<unk> s or SMDCs are built with three modules: a targeting ligand, a linker and a<unk>  payload. The targeting ligands consist of low<unk> r weight, high-affinity ligands that are precisely linked to potent<unk> s. The linkers are designed to be stable in the bloodstream and then release the active<unk>  from the targeting ligand when the SMDC is taken up by the diseased cell. The<unk>  payloads are highly active<unk> s that are too toxic to be administered in their untargeted forms at therapeutic dose levels. This modular approach allows varying targeting ligands, linker systems and<unk>  payloads and generate SMDCs for different diseases. The most advanced SMDC is vintafolide, a derivative of the anti-mitotic chemotherapy<unk>  vinblastine which is chemically linked to folic acid. Potent, bioactive natural products like triptolide that inhibit mammalian transcription has been recently reported as a glucose conjugate for targeting hypoxic cancer cells with increased glucose transporter expression. SMDCs are currently being developed by Endocyte for treating cancer, inflammatory diseases and kidney disease, as well as a companion imaging agent that is created by replacing the potent<unk>  with an imaging agent.
Small molecule drug conjugate
Immunoconjugate
Pharmacological chaperone
Small modular immunopharmaceutical
Monoclonal antibody
Magnetic-targeted carrier
Antimetabolite
Targeted covalent inhibitors