Replies to post #887 on GTC Biotherapeutics (fka GTCB)

[used to make chicken]

I believe their control of glycosylation is actually fairly limited. I haven't read the text of this patent yet, but what I assume at this point is that they can control via minor sequence variations whether a glycosylation site is present, or not. Once a site is present, they cannot control the types of chains that are attached to the protein. Variants at that level can be recognized and purified, but not preferentially generated.

All of this is good though. Just look at Amgen, where a minor change to EPO resulted in NESP, and improved product in terms of performance, not to mention patent protected just in time for the EPO patents to expire.