Registration Statement

BUSINESS

OVERVIEW

Dyax has developed and patented a versatile, high throughput discovery technology with broad applications in the development of new therapeutic, diagnostic and separations products. The Company's proprietary phage display-based technology platform ("Phage Display") permits scientists to rapidly identify compounds that bind to targets of interest. The Company believes that Phage Display is a powerful method that has significant advantages over conventional, combinatorial chemistry and antibody-based approaches, including increased speed and reduced costs for discovery of lead compounds. In addition, the Company develops, manufactures and sells a broad range of chromatography separations products under the Biotage tradename. Dyax is pursuing a diversified business strategy which includes: (i) non-exclusive licensing of its Phage Display patents (currently 30 licensees); (ii) discovery of new therapeutic and diagnostic lead compounds through internal programs (currently three leads) and through collaborative arrangements (currently five arrangements) using Phage Display; (iii) continued expansion of its Biotage separations product lines (sold to over 50 leading pharmaceutical and biotechnology companies); and (iv) application of Phage Display to develop next-generation affinity separations products both through internal programs (currently four programs) and through collaborative arrangements (currently eight arrangements).

BACKGROUND

Molecular binding is the key to the function of most therapeutic, diagnostic and separations products. The binding of a molecule to another molecule (target) is the mechanism nature uses to modulate biochemical and physiological processes such as cellular growth, differentiation, metabolism and death. To effect these processes, naturally occurring binding molecules typically distinguish between the correct target and other closely related molecules (specificity) and bind tightly to the target (affinity) under appropriate physiological conditions. Therapeutic and diagnostic products bind to targets, including cellular receptors, ion channels or enzymes, to achieve a desired effect, and are generally selected for their binding specificity and affinity for the target. Binding also plays a significant role in the separations products used to purify material for the development and manufacture of a therapeutic product.

The discovery, development and commercialization of effective therapeutic, diagnostic and separations products is a time consuming, risky and expensive process. For therapeutic products, the process starts with the identification of a target that is involved in a disease. The safety and efficacy of a therapeutic product is dependent on its specificity and affinity for the target. Scientists typically screen libraries containing tens to hundreds of thousands of naturally occurring or synthesized chemical compounds to identify those that bind to the target. These binding compounds are then optimized one at a time via iterative design, synthesis and testing to achieve desired binding specificity and affinity for the target. Although combinatorial chemistry, computer modeling and automated laboratory equipment have increased the throughput of the screening and optimization process, the number of compounds that can be evaluated is still limited by the time and cost required for chemical synthesis of each selected compound. The accuracy of in vitro and in vivo diagnostic products also is dependent on high specificity and high affinity binding to the target. Mouse monoclonal antibodies continue to be the dominant type of binding compound used for the development of diagnostic products. However, the generation of antibody products using an animal system is a time-consuming, costly process and cannot be used for targets that are toxic or nonimmunogenic to the animal. Products used in traditional separations processes to purify therapeutic compounds also rely on binding. These multi-step processes generally involve chromatography, the separation of different molecules through media in a column. Separations processes are typically developed through time-consuming trial and error and can constitute over 50% of the cost to manufacture a therapeutic product for commercial sales. The failure to achieve high specificity and high affinity binding can result in side effects, toxicities and low levels of efficacy for therapeutic products, inaccurate results for diagnostic products and reduced yield and purity achieved with separations products.

THE DYAX SOLUTION

The Company believes that Phage Display can reduce costs, shorten development times and lead to the commercialization of more effective therapeutic, diagnostic and separations products. Phage Display is a versatile, high throughput technology platform that is used for the discovery and development of binding compounds. Using the speed and diversity of a self-replicating biological system, Phage Display allows scientists to generate and screen quickly up to hundreds of millions of potential binding compounds to identify more rapidly those compounds that bind with the desired specificity and affinity to a target of interest under predetermined conditions. In the discovery of therapeutic products, scientists can use Phage Display to identify high specificity and high affinity binding compounds more rapidly than by other existing methods. In the discovery of diagnostic products, Phage Display can be used to identify and isolate specific binding compounds, including antibodies, more reliably and efficiently than by using an animal system. For separations processes, the Company believes that Phage Display can provide a powerful tool to develop products to purify therapeutic products more cost effectively and efficiently, thereby streamlining the development of manufacturing processes for these products.

Living organisms, such as viruses, have the ability to present (display) a foreign gene product (protein) on their surfaces. Beginning in the late 1980's, scientists began exploring the use of such organisms as a means for the display and identification of proteins of interest. Dyax scientists developed Phage Display, a patented technology for displaying large collections of proteins on filamentous "phage," a virus which infects laboratory bacteria. Dyax's Phage Display has become the preferred method to display and select proteins with desired binding properties.

Features and Advantages of Phage Display

The Company's Phage Display process generally consists of: (i) generating a Phage Display library; (ii) screening the library and isolating phage that display proteins (including structured peptides) that bind to the target of interest; and (iii) producing and characterizing the selected binding compounds. To start the Phage Display process, genes containing the instructions to produce and display a wide variety of new proteins are inserted into phage genomes. Each phage receives one distinct gene variant and, therefore, displays only one new protein on its surface. The collection of phage produced in this manner is known as a Phage Display "library." A Phage Display library can be generated in a few weeks and can contain up to hundreds of millions of proteins that are potential binding compounds. Scientists can screen Phage Display libraries to select rapidly those proteins or peptides that bind to a target of interest. Screening a Phage Display library involves exposing a Phage Display library to the target under conditions in which binding is desired, removing phage that do not bind to the target, dissociating bound phage from the target and amplifying the bound phage by infecting laboratory bacteria. Screening is performed in small volumes, usually less than one milliliter, in standard 96-well plates, and can generally be done in a single day. Phage selected in the first round of screening are generally amplified through growth in the host bacteria and rescreened to narrow down the collection of phage to those that display binding compounds with desired binding properties. The selected phage can then be amplified to produce sufficient quantities for initial evaluation and identification of lead compounds. See "-- Dyax Technology."

The Company believes that Phage Display has the following advantages over combinatorial chemistry and monoclonal antibody technology for the identification of binding compounds:

Diversity: Phage Display libraries can contain up to hundreds of millions of potential binding compounds that are variations based on a single protein or peptide framework. The size of the library (diversity) significantly improves the likelihood of identifying binding compounds with high specificity and high affinity for the target. This diversity is far greater than that achievable with current combinatorial chemistry approaches.

Speed: Phage Display libraries can usually be generated in a few weeks and screened several times in a few days to identify a group of related binding compounds. Using conventional or combinatorial chemistry approaches, this process would generally require between several months and several years to complete. The

Company believes that Phage Display can therefore reduce significantly the time and expense required to identify compounds with desired binding characteristics.

