Vion Initiates Trial of Cloretazine in Relapsed Acute Myelogenous Leukemia

March 29, 2005

Vion Pharmaceuticals has commenced dosing the first patient on the Phase III pivotal trial of its anticancer agent Cloretazine (VNP40101M) in relapsed acute myelogenous leukemia.

Vion recently reached agreement with the FDA on a special protocol assessment for this trial. The trial is a double-blind, placebo-controlled, randomized evaluation of an experimental treatment consisting of Ara-C plus Cloretazine versus a control arm regimen of Ara-C and placebo. This trial is designed to accrue patients in first relapse whose first complete remission (CR) was more than three months but less than 24 months in duration.

Patients will be stratified according to age -- greater than or less than 60 years -- and length of the first CR -- more than or less than 12 months in duration. The primary endpoint for the trial is the objective response rate, defined as CR plus CRp (a complete remission with incomplete recovery of the platelet count). Secondary endpoints include time to progression, duration of response, overall survival and toxicity. An interim analysis is planned.