Lorus Therapeutics Provides an Update on Progress in Virulizin(R) Development Program

TORONTO, July 9 /PRNewswire-FirstCall/ — Lorus Therapeutics Inc. (TSX: LOR, AMEX: LRP) (“Lorus” or the “Corporation”), a biopharmaceutical company specializing in the research and development of pharmaceutical products and technologies for the management of cancer, today announced progress made in the Virulizin(R) development program, including the publication of two research studies on the Virulizin(R) mode of action and the issuance of a new patent for Virulizin(R) in Mexico.

“Publication of these two studies in international scientific journals adds significantly to our previous studies on Virulizin(R) anticancer mechanisms and activities,” commented Dr. Aiping Young, Lorus’ President and CEO. “In addition, allowance of a new patent strengthens the intellectual property position for this product, and protects the potential for expanding the use to other cancer indications in this jurisdiction.”

New Virulizin(R) patent issued in Mexico

The patent, titled “Immunomodulating Compositions from Bile for the Treatment of Immune System Disorders”, protects methods of treating several cancers using Virulizin(R). This is the second patent issued in Mexico for Virulizin(R), and extends patent protection for Virulizin(R) in this country to 2016. Similar patents for Virulizin(R) have also been issued in a number of other countries worldwide, including Canada, Australia, and the United States.

Virulizin(R) is currently approved for the treatment of malignant melanoma in Mexico. The new patent provides protection for the potential treatment with Virulizin(R) of additional cancers, including ovarian and lung cancers. Virulizin(R) composition, manufacturing process, and use in the treatment of cancers are also protected in Mexico under an earlier patent issued to Lorus in 2003.

Virulizin(R) has demonstrated significant anticancer activity against a wide range of human cancers in preclinical studies, and has been tested in several clinical trials in solid tumor indications, including a Phase III clinical trial in combination with gemcitabine in locally advanced and metastatic pancreatic cancer. Lorus has reported that the overall survival data in this Phase III study did not reach statistical significance, although exploratory analysis yielded promising results in specific patient populations including in patients with ECOG performance status of 0 or 1.

In April 2008, Lorus’ subsidiary GeneSense Technologies entered into an exclusive multinational license agreement for Virulizin(R) with Zor Pharmaceuticals LLC to further develop and commercialize Virulizin(R) for advanced pancreatic cancer and other therapy areas in North and South America, Europe, and Israel.

Virulizin(R) study leads to new drug candidate IL-17E

The article entitled “Virulizin(R) induces production of IL-17E to enhance antitumor activity by recruitment of eosinophils into tumors” was published online in the journal Cancer Immunology Immunotherapy and is available through PubMed (http://www.ncbi.nlm.nih.gov/PubMed/).

The study showed that Virulizin(R) treatment stimulates the immune system to produce the cytokine IL-17E, which in turn triggers an anticancer effect through activation and tumor recruitment of eosinophils. This novel aspect of the anticancer mechanism of action for Virulizin(R) adds to previous studies showing that Virulizin(R) activates other cells of the immune system, including macrophages and Natural Killer (NK) cells.

A key finding of this report was that IL-17E itself had significant anticancer activity when used in mouse models of human cancers. Preliminary studies have revealed that IL-17E has potent activity against several human tumor types, including colon cancer, melanoma, and pancreatic cancer, with low toxicity. Lorus has patent applications pending in major markets, including Canada, Europe and the United States, to protect the use of IL-17E in the treatment of these cancers, both alone and in combination with other chemotherapies.

Virulizin(R) stimulates production of the antitumor protein TNFalpha

The article titled “Virulizin(R), a novel immunotherapy agent, stimulates TNFalpha expression in monocytes/macrophages in vitro and in vivo.” was published in the journal International Immunopharmacology (volume 7, issue 10, pages 1350-9).

The study revealed that treatment with Virulizin(R) resulted in a significant induction of the cytokine TNFalpha in tumors in a mouse model of malignant melanoma. Virulizin(R) also stimulated production of TNFalpha in human macrophages in vitro. Importantly, a direct relationship between TNFalpha production by Virulizin(R) and cytotoxic activity towards cancer cells was demonstrated.

TNFalpha is a protein that is produced by cells of the immune system, particularly macrophages, which then activate other immune cells to attack tumor cells. The anticancer properties of TNFalpha are well known, and have been studied in both preclinical and clinical settings. These new findings confirm initial studies indicating that TNFalpha can contribute to the antitumor mechanism of Virulizin(R).

About Virulizin(R)

Virulizin(R) is a novel biological response modifier (or immunotherapeutic agent) that stimulates a patient’s immune system through several mechanisms, including the activation of macrophages and the infiltration of natural killer cells into tumors. In preclinical studies, Virulizin(R) has demonstrated potential high levels of antitumor activity against a number of cancer indications including pancreatic cancer. Virulizin(R) has been granted orphan drug status and fast track status from the United States FDA and orphan designation from the Marketing Authorization Application with the European Medical Evaluation Agency (EMEA). A drug that receives fast track designation must demonstrate that it is intended for the treatment of a serious or life-threatening condition and that it has the potential to address unmet medical needs for the condition. Virulizin(R) is a registered trademark owned by Lorus Therapeutics Inc.

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, and on the American Stock Exchange under the symbol LRP.

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 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.

Should one or more of these risks or uncertainties materialize, or should the assumptions set out in the section entitled “Risk Factors” in our Annual Information Form underlying those forward-looking statements prove incorrect, actual results may vary materially from those described herein. These forward-looking statements are made as of the date of this press release and we do not intend, and do not assume any obligation, to update these forward-looking statements, except as required by law. We cannot assure you that such statements will prove to be accurate as actual results and future events could differ materially from those anticipated in such statements. Investors are cautioned that forward-looking statements are not guarantees of future performance and accordingly investors are cautioned not to put undue reliance on forward-looking statements due to the inherent uncertainty therein.

Lorus Therapeutics Inc.’s recent press releases are available through the Company’s website at http://www.lorusthera.com/. For Lorus’ regulatory filings on SEDAR, please go to http://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).

Lorus Therapeutics Inc.

CONTACT: Lorus Therapeutics Inc., Dr. Saeid Babaei, (416) 798-1200 ext.490, [email protected]