Amplification: Phage Display is based on a self-replicating biological system. Accordingly, the phage displaying a selected binding compound will replicate into millions of identical copies in its bacterial host in less than one day. This provides sufficient phage for initial characterization of the displayed binding compound. Once generated, an entire Phage Display library can be amplified and stored and subsequently used for a potentially unlimited number of screenings. By comparison, amplification of compounds and libraries developed using combinatorial chemistry techniques requires significant additional time and resources for chemical synthesis.

Rapid Optimization: Screening of Phage Display libraries results in the identification of groups of related binding compounds with high specificity and high affinity for the desired target. These compounds can then be used as the basis for successive generations of Phage Display libraries. Due to the relative ease of library generation, Phage Display enables the rapid optimization of compounds for the desired binding specificity and affinity.

Controlled Binding and Release: Phage Display can also be used to select compounds which alternately bind to and release from a target under specific conditions (e.g., changes in acidity or salt concentration or the presence of contaminants) that simulate those encountered in a separations process used in the manufacture of a therapeutic product. The Company believes that this ability to control or predetermine the conditions under which selected compounds bind and release will result in the development of more efficient and cost effective separations products.

Focused Design: Each Phage Display library is generated based on a single protein or peptide framework that allows scientists to select the desired product properties such as structure, size, stability and lack of immunogenicity. During library design, the exact degree and location of the variability is controlled allowing for the conservation of certain of the original framework characteristics.

Small Molecule Design and Discovery: The structural information of binding compounds identified using Phage Display can be used to design small molecule (nonpeptidic) compounds with comparable binding activity. Alternatively, Phage Display-derived binding compounds can be used both for target validation and in high throughput competitive binding assays to screen panels of small molecules for those that interact at the same binding sites on the therapeutic targets.

BUSINESS STRATEGY

Dyax is using Phage Display and its expertise in separations technology to pursue a diversified business strategy of non-exclusive patent licensing, discovery and development of therapeutic and diagnostic products, and development of innovative chromatography and affinity separations products. Dyax is currently generating revenues from sales of its separations products, funding from sponsored research and fees from patent licenses, while maintaining a long-term focus on its therapeutic and diagnostic product development programs, the expansion of its existing separations product lines and the development of affinity separations products. The following are the principal elements of the Company's strategy:

License Phage Display: Dyax intends to continue to license its Phage Display patents widely to permit and encourage the broad application of Phage Display, and to obtain revenues from license fees, potential milestone payments and royalties on Phage Display-derived products. Dyax offers non-exclusive licenses in the fields of therapeutics, antibody-based in vitro diagnostics. Under these licenses, Dyax has retained all rights to practice Phage Display in the fields of separations and in vivo imaging. To date, 30 licensees are licensed under Dyax's Phage Display patents.

Discover and Internally Develop Therapeutic and Diagnostic Leads: To date, Dyax has used Phage Display to identify three proprietary lead therapeutic compounds with potential applications that include inflammatory diseases and certain cancers and one lead diagnostic compound for in vivo imaging of inflammation. Dyax intends to discover and develop additional leads and anticipates that initial leads arising from internally funded programs will be selected for therapeutic and diagnostic targets that are readily available

in the public domain; however, the Company also intends to identify new leads for therapeutic and diagnostic targets that it discovers or licenses from others. Dyax further plans to pursue an internally funded program to use Phage Display to identify and develop new targeting agents for in vivo imaging using nuclear medicine.

Leverage Phage Display Through Collaborations: Dyax is leveraging its proprietary technology in the fields of therapeutics, diagnostics and separations by entering into discovery and development collaborative arrangements with biotechnology, pharmaceutical and diagnostics companies. The Company is currently engaged in four collaborative arrangements and is performing or has completed more than nine funded lead discovery projects. Under these arrangements, Dyax generally receives research funding and potential future revenue upon commercialization of any resulting products. The Company intends to enter into additional collaborative arrangements for new lead discovery and preclinical and clinical evaluation of its current and future lead therapeutic and diagnostic compounds, while potentially retaining product rights by field or geographic area.

Continue to Develop and Market Innovative Separations Products: Dyax believes that it is well positioned to meet the purification challenges of complex therapeutic products such as proteins and vaccines. The Company intends to leverage its existing Biotage chromatography product line through the introduction of innovative affinity separations products designed to meet the emerging needs of the combinatorial chemistry and genomics markets. Through collaborative arrangements with pharmaceutical and biotechnology companies, Dyax is using Phage Display to identify binding compounds, known as "affinity ligands," that can potentially be used in products designed to purify quickly and inexpensively therapeutics in commercial quantities. Dyax plans to develop proprietary affinity separations products for purifying a customer's specific compound and for separating classes of molecules that may be used by a number of customers.

DYAX PROGRAMS AND PRODUCTS

Dyax's business activities consist of: (i) a patent licensing program; (ii) discovery and development programs in therapeutics, in vivo imaging and other diagnostics; and (iii) the manufacture and sale of its Biotage chromatography products and systems and research and development of innovative separations products. See "Risk Factors -- Dependence on Phage Display; New and Uncertain Technology; No Clinical Trials or Sales of Phage Display-Derived Products to Date."

Patent Licensing Program

The Company has established a broad licensing program of its Phage Display patents for use in the fields of therapeutics, antibody-based in vitro diagnostics and Phage Display research kits. Through this program, Dyax grants companies and research institutes non-exclusive licenses to practice Dyax's Phage Display patents in their discovery and development efforts in the licensed fields. Since the inception of this licensing program in 1996, the Company has licensed 30 licensees. Dyax believes that the success of its patent licensing program provides support for its patent position in Phage Display and the utility of Phage Display as an enabling discovery technology. Under these licenses, Dyax has retained all rights to practice Phage Display in the fields of separations and in vivo imaging.

The Company's license agreements generally provide for a signing fee, annual maintenance fees, milestone payments based on successful product development and royalties based on any future product sales. In addition, under the terms of the Company's standard license agreement, the licensee covenants not to sue the Company under certain of the licensee's Phage Display improvement patents, if any, which the Company believes will give it greater freedom to practice enhancements to Phage Display. To date, licensees have been offered standardized payment terms or, for certain fields, the ability to choose from a matrix of fees and royalties. The matrix generally ranges from lower signing and maintenance fees with higher milestone payments and royalties to higher signing and maintenance fees with lower milestone payments and royalties. The fees and royalty rates under this program are subject to change from time to time. In the case of Affymax Technologies, N.V. (and its parent, Glaxo Wellcome PLC), Dyax negotiated a fully paid-up license. See "Management's Discussion and Analysis of Financial Condition and Results of Operations."

