We keep Cetuximab for long periods (months) at 4 degrees and use it for in vitro assays.

I would store it at 4 degrees. Antibodies are usually very stable. You could expect that the antibodies will be active for years at +4C. The problem is that you may get some aggregation that could cause cell activation if you use them in vivo. I would follow the expiry date if I plan to use the antibodies in vivo. If I plan to use the antibodies in vitro I would store the antibodies at 4+C and use the antibody for long times.

Thank you both so much! Do either of you use the infusion-ready commercial product and, if so, is there any further advice specific to that which you could give me?

Thanks!

EF

Yes, we use the commercial product. We take samples under sterile conditions every time and keep the rest a 4 degrees. Perhaps sterility is not strictly necessary, but we use very small amounts (for binding assays) and our storage period is thus long. So we try to be careful.

Ok that is very reassuring! Gertrudis, I know sometimes antibodies in storage will conjugate with one another so a reducer (such as DTT is added). These sizes (15nm, 30nm, 45nm) can be measured using DLS however, my analysis has shown large peaks around 350nm, as well as the expected single antibody size (about 15nm).

Have you ever seen anything like this in your Erbitux?

Thanks so much!

EF

I havent done this kind of characterization. Only binding assays and in vitro neutralization assays, which work fine after long storage periods.

Thank you both for sharing!

EF