Clinical Data from Studies of Bioenvision's Clofarabine to Be Presented at American Society of Hematology Meeting.

Business Editors/Health/Medical Writers

45th Annual Meeting of the American Society of Hematology (ASH)

NEW YORK--(BUSINESS WIRE)--Nov. 7, 2003

Bioenvision, Inc. (Amex:BIV) today announced that three abstracts relating to its lead oncology product, clofarabine, have been accepted for presentation at the 45th Annual Meeting of the American Society of Hematology (ASH), to be held on December 5-9, 2003, in San Diego, CA. The abstracts are available on the ASH website at www.hematology.org.

The three abstracts, entitled: "Clofarabine Is Active in Combination with Cytarabine (ara-C) in Adult Patients (pts) in First Relapsed and Primary Refractory Acute Leukemia and High-Risk Myelodysplastic Syndrome (MDS)" (S. Faderl, V. Gandhi, et al.), "A Phase II, Open-Label Study of Clofarabine in Pediatric Patients with Refractory or Relapsed Acute Myelogenous Leukemia" (S. Jeha, P. Steinherz, et al.), and "A Phase II, Open-Label Study of Clofarabine in Pediatric Patients with Refractory or Relapsed Acute Lymphoblastic Leukemia" (S. Jeha, P. Gaynon, et al.) are scheduled for presentation by clinical investigators.

About Clofarabine

Clofarabine is a second-generation purine nucleoside antimetabolite under development for the treatment of acute pediatric and adult leukemias. Nucleoside analogues are antimetabolites that affect DNA synthesis. Clofarabine was rationally designed to combine many of the favorable properties of the two most commonly used nucleoside analogs, fludarabine and cladribine, but is reported to have greater potency at damaging the DNA of Leukemia cells than these other agents. (Blood, "Mitochondrial Toxicity of Deoxyadenoside Analogs", November 15, 2000, Volume 96, Number 10). In a single center Phase II study of clofarabine in patients with refractory acute myelogenous leukemia (AML), 42% of the patients had a complete response rate (CR) and a further 13% had a partial response (CRp).

Bioenvision granted ILEX the right to develop clofarabine in the United States and Canada. Bioenvision is entitled to milestone payments tied to the development of the compound and is entitled to royalties on North American sales. Bioenvision is developing clofarabine exclusively in the rest of the world. Bioenvision originally obtained clofarabine development and commercialization rights under patents held by Southern Research Institute.

About Bioenvision

Bioenvision's (Amex:BIV) 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 following relapse to initial hormone therapy), and other products in clinical trials. Bioenvision is also developing anti-infective technologies, including the OLIGON technology; an advanced biomaterial that has been incorporated into various FDA approved medical devices. 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.