Bioenvision's Evoltra(R) Achieves High Response Rates in Adult AML; New Interim Data Presented from Phase I/II Clinical Study.

EDINBURGH, Scotland -- Bioenvision (Nasdaq: BIVN) today announced that an overall response had been achieved in 92% of patients over 60 yrs of age with acute myeloid leukemia (AML) given a combination of Evoltra(R) (clofarabine) and daunorubicin as first-line treatment. These interim data were presented at the British Society of Haematology 46th Annual Scientific Meeting in Edinburgh by Professor A. K. Burnett.

The Phase I/II dose-ranging study of Evoltra(R) in combination with daunorubicin had been performed as part of the AML16 intensive trial conducted by the National Cancer Research Institute (NCRI). A total of 30 patients in 4 cohorts have received daunorubicin (50mg daily) plus Evoltra(R) in doses ranging from 15mg/m2 to 30mg/m2. Response data have been analyzed and were presented on the first two dose cohorts (15 and 20mg/m2) comprising of 12 patients. 92% (11/12) achieved a response with 83% (10/12) reaching complete remission. The remaining dose cohorts have now been fully recruited and response data are currently being evaluated. The combination of daunorubacin and Evoltra(R) at the various dose levels has been well tolerated with only minimal toxicity observed.

The success of this Phase I/II study now enables the Phase III study to be initiated which will randomize patient to receive either the combination of Evoltra(R) plus daunorubacin or the current standard of care, ara-C plus daunorubacin.

"We are pleased with the excellent responses we are seeing in these patients with Evoltra(R), and especially how well the patients tolerate the drug combination," said Dr Christopher Wood, CEO and Chairman of Bioenvision. Dr Wood added, "Moving Evoltra(R) into the first line setting for patients with AML who are suitable for intensive therapy represents yet another dimension to our clinical development strategy for this important new agent".

About Evoltra(R)(clofarabine)

On February 23, 2006, the CHMP adopted a positive opinion for the use of Evoltra(R) (clofarabine) in the treatment of acute lymphoblastic leukemia (ALL) in pediatric patients who have relapsed or are refractory to at least two prior regimens and where there is no other treatment option anticipated to result in a durable response. Safety and efficacy have been assessed in studies of patients less than or equal to 21 years old at initial diagnosis.

Bioenvision is also developing Evoltra(R) for the treatment of adult acute myeloid leukemia (AML) as first-line therapy. The Company has completed enrollment of its Phase II clinical trial for the treatment of adult AML in elderly patients unfit for intensive chemotherapy and expects to file a Marketing Authorization Application in mid-2006 for the Company's first label-extension for Evoltra(R).

In addition, clofarabine is in clinical development for the treatment of myelodysplastic syndrome (MDS), chronic lymphocytic leukemia (CLL), chronic myeloid leukemia (CML), non-Hodgkin's lymphoma (NHL), multiple myeloma (MM), solid tumors and as a preconditioning regimen for transplantation under investigator-initiated studies supported by our co-development partner, Genzyme Corporation. Bioenvision is also conducting late-stage preclinical development of Evoltra(R) for the treatment of psoriasis and is planning further worldwide development of Evoltra(R) in autoimmune diseases.

Evoltra(R) (clofarabine) is a next generation purine nucleoside analog. Bioenvision holds an exclusive worldwide license for clofarabine (outside of Japan and Southeast Asia). Bioenvision granted an exclusive sublicense to Genzyme to co-develop clofarabine for cancer indications in the US and Canada. Genzyme is commercializing clofarabine for cancer indications in the US and Canada under the brand name Clolar(R). Bioenvision holds an exclusive license in the US and Canada for all non-cancer indications. Bioenvision originally obtained clofarabine development and commercialization rights under patents held by Southern Research Institute.

Clofarabine has been granted orphan drug designation for the treatment of both ALL and AML in the U.S. and Europe. In Europe, the designation provides marketing exclusivity for 10 years following Marketing Authorization.

About Bioenvision

Bioenvision's primary focus is the acquisition, development, distribution and marketing 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 Genzyme Corporation), 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.