Methods for quantitating individual antibodies from a mixture

A method of quantitating a first antibody and a second antibody in a mixture, the method comprising:

• separating the first antibody from the second antibody by using hydrophobic interaction chromatography high performance liquid chromatography (HIC-HPLC);
• quantitating an amount of the first antibody;
• quantitating an amount of the second antibody;
• wherein each of the first antibody and the second antibody:
• elutes at a distinct run time from other antibodies in the mixture, when individually run on HIC-HPLC;
• and
• is a bispecific antibody.

A method of quantitating antibodies from a co-formulated drug product comprising a plurality of antibodies, the method comprising:

• generating a standard curve for each antibody of the plurality of antibodies;
• separating each antibody of the plurality of antibodies by using hydrophobic interaction chromatography high performance liquid chromatography (HIC-HPLC), wherein each antibody of the plurality of antibodies binds to one or more proteins selected from the group consisting of:
• GITR, LAG3, PD-1, PD-L1, EGFR, CD28, PSMA, CD3, and CD20;
• and
• after separating each antibody, quantitating an amount of each antibody using the standard curve.

A method of quantitating antibodies in a mixture comprising a plurality of antibodies, the method comprising:

• generating a standard curve for each antibody of the plurality of antibodies;
• separating each antibody of the plurality of antibodies by using hydrophobic interaction chromatography high performance liquid chromatography (HIC-HPLC);
• generating a chromatograph from the HIC-HPLC;
• and
• quantitating an amount of each antibody of the plurality of antibodies;
• wherein each antibody elutes at a distinct run time from other antibodies of the of antibodies, when individually run on HIC-HPLC;
• and
• wherein at least one antibody of the plurality of antibodies is a bispecific antibody.