Bioenvision Establishes Corporate Headquarters in New York City.

Business & Health Editors

NEW YORK--(BUSINESS WIRE)--Sept. 17, 2002

Bioenvision, Inc. (OTC BB: BIOV) today announced that it has established its corporate headquarters in midtown Manhattan.

With offices now in London and Manhattan, the Company is better positioned to develop new corporate relationships and to further expand ongoing clinical programs.

"Having a presence both in the U.K. and the U.S. will enable us to take full advantage of the research and partnership opportunities as well as allow us greater exposure to the capital markets in both countries," said Dr. Christopher Wood, President and CEO of Bioenvision.

Background on the Company's programs:

The Company's lead product, clofarabine, is currently being tested clinically in a variety of hematological malignancies as well as solid tumors. Clofarabine is currently being studied in Phase II clinical trials in children with acute lymphoblastic leukemia (ALL), children with acute myelogenous leukemia (AML), and adults with acute myelogenous leukemia (AML). Preliminary clinical data in these indications has looked very promising.

Phase I/II trials are planned to begin this year in Non-Hodgkins Lymphoma and Chronic Lymphocytic Leukemia. Additionally, Phase I clinical testing of clofarabine in patients with solid tumors is set to begin later this year.

Clofarabine is a novel investigational therapeutic designed as a second-generation nucleoside analogue to overcome the limitations of current analogues, such as fludarabine and cladrabine. Clofarabine exhibits the mechanistically favorable properties of both fludarabine and cladrabine in terms of DNA chain termination and inhibition of ribonucleotide reductase, respectively. In several preclinical models, when compared to Fludara, clofarabine has shown several-fold greater lymphocytic potency. It also appears to work through a unique additional mechanism, whereby it directly damages the mitochondria in cancer cells and induces apoptosis (Blood 2000 96: 3537).

Bioenvision is co-developing clofarabine with ILEX Oncology, Inc. (ILXO).

Bioenvision is also developing Modrenal, a compound already approved in the U.K. for the treatment of advanced post-menopausal breast cancer. Clinical trials have shown the compound is effective in breast cancer patients, particularly after treatments with hormonal therapy, for example with tamoxifen, are no longer effective.

Data recently published in the International Journal of Cancer suggest that Modrenal, in addition to inhibiting production of estrogen, also has a novel second mode of action that could explain the drug's broad clinical activity (Puddlefoot J.R. et al Int. J. of Cancer 101; 17-22 2002).

Currently available anti-estrogens, such as tamoxifen, are competitive inhibitors that bind to the ligand binding sites of estrogen receptors (ER). Modrenal does not bind to the receptors but inhibits the receptors from binding to estrogen response elements in DNA and stops estrogen- stimulated gene transcription. Thus, the drug works in the cancer cell at a site different than most other breast cancer drugs and could therefore potentially be used when the other agents have failed. Also, of particular interest is the way in which Modrenal acts on the "second" estrogen receptor, ER beta. Recently published data suggest that ER beta may play an important role in the development of hormone sensitive cancers, such as breast and prostate cancer, and this recently-described receptor has become a prime target for new forms of treatment. A part of Modrenal's action is directed specifically at ER beta.

Bioenvision's OLIGON technology, licensed to a leader in the treatment of cardiovascular disease, utilizes a proprietary process that creates an electrochemical reaction between dissimilar metals (silver and platinum). The OLIGON technology involves the impregnation of a polymer material with silver, platinum and carbon particles. Upon contact with an ionic solution such as saline, medications or body fluids, an electrochemical reaction between the silver and platinum particles is activated, and silver ions are actively released to the surface of the polymer and then into its immediate surrounding environment, a process known as Oligodynamic Iontophoresis.

The OLIGON antimicrobial material can be customized to help prevent infection for any number of devices, including over-the-counter and consumer products, where markets are estimated to be billions of dollars. Bioenvision plans to establish OLIGON as a broadly effective, safe and superior technology. In vitro and animal testing and human clinical trials have shown OLIGON to be superior to antibiotic, antiseptic and other silver technologies in reducing device-related infections.

The first commercial sales of a product using OLIGON, a central venous catheter (CVC) was rolled out in June 2000. The product is the first CVC made of a biocompatible and antimicrobial material, and the Company is currently generating revenues from its sale. Recently, the Company received 510K approval for a pulmonary artery catheter and expects to begin marketing the product soon.

About Bioenvision

Bioenvision's (OTC BB: BIOV) primary focus is the acquisition, development and distribution of compounds and technologies for the treatment of cancer. Bioenvision has a broad pipeline of products for the treatment of cancer, including: clofarabine (in co-development with ILEX Oncology, Inc.); Modrenal(R) (for which Bioenvision has obtained regulatory approval for marketing in the United Kingdom for the treatment of post-menopausal breast cancer); and other products in clinical trials. Bioenvision is also developing anti-infective technologies, including the OLIGON technology, an advanced biomaterial that has been approved for certain indications by the FDA in the U.S. For more information on Bioenvision please visit our Web site at www.bioenvision.com.

Certain statements contained herein are "forward-looking" statements (as such term is defined in the Private Securities Litigation Reform Act of 1995). Because these statements include risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Specifically, factors that could cause actual results to differ materially from those expressed or implied by such forward-looking statements include, but are not limited to: risks associated with preclinical and clinical developments in the biopharmaceutical industry in general and in Bioenvision's compounds under development in particular; the potential failure of Bioenvision's compounds under development to prove safe and effective for treatment of disease; uncertainties inherent in the early stage of Bioenvision's compounds under development; failure to successfully implement or complete clinical trials; failure to receive marketing clearance from regulatory agencies for our compounds under development; acquisitions, divestitures, mergers, licenses or strategic initiatives that change Bioenvision's business, structure or projections; the development of competing products; uncertainties related to Bioenvision's dependence on third parties and partners; and those risks described in Bioenvision's filings with the SEC. Bioenvision disclaims any obligation to update these forward-looking statements.