METHODS OF INACTIVATING VIRAL CONTAMINANTS

1 . A method for preparing a virus-inactivated antibody solution, the method comprising: (i) harvesting antibody material produced by transfected cells comprising coding sequences of an antibody, which transfected cells have undergone cell culture, (ii) subjecting said harvested antibody material to a virus inactivation treatment, wherein said virus inactivation treatment is incubation with a mixture of a solvent and a detergent, wherein said harvested antibody material is a clarified harvest.

2 . The method of claim 1 , wherein said harvested antibody material is produced in non-human mammalian cells.

3 . The method of claim 1 , wherein said harvested antibody material comprises a monoclonal antibody.

4 . The method of claim 3 , wherein said monoclonal antibody is a recombinant antibody.

5 . The method of claim 3 , wherein said monoclonal antibody is multispecific.

6 . The method of claim 1 , wherein said solvent is TnBP and, wherein said detergent is selected from the group consisting of Triton X-100, Polysorbate 80 and Polysorbate 20.

7 . The method of claim 6 , wherein the concentration of said TnBP is between about 0.10% (w/w) and about 1% (w/w).

8 . The method of claim 6 , wherein the concentration of said TnBP is selected from the group consisting of: about 0.1% (w/w), about 0.3% (w/w), about 0.5% (w/w) and about 1% (w/w).

9 . The method of claim 6 , wherein the concentration of said Polysorbate 80 or said Polysorbate 20 is between about 0.1% (w/w) and about 2% (w/w).

10 . The method of claim 6 , wherein the concentration of said Polysorbate 80 or said Polysorbate 20 is selected from the group consisting of: about 0.2%, about 0.5% (w/w), about 0.75% (w/w), about 1% (w/w), and about 1.25% (w/w).

11 . The method of claim 1 , wherein said mixture of a solvent and a detergent is selected from the group consisting of a mixture of 0.3% (w/w) TnBP and 0.5% (w/w) Polysorbate 80, and a mixture of 0.3% (w/w) TnBP and 1% (w/w) Polysorbate 80.

12 . The method of claim 11 , wherein said harvested antibody material is incubated with a mixture of 0.3% (w/w) TnBP and 1% (w/w) Polysorbate 80 for at least 5 minutes.

13 . The method of claim 11 , wherein said harvested antibody material is first subjected to protein A chromatography, and wherein a resulting protein A eluate is incubated with a mixture of 0.3% (w/w) TnBP and 1% (w/w) Polysorbate 80 for at least 10 minutes at room temperature.

14 . The method of claim 11 , wherein said harvested antibody material is incubated with a mixture of 0.3% (w/w) TnBP and 1% (w/w) Polysorbate 80 for about 60 minutes, under agitation, at room temperature.

15 - 20 . (canceled)

21 . The method of claim 1 , comprising a further step (iii) of testing a portion of the virus-inactivated antibody solution with a viral inactivation assay.

22 . A method of production of a bulk drug substance, the method comprising:

(a) culturing host cells which have been transfected with coding sequences of an antibody so as to express the antibody;

(b) harvesting a cell culture containing the antibody to obtain a harvested antibody material;

(c) subjecting of the harvested antibody material to viral inactivation by incubating with a mixture of solvent and detergent, wherein said harvested antibody material is a clarified harvest material and is incubated with a mixture of 0.3% (w/w) TnBP and 1% (w/w) Polysorbate 80 for about 60 minutes, under agitation, at room temperature;

(d) subjecting the resulting viral inactivated solution to protein A chromatography;

(e) neutralizing the protein A eluate to pH 6.0, followed by passing the neutralized protein A eluate through a 0.2 μm filter;

(f) subjecting the neutralized protein A filtrate to cation exchange chromatography to produce a cation exchange chromatography eluate, followed by passing the cation exchange chromatography eluate through a 0.2 μm filter;

(g) concentrating the cation exchange chromatography filtrate by ultrafiltration and continuous diafiltration, followed by passing the concentrated ultra-diafiltrate through a 0.2 μm filter;

(h) purifying the concentrated ultra-diafiltrate by anion exchange chromatography in flow through mode, using membrane adsorption, followed by passing the anion exchange chromatography eluate through a 0.2 μm filter;

(i) subjecting the purified anion exchange chromatography filtrate to virus nanofiltration;

(j) concentrating the nanofiltrate by ultrafiltration and continuous diafiltration into a pre-formulation buffer, followed by passing the ultra-diafiltrate containing pre-formulation buffer through a 0.2 μm filter;

(k) adding excipient to the filtered, ultra-diafiltrate containing pre-formulation buffer to obtain a bulk drug substance with a concentration of about 6 mg/mL in a final formulation buffer by adding 5 mM Citrate, 15% Sucrose, and 0.06% Polysorbate 80 at pH 5.9, followed by passing the bulk drug substance through a 0.2 μm filter; and

(l) filling the filtered bulk drug substance into sterile bags, followed by freezing and storage at −80±20° C.

23 - 24 . (canceled)

25 . The method of claim 6 , wherein the concentration of said Polysorbate 80 or said Polysorbate 20 is between about 0.2% (w/w) and about 1.5% (w/w).

26 . The method of claim 6 , wherein the concentration of said Polysorbate 80 or said Polysorbate 20 is between about 0.75% (w/w) and about 1.25% (w/w).

27 . The method of claim 6 , wherein the concentration of said Triton X-100 is between about 0.1% (w/w) and about 2% (w/w).

28 . The method of claim 1 , wherein said mixture of a solvent and a detergent is selected from the group consisting of: a mixture of 0.3% (w/w) TnBP and 0.2% (w/w) Triton X-100, a mixture of 0.3% (w/w) TnBP and 0.5% (w/w) Triton X-100, and a mixture of 0.3% (w/w) TnBP and 1% (w/w) Triton X-100.