The Company's licensees include Affymax Technologies, N.V. (and its parent, Glaxo Wellcome PLC), Amersham Pharmacia Biotech, Biosite Diagnostics Incorporated, Bristol-Myers Squibb Company, Cambridge Antibody Technology Limited, Chiron Corporation, Chugai Biopharmaceuticals, Inc., Corvas International, Inc., Cytogen Corporation, DuPont Merck Pharmaceutical Company, Genzyme Corporation, IGEN International, Inc., Invitrogen Corp., Merck & Co., Inc., Millennium BioTherapeutics, Inc., Monsanto Company, MorphoSys GmbH, New England BioLabs, Inc., Novagen, Inc., Pharmacia & Upjohn, Co., Praecis Pharmaceuticals Inc., Prizm Pharmaceuticals, Inc., R.W. Johnson Pharmaceutical Research Institute, Scios, Inc., Stratagene, Inc., Tera Biotechnology Corporation, The Burnham Institute, The University of Texas Southwestern Medical Center at Dallas, and Utrecht Biotechnology Systems B.V. The Company expects that the number of its licensees will change from time to time.

Therapeutic and Diagnostic Discovery and Development Programs

Dyax is using Phage Display internally and through collaborative arrangements to discover and develop therapeutic and diagnostic product candidates. The following table summarizes the Company's therapeutic and diagnostic discovery and development programs. This table is qualified in its entirety by reference to the more detailed descriptions appearing elsewhere in this Prospectus.

                                               LEAD
        DISEASE AREA/INDICATION              COMPOUND           STATUS            COLLABORATOR
----------------------------------------  --------------    --------------    --------------------
THERAPEUTICS:
Pulmonary Inflammation/Cystic Fibrosis    EPI-HNE4          Preclinical(1)    Debiopharm

Chronic Inflammation/Hereditary           EPI-KAL2          Lead              Genzyme(4)
  Angioedema and Inflammatory Bowel                         Identified(2)
  Disease

Cancer/Prostate Cancer                    EPI-PLA2          Lead                       --
                                                            Identified(2)
DIAGNOSTICS:
Inflammation/Infection                    EPI-HNE4          Preclinical(1)    University of
                                                                              Massachusetts
                                                                              Medical Center
Pulmonary Disease/Deep Vein Thrombosis          --          Discovery(3)      EPIX Medical
  and Pulmonary Embolism

(2) "Lead Identified" indicates that a lead compound has been identified that meets certain criteria, but which may need to be further evaluated or modified before preclinical development, if any.

(3) "Discovery" indicates initial Phage Display screening or molecular design of a group of compounds before a lead compound is identified.

(4) Subject to negotiation of definitive collaboration agreement. See "Certain Transactions."

Therapeutics

The first step in the discovery and development of a therapeutic product is generally the identification of a molecular target that is involved in a disease. Once a target has been identified, the next step is typically a search for a compound that will bind to this target to achieve a desired effect. This time-consuming and costly step includes the screening of conventional libraries of chemical compounds which can contain tens to

hundreds of thousands of independent potential binding compounds and the development of biological assays for evaluation of selected compounds. The cost and time associated with traditional drug development limits the number of potential drug candidates that can be evaluated. In addition, scientific advances, such as genomics and related target discovery technologies, are resulting in the identification of thousands of new therapeutic target candidates. To take advantage of this increasing number of target candidates, pharmaceutical and biotechnology companies are seeking more efficient methods for target validation and identification of binding compounds that can lead to new therapeutic products. Advances in combinatorial chemistry have increased throughput of binding compound discovery compared to traditional discovery methods, but the chemical synthesis of selected compounds still requires months to years of expensive research.

Using Phage Display, the Company believes scientists can discover binding compounds with high specificity and high affinity more rapidly than by conventional and combinatorial chemistry approaches. Phage Display libraries of up to hundreds of millions of potential binding compounds can be generated in a few weeks. These libraries are thousands of times greater in size than those that can be generated using, for example, combinatorial chemistry. Furthermore, the protein framework of the Phage Display library can be selected or designed to ensure that all compounds in a library have predetermined properties, such as structure, size, stability and lack of immunogenicity. Scientists can then use Phage Display to rapidly select groups of related proteins that bind to a therapeutic target with high specificity and high affinity. The Company believes that by analyzing binding compounds identified through Phage Display with the Company's proprietary structure activity relationship ("SAR") technology, it will be possible to accelerate the process of small molecule drug design. In addition, Phage Display can be used in conjunction with genomics technologies to provide high-throughput analysis and purification of new gene products for validating novel therapeutic targets. See "-- Dyax Technology."

Dyax's current programs in therapeutic discovery and development are:

Inflammation. Inflammatory disorders occur when the immune system overreacts to a perceived foreign substance. One aspect of this overreaction is the activation of neutrophils and the release of neutrophil elastase, an enzyme that digests proteins including bacterial and cellular debris. The unregulated production of neutrophil elastase is thought to be the primary cause of tissue damage and abnormal inflammatory response in disorders such as pulmonary inflammation (cystic fibrosis, chronic bronchitis and emphysema), chronic inflammation and acute inflammatory disorders (appendicitis and acute respiratory distress syndrome). Another protease, plasma kallikrein, is elevated at the inflammatory sites of rheumatoid arthritis and inflammatory bowel disease. Plasma kallikrein is thought to contribute to the pathology of rheumatoid arthritis both by activating an enzyme that degrades the collagen matrix and by causing release of molecules that activate other inflammatory cells. Similarly, activation of a localized inflammatory response by kallikrein may contribute to the pathology of inflammatory bowel disease.

Using Phage Display, Dyax has discovered a proprietary lead compound, EPI-HNE4, that binds to and inhibits human neutrophil elastase. EPI-HNE4 is currently in preclinical development for the treatment of inflammation resulting from cystic fibrosis, an inherited disorder characterized by pulmonary inflammation that leads to abnormally thick mucus secretions which impair pulmonary function and can result in fatal infections. Because EPI-HNE4 binds to its target protease with high specificity and high affinity, the Company believes that it will reduce the inflammatory response while not interfering with other physiological processes. Additional indications for EPI-HNE4 may include other causes of pulmonary inflammation and acute inflammatory disorders. Dyax has entered into an agreement to develop EPI-HNE4 with Debiopharm S.A., a Swiss pharmaceutical company ("Debiopharm"). See "-- Collaborations."

Using Phage Display, Dyax has also discovered EPI-KAL2, a proprietary lead compound which binds to and inhibits plasma kallikrein. Like EPI-HNE4, EPI-KAL2 is a small, stable protein that can be delivered by injection. The Company intends to work with academic investigators to test EPI-KAL2 in animal models of chronic inflammatory disease including hereditary angioedema and inflammatory bowel disease. In June 1998, the Company and Genzyme entered into a non-binding letter of intent for the joint development and commercialization of EPI-KAL2 for the treatment of chronic inflammatory diseases, with initial development to be focused on inflammation resulting from hereditary angioedema. Subject to the negotiation of a definitive

agreement, Dyax will initially fund up to several million dollars of development costs and thereafter the parties will fund equally all development costs. Upon signing the definitive collaboration agreement, Genzyme will extend to the Company a line of credit which the Company may use to fund a portion of such development costs or for any of the Company's other research and development programs. In addition, the Company will be entitled to receive significant milestone payments and up to 50% of the profits from sales of products developed under this collaboration. The Company believes that the proposed collaboration with Genzyme will provide Dyax with significant financial and other resources to continue preclinical and clinical development of this proprietary compound, although there can be no assurance that such an agreement will be consummated. See "Certain Transactions." Genzyme has also committed to purchase $3.0 million of the Company's Common Stock in the Genzyme Investment.

