Bioenvision Announces Latest Data on Evoltra(R) in Pediatric and Adult Leukemias.

Data Presented at the 48(th) Annual Meeting of the American Society of Hematology

ORLANDO, Fla. -- Bioenvision, Inc. (NasdaqGM:BIVN) announced the latest results from clinical studies of clofarabine (Evoltra([R])) were presented in seven posters today at the 48th Annual Meeting of the American Society of Hematology (ASH) in Orlando, Florida. The posters featured data on the efficacy and safety of clofarabine in Acute Lymphoblastic Leukemia (ALL), Acute Myeloid Leukemia (AML) and Myelodysplastic Syndrome (MDS). Of the data presented, Bioenvision's data included:

* A pooled analysis of three studies, BIOV-121, UWCM-0001 and AML-14, showed a 46% complete response rate (CR/CRi) in elderly AML patients with adverse cytogenetics who were unsuitable for standard intensive treatment. The current standard of care low dose Ara-C (LDAC) had a 0% complete response rate. The one-year survival rate for Evoltra was 21%, compared with 0% for LDAC. (Abstract 1985; Poster 163)

* A dose-ranging study assessing the combination of Evoltra([R] )and daunorubicin showed an overall response rate of 65%. In the 20mg cohort the response rate was 100%. The overall survival at 1 year for the full cohort of 37 patients was 62%. The combination of clofarabine 20mg/m(2) plus daunorubacin 50mg/m(2) was well tolerated with acceptable toxicity. This combination has been chosen for the NCRI Phase III AML-16 Intensive Study which is now enrolling patients. (Abstract 1950; Poster 128)

* The latest update from study BIOV-111 showed a complete response rate (CR + CRp) of 31% in heavily pre-treated pediatric patients with relapsed/refractory ALL. These data confirm the results of the pivotal US CLO-212* study and further establish Evoltra([R]) as the standard of care for pediatric patients with relapsed/refractory ALL . (Abstract 1859; Poster 37)

"We are very encouraged about the potential these new data show for Evoltra([R]) to be used alone or in combination with other therapies to treat acute leukemia in children and adults," said Professor Christopher Wood, M.D., Chief Executive Officer and Chairman, Bioenvision. "Based on these results, we are moving ahead with new clinical studies of Evoltra([R]) in other disease areas, such as MDS, chronic leukemias and solid tumors."

"Evoltra([R]) provides elderly patients with AML who are unsuitable for intensive chemotherapy a much higher response rate and a real survival advantage, especially in those patients with additional poor prognostic factors," said Hugh Griffith, Chief Operating Officer, Bioenvision. "These data, along with data to be presented tomorrow, will form the basis for our marketing authorization application to the European Medicines Agency (EMeA) for a label extension of Evoltra([R]) for adults with AML who are unsuitable for intensive chemotherapy."

On Monday at 2:30 p.m., data from Bioenvision's pivotal Phase II trial of Evoltra([R]) in adult AML will be featured in an oral presentation entitled "A Phase II Study (BIOV-121) of Clofarabine Monotherapy First Line in Patients Aged 65 Years or Older with Acute Myeloid Leukemia for Whom Standard Intensive Chemotherapy Is Not Considered Suitable." Alan Burnett, M.D., Chairman of the UK National Cancer Research Institute (NCRI) Hematological Oncology Study Group, will present these data in Hall F5.

Investor Conference Call and Meeting at ASH

In conjunction with the release of the data at ASH, Bioenvision will host an investor meeting, conference call and webcast on Monday, December 11, 2006 at 7:15 p.m. ET.

Conference Call Information:
Date: 12/11/06
Time: 7:15 p.m. ET
Toll free: 866-585-6398
International: 416-849-9626
Web cast: www.bioenvision.com

A replay of the call and web cast will be available for 14 days.
Replay number toll free: 866-245-6755
Replay number international: 416-915-1035
Replay passcode: 780114
Web cast replay: www.bioenvision.com

About Evoltra([R]) (clofarabine)

The European Marketing Authorization for Evoltra([R]) (clofarabine) is for "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."

Clofarabine is in clinical development for the treatment of other hematological cancers and solid tumors. Bioenvision is also conducting pre-clinical studies 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 (excluding U.S. and Canada) for the cancer applications of clofarabine and an exclusive worldwide license for all non-cancer indications. Bioenvision granted an exclusive sublicense to Genzyme Corporation to develop and commercialize clofarabine for certain cancer indications in the U.S. and Canada, which Genzyme markets under the name of Clolar([R]). 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.

* CLO-212 was conducted by Genzyme Corporation.

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: Evoltra([R]), 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. Bioenvision is also developing anti-infective technologies, including the OLIGON([R]) technology; an advanced biomaterial that has been incorporated into various FDA approved medical devices and Suvus([R]), an antimicrobial agent currently in clinical development for refractory chronic hepatitis C infection. 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.