Budget impact model in moderate-to-severe psoriasis vulgaris assessing effects of calcipotriene and betamethasone dipropionate foam on per-patient standard of care costs

Aims: To develop a budget impact model (BIM) for estimating the financial impact of formulary adoption and uptake of calcipotriene and betamethasone dipropionate (C/BD) foam (0.005%/0.064%) on the costs of biologics for treating moderate-to-severe psoriasis vulgaris in a hypothetical US healthcare plan with 1 million members. Methods: This BIM incorporated epidemiologic data, market uptake assumptions, and drug utilization costs, simulating the treatment mix for patients who are candidates for biologics before (Scenario #1) and after (Scenario #2) the introduction of C/BD foam. Predicted outcomes were expressed in terms of the annual cost of treatment (COT) and the COT per member per month (PMPM). Results: At year 1, C/BD foam had the lowest per-patient cost ($9,913) necessary to achieve a Psoriasis Area and Severity Index (PASI)-75 response compared with etanercept ($73,773), adalimumab ($92,871), infliximab ($34,048), ustekinumab ($83,975), secukinumab ($113,858), apremilast ($47,960), and ixekizumab ($62,707). Following addition of C/BD foam to the formulary, the annual COT for moderate-to-severe psoriasis would decrease by $36,112,572 (17.91%, from $201,621,219 to $165,508,647). The COT PMPM is expected to decrease by $3.00 (17.86%, from $16.80 to $13.80). Limitations: Drug costs were based on Medi-Span reference pricing (January 21, 2016); differences in treatment costs for drug administration, laboratory monitoring, or adverse events were not accounted for. Potentially confounding were the definition of "moderate-to-severe" and the heterogeneous efficacy data. The per-patient cost for PASI-75 response at year 1 was estimated from short-term efficacy data for C/BD foam and apremilast only. Conclusions: The introduction of C/BD foam is expected to decrease the annual COT for moderate-to-severe psoriasis treatable with biologics by $36,112,572 for a hypothetical US healthcare plan with 1 million plan members, and to lower the COT PMPM by $3.00.