Dyax is using its SAR technology to design and synthesize an orally available small molecule with the inhibitory capabilities of EPI-HNE4 and intends to similarly design and synthesize a small molecule comparable to EPI-KAL2. Orally available drugs are generally preferred for use in patients with chronic inflammatory conditions compared to drugs delivered by inhalation or injection. Dyax scientists have used the SAR data generated from EPI-HNE4 and related binding compounds selected through Phage Display to design and synthesize small molecule compounds that retain the neutrophil elastase inhibitory activity of EPI-HNE4 and have affinities in the range of existing therapeutic products. Dyax is continuing to design additional small molecule compounds with the same inhibitory profile, aiming to achieve higher specificity, higher affinity and potentially greater efficacy with fewer side effects than existing treatments for inflammation.

Cancer. Cancer is characterized by uncontrolled cellular growth, which can lead to death. Growth and metastasis of some cancers has been shown to be dependent on the activity of the protease, plasmin. Using Phage Display, Dyax has discovered EPI-PLA2, a potent and specific inhibitor of plasmin. Dyax is evaluating EPI-PLA2 in cell-based models of prostate cancer metastasis in collaboration with the M.D. Anderson Cancer Center at the University of Texas. The Company also intends to evaluate EPI-PLA2 for treatment of other metastatic cancers.

Other Therapeutic Discovery Programs. The Company is also planning to pursue other therapeutic discovery programs. One such indication is multiple sclerosis ("MS"), the primary neurodegenerative disease of young adults, which is caused when the patient's immune system attacks the protective protein layer that insulates neurons of the central nervous system. The research group of Dr. Stephen Hauser, a leading investigator in MS at the University of California, San Francisco, has identified a protease involved in the entry of immune system components into the central nervous system, where they attack the neurons and initiate an MS episode. Dyax recently entered into a consulting agreement with Dr. Hauser to assist the Company in developing a program to use Phage Display to discover and develop a potential treatment for MS. The Company intends to identify other opportunities for therapeutic product discovery and development using Phage Display.

Therapeutic Discovery Collaborations. The Company has also entered into funded discovery collaborative arrangements with Athena Neurosciences, Inc., SangStat Medical Corporation and Tularik Inc. Generally, in these collaborative arrangements, the Company screens its Phage Display libraries to identify compounds that bind to a collaborative partner's therapeutic or diagnostic targets of interest. Generally, if the collaborative partner chooses to continue to develop the binding compound into therapeutic lead candidates, the Company will be entitled to receive milestone payments and/or royalties on future product sales based on the collaborative partner's successful development and marketing of such leads as products.

Diagnostics

A diagnostic product generally consists of a detectable marker linked to a binding compound with specificity and affinity for a molecular target, thereby indicating the presence or absence of that target. The higher the specificity and affinity of the binding compound used in a diagnostic product, the more accurate and sensitive the test. In the case of in vivo diagnostic imaging to detect certain disease conditions, it is also necessary to have a targeting agent that will localize rapidly to the target tissue or organ after it is administered to the patient.

For the past twenty years, the method of producing monoclonal antibodies using the natural immune system of the mouse (hybridoma technology) has been the best available means of supplying binding compounds for in vitro and in vivo diagnostics. In this method, a desired target is selected and injected into a mouse, which produces antibodies. The mouse antibody-producing cells are then isolated and propagated outside the animal. However, using hybridoma technology for the discovery and development of antibody products has inherent limitations, such as time, the inability to utilize certain types of targets (including those which are toxic or nonimmunogenic to the animal) and the inability to control specificity of antibodies produced in the mouse. As targeting agents for in vivo imaging, mouse antibodies have additional limitations, including long clearance times and slow penetration to the disease foci requiring 24 to 48 hours of hospitalization after injection before a useful image can be obtained and immunogenicity that limits the number of times a patient can be safely imaged with any mouse antibodies.

For in vivo diagnostic imaging products, Dyax believes that Phage Display will enable the identification of binding compounds that are smaller in size and have higher specificity and affinity and greater bioavailability than mouse monoclonal antibodies, and that these compounds will be more effective diagnostic imaging agents that will permit more accurate and, in some cases, earlier diagnosis of disease. For in vitro diagnostic applications, the most immediate opportunity is the use of Phage Display as a source of monoclonal antibody reagents. Phage Display can be used to display large collections of human antibodies. The Company believes that Phage Display allows more rapid identification of antibodies and other binding compounds than hybridoma technology and could potentially replace animals as a source of antibodies for diagnostic and research applications. Phage Display libraries can be screened in high throughput formats so that antibodies that bind to any diagnostic target can be isolated cost-effectively in a few weeks, compared to the six to nine months required to immunize, isolate and propagate antibody-producing cells from mice.

Dyax's current programs for the discovery and development of in vivo diagnostics are:

Inflammation/Infection Imaging. Disease indications that are likely candidates for inflammation-infection imaging include inflammatory bowel disease, fever of unknown origin, arthritis, certain autoimmune disorders and pulmonary diseases. The Company believes that there is a need for an imaging agent that can provide early and accurate identification of both sterile and infectious inflammatory sites in vivo and that there are no sensitive, specific products for rapid diagnosis of these disorders currently available. The most common tools currently available for locating inflammation are time-consuming, inaccurate and/or expensive. Dyax is evaluating a modified form of EPI-HNE4 in preclinical studies as a diagnostic imaging agent for sites of inflammation (including infection) in collaboration with scientists at the University of Massachusetts Medical Center. Preclinical development of EPI-HNE4 as an agent for imaging inflammation has been supported by a Phase I Small Business Innovation Research grant from the National Institutes of Health. The imaging agent being developed by Dyax consists of EPI-HNE4 as the targeting portion with technetium-99 as the detectable marker.

Cardiovascular Imaging. Disease indications that are likely candidates for cardiovascular imaging include deep vein thrombosis ("DVT") and pulmonary embolism ("PE"). DVT is caused by the formation of a fibrous blood clot in the veins of the lower limbs. PE results when a DVT clot breaks loose and travels to the lungs, where it can block blood flow. Dyax is collaborating with EPIX Medical Inc. ("EPIX") using Phage Display to identify binding compounds for a molecular component of fibrous blood clots which could be used in an imaging agent for DVT and PE. Under the collaborative arrangement, Dyax has identified a group of potential binding compounds. The product under development with EPIX will be based on a novel labeling chemistry that increases the sensitivity of an image generated using magnetic resonance imaging ("MRI"). EPIX plans to develop the identified binding compounds for use in MRI, while Dyax has retained the right to develop these compounds for use in nuclear medicine imaging. See "-- Collaborations."

