medicine consortium with multiple industry partners, and grants from an Innovative Medicines Initiative (Horizon 2020)-funded European consortium with multiple industry partners; she is also chair of UK guidelines on biologic therapy in psoriasis. T.M. reported receiving honoraria from AbbVie, Almirall, Galderma, LEO Pharma, Lilly, Pfizer, Sanofi and UCB. C.E.M.G. reported receiving honoraria and/or research grants from AbbVie, Almirall, Anaptysbio, Boehringer Ingelheim, Bristol Myers Squibb, Celgene, Eli Lilly and Company, Evelo Bioscience, Galderma, GSK, Janssen, Inmagene, Kyowa Kirin, LEO Pharma, Novartis, ONO Pharmaceutical Co., Ltd, Pfizer and UCB Pharma, and was supported in part by the Manchester NIHR Biomedical Research Centre. R.B.W. reported receiving research grants from AbbVie, Almirall, Amgen, Celgene, Janssen, Lilly, LEO Pharma, Novartis, Pfizer and UCB; and consulting fees from AbbVie, Almirall, Amgen, Arena, Astellas, Avillion, Biogen, Boehringer Ingelheim, Bristol Myers Squibb, Celgene, DiCE, GSK, Janssen, Lilly, LEO Pharma, Novartis, Pfizer, Sanofi, Sun Pharma, UCB and UNION. The remaining authors declare they have no conflicts of interest.