Many Factors Must Be Weighed In Decision To Purchase Antibodies

Sidebars New Antibody Technologies On Tap? Selected Suppliers of Antibodies During the past decade, few biological disciplines have captivated researchers as dramatically as immunology. Of particular interest are the molecules known as antibodies -- naturally occurring immune system proteins that seek out and bind to a virtually unlimited number of antigens, peptides, receptors, infectious organisms, other proteins, and so on. Their remarkable specificity and selectivity have driven the growth in the use of antibodies as the basis of dozens of commercial diagnostic processes and products. ACCURATE OFFERINGS: Accurate Chemical and Scientific's Axell polyclonal rabbit anti-CD44v3, left, for study of changes during tumor metastasis, and Axyll monoclonoal rat anti-MMSTR (metastasis marker for solid tumors) Like hundreds of other companies involved in biomedical research, Amersham International plc is finding its fortunes increasingly linked to antibody technology. Offering some 2,000 products pegged to major pharmaceutical companies, researchers, and other customers in the life sciences, Buckinghamshire, England-based Amersham has become a large-scale consumer of antibodies for use in developing test kits for drug screening and similar applications. Large volumes of antibodies for diagnostic, treatment, and research have traditionally been produced by only three methods: ascites (that is, in living animals), fermentation or stirred-tank reactors, and hollow-fiber bioreactors. Each has its own advantages. The ascites method, while highly labor-intensive, is generally recommended for the relatively economical production of small volumes of antibodies -- typically milligrams or less. Stirred-tank reactors are widely used for larger commercial volumes (usually more than 5 kg/year), although purification and separation costs tend to be high. Designers of the relatively new hollow-fiber reactors claim to offer much higher protein densities, and therefore improved efficiency and economics. Many such systems, however, are still under development, and actual performance remains to be verified in commercial practice. But producers of antibodies and other important proteins may one day be able to crank out their products from genetically engineered plants and animals as well -- at higher efficiency rates and, allegedly, dramatically lower costs. Speaking at a spring conference sponsored by Southborough, Mass.-based International Business Communications, James S. Tuan, business development director for Middleton, Wis.-based Agracetus Inc., a plant-genetics R&D unit of Monsanto Co., described a proprietary "plant bioreactor system" that is said to yield "kilograms per acre" of unpurified proteins. Working now with corn and soybean, company researchers inject DNA into plant cells using Agracetus's proprietary Accell gene-delivery system. The cells are then grown and harvested by ordinary agricultural methods. Agracetus predicts an economic advantage of two to four orders of magnitude compared with conventional animal-cell culture and fermentation reactors. Scale-up, according to the company, is achieved simply by planting more seeds as required. At the same conference, Harry Meade, director of research for Framingham, Mass.-based Genzyme Transgenics, related the company's experiments with genetically altered goats as protein sources. Genzyme Transgenics, a new research subsidiary of Genzyme Corp., has no products at this point. The advantage of the method, Meade maintains, is that the protein of interest is produced in the animal's milk by the mammary gland-an organ whose primary function is to secrete protein. By Meade's calculation, a transgenic goat (which can develop in just 18 months from a genetically altered cell to a lactating adult) can produce up to 500 liters of milk per year. That volume of milk, he says, can produce up to a kilogram of recoverable unpurified protein per year, at only about $2 per gram. Genzyme Transgenics is now said to be producing monoclonal antibodies and other proteins (including anti-thrombin III) in approximately 200 animals. -H.G.D. Most research scientists who require an antibody that is not readily available can choose between two options: They can either produce the proteins themselves (assuming that the corresponding antigen -- a peptide, for example, or a cellular receptor -- has been identified and isolated), or arrange to have them manufactured by an outside source. At Amersham, the choice is an easy one. "Our emphasis is on [developing] the finished products," explains John Whateley, senior project leader at the company's Cardiff, Wales, research unit. To attempt to raise in vivo antibodies in-house could save the company a modest sum of money, but also risks running afoul of Europe's ever-more-stringent animal-care regulations. More important, perhaps, it would effectively limit Amersham to a single source of raw material that is essential to its business. "Our prime concern is not the cost [of producing the antibody]," says Whateley. "It's more important to assure ready availability and reproducibility." The make-vs.