ZIOPHARM Oncology commences Phase I/II study of Zybulin for metastatic breast cancer

ZIOPHARM Oncology, Inc. (Nasdaq: ZIOP), announced today it has initiated a Phase I/II study at Memorial Sloan-Kettering Cancer Center for the novel, mathematically - determined administration of oral indibulin (Zybulin™ or ZIO-301) in the treatment of metastatic breast cancer.

The Phase I trial is expected to enroll approximately 20 patients and will determine the maximum tolerated dose of oral indibulin implementing the "mathematically modeled" dose administration schedule - 5 days on and 9 days off - that capitalizes on the convenience of oral administration, but also maximizes drug activity, limiting potential toxicity and resistance.

Indibulin is a novel, oral tubulin binding agent that targets both mitosis and cancer cell migration. It is expected to have several potential benefits, including oral dosing, application in multi-drug resistant tumors, no neuropathy, and minimal overall toxicity. In multiple Phase I trials, oral indibulin has been administered both as a single agent and in combination with favorable activity, and has a promising safety profile that does not include the neurotoxicity seen with all of the other classes of tubulin binding agents. The trial will be continued into Phase II once dose has been established in Phase I.

Clifford A. Hudis, M.D., Chief of the Breast Cancer Medicine Service at Memorial Sloan-Kettering Cancer Center, noted, "The development of an additional new therapy for breast cancer that is effective but with fewer of the more significant side effects associated with many commonly used therapies would be an important step in the treatment of this disease. We look forward to testing this novel agent and dosing schedule in patients."

The study will implement a mathematically modeled drug administration schedule that was developed in preclinical studies by Larry Norton, M.D. as a consultant to ZIOPHARM Oncology, Inc. The model capitalizes on the convenience and scheduling flexibility of oral administration to maximize anticancer activity, minimize potential toxicity and resistance, and exploit the drug's mechanisms of action on both cancer cell division and cell movement. Findings from the preclinical studies were presented at the 2009 American Society of Clinical Oncology annual meeting.

Memorial Sloan-Kettering's Breast Cancer Medicine team, under the direction of Dr. Hudis, has successfully translated preclinical work into meaningful clinical treatment in past studies, and will lead this Phase I/II trial.

Source ZIOPHARM Oncology, Inc.