REDWOOD CITY, Calif., Dec. 7, 2009 (GLOBE NEWSWIRE) -- Threshold Pharmaceuticals, Inc. (Nasdaq:THLD) today announced preclinical results related to Threshold's clinical stage hypoxia-activated prodrug, TH-302. The results were presented today at the American Society of Hematology (ASH) Meeting being held December 5 to 8, 2009, in New Orleans, LA.
"Hypoxia is known to be linked to increased metastatic potential and poorer disease outcomes," said Karin Vanderkerken, Ph.D., Department of Hematology and Immunology-Myeloma Center Brussels, Belgium. "This study has demonstrated that hypoxia exists in the bone marrow in an established model of myeloma and, importantly, TH-302 has had an impressive treatment effect in this preclinical model."
Hypoxia is known to be associated with poor prognosis and tumor progression in solid tumors. Scientists have also been studying the effects of hypoxia on hematopoetic stem cells in the bone marrow. Thus, a preclinical study was undertaken to evaluate the hypoxic condition in the bone marrow in a murine model of multiple myeloma (MM), the 5T33MM syngeneic model, using the hypoxia-activated prodrug, TH-302.
The study found that almost all of the MM cells in the model reside in a hypoxic environment in the bone marrow and that these tumor cells may be a target for tumor-specific treatment with TH-302. In vivo, animals treated prophylactically with TH-302 showed decreased serum paraprotein compared to those not treated with TH-302. The frequency of apoptotic MM cells in bone marrow sections was also significantly increased in animals treated with TH-302. In vitro, 5T33 cell-based assays demonstrated TH-302 induces cell cycle arrest and triggers apoptosis in an oxygen concentration-dependent manner. Taken together, these results support continued investigation with TH-302 as a potential treatment for multiple myeloma.
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About Multiple Myeloma
There are approximately 45,000 people in the United States living with multiple myeloma, and the American Cancer Society estimates that approximately 14,600 new cases of myeloma are diagnosed each year in the United States. Multiple myeloma is the second most prevalent blood cancer (10%) after non-Hodgkin's lymphoma. It represents approximately 1% of all cancers and 2% of all cancer deaths. Although the peak age of onset of multiple myeloma is 65 to 70 years of age, recent statistics indicate both increasing incidence and earlier age of onset. Multiple Myeloma affects slightly more men than women.
About Threshold Pharmaceuticals
Threshold is a biotechnology company focused on the discovery and development of drugs targeting Tumor Hypoxia, the low oxygen condition found in microenvironments of most solid tumors. This approach offers broad potential to treat most solid tumors. By selectively targeting tumor cells, we are building a pipeline of drugs that hold promise to be more effective and less toxic to healthy tissues than conventional anticancer drugs. For additional information, please visit the website (www.thresholdpharm.com).
Forward-Looking Statements
Except for statements of historical fact, the statements in this press release are forward-looking statements, including statements regarding TH-302, clinical trial results and plans, and potential therapeutic uses and benefits of TH-302. These statements involve risks and uncertainties that can cause actual results to differ materially from those in such forward-looking statements. Potential risks and uncertainties include, but are not limited to, Threshold's ability to enroll and complete its current and anticipated clinical trials, the time and expense required to conduct such clinical trials and analyze data, the possibility that results from these trials will not be confirmed with larger numbers of patients or in subsequent trials, potential adverse side effects, issues arising in the regulatory or manufacturing process and the results of such clinical trials (including product safety issues and efficacy results). Further information regarding these and other risks is included under the heading "Risk Factors" in Threshold's Quarterly Report on Form 10-Q, which was filed with the Securities and Exchange Commission on November 5, 2009 and is available from the SEC's website (www.sec.gov) and on our website (www.thresholdpharm.com) under the heading "Investors." Threshold does not intend to update any forward-looking statement made in this news release.