Abstract
The aim was to explore the availability of biosimilar insulins on the national market in Bulgaria and their impact on prices and utilization. This was a retrospective, quantitative, longitudinal study during the period 2014-2020. Authorized-for-sale, biosimilar insulins at the European level were compared with those on the national market. Prices and utilization were compared in value, number of defined daily dose (DDD), and DDD/1000 inh/day. Almost all types of insulins possessed biosimilars, and even more than one on the European market, but only two were found to be available and reimbursed on the national market. The total number of reimbursed INNs was 11, and for seven of them, changes in reference price per DDD were found. The highest price decrease was observed for insulin (price per DDD decline from 2.77 to 2.22 Bulgarian Leva (BGN)). The total expenditure for insulin increased from 68 to approximately 72.8 mil BGN (34 to approximately 37 mil Euro). The utilization in DDD/1000/inh/day decreased from 16.12 to 15.31. Only two biosimilar insulins were found to be available on the national market, with a slow decrease in prices and stable utilization. Other regulatory and financial measures are probably necessary to foster the insulins' competition at the biosimilar level.