Epidermal growth factor receptor inhibitors

A method of promoting internalisation and/or lysosomal degradation of EGFR in a cell, said method including the step of contacting the cell with an effective amount of a cyclic peptide comprising the sequence of the formula:

• Xaa1-Xaa2-Xaa3-Xaa4-Xaa5
• in which:
• Xaa1 is F or 1NapA;
• Xaa2 is L or I;
• Xaa3 is S or T;
• Xaa4 is F or 2NapA;
• and
• Xaa5 is R or K;
• or a pharmaceutically acceptable salt, solvate or prodrug thereof, to thereby promote internalisation and/or lysosomal degradation of EGFR in the cell.

A method of identifying, designing or producing an agent capable of interacting with or binding to a ligand binding domain of EGFR, said method including the steps of:

• (a) contacting a cell expressing EGFR with a candidate agent, wherein the candidate agent is a derivative, variant or analogue of:
• (i) cyclo-((2-Nal)-Leu-Ser-(2-Nal)-Arg);
• or (ii) a cyclic peptide of the formula:
• Xaa1-Xaa2-Xaa3-Xaa4-Xaa5
• in which:
• Xaa1 is F or 1NapA;
• Xaa2 is L or I;
• Xaa3 is S or T:
• Xaa4 is F or 2NapA;
• and
• Xaa5 is R or K;
• or a pharmaceutically acceptable salt, solvate or prodrug thereof;
• and
• (b) determining whether the candidate agent inhibits the binding of an EGFR ligand to EGFR of the cell.