Vion Pharmaceuticals has temporarily suspended enrollment and further treatment in its Phase III study of Cloretazine® in patients with relapsed adult myelogenous leukemia (AML) based on mortality concerns. The company lost almost 56% of its value to open trading at $0.89.
The trial's independent Data Safety Monitoring Board (DSMB) conducted a planned preliminary review of data from the first 210 treated patients. This DSMB found that any advantage in complete remission could be compromised by the observed on-study mortality to date.
"There will be a thorough analysis of all the data to date from this trial,” CEO, Alan Kessman, asserts. “We will base any decision on the continuation, possible modification, or termination of the study on the available data. We will provide an update on the status of the analysis as soon more information is available."
The Phase III trial was designed as a double-blind, placebo-controlled, randomized evaluation of Ara-C plus Cloretazine versus Ara-C and placebo. The trial accrued patients in first relapse AML whose first complete remission (CR) was more than three months but less than 24 months. The primary endpoint is the objective response rate defined as CR plus CRp (a complete remission with incomplete recovery of platelet count). Secondary endpoints include time to progression, duration of response, overall survival, and toxicity.
Vion also is evaluating Cloretazine as a single agent in a Phase II trial in elderly patients with de novo poor-risk AML. This trial is being conducted in over 20 sites in the U.S. and Europe. Enrollment is expected to end to occur in June or July 2007.