FARMACOECONOMIA APPLICATA ALLE MALATTIE INFIAMMATORIE CRONICHE CUTANEE (PSORIASI E DERMATITE ATOPICA)

Psoriasis and atopic dermatitis (AD) are common chronic immune-mediated diseases. Psoriasis affects 1-4% of the Western population, and about 14 million people in Europe. About 20-30% of psoriatic patients have a moderate-to-severe form of the disease and are candidate for phototherapy or to systemic treatments such as conventional systemic agents (acitretin, cyclosporine, methotrexate, fumarates) and targeted therapies (biologics and small molecules). The treatment of moderate-to-severe psoriasis with biologic agents poses a significant economic burden to the health systems. Psoriasis can be associated with several comorbidities, including psoriatic arthritis (PsA), cardiovascular diseases, metabolic syndrome, inflammatory bowel diseases and psychiatric diseases. Among biological treatments, adalimumab belongs to the class of TNF-a inhibitors. In the last few years, the expiration of biologic patents of some TNF-a inhibitors, has encouraged certain companies to produce biosimilars, with a reduced cost even though they have the same safety and efficacy profile, compared to their originator. The use of biosimilars is a valuable pharmacoeconomic strategy to lower healthcare costs in patients with psoriasis, leading to a more accessible therapeutic option, when introduced earlier. The early intervention with biosimilars may prevent progression to PsA, with a more persistent efficacy and may modify the natural history of psoriasis. AD affects more than 20 million people in Europe and is characterized by a chronic and relapsing course. Many children experience the onset of AD in infancy or early childhood (5-20%), and it often improves with age, although it can persist or recur. Approximately 5-8% of adults are affected by AD, with 66% having persistent AD from childhood, while 33% experience adult-onset AD. In developed countries, adult prevalence is sometimes higher, particularly among individuals who had AD as children. Moderate-to-severe forms of AD require systemic drugs, such as conventional systemic immunosuppressive drugs such as methotrexate, cyclosporine, mycophenolate, biological therapies such as dupilumab, tralokinumab and lebrikizumab, or JAK inhibitors such as abrocitinib, baricitinib, upadacitinib. Pharmacoeconomic evaluation of these new drugs for psoriasis and for AD is lacking. Pharmacoeconomic principles provide an essential framework for evaluating the value of therapeutic interventions. By integrating clinical outcomes with economic considerations, these analyses support evidence-based allocation of healthcare resources and facilitate informed clinical decision-making. In chronic inflammatory skin diseases such as psoriasis and AD, pharmacoeconomic evaluations can help clinicians and policy makers to identify treatments that maximize both clinical benefit and sustainability for healthcare systems. The following chapters apply these principles to real clinical scenarios, focusing on cost-per-responder analyses of systemic therapies in patients with psoriasis and with AD from the perspective of the Italian National Health System.