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

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

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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).