John,
You really don't wnat to look at things with an even hand. It is also clear you didn't take the time to read what I said or don;'t underastand what I said.
First, it didn't take GTCB 15 years to produce one protein in milk. It took 15 years or so for GTCB to build a portfolio or proprietary proteins, FOBs and biosimilars, get a protein approved in Europe, have the same protein about to be submitted for approval in the USA and secure multiple partners. All Glycofi did was do the basic initial step of modifying a yeast that can expresss proteins which appear to be glycolsyated similaryly to human cells. Please don't act as if they are at equivalent stages or that Glcofi is far more advanced, because it is way behind. When you suggest equivalence or even superiority, you only embarass yourself.
What the Glycfi sale means is that the developers were very happy to take the money, and sell the company and a bigshot in Merck decided it was a good purchase. You equate these events as proof this yeast is superior to GTCB's goats. Maybe the developers saw how long it would take to get a drug, any drug to FDA approval and they didn't want to work that long and hard so took the quick easy money. Executives make many mistakes and play things safe so you can't read very much into it other than one person thought it was money well spent. sucha deciosn.
<<vinny, I am guessing the disadvantage to using goats and mammary glands is that the genes are much more difficult to manipulate and more time consuming to arrive at a new protein expression.>>
Building the DNA constructs takes about the sames time, inserting them into cells takes about the same time, or a bit faster in yeast, but we are talking a few weeks. Yes, it will take longer to get a mature producing goat, but you could do tests in mice or rabbits while the goats are maturing. In any event, you are not going to be contiunously chanige the protein and then expect to get approval. You can make multiple versions in mice and tets then and quickly change to rabbit or goats. Beiosde for FOBs or biosimilars, you are ogign to want to get as close to the original molecular structure as possible. If you start tinkering you can get unwanted and unexpected surprises and will likely have to run the risk of doing long clinical trials.
<But it is ironic that you are now arguing that transgenic goats are a more natural way of expressing glycoproteins Vs genetically altered yeast.>
Yes, that is exactly what I am saying, and it is valid and logical. What is ironic about this? Do you know what ironic means? You are embarrassing yourself if you think that making yeast glycosylation similar to human glcyocsylation means the yeast produced protein is now fully equivalent to CHO cell culture or GTCB's goats. I am talking about reality as glcyoslyation is only one post-translational modification of proteins. I also told you about chaperones being needed to properly fold proteins, other proteolytic cleavage events which may be related to form a mature, functional protein. Did you know that misfolded proteins can generate an immune response so even if the yeast could make as much protein, significant misfolding could trigger unwanted reactions and lower specific activity.
<<In addition to all the other proteins that get expressed at the same time and the concern about prions.>>
Ah, the prion card emerges. GTCB has already shown they can prions and separate them away from the rATIII during their purification process, so you have struck out here. Do you know where and how prions emerge? Did you know GTCB's herd are certified prion free, and form prion free stock? Did you know that years have prions too? Go back and read carefully my previous post and then read some basic biology about protein folding and secretion and then come back. You are really annoying me with your wild and unsubstantiated jumps based on little or no information. Good night.
