Production of heterodimeric proteins

1. An in vitro method for production of a heterodimeric antibody comprising the following steps:

a) incubating in a composition a first homodimeric antibody with a second homodimeric antibody under reducing conditions sufficient to allow reduction of the inter-chain disulfide bonds in the hinge region,

wherein said first homodimeric antibody comprises an Fc region of an immunoglobulin, said Fc region comprising a first human IgG1 CH3 region, and said second homodimeric antibody comprises an Fc region of an immunoglobulin, said Fc region comprising a second human IgG1 CH3 region, wherein said first homodimeric antibody has a K409R amino acid substitution (numbering according to the EU Index), and said second homodimeric antibody has an amino acid substitution selected from the group consisting of: L368A, L368D, L368E, L368G, L368H, L368I, L368N, L368Q, L368R, L368S, L368T, L368V, L368W, D399A, D399F, D399H, D399K, D399R, D399Y, F405A, F405D, F405E, F405H, F405I, F405K, F405L, F405M, F405N, F405Q, F405S, F405T, F405V, F405W, F405Y, Y407G, Y407L, Y407M, and Y407W (numbering according to the EU Index), and wherein the reducing conditions comprise adding a reducing agent,

b) subjecting the composition obtained from step a) to oxidizing conditions sufficient to allow oxidation of cysteines in the antibodies to inter-chain disulfide bonds, thereby obtaining a heterodimeric antibody.

2. The method according to claim 1 , wherein the reducing conditions in step a) comprise adding a reducing agent.

3. The method according to claim 2 , wherein the reducing agent is selected from the group consisting of: 2-mercaptoethylamine, a chemical derivative of 2-mercaptoethylamine, L-cysteine, and D-cysteine.

4. The method according to claim 1 , wherein step a) comprises adding a metal chelating agent.

5. The method according to claim 4 , wherein the metal chelating agent is EDTA, EGTA or citric acid.

6. The method according to claim 1 , wherein the reducing conditions in step a) comprise reducing the amount of oxygen in the composition in step a).

7. The method according to claim 1 , wherein step a) is performed under reducing conditions with a redox potential between −150 and −600 mV.

8. The in vitro method according to claim 1 , wherein step a) comprises incubation for at least 30 min at a temperature of at least 20° C. in the presence of at least 25 mM of a reducing agent selected from the group consisting of 2-mercaptoethylamine, L-cysteine and D-cysteine.

9. The method according to claim 1 , wherein the first and second homodimeric antibodies are in a buffer selected from the group consisting of a) 8.1 mM sodium phosphate (Na 2 HPO 4 -7H 2 O), 1.5 mM potassium phosphate (KH 2 PO 4 ), 138 mM sodium chloride (NaCl), 2.7 mM potassium chloride (KCl) pH 5.0; b) 8.1 mM sodium phosphate (Na 2 HPO 4 -7H 2 O), 1.5 mM potassium phosphate (KH 2 PO 4 ), 138 mM sodium chloride (NaCl), 2.7 mM potassium chloride (KCl) pH 7.0; and c) 20 mM Tris-HCl, pH 7.8.

10. The method according to claim 1 , wherein step b) comprises a pH in the range of 6-8.5.

11. The method according to claim 1 , wherein the oxidizing conditions in step b) comprise adding oxygen or an oxidizing agent.

12. The method according to claim 11 , wherein the oxidizing agent is dehydroascorbic acid (dhAA).

13. The method according to claim 1 , wherein step b) comprises separating the heterodimeric antibody and the reducing agent.

14. The method according to claim 1 , wherein the oxidizing conditions in step b) comprise the steps of:

I) diafiltration of the composition obtained from step a),

II) incubation of the retentate obtained from step I), and

III) diafiltration of the composition obtained from step II).

15. The method according to claim 1 , wherein the oxidizing conditions in step b) comprise a metal ion or adding a metal ion.

16. The method according to claim 15 , wherein the metal ion is selected from the group consisting of: Copper, Manganese, Magnesium, Iron, Nickel and Cobalt.

17. The method according to claim 1 , wherein the ratio of first to second homodimeric protein in step a) is in the range of 1:1.01 to 1:2.

18. The method according to claim 1 , wherein said first homodimeric antibody has no more than one amino acid substitution in the CH3 region, and the second homodimeric antibody has no more than one amino acid substitution in the CH3 region relative to the wild-type CH3 regions.

19. The method according to claim 1 , wherein said first homodimeric antibody has Arg at position 409 and said second homodimeric antibody has Leu at position 405.

20. The method according to claim 1 , wherein the first and/or second homodimeric antibody do not contain the c-terminal lysine.

21. The method according to claim 20 , wherein the first and/or second homodimeric antibodies are genetically modified to lack the c-terminal lysine in the heavy chain, or wherein the c-terminal lysine is removed from the heavy chain.