Other In Vivo Diagnostic Programs: Dyax intends to evaluate additional Phage Display-derived binding compounds for use in in vivo diagnostic imaging. These compounds may be discovered through internally funded programs or may be licensed from other sources. For example, the Company recently signed an agreement with The Burnham Institute ("Burnham"), one of the Company's patent licensees, to evaluate for use in in vivo diagnostic imaging Phage Display-derived binding compounds discovered at Burnham's. Under

the terms of this agreement, the Company has the exclusive right to evaluate all of these binding compounds and the option to license them exclusively for in vivo diagnostic imaging.

Biotage Separations Products and Research and Affinity Separations Development Programs

Purification of a therapeutic product is a complex, multi-step process, which can account for over 50% of a product's manufacturing costs. A widely used separations technology, chromatography, is used to purify the desired product or to remove impurities from the production mixture during the discovery, development and manufacturing of a therapeutic product. Chromatography is a technology that separates molecules in a liquid mixture using differential adsorption of molecules. In this technology, molecules pass through a chamber, or column, packed with separations media. The migration rates of different molecules through the column vary due to differences in the strength of binding interactions with the media in the column. In conventional chromatography, separations are based on broad physical properties such as size, charge or hydrophobicity, and the types of available, standard chromatography media has changed little in recent years. Chromatographic separations are achieved by selection of the surface chemistry of the media and the solvent composition such that different molecules exit the column at different times and therefore can be collected and/or detected in purified form. For a given separation, the available media generally has unpredictable specificity and there has been no practical way to modify the existing materials to create specific binding to a particular target. Thus, the development of useful separation processes relies on trial and error and is time consuming and labor intensive.

The Company believes that Phage Display is a powerful tool for developing new affinity separations media that can cost effectively and efficiently purify increasingly complex therapeutic products. In affinity chromatography, a ligand that binds with high specificity and high affinity to either the desired compound or a specific class of impurities to be removed is attached to the media. When the desired compound is captured on the affinity media, impurities are washed away. By changing the solvent conditions, the desired compound can be released from the media resulting in a product that is (in most cases) at higher concentration than in the original mixture. Alternatively, a specific class of impurities is captured on the media to allow the desired product to flow through in a purified form. Phage Display can be used to generate small, stable ligands that have high specificity and high affinity for the desired compound or impurity. Since affinity chromatography can purify the desired compound in one column, one such affinity chromatography column can replace multiple conventional chromatography columns which otherwise would be required. Dyax has developed compounds that bind and release in predetermined conditions, such as those conditions that can be used for process-scale separations. The Company believes that these new affinity separations products can reduce the time, cost and risk associated with pharmaceutical purification at the discovery, development and production scale. Dyax plans to combine its Biotage chromatography systems with any affinity chromatography media that may be derived through Phage Display to provide system solutions for the purification of natural products, peptides, proteins, organic compounds and other molecules. See "Risk Factors -- Limited Revenues to Date from Separations Products; Need to Develop New Separations Products."

Biotage Separations Products

Dyax develops, manufactures and sells chromatography separations systems and is a leader in the development, manufacture and sale of cartridge chromatography products and systems, which it sells under the Biotage trade name. The Company's prepacked, disposable cartridges can be packed with a wide range of media from a variety of sources. The Company believes that its cartridge-based systems provide competitive advantages to its customers compared to manually packed systems, including greater speed and convenience, lower cost, improved safety (no exposure of production personnel to media) and reproducible performance leading to significant cost savings due to reduction of labor and decreased solvent usage. The Company has sold its current line of Biotage chromatography products and systems to over 50 leading pharmaceutical and biotechnology companies worldwide, including Bachem AG, Bayer Corporation, Genentech, Inc., F. Hoffmann-La Roche, Ltd., Merck & Co., Inc., Novartis, Pfizer, Inc., Pharmacia & Upjohn Co. and Wyeth-Ayerst Laboratories, Inc. (a subsidiary of American Home Products Corporation).

The following are the Company's principal chromatography products:

FLASH Chromatography Systems and Cartridges: FLASH systems are designed to efficiently and cost effectively purify a single chemical compound from a complex synthetic mixture. The FLASH systems range in price from $2,500 for discovery and development scale systems to over $100,000 for production scale systems. The manufacturing scale systems can replace other processes, including chromatography using large glass or steel columns or batch adsorption and filtration using larger tanks and filters. The FLASH systems include radial compression modules that are designed to enhance performance by stabilizing the media and increasing flow rates. The Company believes that the FLASH product line, which was introduced by the Company in 1994, is the only commercially available line of prepacked disposable cartridges for separations from the discovery scale to the manufacturing scale.

Parallex Parallel Purification System: Dyax's automated Parallex system is a high throughput, high-resolution chromatography workstation designed for the combinatorial chemistry market. The integrated system includes four independent high pressure liquid chromatography ("HPLC") columns, bar-coded sample input and intelligent fraction collection based on analysis of the compounds as they emerge from the columns using a proprietary four-channel, dual wavelength UV detector. HPLC technology is widely used in the pharmaceutical industry, particularly for purification of synthetic organic molecules, synthetic peptides, oligonucleotides and natural products. Information is tracked and stored using the Company's proprietary software that can interface with commercially available central data management systems. Up to 900 samples can be run and purified automatically in a 24-hour period. To the Company's knowledge, there is currently no similar product available for this emerging market that can integrate the data from several hundred samples per day at comparable efficiency. The list prices for the Parallex systems, which were introduced by the Company in 1997, range from $190,000 to over $240,000.

Kiloprep Systems and Cartridges: The Company's Kiloprep systems are high resolution chromatography systems that use prepacked HPLC cartridges and radial compression technology for discovery, development and manufacturing scale purifications. Kiloprep HPLC systems work with a variety of solvents, include advanced automation features and provide documentation and validation for current GMP regulatory environments. Manufacturing scale Kiloprep systems are built to individual customer specifications. By contrast, competing process-scale HPLC systems rely on prepacked stainless steel columns or user-packed HPLC columns. Kiloprep cartridges are used exclusively in the Kiloprep system for purifications from the milligram to the kilogram scale. The list prices for the Kiloprep systems, which were introduced by the Company in 1990, range from $50,000 for laboratory systems to over $300,000 for custom ordered manufacturing scale systems.

ProPrep Chromatography Systems: The Company's ProPrep systems are customized to meet the requirements of development and manufacturing scale chromatography applications for cGMP production of biologics. The Company believes that, compared to other commercially available systems, the ProPrep line provides a superior turn-key, highly engineered system with superior gradient performance and an "explosion proof" design that allows the system to be used in a hazardous manufacturing plant environment. These systems will be used to support the new BioFLASH prepacked chromatography cartridges described below. The Company also plans to improve overall purification performance of any new affinity separations media that incorporate binding compounds discovered through Phage Display by using the ProPrep hardware and software technology platforms. The prices for ProPrep systems, which were introduced by the Company in 1993, range from $150,000 to over $500,000.

