Affordability and relative economic burden of multiple sclerosis biologics in South America: a cross-country analysis of prices, purchasing power and regulatory access

High-cost biological therapies for multiple sclerosis (MS) may have lower nominal prices in middle-income countries yet impose greater burden relative to local purchasing capacity. We compared regulatory availability, price transparency and relative economic burden. We analyzed alemtuzumab, interferon beta-1a, natalizumab and ocrelizumab in Brazil, Colombia, Peru and the United States. Prices were compared in nominal US dollars, purchasing power parity-adjusted international dollars and against minimum wages. Defined daily doses supported standardized comparisons; regimen-based costs used reference dosing schedules. Outcomes included historical marketing authorization, observable prices, wage-based affordability and annual acquisition cost relative to gross domestic product per capita Historical marketing authorization was documented in all 16 medicine–country combinations (100%), and observable prices were identified in 14 (87.5%). None of the 14 assessable combinations met the adapted regimen-based affordability criterion. Under primary price scenarios, monthly-equivalent burden ranged from 27.2 calendar-day equivalents of statutory minimum-wage income for interferon beta-1a in Peru to 326.2 for alemtuzumab in Brazil. Although US nominal prices were generally highest, purchasing-power and wage adjustment altered country rankings. Historical marketing authorization and lower nominal prices did not imply economic accessibility. Cross-country assessments should integrate purchasing power, wages and regimen-based acquisition costs.