Conjugates comprising an anti-EGFR1 antibody

A conjugate comprising an anti-EGFR1 antibody, or a Fab or F(ab′)2 fragment thereof, and at least one dextran derivative, wherein

• the dextran derivative comprises at least one D-glucopyranosyl unit comprising at least one carbon selected from carbon 2, 3 or 4 thereof comprising:
• —O—(CH2)n—S—B12H112−
• wherein n is in the range of 3 to 10;
• the dextran derivative is bound to the anti-EGFR1 antibody or a Fab or F(ab′)2 fragment thereof via a bond formed by a reaction between at least one aldehyde group of a D-glucopyranosyl unit of the dextran derivative and a lysine of the anti-EGFR1 antibody or Fab or F(ab′)2 fragment thereof;
• the anti-EGFR1 antibody or Fab or F(ab′)2 fragment thereof binds EGFR1, is internalized by a cell expressing EGFR1;
• and,
• the anti-EGFR1 antibody or Fab or F(ab′)2 fragment comprises:
• the amino acid sequence of SEQ ID NO:
• 2 and SEQ ID NO:3;
• the amino acid sequence of SEQ ID NO:
• 3 and SEQ ID NO:
• 6;
• the amino acid sequence of SEQ ID NO:
• 3 and SEQ ID NO:
• 7;
• the amino acid sequence of SEQ ID NOS:
• 4 and SEQ ID NO:
• 5;
• the amino acid sequence of SEQ ID NO:
• 14;
• the amino acid sequence of SEQ ID NO:
• 15;
• a light chain variable region encoded by polynucleotide at least 90% identical to SEQ ID NO:
• 8 and a heavy chain variable region encoded by polynucleotide at least 90% identical to SEQ ID NO:
• 9;
• a light chain encoded by polynucleotide at least 90% identical to SEQ ID NO:
• 10 and a heavy chain encoded by polynucleotide at least 90% identical to SEQ ID NO:
• 11;
• an amino acid sequence encoded by a polynucleotide at least 90% identical to SEQ ID NO:12;
• or,
• an amino acid sequence encoded a polynucleotide at least 90% identical to SEQ ID NO:13;
• wherein said conjugate is produced by:
• a) combining X—(CH2)mCH═CH2 wherein m is in the range from 1 to 8, and X is Br, Cl, or I, and dextran comprising multiple D-glucopyranosyl units, to produce allylated dextran comprising —OCH2CH═CH2 at C2, C3 or C4 of at least one of said D-glucopyranosyl units, said allylated dextran further comprising unmodified D-glucopyranosyl units;
• b) reacting B12H11SH, and said allylated dextran in the presence of a radical initiator selected from the group consisting of ammonium persulfate, potassium persulfate, or UV light to produce borocaptate dextran (BSH-dextran) comprising —O(CH2)n—S—B12H11 at said C2, C3 or C4 of said at least one D-glucopyranosyl unit;
• c) oxidizing said BSH-dextran using an oxidizing agent selected from the group consisting of sodium periodate, periodic acid, and lead(IV) acetate to produce oxidatively cleaved BSH-dextran comprising free aldehydes on at least one of said unmodified D-glucopyranosyl units;
• and,
• d) producing a conjugate of said oxidatively cleaved BSH-dextran and said anti-EGFR1 antibody Fab or F(ab′)2 fragment by reacting at least one of said free aldehydes of said oxidatively cleaved BSH-dextran with at least one lysine of the anti-EGFR1 antibody or Fab or F(ab′)2 fragment;
• and,
• wherein unreacted aldehyde groups of the oxidatively cleaved BSH-dextran obtained from step c) or a conjugate obtained from step d) are capped using a hydrophilic capping agent.