-buy decision regarding antibodies is more than an academic debate among immunological researchers. With dozens of in vivo and in vitro antibody-based diagnostic applications now under development, research labs need much more than good science. They also must weigh complex factors such as cost-effectiveness, long-term reliability of the supply source, allocation of time and labor among lab personnel, quality control and assurance, documentation, and regulatory issues. In dollar terms alone, for example, "the researcher needs to be aware of the total cost," advises Rudy Rosenberg, president of Accurate Chemical and Scientific Corp. The Westbury, N.Y.-based company supplies monoclonal and polyclonal antibodies for the detection of various tumor markers, prostaglandins, fibrin, and fibrinogen. That bottom line, adds Rosenberg, includes overhead, laboratory space and facilities, regulatory compliance, insurance, and skilled-labor costs. The decision process has been further complicated by two recent developments. First, two research teams earlier this year announced intriguing novel technologies for producing antibodies, which may provide important alternatives to today's manufacturing methods (see story on page 20). Second, the Food and Drug Administration (FDA) has proposed new regulations, due for review this month, that could dramatically restrict or actually cut off the supply of even minute quantities of antibodies for research purposes. If adopted, the new rules would add a layer of regulatory complexity that could effectively force some antibody producers out of business. "Many manufacturers say that the market [for certain proteins] is so small that the cost of compliance won't allow them to stay in the market," says Peter Takes, chairman of the executive board of the Joint Council of Immunohistochemical Manufacturers (JCIM) in Crestwood, Mo. Market factors aside, the result of the make-vs.-buy decision process depends on several issues. "Many younger investigators think it's better to buy the antibody or contract to have it produced," says Phillip E. Schwartz, project manager at Affinity BioReagents Inc. in Golden, Colo. "In that case, the researcher can take advantage of publication data and the product's track record." AFFINITY PRODUCTS: Affinity BioReagents offers, from left, Monoclonal (Rabbit) Anti-Cytochrome P450 4A, Monoclonal (Mouse) Anti-Thyroid Hormone Receptor Antibody, Monoclonal (Mouse) Anti-SERCA1 ATPase Antibody, Polyclonal (Rabbit) Anti-Cytochrome P450 2C11 Antibody, Monoclonal (Rat) Anti-Androgen Receptor Antibody, and Monoclonal (Mouse) Anti-Estrogen Receptor Antibody. Characterizing a new cell line, he adds, is relatively quick and inexpensive, and the required data and protocols have already been established. Affinity BioReagents supplies the research sector with primary monoclonal and polyclonal antibodies, typically in 50- to 100-microgram quantities. Examples include proteins against cytochromes, androgen and estrogen receptors, the thyroid hormone receptor, and pulmonary adenocarcinoma. The company is not involved in the commercial or clinical market. On the other hand, notes Schwartz, some scientists may seek special benefits in producing their own antibodies. "If a pharmaceutical company sees a need to maintain secrecy or protect its patent position, it may make sense to them to keep the entire process in-house." Most contract manufacturers provide for customer confidentiality in their contracts, adds Holly Scribner, president of BioDesign International in Kennebunk, Maine. Referring to itself as "the antibody source," the company offers some 4,000 polyclonal and monoclonal antibodies and custom production services. Examples include antibodies to drugs of abuse, infectious agents, pesticides, and tumor markers. "Some people want to maintain total control of the process," Scribner comments, noting that many don't have the expertise needed to perform cell fusions to create hybridomas, for example. Indeed, most researchers themselves make a strong case for contract antibody manufacture. Omar Skalli, an assistant professor in the department of anatomy and cellular biology at the University of Illinois in Chicago, recalls needing a novel antibody to screen for a new, as-yet-uncharacterized protein in connection with his work in tumor morphology. Although Skalli could have raised the polyclonal antibody himself, he decided to give the job to BioDesign. "They provided me with more serum than I could have obtained," he reports, "and it was more efficient than doing the work myself." BioDesign supplied the antibody within a month after receiving the antigen, at a cost of about $400. "I probably could have done it cheaper," Skalli acknowledges, "but it would have taken a lot of time and skill in breeding rabbits. It's also a very labor-intensive process that requires an hour here, an hour there, and a lot of time traveling between my lab and the animal facility." Not surprisingly, immunological researchers have a veritable universe of experienced producers from which to choose. In addition to Affinity, BioDesign, and Accurate Chemical and Scientific, service and reagent suppliers include Antigenix America Inc. of Franklin Square, N.Y.; BioSource International Inc. in Camarillo, Calif.; BioWhittaker Inc., based in Walkersville, Md.; Chemicon International Inc., headquartered in Temecula, Calif.; Lampire Biological Laboratories of Pipersville, Pa.; and Pierce Chemical