Ziopharm Oncology, Inc., has signed a definitive agreement to acquire Indibulin, a novel synthetic anti-cancer agent that targets mitosis like the taxanes, from affiliates of Baxter Healthcare Corporation.

Indibulin is available as both an oral and a proprietary nanosuspension intravenous (IV) form with the oral form in a phase I trial and the nanosuspension in late preclinical. Indibulin, now designated as ZIO-301, may offer efficacy, dosing and toxicity advantages as compared to marketed taxanes, including paclitaxel (taxol, paclitaxel protein-bound particles for injectable suspension (abraxane, and docetaxel taxotere). Indibulin is the subject of both issued patents and applications worldwide.

The phase I trial is ongoing at the Netherlands Cancer Institute and University Medical Center, Utrecht with Prof. Jan Schellens as principal investigator. As part of the purchase, the company has acquired the existing drug supply manufactured by Baxter and has assumed all responsibility for the phase I trial. The company expects to file an IND in the US to initiate a phase II study with the oral form in the first half of 2007 followed by phase I trials with the nanosuspension IV formulation.

Taxanes are administered by intravenous administration (IV) and are among the most effective clinical chemotherapeutic agents in the world today, with 2005 sales in excess of $3 billion. Notwithstanding this extensive use, all of the marketed agents are associated with severe toxicities, primarily neurotoxicity and myelosuppression. The company believes that Indibulin has the potential to provide important competitive advantages over currently marketed taxanes, including the availability of both an oral and a proprietary IV nanosuspension, preclinical evidence of activity against multi-drug and taxane resistant tumours, and reduced toxicity.

"Taxanes are well established as standard of care for treating a great variety of solid cancers", commented Prof. Jan Schellens of the Netherlands Cancer Institute and the Principal Investigator for the ongoing phase I trial. "Indibulin appears to have a unique mechanism of action and it is orally bioavailable and so far lacking neurotoxicity. We look very forward to collaborating with Ziopharm on this program."

Terms of the acquisition include an upfront cash payment, clinical and regulatory-based milestone payments, and royalties on net product sales typical of a product at this stage of development.

"We're excited about adding a third potential phase II candidate to our portfolio," commented Jon Lewis, MD, PhD the company's chief executive officer. "This transaction is synergistic with our ongoing ZIO-101 and ZIO-201 programs. The expected near-term availability of an oral version of ZIO-101, our organic arsenic, along with the possibility of an oral ZIO-201, means we should be uniquely positioned among our peers with three proprietary oral anti-cancer agents in clinical trials in 2007, a year that promises to be a very exciting one for Ziopharm."