( le cytogenetics havetraditionally not ...)Vion Pharmaceuticals Presents Clinical Data from a Phase II Trial,of Cloretazine (VNP40101M) in Elderly AML Patients with Unfavorable,Cytogenetics at EHA Meeting,Health

Ann Cahill, Vion's Vice President, Clinical Development, said, "Elderly AML patients with unfavorable cytogenetics have few available treatment options." Ms. Cahill added, "Our ongoing pivotal Phase II trial is designed to confirm the activity of Cloretazine(R) (VNP40101M) in poor-risk patients, including those with unfavorable cytogenetics."

A pivotal Phase II clinical trial in elderly patients with de novo poor- risk AML is underway currently in over 20 sites in North America and Europe. Completion of accrual to this trial is expected in June or July 2007.

Vion Pharmaceuticals, Inc. is committed to extending the lives and improving the quality of life of cancer patients worldwide by developing and commercializing innovative cancer therapeutics. Vion has two agents in clinical trials. Cloretazine(R) (VNP40101M), a unique alkylating agent, is being evaluated in a Phase II pivotal trial as a single agent in elderly patients with previously untreated de novo poor-risk acute myelogenous leukemia. An additional trial of Cloretazine(R) (VNP40101M) as a single agent in small cell lung cancer is also underway. Triapine(R), a potent inhibitor of a key step in DNA synthesis, is being evaluated in clinical trials sponsored by the National Cancer Institute. In preclinical studies, Vion is also evaluating VNP40541, a hypoxia-selective compound, and hydrazone compounds. The Company also is seeking development partners for TAPET(R), its modified Salmonella vector used to deliver anticancer agents directly to tumors. For additional information on Vion and its product development programs, visit the Company's Internet web site at www.vionpharm.com.

This news release contains forward-looking statements. Such statements are subjec
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