Therapeutic Target Database (TTD) is a pharmaceutical and medical repository constructed by the Innovative Drug Research and Bioinformatics Group (IDRB) at Zhejiang University, China and the Bioinformatics and Drug Design Group at the National University of Singapore. It provides information about known and explored therapeutic protein and nucleic acid targets, the targeted disease, pathway information and the corresponding drugs directed at each of these targets. Detailed knowledge about target function, sequence, 3D structure, ligand binding properties, enzyme nomenclature and drug structure, therapeutic class, and clinical development status. TTD is freely accessible without any login requirement at https://idrblab.org/ttd/.
This database contains 3,730 therapeutic targets (532 successful, 1,442 clinical trial, 239 preclincial/patented and 1,517 research targets) and 39,862 drugs (2,895 approved, 11,796 clinical trial, 5,041 preclincial/patented and 20,130 experimental drugs). The targets and drugs in TTD cover 583 protein biochemical classes and 958 drug therapeutic classes, respectively. The latest version of the International Classification of Diseases (ICD-11) codes released by WHO are incorporated in TTD to facilitate the clear definition of disease/disease class.
Target validation normally requires the determination that the target is expressed in the disease-relevant cells/tissues, it can be directly modulated by a drug or drug-like molecule with adequate potency in biochemical assay, and that target modulation in cell and/or animal models ameliorates the relevant disease phenotype. Therefore, TTD collects three types of target validation data:
The therapeutic targets in TTD are categorized into successful target, clinical trial target, preclinical target, patented target, and literature-reported target, which are defined by the highest status of their corresponding drugs.
The molecular types of therapeutic targets in TTD include protein, nucleic acid, and other molecule.
The main drug types in TTD include small molecule, antibody, nucleic acid drug, cell therapy, gene therapy and vaccine.
<big>â </big> Target druggability illustrated by molecular interactions or regulations;
<big>â </big> Target druggability characterized by different human system features;
<big>â </big> Target druggability reflected by diverse cell-based expression variations;
<big>â </big> Structure-based activity landscape and drug-like property profile of targets;
<big>â </big> Prodrugs together with their parent drug and target;
<big>â </big> Co-targets modulated by approved/clinical trial drugs;
<big>â </big> Poor binders and non-binders of targets;
<big>â </big> Target regulators (microRNAs & transcription factors) and target-interacting proteins;
<big>â </big> Patented agents and their targets (structures and experimental activity values if available);
<big>â </big> Differential expression profiles and downloadable data of targets in patients and healthy individuals;
<big>â </big> Target combination of multitarget drugs and combination therapies;
<big>â </big> Cross-links of most TTD target and drug entries to the corresponding pathway entries;
<big>â </big> Access of the multiple targets and drugs cross-linked to each of these pathway entries;
<big>â </big> Biomarkers for disease conditions;
<big>â </big> Drug scaffolds for drugs/leads;
<big>â </big> Target validation information (drug-target-disease);
<big>â </big> Quantitative structure activity relationship models (QSAR) for compounds;
<big>â </big> Clinical trial drugs and their targets;
<big>â </big> Similarity target and drug search.