YM BioSciences Inc, a life sciences product development company that identifies and advances a diverse portfolio of promising cancer-related products at various stages of development, announced that preclinical results for CYT997 were presented in a poster by Cytopia Limited at the 2009 AACR-NCI-EORTC Molecular Targets and Cancer Therapeutics conference in Boston, Massachusetts. CYT997 is an orally available, small molecule vascular disrupting agent (VDA) currently in phase-II clinical studies. A proposal to merge Cytopia into YM has been previously announced and is pending approval by Cytopia shareholders, Australian court and other regulatory approvals.

The results reportedly demonstrate that when administered metronomically (in frequent, low doses), CYT997 is able to produce potent vascular disrupting effects in tumours (colon adenocarcinoma xenograft model), and in combination with cisplatin dosed weekly leads to enhanced antitumor effects compared to cisplatin alone. Administration of CYT997 reportedly resulted in a time and concentration-dependent shutdown of tumor vasculature. Daily administration of CYT997 reportedly resulted in a sustained shutdown of tumour vasculature, increased necrosis and increased survival.

"The results of this study appear to demonstrate the broad potential utility of CYT997 as an anticancer agent. The ability to administer CYT997 orally differentiates it from most other VDAs in development and allows more flexible dosing regimes than would be possible for agents that can only be administered intravenously," said Chris Burns, director of Research of Cytopia.

"Metronomic administration of a VDA may likely result in more consistent and prolonged collapse of tumor vasculature and an orally administered VDA would be ideal for this type of administration," noted Dr Robert Kerbel, professor (adjunct), Cancer Biology, Medicine, MD Anderson Cancer Center, University of Texas and Professor, Medical Biophysics, University of Toronto.

Dr Chris Burns presented the poster entitled, 'Antitumour activity of CYT997: A phase-II vascular disrupting agent administered orally in combination with cisplatin in a colon adenocarcinoma xenograft mode' at the Angiogenesis and Antiangiogenesis Agents poster session on Monday 16 November 2009.

"CYT997 is substantially distinct from the other VDAs in that it can be delivered orally, as well as intravenously, facilitating more frequent administration at lower doses, a regimen likely to enhance both its safety and efficacy. We believe this unique aspect of CYT997 could significantly expand its utility and that its development could add to existing treatment protocols and lead to new and important regimens for a wide range of tumour types," said David Allan, chairman and CEO of YM BioSciences.

Cytopia Ltd is an Australian biotechnology company focused on the discovery and development of new drugs to treat cancer and other diseases.

YM BioSciences is a life sciences product development company that identifies and advances a portfolio of promising cancer-related products at various stages of development.