ANX Mast Therapeutics, Inc.

SAN DIEGO, Dec. 5 /PRNewswire-FirstCall/ -- ADVENTRX Pharmaceuticals, Inc. (AMEX:ANX), a biopharmaceutical research and development company focused on commercializing proprietary product candidates for the treatment of cancer and infectious diseases, announced today that it has completed patient enrollment in its Phase 2 clinical trial of ANX-510, or CoFactor, for the treatment of advanced breast cancer. "Data on the primary endpoint in this study, along with overall survival data from our Phase 2b study and available data from our discontinued Phase 3 study, all of which we expect in the second quarter of 2008, will expand our understanding of CoFactor's safety and efficacy," said Evan M. Levine, chief executive officer of ADVENTRX. "By mid-next year we should have greater insight into our ability to develop CoFactor in breast cancer and other indications." The Phase 2 clinical trial is a single arm, multicenter study to evaluate the safety and efficacy of treatment with CoFactor plus 5-fluorouracil (5-FU) in advanced breast cancer patients who have failed anthracycline and taxane chemotherapies. Patients are treated with CoFactor followed by 5-FU administered by IV bolus weekly for 6 weeks, with tumor and safety assessments every 8 weeks. The primary endpoint for the study is objective response rate as defined by Response Evaluation Criteria in Solid Tumors (RECIST) criteria, and secondary endpoints are duration of response, progression free survival, overall survival and incidence and severity of adverse events, as defined by the National Cancer Institute (NCI) Common Terminology Criteria. A total of 32 patients were enrolled in this study. According to the American Cancer Society, breast cancer is the most frequently diagnosed cancer in American women and the second leading cause of cancer-related deaths in women after lung cancer. Over 214,000 new cases of breast cancer and over 41,000 deaths from breast cancer are expected in the U.S. in 2006. Despite advances made in treatment options that have led to a significant increase in survival and quality of life, metastatic disease is still incurable. Five-year survival rates decrease with advancing disease stage: from 98% in localized disease to 80% with regional spreading to only 26% with metastatic disease. About ANX-510, or CoFactor CoFactor is a folate-based biomodulator drug designed to replace leucovorin as the preferred method to enhance the activity and reduce associated toxicity of the widely used cancer chemotherapeutic agent 5-FU. Compared to leucovorin, CoFactor creates more stable binding of the active form of 5-FU to the target enzyme, thymidylate synthase (TS). CoFactor bypasses the metabolic pathway required by leucovorin to deliver the active form of folate, potentially allowing 5-FU to work more effectively. In October 2007, ADVENTRX announced the results from its Phase 2b clinical trial of CoFactor for the treatment of metastatic colorectal cancer. The CoFactor/5-FU arm did not demonstrate statistically significant improved safety in the trial's primary endpoint, a reduction in the proportion of patients reporting at least one hematological or gastrointestinal adverse event of grade 3 or greater. Further analysis of the Phase 2b study, in which 5-FU was administered by infusion, has uncovered no significant differences between the study arms with regard to either efficacy or safety. In November 2007, ADVENTRX announced that it would discontinue enrolling patients in its Phase 3 clinical trial of CoFactor for the first-line treatment of metastatic colorectal cancer. About ADVENTRX Pharmaceuticals ADVENTRX Pharmaceuticals is a biopharmaceutical research and development company focused on commercializing proprietary product candidates for the treatment of cancer and infectious diseases. The Company seeks to improve the performance and safety of existing treatments by addressing significant problems, such as drug metabolism and bioavailability, excessive toxicity and treatment resistance. More information can be found on ADVENTRX's web site at http://www.adventrx.com/. Forward Looking Statements ADVENTRX cautions you that statements included in this press release that are not a description of historical facts are forward-looking statements that involve risks and assumptions that, if they materialize or do not prove to be accurate, could cause ADVENTRX's results to differ materially from historical results or those expressed or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to: the risk that ADVENTRX will be unable to partner its product candidates and the terms of any related transaction; the results of pending clinical trials; the potential for ADVENTRX's product candidates to receive regulatory approval for one or more indications on a timely basis or at all, and the uncertain process of seeking regulatory approval; difficulties or delays in developing, testing, manufacturing and marketing of and obtaining regulatory approval for ADVENTRX's product candidates; the market potential for ADVENTRX's product candidates and ADVENTRX's and any future partners' ability to compete in those markets; unexpected adverse side effects or inadequate therapeutic efficacy of ADVENTRX's product candidates that could delay or prevent regulatory approval or commercialization, or that could result in recalls or product liability claims; the risk that preclinical and clinical results are not indicative of the success of subsequent clinical trials and that products will not perform as preclinical and clinical data suggests or as otherwise anticipated; the risk that ADVENTRX will be unable to raise sufficient capital to fund the projects necessary to meet its anticipated or stated goals and milestones; and other risks and uncertainties more fully described in ADVENTRX's press releases and periodic filings with the Securities and Exchange Commission. ADVENTRX's public filings with the Securities and Exchange Commission are available at http://www.sec.gov/. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date when made. ADVENTRX does not intend to update any forward-looking statement set forth in this press release to reflect events or circumstances arising after the date on which it was made. DATASOURCE: ADVENTRX Pharmaceuticals, Inc. CONTACT: Ioana C. Hone of ADVENTRX Pharmaceuticals, +1-858-552-0866 Web site: http://www.adventrx.com/

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