OBJECTIVES: Although drug repurposing (DR) is associated with many anticipated benefits, its full potential has not been realised due to barriers at points throughout the development pathway. The EU-funded REMEDi4ALL Consortium sought to identify policy-related barriers to the full development of repurposed medicines.

METHODS: A systematic literature review (SLR), complemented by interviews with all 24 REMEDI4ALL consortium partners, was performed. The SLR searched English language articles published between 2013-2023 on PubMed and Embase. After deduplication of 4059 records, 307 were reviewed in full text and 141 were extracted. Of 91 reports identified via grey literature and reference searching, 49 were eligible for data extraction. A thematic analysis, using a two-level multi-round coding of extracted data was performed to categorize listed barriers into different topics. The final barrier tree was developed iteratively through deliberation, first per topic and then merged, aiming to minimize overlap and redundancy among themes.

RESULTS: 32 barriers were identified and categorized into 9 themes: Perception of repurposing of off-patent medicines (3 barriers, on general- and R&D cost perception); Business case for repurposing on-patent compounds (2, on data exclusivity and company portfolio); Business case for repurposing off-patent medicines (2, on free ridership and return-on-investment); Non-industry funded DR (5, on interest and availability of funding); Ecosystem for non-profit or SME driven drug repurposing (5, on infrastructure, data and capabilities); Market Authorization (5, on evidence generation, pathway and off-label use); Exclusivity rights (5, on regulatory and patent protection); Health technology assessment (2, on evidence requirement and process); Pricing (3, on price potential and differential pricing).

CONCLUSIONS: Our comprehensive list of barriers provides a starting point to prioritize policy issues according to their perceived impact and actionability by different stakeholders and to identify intervention areas to improve the DR ecosystem.