A patent review of galectin-1 and galectin-3 inhibitors and their potential therapeutic applications (2022-present): an update

INTRODUCTION: Galectin-1 (Gal-1) & Galectin-3 (Gal-3) are carbohydrate-binding proteins implicated in diverse pathological processes. These galectins have emerged as key therapeutic targets, with significant presence in drug discovery pipelines and clinical investigations. Their unique glycan-binding properties and immunomodulatory effects have prompted the development of inhibitors to modulate their function. AREAS COVERED: This review presents a comprehensive summary of 19 small-molecule patents targeting Gal-1 and Gal-3, published from January 2022 to June 2025. A systematic search of Reaxys and WIPO databases yielded patents spanning modified monosaccharides & disaccharides, non-carbohydrate chemotypes and metal-coordinated complexes. EXPERT OPINION: The patent landscape is dominated by β-D-galactopyranose and thiodigalactoside scaffolds, with limited innovation and unresolved issues in selectivity, drug-likeness, and efficacy, highlighted by GB0139's Phase II failure. Moreover, only a few patents provide structural evidence and strong in vitro/in vivo data, limiting confidence in their therapeutic outcome. By contrast, some diversification has emerged, including spirocyclic sugars, ruthenium-conjugates and non-carbohydrate ligands such as heterocycles and repurposed drugs. These highlight underexploited avenues with promise. Yet, robust biochemical data and structural proof of binding remain scarce. To move the field forward, future patents must diversify chemotypes, substantiate binding modes with crystallography or NMR, and demonstrate translation in relevant disease models.