GTC Biotherapeutics (fka GTCB)

[DewDiligence]

Alternative Biomanufacturing Opportunities Abound

[This somewhat superficial overview of the transgenics field is from a trade magazine for contract manufacturers. Among the companies mentioned are Ventria Bioscience, Sigma-Aldrich, Biolex, SemBiosys, Origen, AviGenics, Trans Ova, Hematech, Pall, Pharming and, of course, GTC. #msg-18566945 and #msg-16835174 make good companion reads. Don’t miss Tom Newberry’s DVD analogy near the end of the article.]

http://contractpharma.com/articles/2007/10/bio-news-views

>>
by Paul Di Filippo
Contract Pharma
October 2007

Through selective breeding, humanity has been improving on the products of natural evolution for at least 15,000 years. The urge to tinker with plants and animals and other organisms to bring them closer to the needs, desires, and even whims of our species is a strong and constant imperative. But it's only since 1973, when the first E. coli was engineered to express an inserted salmonella gene, that we have had the powerful ability to radically alter the genomes of organisms by implanting genes from other species into the hosts, thus causing them at times to express useful compounds alien to their evolution. This powerful recombinant technique produces transfected cells or entire organisms commonly called "transgenics."

Today, after a period littered with false starts and failures -- for instance, Monsanto abandoned its transgenic division, Integrated Protein Technologies, in 2003, Large Scale Biology went bankrupt and Viragen has likewise left the field -- transgenics are finally beginning to fully assume a role in the biotech industry that has been predicted for them over the last several decades. Approximately 300 companies and 150 academic centers are active on this front today. [Only a few of these organizations have anything close to a commercial platform, however.]

Transgenic organisms of all types, engineered to produce a variety of biologically active agents, are coming online in sufficient quantities to produce clinical and commercial amounts of product, rivaling and often outperforming traditional cell culture methodologies. Kinks in expression, harvesting and refinement of their output have been overcome. Clinical trials are underway on many products of transgenic origin intended for direct use by consumers. And in fact, the very first such drug, ATryn®, a human antithrombin or anticlotting protein secreted into the milk of transgenic goats developed by GTC Biotherapeutics, has just been approved for human use in Europe.

Admittedly, even in conventional bioreactors and fermentation facilities, the mammalian or microbial cultures generally qualify as transgenics, having been created through recombinant means. But there is undeniably a more striking, more visceral, science-fictional quality about a multi-celled transgenic creature, a higher organism such as a plant or animal, which commands awe and sometimes provokes fear and suspicion.

These new plants and animals represent the bold, expanding frontier of co-opting evolution's own rooted, clawed, finned and hooved "factories" to express a whole range of biotherapeutics. The field is rich with potential, but also not without its stumbling blocks, both in terms of the science involved and public perceptions.

Plants

Agriculture is a defining quality of civilization. It's second-nature for us to plant and reap. The technologies involved in agriculture are well-known and time-tested. (The same is true of animal husbandry, of course.) Thus it makes good sense to utilize common crops in a transgenic fashion. If familiar plants such as rice, corn and tobacco can be made to express novel proteins by the insertion of human or other genes, then easy cultivation and large-scale harvests will achieve economies unavailable to pre-existing industrial methods, lowering the unit cost of drugs and increasing their availability.

A large number of firms are already active or moving into this area. Sacramento-based Ventria Bioscience has recently secured preliminary USDA approval to begin planting as many as 3,200 acres in Geary County, KS, with its rice that produces human immune proteins such as lactoferrin and lysozyme. These proteins would find their role as anti-diarrhea medicines.

Meanwhile, Sigma-Aldrich is already selling aprotinin derived from transgenic tobacco plants. Aprotinin is a crucial reagent used in the creation of vaccines and antibodies, the natural source of which is bovine lung tissue. As one might imagine, harvesting aprotinin from plants avoids bottlenecks and fluctuations associated with the slaughterhouse sources. Sigma-Aldrich also offers TrypZean, its alternative to bovine and porcine trypsin. TrypZean is expressed in corn.

Surely one of the more exotic plants dragooned into humanity's vegetable army is lemna, more commonly known as duckweed. This aquatic plant possesses the advantages of clonal replication, a 36-hour doubling time, and high expression rates. These features are to be found in Biolex Therapeutics's LEX (Lemna Expression) System. Biolex has induced lemna to express Locteron™, the first controlled-release interferon alfa [#msg-23627875], to be used in the treatment of chronic hepatitis C. Additionally, the company has coaxed lemna to produce BLX-155, their equivalent of human plasma-derived plasmin, a useful thrombolytic agent.

