BONITA SPRINGS, Fla., May 26, 2011 -- Tigris Pharmaceuticals, Inc., today announced enrollment of its first patient in a randomized Phase 2 clinical trial of AFP-464 (aminoflavone prodrug) with or without Faslodex® (fulvestrant) in estrogen receptor (ER)-positive breast cancer patients. Molecular profiling will be used to pre-screen patients for a biomarker called Aryl Hydrocarbon Receptor (AhR), which has shown to predict sensitivity to AFP-464.

It is estimated that approximately 70 percent of breast cancers are ER-positive. "The promise of personalized medicine is being realized with this study of AFP-464," said Edmundo Muniz, M.D., Ph.D., president and chief executive officer of Tigris Pharmaceuticals. "Matching specific markers and gene variations to particular medicines is a more efficient way of developing new anti-cancer agents and more importantly, will enable doctors to make more informed prescribing decisions, reducing risks of side effects and increasing chances of treatment success."

The primary endpoint of the study is to determine the percentage of patients that achieve a Clinical Benefit Response.

The randomized, proof-of-concept trial is led by Joanne Blum, M.D., Ph.D., director of the Hereditary Cancer Risk Program at Baylor-Sammons Cancer Center in Dallas, Texas. The study is open for accrual with the US Oncology Research Network, the largest community-based cancer research network in the nation.

"We are fortunate there are approved therapies to treat metastatic breast cancer, but the majority of patients with this disease will become refractory during treatment," said Dr. Blum. "This study is exciting in that it may have the potential to improve our ability to deliver targeted cancer therapy at the outset of treatment providing another option for these patients. Additionally, this agent may help to overcome endocrine resistance, one of the major problems for patients with ER positive metastatic disease."

About AFP-464

AFP-464 is a novel anti-cancer agent currently being studied by Tigris Pharmaceuticals in a randomized Phase 2 clinical trial with ER-positive breast cancer patients. AFP-464 is also being studied by the National Cancer Institute ("NCI") under a Cooperative Research and Development Agreement (CRADA). NCI is sponsoring two Phase 1 clinical trials in patients with solid tumors under the CRADA. Pre-clinical studies into AFP-464's mechanism of action have shown that AFP-464 is converted to metabolites, which bind covalently to DNA, resulting in p53 activation and apoptosis. AFP-464 has shown a unique pattern of growth inhibitory activity in the NCI's 60 tumor cell line screen, with breast, ovarian, lung and renal tumor cell lines exhibiting particular sensitivity to the compound. In vivo anti-tumor activity of AFP-464 has been demonstrated in several xenograft studies in mice bearing renal and breast cancer. Pre-clinical studies have shown that tumors (breast, ovarian, pancreatic and renal) with AhR localized in the cytoplasm are very sensitive to AFP-464 while those with AhR localized in the nucleus are more resistant.

About Tigris Pharmaceuticals, Inc.

Tigris Pharmaceuticals, Inc. is a privately held biopharmaceutical company that acquires, develops and commercializes innovative specialty care therapies to treat oncology, pain, inflammation, acute and supportive care areas of unmet medical need. Tigris' mission is to efficiently move its existing and future technologies through the various stages of clinical development in order to meet patients' needs for safe and effective treatments of human illnesses.

Contacts:
Alexander Mironov
Vice President of Operations
Tigris Pharmaceuticals, Inc.
(239) 444-5400
info@tigrispharma.com

This news release contains forward-looking statements. Such statements are valid only as of today, and Tigris disclaims any obligation to update this information. These statements are subject to known and unknown risks and uncertainties that may cause actual future experience and results to differ materially from the statements made. These statements are based on the company’s current beliefs and expectations as to such future outcomes. Drug development involves a high degree of risk. Factors that might cause such a material difference include, among others uncertainties related to Tigris’ ability to attract and retain partners for its technologies, the identification of lead compounds, the successful preclinical development thereof, the completion of clinical trials, the FDA review process and other governmental regulation, its pharmaceutical collaborator’s ability to successfully develop and commercialize drug candidates from other pharmaceutical companies, product pricing and third party reimbursement.