Lexicon · NucLex for innovators
Off-target binding
Fully specified name: Off-target binding (concept)
Binding to an entity other than the intended target for a purpose.
- Scope note
- This label alone does not quantify clinical consequences.
- Synonyms
- None recorded as true synonyms in this context.
- Monograph
- Molecular targeting (planned; brief only)
- External mappings
- None recorded. In W0 no mapping to SNOMED CT® or any external authority is asserted for this entry. A future mapping record will carry source system, identifier, version, relation type, evidence, author, confidence where meaningful, and review state.
- Formal status
- Editorial entry only. It is not part of any released ontology and a prose edit here changes no formal definition.
Draft. This entry is an unreviewed draft. Its sources have not been checked by a named person and no domain reviewer has approved it. Treat every claim as provisional.
Notes
Off-target binding is binding to something other than the molecular target an agent was designed or chosen to reach. The phrase is defined relative to a purpose: a molecule that binds two receptors is "off target" at one of them only once an investigator has declared the other to be the goal. The ontology therefore records off-target binding as an interaction with a stated intended target, not as a defect of the molecule in isolation.
Several distinct phenomena hide under the one label. An agent may bind a structurally related molecule it was not designed for. It may bind the intended target where that target is expressed in normal tissue rather than in disease, which is sometimes called on-target but off-tumor. It may accumulate in an organ for reasons unrelated to binding, such as filtration by the kidney or uptake by cells that take up many substances. A pharmacologist, a toxicologist, and an imaging physician may each use "off-target" for a different one of these.
Naming an off-target interaction says nothing by itself about how much agent goes there, how long it stays, or what harm or benefit follows. Those are questions for biodistribution, dosimetry, and clinical study. NucLex links an off-target binding record to the affinity, biodistribution, and evidence records that bear on it and leaves the consequences to be stated separately.