Enzon is a biopharmaceutical company that develops and commercializes enhanced therapeutics for life-threatening diseases through the application of our two proprietary platform technologies: PEG and single-chain antibodies (SCA®). Enzon applies its PEG, or polyethylene glycol, technology to improve the delivery, safety and efficacy of proteins and small molecules with known therapeutic efficacy. Enzon uses its single-chain antibody, or SCA, technology to discover and produce antibody-like molecules that offer many of the therapeutic benefits of monoclonal antibodies while addressing some of their limitations.

Enzon has significant expertise and intellectual property in the methods by which PEG can be attached to a compound, the selection of appropriate sites on the compound to which PEG is attached, and the amount and type of PEG used. Given their expertise, scientists at Enzon are able to tailor the technology to produce the desired results for the particular substance being modified. Enzon’s proprietary PEG technology can be used with therapeutic proteins and small molecules.

Enzon develops and markets products on its own, as well as through strategic partnerships. These partnerships increase the availability of resources, thus enabling Enzon to expand its capabilities and ultimately broaden the product pipeline. An example of this strategy is PEG-Intron, a PEG-enhanced version of Schering-Plough's alpha interferon product, INTRON A. Enzon has designed PEG-Intron to have an improved side effect profile, to yield greater efficacy as compared to INTRON A and to allow once per week dosing as compared to three times per week for INTRON A.

APPROVED PRODUCTS: Enzon has two FDA approved products, which utilize PEG-technology. The first FDA approved product, ADAGEN® (pegademase bovine), was approved in March 1990. ADAGEN is a PEG-modified version of the bovine enzyme adenosine deaminase (ADA) which Enzon developed and markets. The second product, ONCASPAR® (pegaspargase), was developed and is manufactured by Enzon. ONCASPAR, which was approved in February 1994, is a PEG-modified version of the enzyme L-asparaginase, a mainstay in chemotherapy for acute lymphoblastic leukemia (ALL).

Products in development: PROTHECAN is a PEG-enhanced version of a small molecule called camptothecin, which is an anticancer compound in the class of drugs called topoisomerase inhibitors. Enzon believes that by adjusting the way PEG is covalently attached to camptothecin, the PEG attachment can be used to inactivate the compound's toxic mechanism, which allows it to circulate in the bloodstream for long periods of time. This allows the compound to accumulate in the proximity of tumor sites. Enzon is currently conducting a Phase I clinical trial of PROTHECAN in treating various types of cancers.

Contact: Josef Bossart, Ph.D., Vice President Business Development, ENZON, Inc.

Tel: 1(732)980-4505; fax: 1(732)980-9606; e-mail: jbossart@enzon.com;

Alexander Shtilbans, Business Associate, tel: 1(732)980-4602; e-mail: alex.shtilbans@enzon.com