ABSTRACT:
Equitable access to high-cost medicines remains a persistent challenge for universal health systems. Cystic fibrosis (CF) exemplifies the social and financial burden of rare diseases, where timely treatment can prevent avoidable morbidity and improve quality of life. This study assessed regional and socioeconomic inequalities in access to dornase alfa within Brazil’s Unified Health System (SUS), using the medicine as a tracer to evaluate distributive equity in rare disease care. We conducted a cross-sectional study using secondary data from the SUS Outpatient Information System (SIA/SUS). Outpatient authorizations (APACs) for dornase alfa were aggregated by Brazilian macro-region for 2021. Three indicators were estimated: (1) average per capita expenditure; (2) average per capita consumption; and (3) the proportion of treated patients relative to the estimated CF population adjusted to SUS coverage. Eligible population estimates were derived from the Brazilian Cystic Fibrosis Registry and adjusted to the proportion of patients covered by SUS. Descriptive analyses compared indicators across macro-regions. Dornase alfa was selected as a tracer drug because centralized procurement and standardized clinical guidelines should, in principle, reduce variation and therefore reveal distribution failures. Only 41% of CF patients dependent on SUS received dornase alfa. Coverage differed markedly by region, reaching 50.9% in the Center-West but only 34.3% in the Northeast. Average per capita expenditure ranged from US$123.50 in the North to US$140.70 in the Northeast. Annual consumption varied between 97.2 and 136.1 vials per treated patient, suggesting differences in treatment intensity and continuity. Despite uniform national procurement, access and consumption were lower in socioeconomically disadvantaged regions, indicating a mismatch between financial allocation and effective treatment delivery. These gaps highlight structural limitations of SUS in translating centralized purchasing into equitable, real-world access to essential high-cost therapies for rare diseases. Equity-focused monitoring can guide corrective allocation actions.