Transgenic plants are hardly limited to the U.S. Over the border in Calgary, Canada, we find a company called SemBioSys, whose president and chief executive officer, Andrew Baum, made time in his busy schedule to be interviewed by Contract Pharma.

After detailed comparisons between various oilseed crops, SemBioSys chose to focus on the humble safflower plant in its Stratosome™ Biologics System. As its website explains, "SemBioSys' proprietary technology harnesses the natural ability of seeds to produce, extract and purify proteins in large quantities and at low cost, while dramatically reducing downstream purification costs. It is unique as the only transgenic technology that addresses protein recovery and purification simultaneously with bulk protein production. SemBioSys' technology is compatible with simple peptides, polypeptides and complex proteins such as antibodies." [However, the first two projects are insulin, the simplest of proteins, and Apo A1; no antibodies have yet been produced using the company’s transgenic platform.]

Mr. Baum asserted that the system can "reduce capital costs by 70% or more [and] costs of goods by 40-80%, depending on the protein." So far SemBioSys is focusing on the production of insulin and Apolipoprotein AI (a cardiovascular treatment to reduce plaque). "We have achieved commercial levels of production [of insulin] and are in a position to go into the clinic with that product early next year," he noted.

SemBioSys has paid heed to public concerns about growing human proteins outdoors, a contentious issue that Ventria has also had to face [#msg-18566945]. Mr. Baum remarked, "We need to be sensitive to environmental concerns. Safflower pollen isn't windborne. There are no weedy relatives in the western hemisphere. The seed doesn't over-winter or compete well, and it's very easy to obtain segregation [from conventional safflower crops]."

With additional products on the horizon – SemBioSys has recently confirmed that it has developed commercial levels of Apo AI Milano in its safflower seed lines [#msg-22266007], and expects to have the native Apo AI commercial levels of accumulation later this year -- Mr. Baum confidently stated, "Our technology platform is unique and allows us to fundamentally address the economics of protein manufacturing."

Avians

Moving away from the plant kingdom, the animal options for transgenic drug production are numerous. Robert Kay, chief executive officer of Origen Therapeutics, foresees the commercialization of many different animal platforms, including mice, rats, goats, cows, pigs, sheep and chickens. It's that last species that Origen has bet on, working to create a line of birds that will express polyclonal antibodies in their eggs.

(Many of the advances in using chickens as transgenic organisms stem from the pioneering research of Helen Sang at the Roslin Institute.)

One of the leaders in avian "bioreactors" is AviGenics, based in Athens, GA. Founded more than 10 years ago and inspired by the work of Dr. Robert Ivarie at the University of Georgia, AviGenics today stands as a survivor of the first wave of industry excitement, when it seemed possible that transgenics might produce "kilos and kilos of drugs for a penny." The firm's chief executive officer, Yashwant Deo, made a strong case in his interview for the superior utility of his feathered platform.

He remarked, "In 2003, we concluded that contract manufacturing is not the way we want to go. We have a unique technology that can overcome several intellectual property problems. Plus we can produce proteins very efficiently and inexpensively. This combination drove us into biotherapeutics.

"We have produced several bio-therapeutic proteins using our transgenic avian system; cytokines, monoclonal antibodies, fusion proteins, enzymes etc. Two of these products, human Interferon and human G-CSF, have been shown to be safe and effective in FDA-approved Phase I human clinical trials. A Phase II clinical trial is in progress and clinical testing for other products will follow soon. G-CSF alone is a $4 billion market today."

One advantage derives from the fact that the drugs produced in the transgenic avian eggs are concentrated solely in the whites of each egg, and, according to Dr. Deo, "the whites are a very simple matrix. When you produce something in bacterial or mammalian cell cultures, there are all kinds of contaminants; numerous known and unknown proteins, DNA, RNA, lipids, carbohydrates etc… Egg white is a pure mixture of carbohydrates, known proteins, water and minerals. Easier to purify the bio-therapeutic protein from." Also, glycolysation [sic], an important step in protein formation that transgenic plant-based manufacturers often have to undertake separately, occurs naturally in the egg derived proteins.

Transgenic chickens individually produce about 250 eggs per year, and they mature and ‘come online' much faster than mammals. But a life of drug production does not preclude the well-being of the birds. Said Dr. Deo, "The chickens on our farms live far better than any other chickens in the world. They are not killed like commercial birds at six months, but live out their natural lives. The product is harvested only from the eggs."

