Therapeutic Target Database (TTD)

The Therapeutic Target Database (TTD) lists therapeutic targets together with the approved and investigational drugs directed at each of them, which makes it a record of every protein anyone has tried to drug and what they tried. For each entry it records the target's validation status and the clinical stage reached by each drug, so a reader can see how far an attempt progressed. It is maintained by Zhejiang University and NUS and is free to use. OnCo lists it among its target and drug reference collections for tracing which targets have been pursued and with what.