Meditopes and meditope-binding antibodies and uses thereof

A complex comprising:

• a meditope-enabled antibody or antigen-binding fragment thereof, wherein the meditope-enabled antibody or antigen-binding fragment thereof comprises a meditope-binding site which (i) comprises a light chain variable (VL) region comprising a threonine at position 40, an asparagine at position 41, and an aspartate at position 85, according to Kabat numbering, and a heavy chain variable (VH) region comprising a serine or proline at position 40 and an isoleucine, tyrosine, methionine, phenylalanine, or a tryptophan at position 89, according to Kabat numbering and (ii) can bind to a peptide comprising the amino acid sequence of SEQ ID NO:
• 1 or 2;
• a meditope bound to the meditope-binding site;
• and
• a chemotherapeutic agent conjugated to the meditope,
• wherein the meditope comprises the formula:
• X1-X2-X3-X4-X5-X6-X7-X8-X9-X10-X11-X12 (SEQ ID NO:191) (Formula I), wherein:
• X1=Cys, Gly, β-alanine, 2,3-diaminopropionic acid, or null;
• X2=Gln or null;
• X3=Phe, Tyr, β-β′-diphenyl-Ala, 2-bromo-L-phenylalanine, 3-bromo-L-phenylalanine, or 4-bromo-L-phenylalanine;
• X4=Asp or Asn;
• X5=Leu, β-β′-diphenyl-Ala or Phe;
• X6=Ser;
• X7=Thr or Ser;
• X8=Arg or a modified Arg;
• X9=Arg or Ala;
• X10=Leu, Gln, or Glu;
• X11=Lys;
• and
• X12=Cys, 7-aminoheptanoic acid, β-alanine, or null,
• wherein:
• the modified Arg has a structure of the formula
• and
• wherein the meditope-enabled antibody or antigen-binding fragment thereof is not cetuximab.