With the proven ability to produce a variety of proteins, AviGenics' birds can turn out human antibodies and other biotherapeutics, insuring that AviGenics will continue to play a prominent part in the industry, benefiting also from Georgia's role as the dominant poultry state in the nation.

Mammals

When the platform for transgenic drug production shifts to mammals, a whole new set of issues related to both breeding and husbandry arise.

For breeding concerns, it helps newcomers to have a source of expert established advice, such as that provided by Trans Ova Genetics, of Sioux Center, Iowa. [TransOva was GTC’s partner on the albumin program that has effectively been shelved.] Established in 1980 and at first focused mainly on standard Embryo Transfer and IVF technologies, Trans Ova has come to play a significant role in the creation of transgenics.

President David Faber explained, "We work with companies such as Hematech and GTC Biotherapeutics to bridge the gap between molecular biology and product. With transgenics, the gap involves embryo technology, recipient animals, gestation, calving and rearing, collection of material for preclinical trials, and so on."

Trans Ova's specialty is bovines. They maintain 3,000 to 5,000 recipient cows at various centers, and have extensive experience with both embryo microinjection and cloning technologies. "We have the capability to assist [transgenic firms] and do things more efficiently and quickly than they could by attempting to build a system on their own."

Hematech, a subsidiary of the Japanese firm Kirin Pharma Company, Ltd. and located in Sioux Falls, SD, is one of those firms that has used Trans Ova's bovine expertise and their own "unique TC Bovine technology" to develop "human antibody-producing cows, making it possible to create an efficient, safe, and steady supply of polyclonal antibodies in larger quantities."

But cows are only one mammalian platform, as the people at Pharming, a Dutch firm, will attest. They have created transgenic rabbits that express in their milk Rhucin, a recombinant human C1 esterase inhibitor used to treat acute attacks of Hereditary Angioedema (HAE). Pharming's chief commercial officer Rein Strijker touts his firm's ability to produce massive quantities of drug: between 10 and 12 grams of protein per liter of rabbit milk, as opposed to highly optimized cell cultures that generate usually 0.2 to 1 grams of protein per liter of culture medium.

Meanwhile, at GTC Biotherapeutics in Framingham, MA, goats seem to be the ideal solution to that company's particular quest. And certainly this choice of caprine platform has paid off enormously; GTC can now boast a historical milestone with the release of "ATryn®, our recombinant form of human antithrombin, the first transgenically produced protein to be approved anywhere in the world, having recently been approved by the European Commission for the prophylactic treatment of deep vein thrombosis in patients with hereditary antithrombin deficiencies that are undergoing surgical procedures," according to a company statement.

But this victory occurred only after the long passage of 14 years from the creation of the first ATryn® goat, and also after an initial disappointing denial by the European Medicines Evaluation Agency (EMEA).

Tom Newberry, vice-president of corporate communications at GTC, detailed the strategies behind his company's tenacious success: "You pick one thing and try to be the best at that thing." In GTC's case, goat's milk was that one thing. "The epithelial cells in the mammary gland are in an optimum nutrient environment and very densely packed. Their job is to express proteins into the fat-soluble solution we call milk. You're not trying to take a single cell out of its natural environment and culture it up in an environment that's not necessarily as conducive, and trying to find a new set of optimum nutrients. And then trying to get the cell to do something it doesn't normally do. And because the mammary gland is somewhat resistant to leakage back into the animal, you can produce drugs with relatively high activity without harming the animal. That's important to us as well."

This regard for the welfare of their animals echoes AviGenics concern for its chickens. And like SemBioSys, GTC has insured that its altered animals interact properly with the local environment.

"The first objective of our biosecurity measures is to insure that the animal isn't sick. It's a closed herd here. All breeding is done on the site, and no animals ever leave alive. They're behind double separation. We have insect- and bird-control measures. But we don't try to hermetically seal the goats away. They get fresh air and sunshine and can go outdoors. And their health plan is far better than anything I get," said Mr. Newberry.

With this solid system in place, GTC is moving ahead on producing alpha-1 antitrypsin, human serum albumin, CD20 monoclonal antibody, and Factor VIIa. Factor VIIa, a coagulation treatment, currently sells for one million dollars per gram, offering the potential for hefty profits down the line.

Purification

Researching products, creating and breeding and managing the transgenics themselves, performing clinical trials… isn't there any part of this whole process that can be passed off to someone else?

As a matter of fact, there is! The purification and concentration steps! Many specialized companies exist which already handle the output of industrial bioreactors and fermentors. They are superbly equipped -- with some ingenious modifications -- to handle the milk, blood, other fluids and plant biomass that the transgenics produce. For instance, SemBioSys utilizes Cangene for its insulin refining.

