April 20, 2009 08:15 ET

Lorus Therapeutics Presents New Findings for First-in-class Anticancer Drug Candidate LOR-253

- Scientific Presentation at the 100th Annual Meeting of the American Association for Cancer Research (AACR) -

TORONTO, ONTARIO--(Marketwire - April 20, 2009) - Lorus Therapeutics Inc. (TSX:LOR) ("Lorus"), a biopharmaceutical company specializing in the research and development of pharmaceutical products and technologies for the management of cancer, today announced the presentation of preclinical data for its lead small molecule anticancer drug candidate LOR-253 at the Annual Meeting of the AACR in Denver, CO, April 18-22, 2009.

The presentation entitled "Mechanistic studies of a novel small molecule anticancer drug, LOR-253, on cell cycle arrest and angiogenesis" was presented on April 19, 2009. The abstract for the presentation (Abstract Number: 1822) is available online on the AACR website (http://www.aacr.org).

In the presentation, Lorus provided new data from the preclinical evaluation of LOR-253 (formerly known as LT-253), a novel first-in-class inhibitor of the target Metal Responsive Transcription Factor-1 (MTF-1).

The studies presented further explore the detailed mechanism of action of LOR-253. The key findings include MTF-1 dependent induction of a novel tumor suppressor, namely Krupple Like Factor-4 (KLF-4), leading to activation of several inhibitors of tumor growth as well as repression of several tumor promoters. These alterations were demonstrated specifically in cancer cells, but not in normal cells, which supports a strong LOR-253-mediated antitumor activity. These observations occurred at safe doses in several animal studies.

Lorus also reported for the first time that LOR-253 inhibits angiogenesis, which is the formation of new blood vessels that promotes tumor growth. In animal studies, non-small cell lung tumors isolated from LOR-253 treated mice showed reduced blood vessel density, indicating inhibition of tumor angiogenesis. The tumors also showed reduced expression of Hypoxia Induced Factor-1 alpha (HIF-1 alpha) a known angiogenesis stimulator, through inhibition of MTF-1.

LOR-253 is currently in late stage preclinical development. An Investigational New Drug (IND) application for LOR-253 is being finalized and is to be filed with the U.S. FDA in Q2 2009 for a Phase I dose escalation trial in selected solid tumors.

"These new results provide additional proof of anticancer mechanisms for LOR-253, and demonstrates the value of this novel compound to our pipeline", said Dr. Aiping Young, Lorus' President and CEO. "We are especially pleased to report that LOR-253 inhibits angiogenesis, which is a well validated mechanism for progression of cancer and other diseases".

About LOR-253

LOR-253 is a small molecule compound that has shown selective and potent antitumor activity in a variety of human cancers, including colon cancer and non-small cell lung cancer, and has an excellent therapeutic window due to its low toxicity. LOR-253 is a first-in-class inhibitor of the novel cancer target Metal-Responsive Transcription Factor 1 (MTF-1). The mode of action of LOR-253 involves the downregulation of cyclin D1, an important regulator of cell cycle progression and cell proliferation, and decreased expression of genes involved in tumor hypoxia (low oxygen content) and angiogenesis. Increased angiogenesis and alterations in the cyclin D1 regulatory pathway and have been linked to the development of cancer.

About Lorus

Lorus is a biopharmaceutical company focused on the research and development of novel therapeutics in cancer. Lorus' goal is to capitalize on its research, preclinical, clinical and regulatory expertise by developing new drug candidates that can be used, either alone, or in combination with other drugs, to successfully manage cancer. Through its own discovery efforts and an acquisition and in-licensing program, Lorus is building a portfolio of promising anticancer drugs. Lorus Therapeutics Inc. is listed on the Toronto Stock Exchange under the symbol LOR.

Forward Looking Statements

This press release may contain forward-looking statements within the meaning of Canadian and U.S. securities laws. Such statements include, but are not limited to, statements relating to: our research program plans, our plans to conduct clinical trials, the successful and timely completion of clinical studies and the regulatory approval process, our ability to fund future research, our plans to obtain partners to assist in the further development of our product candidates, the establishment of corporate alliances, the Company's plans, objectives, expectations and intentions and other statements including words such as "continue", "believe", "plan", "expect", "intend", "will", "should", "may", and other similar expressions. Such statements reflect our current views with respect to future events and are subject to risks and uncertainties and are necessarily based upon a number of estimates and assumptions that, while considered reasonable by us are inherently subject to significant business, economic, competitive, political and social uncertainties and contingencies. Many factors could cause our actual results, performance or achievements to be materially different from any future results, performance, or achievements that may be expressed or implied by such forward-looking statements, including, among others: our ability to continue as a going concern, our ability to repay or refinance the convertible debentures by October 2009; our ability to obtain the capital required for research and operations, the inherent risks in early stage drug development including demonstrating efficacy, development time/cost and the regulatory approval process; the progress of our clinical trials; our ability to find and enter into agreements with potential partners; our ability to attract and retain key personnel; changing market conditions; and other risks detailed from time-to-time in our ongoing quarterly filings, annual information forms, annual reports and annual filings with Canadian securities regulators and the United States Securities and Exchange Commission.

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Lorus Therapeutics Inc.'s recent press releases are available through the Company's website at www.lorusthera.com. For Lorus' regulatory filings on SEDAR, please go to www.Sedar.com. For SEDAR filings prior to July 10, 2007 you will find these under the company profile for Global Summit Real Estate Inc. (Old Lorus).

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