Off-target protein (None)

The term 'Off-target protein' refers to any biological molecule that a drug binds to or modulates unintentionally, rather than its intended therapeutic target (Bowes et al., 2012). These interactions are a primary cause of adverse drug reactions and toxicities, often leading to the failure of drug candidates during clinical trials (Lounkine et al., 2012). Off-target effects typically arise from a lack of molecular selectivity, where a drug's chemical structure allows it to interact with proteins that share structural motifs with the primary target (Lin et al., 2019). Common off-target proteins include the hERG potassium channel, which is associated with cardiac arrhythmia, and various cytochrome P450 enzymes that influence drug metabolism (Whitebread et al., 2005). In modern drug discovery, safety pharmacology profiling is employed to identify these unintended interactions early in the development process. By characterizing the off-target profile of a compound, researchers can optimize its chemical structure to improve safety and increase the therapeutic index. Ultimately, minimizing off-target activity is essential for ensuring that a drug is both safe and effective for patient use.

Other names

Off-targetNon-target proteinUnintended targetSecondary targetBystander protein

Unintended binding or modulation of a protein other than the primary therapeutic target.