Vion has announced the initiation of a pivotal Phase II trial of Cloretazine as a single agent in previously untreated elderly patients with de novo poor-risk acute myelogenous leukemia. The Phase II trial is expected to be conducted in over 20 North American and European sites. Accrual of 85 patients is expected to take approximately one year.

Cloretazine is a novel alkylating agent, which is also being evaluated in a pivotal Phase III trial in combination with cytarabine for the treatment of patients of any age with relapsed AML. This 420-patient Phase III trial is being conducted in 65 North American and European sites, and is expected to reach its interim evaluation point in the second half of 2006.