OBJECTIVES: The aim of this study was to investigate the availability of generic drugs in Spain for medications that initially had at least one orphan designation.

METHODS: A systematic review was performed focusing on drugs with at least one expired orphan designation by EMA, that are available within the Spanish Health System, until June 2024. Also, the included drugs did complete the market protection granted by the EMA due to the orphan designation, as early withdrawal could introduce bias to the analysis. The study analyzed information from various sources including CIMA, BIFIMED, the Community Register of Orphan Medicinal Products for Human Use, and drug Summary Product Characteristics. A descriptive analysis based on availability of generic/biosimilar drug was performed and subgroup analysis of biologic drugs and ATC groups were conducted.

RESULTS: The study found that out of the total 56 drugs analyzed, only 21 (38%) have generic/biosimilar versions available. Notably, only 1 of the 11 (9%) biologic drugs have biosimilars available. In contrast, among the 45 non-biologic drugs, 20 (44%) have generics.

In terms of ATC codes, Group L, which includes antineoplastic and immunomodulating agents, comprised half of the studied drugs, with 52% of them having generic/biosimilar alternatives. This group also accounts for more than half of the generics (12 out of 21). Other ATC groups with available generics include Group A (4 generics), Group B (2 generics) and Groups C and G with 1 generic each.

CONCLUSIONS: The study reveals a low availability of generic drugs and biosimilars for orphan medications in Spain. It highlights the need to study the prices evolution for these drugs to determine if, despite the low availability of generic alternatives, prices are decreasing over time. Such a trend could facilitate the adoption of new orphan drugs without significantly increasing the overall cost for the System.