Co. in Rockford, Ill. With such a large and growing selection of suppliers, how can a researcher decide on the best source? One factor to consider is the time frame within which the company can supply an antibody to a specific antigen. "Academic institutions can be highly bureaucratic," notes Scribner of BioDesign International. "It's often possible to get a faster turnaround simply by [issuing] a purchase order." Commercial considerations also may favor a fast production response. "Speed is very important," cautions Whateley of Amersham. "If you can publish your results first, it can give you an edge on the market." Chris Cunneen, technical service representative for BioSource International, claims her company can provide polyclonal antibodies against a purified recombinant antigen in eight to 10 weeks-time that the researcher can almost always use for more productive pursuits. BIODESIGN PRODUCTS: BioDesign International offers some 4,000 polyclonal and monoclonal antibodies, as well as custom production service. Once he had identified an antigen that was critical to certain disease pathways, for example, Harry Ischiropoulos, an assistant professor of environmental medicine at the University of Pennsylvania, turned development of the corresponding antibody over to Affinity. "It was a better use of our time and expenses," he recalls. "It allows us to focus on more critical problems." Accurate Chemical and Scientific Corp. Affinity BioReagents Inc. Antigenix America Inc BioDesign International BioSource International Inc. BioWhittaker Inc. Chemicon International Inc. Lampire Biological Laboratories Pierce Chemical Co. A supplier's track record and range of capabilities are also important considerations. "There now are so many antibody companies that the researcher should take the time to get referrals from other users," cautions Dennis C. Klenk, vice president of research and development for Pierce Chemical. Pierce is a developer of reagents and kits-Immunogen Conjugation Kits and Immobilized Protein A, G, and A/G, for example-for the production and purification of antibodies. These products, Klenk says, are used by many of the contract antibody manufacturers, and complete kits are available for independent laboratory researchers who "make a few antibodies here and there." Adds Len Bottone, general manager at Antigenix America: "Researchers need a company that can work with [them] from start to finish -- raise the antibody, test it, select the clone, perform the conjugation, and so on." Scientists are also advised to invest some up-front time in the testing and verification processes. While most reputable antibody companies offer a full range of documentation on quality-assurance, purity, shelf life, and so forth, "it's also helpful to establish all the necessary testing yourself," says Bryan Christiansen, product development scientist at ImmunoMatrix in Gaithersburg, Md., a supplier of custom dry-strip immunological tests used for point-of-care application. Casting a cloud over the entire research-antibody landscape are recent proposed rules by FDA. In effect, the rules would classify even small quantities of antibodies -- even those sold entirely for research purposes -- as prescription drugs subject to FDA review. (Antibodies used for diagnostics or as injectables are now tightly regulated.) The new regulations, if implemented as proposed, would cost manufacturers anywhere between $10,000 and $40,000 per antibody just to do the required clinical studies, according to a recent JCIM survey of its membership. The problem is that many antibodies now used at the research level generate far less than that in sales by their suppliers. The regulations "could put us out of business," says Rosenberg of Accurate Chemical and Scientific. "Many of our products are made in very small R&D quantities, and bring in less than $3,000 over their lifetimes." Companies that aren't forced to close down will likely pass along the expense of the regulatory costs through higher prices for other products. The rules will not affect antibodies that are created and used entirely in-house, notes JCIM's Takes. But clinical laboratory researchers may no longer have access to currently used, commercially available antibodies. Meanwhile, new proteins, such as the antibody for the recently identified subclass of the estrogen receptor, would be available only to the scientist who developed it. Licensing and marketing of the protein would be severely restricted. The bottom line, says Takes: "Researchers who are now buying antibodies might be advised to learn how to perform the process themselves." Even if the supply isn't threatened, he adds, the price could as much as triple. Cunneen of BioSource International concurs. "The rules as proposed will drive up the cost of our products," she predicts. At least one researcher admits to be worried by the proposal. "Our access to this antibody really advances knowledge," says Ischiropoulos, who now buys the necessary protein from Affinity. "Cutting down on its use doesn't make sense. We would have to make them on our own, and that isn't productive for us." H. Garrett DeYoung is a freelance science writer based in Scituate, Mass.

Many Factors Must Be Weighed In Decision To Purchase Antibodies

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