BioFLASH Prepacked Cartridges and Systems: The Company's BioFLASH cartridges, which are expected to be introduced in the second half of 1998, will consist of prepacked, disposable cartridges containing media specifically designed for separations of biological materials. Virtually any chromatography media for separating biological material can be packed in these cartridges. This product line, which is derived from the Company's FLASH chromatography systems for traditional chemical separations, is designed to allow operation of the BioFLASH cartridges in a stand alone or radially compressed format. The Company believes that BioFLASH cartridges and systems will have competitive advantages over

existing products for development and manufacturing scale because they provide reproducible performance, higher pressure ratings (i.e., faster, higher resolution separations) and reduced cross-contamination and sterilization capability for virtually any bioseparation that is currently carried out in a glass or stainless steel column. The Company plans to use the BioFLASH product line as the platform for its Phage Display-derived affinity separations products under development.

Affinity Separations Development Programs

Dyax is using Phage Display to develop new affinity separations products which it believes will be more effective than conventional separations technologies. The Company has established a collaborative arrangement with Novo Nordisk to use Phage Display to develop new tools for the rapid evaluation of certain of Novo Nordisk's therapeutic candidates. Dyax has several funded discovery projects with different companies, including Argonex, Inc., Genetics Institute, Inc., Genzyme Transgenics Corporation, Glaxo Research and Development Limited, Merck & Co., Inc. and Pall Corporation. These projects seek to identify one or more potential binding compounds that can be attached to media for development into affinity separations products for purification of the collaborative partner's designated therapeutic product. To date, Dyax has discovered affinity ligands for such products as a viral vaccine, tissue plasminogen activator, a recombinant blood product and transgenic animal and plant products. Under certain of these programs, the Company has delivered affinity separations products containing Phage Display-derived affinity ligands for testing and evaluation. Further, in one of these programs, the partner has agreed to proceed with the development of the affinity ligand for use in purification of a biotherapeutic product. The Company is continuing to seek collaborative partners in the discovery and development of affinity separations products.

In addition to its custom-designed affinity separations products program, Dyax is developing proprietary affinity separations products, including products under development in a collaborative arrangement with CropTech for broad commercial applications. The Company believes that these products will have applications in research as well as in the process and manufacturing markets. To date, none of the Company's affinity separations products have been used for commercial scale manufacturing and there can be no assurance that such products or other products developed in the future, if any, will be used for commercial scale manufacturing. See "-- Collaborations."

DYAX TECHNOLOGY

Phage Display

Phage Display is used to select proteins that bind to a target of interest. The selection is made from a diverse set of up to hundreds of millions of proteins displayed on the surface of a bacterial virus, bacteriophage, known commonly as "phage." The Company's Phage Display process generally consists of:
(i) generating a large collection of phage, known as a "library," that contains genes encoding up to hundreds of millions of related proteins, or potential binding compounds, (ii) screening the library by exposing it to a specified target and isolating those phage whose displayed proteins bind to the target; and (iii) analyzing the selected binding compounds by sequencing their genes and by producing and characterizing small quantities for relative specificity and affinity to the target.

Generating a Phage Display Library. The generation of a Phage Display library is based upon a single protein framework and contains up to hundreds of millions of variations of this protein. The first step in generating a library is the selection of the protein framework upon which the library will be created. This selection is based on desired product properties, such as structure, size, stability, or lack of immunogenicity. Scientists then determine which amino acids in the framework will be varied. Amino acids that contribute to the chosen framework properties are not varied. The exact number and type of different amino acids that are varied is also controlled, so that the resulting Phage Display library consists of a diverse set of chemical entities, each of which retains the desired physical and chemical properties of the original framework.

GENERATING A PHAGE DISPLAY LIBRARY

[GENERATION OF A PHAGE DISPLAY LIBRARY]

The next step is the creation of a collection of genes encoding the designed variations of the framework protein. Scientists can easily generate diverse collections of up to hundreds of millions of different synthetic DNA sequences. Each new DNA sequence, or gene, encodes a single protein sequence that will be displayed on the surface of the individual phage that contain this gene. The new DNA sequences are combined with phage genome DNA and certain enzymes so that the new DNA is inserted into a specific location of the phage genome, such that the encoded protein will be displayed on the phage surface as a fusion to one of the existing (naturally occurring) phage proteins. The phage is a physical link between the displayed protein and its gene.

The new phage genomes are then transferred into laboratory bacteria, where the phage genome directs the bacterial cells to produce thousands of copies of each new phage. The resulting collection of phage is the Phage Display library. Because the Phage Display library can be reproduced by infecting a new culture of laboratory bacteria to produce thousands more copies of each phage, libraries can be maintained for a potentially unlimited number of screenings.

In addition to the creation of synthetic DNA sequences for a Phage Display library, scientists can also use naturally occurring genes, such as genomic DNA (all genes in an organism) or cDNA (sequences that represent all the expressed genes in a cell or organism) as sources of the genes for a library. For example, Phage Display libraries of human antibodies can be used to isolate monoclonal antibodies in a significantly shorter period of time than required for existing hybridoma technology.

Screening Phage Display Libraries. Once a Phage Display library is generated, scientists can select binding compounds with high specificity and high affinity by exposing the library to specified targets of interest and isolating the phage that display compounds that bind to the target. For certain applications of Phage Display, such as separations, scientists can design the binding and release conditions into the selection. Each individual phage contains the gene encoding one potential binding compound, and when its displayed protein is selected in the screening procedure, it can be retrieved and amplified by growth in laboratory bacteria.

To screen a Phage Display library, the library is exposed to the target under desired binding conditions. The target is normally attached to a fixed surface, such as the bottom of a tube, or a bead, allowing phage whose potential binding compounds do not bind to the target to be removed. Once these unbound phage are washed away, the phage containing the selected binding compounds can be released from the target. Since the phage are still viable, they can be amplified rapidly by again infecting bacteria. This property of ready amplification is unique to biological systems. Binding compounds identified during the first round of selection generally include some that bind to the target molecule with varying degrees of specificity and affinity.

Therefore, the amplified phage are again exposed to the target molecule in another round of screening, to enrich for those phage whose displayed binding compounds have the desired specificity and affinity. The procedure is repeated several times until a group of related binding compounds with the desired characteristics can be identified.