Two other companies with vast experience in this field are Pall Corporation and SAFC, a unit of Sigma Aldrich. GTC has had preliminary discussions with SAFC about producing ATryn for the DIC indication (#msg-23290951).]

Jerold Martin, senior vice president for Scientific Affairs at Pall, shared with us his company's role in facilitating the production of transgenic drugs. "We don't do any of the purification ourselves, but we manufacture the filtration and chromatography equipment that are used for purification and sell it to either the companies that are producing drugs in-house, or to the contract manufacturers," said Mr. Martin. "One of the ways that Pall plays a leading role in transgenic drug manufacturing stems from being an industrial filtration company. For instance, we are also the leading supplier of filters in beer production."

Pall's vast experience with foodstuffs and biomass has allowed it engineer equipment such as ceramic filters and vibrating filters, ultrafilters and chromatography rigs specifically designed to deal with purifying transgenically produced molecules.

"Companies come to us and ask us to help them design the processes that will clarify and purify their feeds. We do preliminary work in our own lab to determine what is the best technology to apply. Then, once we establish that, we go out in the field with that equipment and work to optimize the process. We're the enabler."

At SAFC, however, particularly at their facility in St. Louis, MO, actual processing and manufacturing on a large scale are the order of the day. According to a company statement, the 25,000-sq.-ft. aqueous extraction/cGMP purification facility can process more than 6 tons of biomass per week from plant biomass and depending on the expression level produce up to 5kg of therapeutic protein per batch. The new facility has 3, 2500 L extraction tanks that are set up for semi-continuous processing and large upstream clarification suites for the initial solid separation steps. cGMP purification is performed in a 1,100-sq.-ft., class 100,000 (ISO 8) purification suite or a 700-sq.-ft., class 10,000 (ISO 7) purification suite, using up to 1 meter chromatography columns, ultrafiltration, and/or aseptic filling in a class 100 (ISO 5) biosafety hood.

Tom Gelineau, director of business development at SAFC, tells Contract Pharma, "We deal with just about every transgenic company. We consider ourselves the leading company in providing contract purification services for transgenic products."

Mr. Gelineau explained that plant and animal input streams have to be kept separate. "Companies don't like you to mix plant and animal products in the same facility."

The multistage purification process ends with a certain amount of waste material. Currently, the quantities are so small as to allow disposal by incineration or burial. But in the future, "If we ever generate hundreds and hundreds of tons of biomass, we will look into using it in a commercial application."

With its ability to flourish outside traditional biotech centers, in any geographic locale that has a tradition of supporting agriculture or animal husbandry, and with a vigilant eye toward maintaining good relations with the citizenry and quelling their doubts and fears by implementation of well-designed safeguards, transgenic drug production has the potential to be the ideal green-yet-high-tech industry, both profitable to investors and beneficial to consumers.

Enlisting support on the front end from firms such as Trans Ova, and on the back end from corporations like Pall and SAFC, the plant and animal genetic engineers in the middle can focus on developing new biotherapeutics, selecting the best platforms, and creating the most efficient system of fields and herds and flocks that will produce the most valuable biomass.

"It's an exciting time," opined Mr. Newberry of GTC. "It's similar to when DVDs arrived as a new way of viewing movies, as opposed to VHS tapes. Many people in the industry today understand cell culture -- the equivalent of a closet full of tapes. They have a little bit of a don't-bother-me syndrome. But like DVDs, transgenics offer a much broader range of technical capabilities delivered in an efficient manner. People will find uses for that."

"Transgenics are just now starting to take off," said Mr. Gelineau of SAFC. "The hope is that this industry will allow us to make drugs more cost-effectively."

"The market needed to gain confidence in these platforms," Mr. Faber of Trans Ova maintained. "They're gaining momentum, and transgenic animals have the ability to serve many market spaces."

Mr. Newberry added, "Transgenic technology delivers three benefits that are difficult to get out of traditional technology. You can express proteins that are otherwise difficult to do in other cell cultures, at least at a commercially viable level. You can get to very large volumes at a very low investment. And once you have a product being expressed, you can scale up in a linear fashion that can be matched to your demand curve."

Mr. Baum of SemBioSys sensibly summed up the industry outlook: "The early promise of transgenics was oversold. Then, people got overly pessimistic. Now we have a more balanced, nuanced view of the industry. Transgenics are a hammer useful for certain nails, but not every protein is a nail."
<<