Patent ID: 8158132

Claim:
A non-cytotoxic agent that binds to a nociceptive afferent neuron, comprising: a Targeting Moiety (TM) coupled to a modified clostridial neurotoxin in which the TM comprises a ligand to a cell-surface binding site present on a nociceptive afferent neuron; and the heavy chain (H-chain) of the clostridial neurotoxin is removed or modified by chemical derivatisation, mutation or proteolysis to reduce or remove its native binding affinity for motor neurons; and the light chain (L-chain) of the clostridial neurotoxin or a fragment thereof retains a protease activity specific for components of the neurosecretory machinery; the TM and the modified H-chain, if present, forming a molecule that introduces the L-chain or fragment thereof into the cytosol of a nociceptive afferent neuron, thereby inhibiting the transmission of signals between a nociceptive afferent neuron and a projection neuron by controlling the release of at least one neurotransmitter or neuromodulator from the nociceptive afferent neuron; and wherein the modified clostridial neurotoxin component is not obtained from tetanus neurotoxin; wherein the TM is selected from the group consisting of human nerve growth factor, human pro-nerve growth factor, human enkephalin, human leu-enkephalin, human met-enkephalin and human bradykinin.