Replies to post #4663 on GTC Biotherapeutics (fka GTCB)

[kris_kade]

This is from Q1 2006 CC transcript..which should clear any misgivings related to immmunogenicity issues.

On the issue of immunogenicity, I have stated many times that we have not seen any anaphylactic or allergic responses in any of the over 200 patients who have been treated with ATryn® in a number of clinical studies, including those patients given multiple doses. Nor have we identified antibody response to goat proteins or goat antithrombin nor inhibiting antibodies to ATryn®, and we have looked intensively for evidence of these.

We have argued the immunogenicity issue strongly in our response. Remember that the total potential level of contaminating proteins that may be present is 5 parts per million, or to say it another way, ATryn® is 99.9995% pure. This is a remarkably pure product, and as such, we believe carries a low inherent risk for immunological concerns from contaminated proteins

[vinmantoo]

You fearmonger shorts make me laugh. I never said it carries the same risk. I said the same issues are in play for purification.

<The same issues are in play for purification of proteins or antibodies from CHO cells (Chinese Hamster ovary).>

Do you need it spelled out more? Do you think CHO cells only secrete the exogenous protein that you express?