SCREENING A PHAGE DISPLAY LIBRARY

[SCREENING OF A PHAGE DISPLAY LIBRARY]

Evaluation of Selected Binding Compounds. Screening Phage Display libraries generally results in the identification of one or more groups of related binding compounds. These groups of compounds are valuable in providing information about which chemical features are necessary for binding to the target with specificity and affinity, as well as which features can be altered without affecting binding. Using DNA sequencing, scientists can determine the amino acid sequences of the binding compounds and identify the essential components of desired binding properties by comparing similarities and differences in such sequences. If desired, the binding compounds can be further optimized by building additional Phage Display libraries based on these key components and repeating this process. Small amounts of the binding compound can be produced by growing and purifying the phage. For production of larger amounts, the gene can be removed from the phage DNA and placed into a standard recombinant protein expression system. Alternatively, if the identified binding compound is sufficiently small, it can be chemically synthesized. These binding compounds can be evaluated for desired properties including affinity, specificity and stability under conditions that will be encountered in its intended use. From each group of compounds, a lead compound with the best properties can be identified and developed and tested as a therapeutic, diagnostic or affinity separations product.

Other Technologies

Structure Activity Relationship Technology. The SAR information obtained from the group of Phage Display-derived binding compounds can be used to initiate small molecule drug design. The framework selected or designed to generate a Phage Display library can be structured so that the amino acids that interact with the target during binding are from a small, structurally constrained region of the protein framework. Selection of binding compounds from such Phage Display libraries does not yield a single result, but rather a group of closely related variants of the framework protein that bind to the target. Dyax believes that its proprietary SAR technology, including molecular modeling and computational chemistry capabilities, can be used for the discovery of small molecules that are potentially orally available drug candidates. Traditionally, structure-based rational drug design has relied on determination of the three dimensional structure of the therapeutic target, which requires large quantities of purified material. In contrast, Dyax's SAR approach does

not require structural information regarding the target molecule. Small molecule drug candidates are instead designed using information derived from the group of binding compounds selected through Phage Display, and can be performed with a part of the target or with impure preparations of the whole target. The structured peptide and small protein binding compounds discovered through Phage Display are less complex and substantially more accessible to three-dimensional structural determination through nuclear magnetic resonance and X-ray crystallography methods than most therapeutic targets. Dyax has used this strategy to design small molecule neutrophil elastase binding compounds that have demonstrated the desired inhibitory activity in in vitro assays. See "-- Dyax Programs and Products -- Therapeutic and Diagnostic Discovery and Development Programs -- Therapeutics."

Subtractive Antibody Screening. Subtractive antibody screening ("SAS") is a differential screening technology that identifies genes encoding cell surface or secreted proteins that are expressed in one cell type (target cell type), such as a diseased tissue type and not in another cell type (subtractive cell type). Most therapeutic targets for which drugs exist today are either cell surface or secreted proteins, which are more accessible to drugs. Dyax has licensed exclusive rights to SAS technology developed by the Whitehead Institute for Biomedical Research at the Massachusetts Institute of Technology and Massachusetts General Hospital. Scientists using the SAS technology first isolate the cell surface or secreted proteins from the target cell type. These proteins are injected into an animal to generate antibodies. The antibodies that recognize proteins from a subtractive cell type, such as a normal tissue type, are removed. The remaining antibodies will bind to proteins that are unique to the target cell or tissue type. The genes encoding protein products which react with the remaining antibodies can be cloned using existing cDNA expression cloning techniques. Dyax scientists plan to use SAS to identify novel accessible target proteins. Dyax intends to use targets identified through SAS to screen its Phage Display libraries to discover binding compounds that could be leads for therapeutic and diagnostic products.

COLLABORATIONS

To date, the Company has received a significant portion of its revenue from its corporate collaborative partnerships and funded discovery projects and the Company expects that it will continue to rely on several collaborative partners to fund different product development efforts and new research and development efforts for the foreseeable future.

Therapeutics and Diagnostics

Dyax is leveraging its Phage Display in therapeutics and diagnostics through discovery and development collaborative arrangements with biotechnology, pharmaceutical and diagnostics companies. Currently, the Company has two corporate collaborative partnerships (under which Dyax and its partner each have on-going development rights and/or obligations) and three funded discovery projects (under which Dyax's obligation, absent further agreement, is limited to conducting a discovery project and Dyax is entitled to milestone and royalty payments if the other party proceeds with development) for applications of its Phage Display technology. The Company's principal ongoing therapeutic and diagnostic corporate collaborative partnerships are:

Debiopharm. In March 1997, Dyax entered into a Research and Development Agreement with Debiopharm for the clinical development of the Company's neutrophil elastase inhibitors, including EPI-HNE4. Under the terms of the agreement, Debiopharm will undertake at its own expense the development and production of EPI-HNE4 for the treatment of inflammation resulting from cystic fibrosis and other chronic pulmonary inflammatory disorders, in exchange for an option to obtain an exclusive commercial license for therapeutic uses of EPI-HNE4 in the European market. This option is exercisable by Debiopharm at no additional cost until March 2000, subject to extension. Dyax has the right to use the regulatory information, including preclinical, clinical and manufacturing data, generated by Debiopharm and retained all rights to develop and produce EPI-HNE4 in all other fields and territories. If Debiopharm exercises the option, the Company is entitled to receive a royalty on revenues received by Debiopharm from the use or sale in the European market of therapeutic products developed using such information. In the event the Company chooses to use information owned solely by Debiopharm for therapeutic uses of EPI-HNE4, the

Company will be obligated to pay to Debiopharm a royalty on revenues received by the Company from the use or sale of products outside Europe.

EPIX. In June 1997, Dyax entered into a Collaboration Agreement with EPIX pursuant to which EPIX agreed to fund a research program in which the Company will use Phage Display to identify peptides for use in thrombi imaging applications. EPIX and Dyax agreed, following the completion of the research program, to jointly identify and develop compounds that specifically target pulmonary embolism and deep vein thrombosis for use in MRI and nuclear medicine in vivo imaging agents used to diagnose these disorders. EPIX will be responsible for the development of, and will have exclusive commercial rights to, imaging agents developed for the MRI field and the Company will be responsible for the development of, and will have the exclusive commercial rights to, imaging agents for the nuclear medicine field. If any products are successfully developed under the agreement, the Company is entitled to receive royalties from sales of MRI products and EPIX is entitled to receive royalties from any sales of nuclear medicine products. EPIX may terminate the agreement during the Research Program, and either EPIX or the Company may terminate the agreement after the completion of the Research Program, upon three months' prior notice. Unless sooner terminated, the EPIX agreement terminates with respect to the covered products on a country by country basis 15 years after the first commercial sale of such products in each country.

Discovery Projects. In addition to the two corporate collaborative partnerships described above, the Company has also entered into funded discovery projects with Athena Neurosciences, Inc., SangStat Medical Corporation and Tularik Inc. Generally, the Company screens its Phage Display libraries to identify compounds which bind to a collaborative partner's therapeutic or diagnostic targets of interest. In addition, if the collaborative partner chooses to continue to develop the binding compound into therapeutic leads, then the Company will be entitled to receive milestone payments and/or royalties on product sales based on the collaborative partner's successful development and marketing of leads as products.

