98th Annual Meeting of the American Association for Cancer Research (AACR) TORONTO, April 17 /PRNewswire-FirstCall/ -- Lorus Therapeutics Inc. ("Lorus") (TSX: LOR; AMEX: LRP) today announced presentation of research on their lead antisense and siRNA compounds at the 98th Annual Meeting of the AACR in Los Angeles, CA, April 14-18, 2007. The first presentation titled, "Determination of optimized administration schedule of GTI-2040 and docetaxel combination treatment for NSCLC cells in vitro and in vivo," was presented on April 15, 2007. This research determined a new optimal dosing schedule of GTI-2040 and docetaxel, which resulted in greatly enhanced synergy when docetaxel was given 48 hours after GTI-2040 compared to concomitant administration. This strong synergy was seen in vivo even after a single dose of GTI-2040. The discovery that administration of GTI-2040 prior to docetaxel is associated with this synergy, possibly through a 'stressor' effect due to decreased levels of R2 target expression, may potentially apply to other GTI-2040 combinations as well. This new sequential dose strategy will be an important consideration to maximize efficacy in the GTI-2040 clinical program. The second presentation titled, "siRNAs targeting the R2 subunit of human ribonucleotide reductase exhibit in vitro and in vivo antitumor activity," will be presented on April 17, 2007. In this research, Lorus screened a series of siRNAs to select a lead drug candidate, siRNA-1284. siRNA-1284 demonstrated potent antiproliferative and antitumor activity both in vitro and in vivo, coinciding with specific target silencing. These data warrant further development of siRNA-1284 as an anticancer agent. Lorus is also pursuing other cancer targets with its siRNA platform technology to screen and evaluate novel siRNA drug candidates. "The research announced today provides important supporting data for Lorus' drug development strategies involving antisense and siRNA," commented Dr. Aiping Young, Lorus' President and CEO. "The novel findings involving GTI-2040 combined with docetaxel provide an important new approach for optimizing combination therapies with GTI-2040, which may be particularly relevant to future GTI-2040 trials in solid tumor indications. We are also very pleased with the identification of our lead siRNA drug, adding to our growing platform of DNA/RNA-based medicines." About GTI-2040 GTI-2040 is an antisense drug that specifically targets the R2 component of ribonucleotide reductase, which is required for DNA synthesis and cell proliferation. R2 has also been described as a malignant determinant that is elevated in a wide range of tumors, and through down regulation can cooperate with a variety of cellular cancer causing genes known as oncogenes to enhance tumor growth and metastatic potential. About siRNA siRNA is a novel class of molecules that can decrease cellular target RNA expression through an antisense process known as RNA interference (RNAi). Because of its target specificity, RNAi is increasingly being examined as a potential therapy for a variety of diseases including cancer. From an evolutionary perspective, RNAi helps protect cells from viruses and transposable genetic elements in addition to carrying out more routine cellular tasks essential to development and growth. In mammalian cells siRNAs have been shown to be the most effective tools for RNAi, allowing for the development of clean and easily regulated methods for disruption of gene expression. siRNA technology allows for a range of new applications including target validation for drug discovery and medical therapeutics. 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 has several product candidates in multiple Phase II clinical trials and has completed one Phase II and one Phase III clinical trial. 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/. DATASOURCE: Lorus Therapeutics Inc. CONTACT: Lorus Therapeutics Inc., Dr. Saeid Babaei, (416) 798-1200 ext. 490,

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