OBJECTIVES: Moderate-to-severe psoriasis requires biologics or oral systemic therapies. Four out of 13 biologics have biosimilars approved. Previous studies have evaluated the cost-effectiveness of biologics and other commonly used therapies. However, it remains unknown about the cost-effectiveness of biosimilars and recently approved biologics. This study aims to compare the cost-effectiveness of adalimumab and its biosimilars, infliximab and its biosimilars, brodalumab and bimekizumab in patients with moderate-to-severe psoriasis.

METHODS: A Markov model was constructed using TreeAge Pro. The study was conducted from US payer perspective over a 10-year horizon, with 16-week cycle length. We assumed that patients without adequate response can switch to subsequent therapy or non-targeted therapy. Medication costs were derived from the Redbook. Utilities were calculated using the Psoriasis Area and Severity Index (PASI). Transition probabilities were obtained from two network meta-analysis studies. All costs were reported as 2023 dollars. Future costs and effectiveness were discounted at 3% annually. Deterministic and probabilistic sensitivity analyses were conducted to account for parameter uncertainties.

RESULTS: In base-case analysis, biosimilars of infliximab had the lowest cumulative costs ($263,887.36), while bimekizumab had the highest cumulative costs ($363,556.94). Bimekizumab had the highest cumulative effectiveness of 18.75 QALY, while adalimumab and its biosimilars had the lowest cumulative effectiveness of 18.47 QALY. Infliximab biosimilars were the most cost-effective options among all comparators. The base-case ICERs were $202,241.35/QALY for brodalumab and $556,677.34/QALY for bimekizumab, compared to infliximab biosimilars. Patients in all arms had shifted to non-targeted therapy after 10 years. Sensitivity analysis indicated that ICER was most sensitive to the cost of non-targeted therapy across all pairwise comparisons.

CONCLUSIONS: Biosimilars of infliximab were likely the most cost-effective option among all six treatment arms while bimekizumab was the least cost-effective option. Due to high switching rates, the results are sensitive to costs of non-targeted therapy.