Separations

Dyax is also leveraging its Phage Display in the field of separations to develop novel affinity separations technologies and products. In this field, the Company has two corporate collaborative partnerships and several funded discovery projects.

Novo Nordisk. Also in March 1997, the Company and Novo Nordisk A/S established a two-year collaboration to use the Company's Phage Display technology to develop new tools for the rapid purification and evaluation of certain of Novo Nordisk's therapeutic candidates. During such period the Company expects to perform agreed upon research in this field in exchange for funding from Novo Nordisk in an amount equal to the cost of one full-time scientist. Novo Nordisk has the right to develop further any purification tools identified by Dyax in its therapeutic development programs, and if Novo Nordisk does so, the Company will be entitled to receive license and product-development milestones in the future.

CropTech. In October 1997, in connection with a $4.3 million Advanced Technology Program grant from the National Institute of Standards and Technology, CropTech Development Corporation ("CropTech") and Dyax entered into a four-year Joint Collaboration Agreement to develop novel technologies for the production and separation of large volume protein products, therapeutic glycoproteins and bioactive peptides. Under the agreement, CropTech agreed to use its transgenic plant technology to develop novel expression systems for these therapeutic products and Dyax agreed to use Phage Display to develop affinity separations systems for use in purifying the protein and peptide products.

Discovery Projects. Typically, in the funded discovery projects, the corporate sponsors have agreed to fund the Company to use Phage Display to discover affinity ligands for evaluation in the purification and separations processes of the sponsor's pharmaceutical product candidates. These sponsors, which include Argonex, Genetics Institute, Genzyme Transgenics, Glaxo Research and Development Limited, Merck and Pall, generally fund the Company's costs of identifying and testing a custom affinity ligand and are obligated to make a milestone payment upon the successful evaluation of the ligand. Upon completion of the discovery phase, the sponsor generally has the option to expand the project to a development phase and/or to negotiate a license agreement for the commercial use of the affinity ligand in conjunction with a media to purify the

sponsor's product, although no product has yet reached this stage. The Company's discovery phase projects to date have included discovery of affinity ligands for such products as a viral vaccine, tissue plasminogen activator, a recombinant blood product and transgenic animal and plant products.

The Company's collaborative arrangements are generally subject to termination on prior written notice from the collaborative partner. One collaborative arrangement was terminated in 1998. See "Management's Discussion and Analysis of Financial Condition and Results of Operations." In addition, there can be no assurance that the Company will be able to negotiate collaborative arrangements on acceptable terms in the future, if at all, or that the Company's current or future collaborative arrangements will be successful and provide the Company with the anticipated benefits, or that current or future collaborative partners will not pursue or develop alternative technologies or products. See "Risk Factors -- Dependence on Collaborations and Licensing."

              NAME                          PROFESSIONAL AFFILIATION             ADVISOR SINCE
              ----                          ------------------------             -------------
STRATEGIC ADVISORS

Charles L. Cooney, Ph.D.........  Professor, Department of Chemical and              1992
                                  Biochemical Engineering and Executive
                                  Officer, Department of Chemical Engineering,
                                  Massachusetts Institute of Technology.
Peter Feinstein.................  Chairman, Feinstein Kean Partners Inc. and         1997
                                  Kendall Strategies Inc.
James W. Fordyce................  General Partner, Prince Ventures LP, and           1997
                                  President, Albert and Mary Lasker Foundation.
John G. Gorman, M.D.............  Director, Blood Bank and Professor of              1998
                                  Pathology, New York University School of
                                  Medicine.
Harvey F. Lodish, Ph.D..........  Professor of Biology, Massachusetts Institute      1997
                                  of Technology and Member, Whitehead Institute
                                  for Biomedical Research.
William A. Scott, Ph.D..........  President and Chief Executive Officer,             1997
                                  Physiome Sciences, Inc., and previously
                                  Senior Vice President of Exploratory and Drug
                                  Discovery Research, Bristol-Myers Squibb
                                  Pharmaceutical Research Institute.
Thomas P. Stossel, M.D..........  American Cancer Society Professor of               1995
                                  Medicine, Harvard Medical School, and Senior
                                  Physician, Hematology-Oncology Division,
                                  Brigham and Women's Hospital.
Henri A. Termeer................  Chairman, President and Chief Executive            1997
                                  Officer, Genzyme Corporation.
Christopher T. Walsh, Ph.D......  Hamilton Kuhn Professor, Department of             1997
                                  Biological Chemistry and Molecular
                                  Pharmacology, Harvard Medical School.
George M. Whitesides, Ph.D......  Mallinckrodt Professor of Chemistry, Harvard       1995
                                  University.
Peter Wirth, Esq................  Executive Vice President and Chief Legal           1997
                                  Officer, Genzyme Corporation.

              NAME                          PROFESSIONAL AFFILIATION             ADVISOR SINCE
              ----                          ------------------------             -------------
SCIENTIFIC ADVISORS -- THERAPEUTICS AND DIAGNOSTICS

Thomas J. Brady, M.D............  Director, Nuclear MRI Center, Massachusetts        1996
                                  General Hospital; Professor of Radiology,
                                  Harvard Medical School.
Alan J. Fischman, M.D., Ph.D....  Director, Nuclear Medicine Massachusetts           1998
                                  General Hospital
Leonard Guarente, Ph.D..........  Professor of Biology, Massachusetts Institute      1995
                                  of Technology.
Jordan Gutterman, M.D...........  Virginia Cockrell Professor of Medicine,           1996
                                  University of Texas, M.D. Anderson Cancer
                                  Center.
Phillip W. Robbins, Ph.D........  Professor of Biochemistry, Massachusetts           1995
                                  Institute of Technology.
Thomas M. Roberts, Ph.D.........  Chair, Department of Cancer Biology at Dana        1995
                                  Farber Cancer Institute; Chair, Division of
                                  Medical Sciences and Professor of Pathology,
                                  Harvard Medical School.
H. William Strauss, M.D.........  Chief, Division of Nuclear Medicine, Stanford      1998
                                  University.
Ralph Weissleder, M.D.. Ph.D....  Director, Center for Molecular Imaging             1998
                                  Research, Massachusetts General Hospital
Andrew Wright, Ph.D.............  Professor of Microbiology, Tufts University        1995
                                  Medical School.

SCIENTIFIC ADVISORS -- SEPARATIONS

Stuart E. Builder, Ph.D.........  Consultant, and formerly Staff Scientist,          1996
                                  Strategic Development, Genentech Inc.
Hubert Koster, Ph.D.............  Professor of Chemistry and Biochemistry,           1997
                                  University of Hamburg; President and Chief
                                  Executive Officer, Sequenom, Inc.
Jack Johanssen, Ph.D............  President and CEO, Boston Probes, Inc.             1997
Irving W. Wainer, Ph.D..........  Professor of Pharmacology, Georgetown              1996
                                  University Medical Center; Director,
                                  Georgetown University Bioanalytical Center.