Transgenic drug market heats up

The European Commission approved the first drug mass-produced by whole transgenic animals on Wednesday (August 2). Another similar drug has received fast-track approval status by the U.S. Food and Drug Administration (FDA), suggesting the products may be overcoming long-held concerns over their feasibility.

The drug approved in Europe, ATryn, is recombinant human antithrombin, an anticlotting protein secreted into the milk of transgenic goats developed by GTC Biotherapeutics in Framingham, Mass. Last year, ATryn went through regulatory pinball with the European Medicines Evaluation Agency (EMEA), who rejected it in February but then approved it upon further review in June.

Biotechnology most often employs cultured mammalian cells to generate protein drugs -- generally, an expensive process. The capital costs for a mammalian cell fermentation system that generates 100 kilograms of drug a year would run from $300 to $500 million, but 150 of GTC's goats can produce roughly the same amount of drug and cost a tenth as much, the company explained.

"The approval is a very significant milestone for the field of transgenic animal biotherapeutics," Burlingame, Calif.-based Origen Biotherapeutics president and CEO Robert Kay, whose company is developing transgenic chickens as drug manufacturing platforms, told The Scientist.

Meanwhile, across the pond, the U.S. is also reviewing drugs produced by whole transgenic animals. The drug candidate rhC1INH from Pharming Group in the Netherlands, which is directed against hereditary angioedema, is derived from transgenic rabbits, and received a fast-track designation for review by the FDA on July 28. "They're the closest to regulatory clinical status by far in the U.S.," GTC spokesman Thomas Newberry told The Scientist. GTC is currently working through a phase III trial for ATryn with the FDA.

Some experts have suggested that using transgenic animals is risky, given that if a product fails, the animals can't be used to make a different product. In addition, there are safety concerns that drugs made from transgenic animals might contain unintended modifications or contaminants. Biotechnology analyst Philip Nadeau at Cowen and Company in New York told The Scientist ATryn's approval "removes any lingering concerns that proteins manufactured like this simply aren't approvable."

However, Nadeau added that the recent approvals don't suggest transgenic platforms will completely replace the current infrastructure. "I don't expect a wholesale switch from the tried and true cell culture methodologies to transgenic production of proteins. So many drugs are produced by traditional cell culture methods, and the pharmaceutical industry doesn't like deviating too far from the trodden path."

Charles Choi
cchoi@the-scientist.com

Links within this article

European Commission Approves ATryn
http://www.transgenics.com/news.html

A McCook, "Manufacturing on a grand scale," The Scientist, February 14, 2005.
http://www.the-scientist.com/article/display/15256/

ATryn
http://www.transgenics.com/products/atryn.html

GTC Biotherapeutics
http://www.transgenics.com

EMEA Rejects ATryn
http://www.emea.eu.int/pdfs/human/opinion/QandA_Atryn_6202206en.pdf

EMEA Approves ATryn
http://www.emea.eu.int/pdfs/general/direct/pr/20316306en.pdf

Pharming Group
http://pharming.com/index.php?act=prod

Pharming Receives Fast Track Designation From US FDA For Recombinant Human C1 Inhibitor, July 28, 2006.
http://pharming.com/index.php?act=show&pg=289