Millennium Pharmaceuticals Inc and Xenova Group plc announced the initiation of a phase I clinical trial of MLN944 (also known as XR5944). MLN944 is a novel DNA targeting agent under investigation for the treatment of advanced cancers. The phase I clinical trial is an open label, dose-escalation study in adult patients with advanced solid tumors to evaluate the safety and tolerability, as well as pharmacokinetic properties of MLN944. The study will be conducted at three centers in the United Kingdom and will include approximately 40 patients.

MLN944 is a novel DNA targeting agent that in preclinical studies has demonstrated a high level of anti-tumor activity, both in vitro and in vivo, against a number of human tumor models. In human tumor xenograft models, treatment with MLN944 caused both partial and complete regression of large established tumors. Recent data suggests that MLN944 acts through a novel mechanism of action distinct from other current cytotoxic agents. Further exploration into the mechanism of action is ongoing.

"MLN944 is an important compound in our oncology portfolio that we believe holds great potential and is based on the Millennium commitment to breakthrough science and breakthrough medicine," said Barry Greene, general manager of oncology at Millennium. "With both the preclinical activity data and our growing understanding of the novel mechanism of action, we are optimistic that MLN944 may provide patients with an important new therapeutic option."

"MLN944 has one of the best preclinical profiles we have seen both in vitro and in vivo," said David Oxlade, Xenova's Chief Executive Officer. "We are hopeful that the exciting MLN944 preclinical activity will translate into a clinical compound that helps address the clear and growing need in the marketplace for better, more efficacious cancer treatments."

Millennium licensed MLN944 from Xenova Group plc in December 2001 as part of a larger collaboration including two other compounds MLN576 (XR11576) and MLN612 (XR11612). Millennium is currently funding Xenova to implement development activities associated with the program to the completion of phase II clinical trials, at which time Millennium has the right to assume development responsibility in North America. Xenova retains commercialization and development responsibility for the rest of the world. Enrollment for MLN576 is currently completing in its UK-based Phase I trials and the study data will then be reviewed to assess further development plans.