OBJECTIVES:

So far, no consensus exists on the fact that disease prevalence is a key factor in the definition of reimbursed drug price. The aim of the study was to investigate the existence of a correlation between the prevalence of rare diseases and related treatment costs for drugs reimbursed in Italy.

METHODS:

A Microsoft Excel database was built, including a total of 80 drugs/indications for rare diseases reimbursed in Italy between January 2016 and December 2021. For each of them, the treatment cost was calculated based on net prices and dosing regimens as per SmPCs. European prevalence data (EMA, Orphanet) were considered, and a linear regression analysis was performed to investigate the correlation between prevalence and treatment costs. Subgroup analyses were also performed for ultra-rare diseases (≤1/50,000), orphan, innovative, chronic indications, and hospital drugs.

RESULTS:

For the 80 indications considered, a statistically significant inverse correlation was found (r=-0.3037): each percentage point increase in prevalence corresponds to an average reduction of about €41,000 in the treatment cost (X1=-40,671; IC95% [-69,435; -11,908]; p= 0.006)). An even stronger inverse correlation was found by conducting the analysis for chronic indications: each percentage point increase in prevalence corresponds to an average reduction in treatment cost of €47,000 (X1= -55,553 IC95% [-69,229; -25,181]; p<0.00001).

CONCLUSIONS:

Although pricing outcomes come from a multifactorial process with several determinants, such as unmet medical need, availability of therapeutic alternatives, clinical added value, and national P&R policies, the results of this study show that epidemiology can be also considered one of the drivers in pricing decisions, at least in the field of rare diseases. However, these results must be read considering some limitations such as the small sample size, especially for subgroup analyses, and the absence of specific prevalence data referring to the Italian context.