ZIOPHARM receives Notice of Allowance for palifosfamide from U.S. patent office

ZIOPHARM Oncology, Inc. (Nasdaq: ZIOP) announced today that it has received a Notice of Allowance from the U.S. Patent and Trademark Office for Application Serial No. 11/257,766 entitled “Salts of Isophosphoramide mustard and analogs thereof as anti-tumor agents” with claims directed to compounds, pharmaceutical compositions, and lyophilisates. These claims cover the Company’s proprietary palifosfamide composition (ZIO-201 or Zymafos^TM). The Company has recently reported positive randomized Phase II sarcoma interim data for intravenous palifosfamide at the Annual Meeting of the Connective Tissue Oncology Society (CTOS) on November 6, 2009 and expects, following U.S. Food and Drug Administration (FDA) review, to initiate a registration trial the first half of 2010.

“Salts of Isophosphoramide mustard and analogs thereof as anti-tumor agents”

ZIOPHARM has also recently been granted United States Patent No. 7,619,000 covering the oral administration of various organic arsenic compounds, including darinaparsin, for the treatment of cancer. Darinaparsin (ZIO-101 or Zinapar^TM) is a novel mitochondrial-targeted agent having been studied intravenously in Phase II for the treatment of lymphoma while the oral form continues in Phase I study for both hematological malignancies and solid tumors. The Company also expects to initiate a registration trial for darinaparsin in peripheral T-cell lymphoma following FDA review.

Additionally, ZIOPHARM has been granted Patent No. 2,326,833 by the Canadian Intellectual Property office covering certain N-substituted indole-3-glyoxylamides, including indibulin, for use as an antitumor agent. Indibulin (ZIO-301 or Zybulin^TM) is the Company’s novel oral microtubule inhibitor being developed for the treatment of breast cancer sub-types and is expected to enter Phase I study in the first quarter of this year in collaboration with the Memorial Sloan-Kettering team and using a novel biologically- and mathematically-driven schedule of administration developed preclinically by Dr. Larry Norton.

“With this notice of allowance for palifosfamide, we now have established a U.S. patent position for all three of our product candidates,” said Jonathan Lewis, MD, PhD, Chief Executive Officer of ZIOPHARM. “With the additional issuances for darinaparsin and indidibulin, we continue to add to our patent estates, and will continue doing so for all three programs.”