Tekmira Pharmaceuticals Collaborator National Cancer Institute Presents Anti-Tumor Data at Liver Cancer Conference

Tekmira Also Presents at Charles River Biotech Symposium

Tekmira Pharmaceuticals Corporation (TSX:TKM) announced today that one of its collaborators, the National Cancer Institute (NCI), has presented promising pre-clinical data treating liver cancer using small interfering RNA (siRNA) enabled by Tekmira's SNALP (stable nucleic acid-lipid particles) delivery technology.

Dr. Yun-Han Lee, a member of the NCI's Laboratory of Experimental Carcinogenesis (LEC), presented the data at the International Liver Cancer Association (ILCA) meeting being held in Chicago, IL September 5-7, 2008.

Scientists at the LEC and the Surgery Branch of the NCI worked in collaboration with Tekmira scientists to develop siRNA to silence the CSN5 gene. The CSN5 siRNA delivered systemically using Tekmira's SNALP technology resulted in a significant reduction in tumor burden in human hepatocellular carcinoma (HCC) tumor bearing mice.

CSN5 could represent a novel therapeutic target to treat HCC. Down regulation of CSN5 using siRNA increases apoptosis (programmed cell death) by restoring levels of tumor suppressor proteins p53 and p27. Silencing the CSN5 gene has also been shown to decrease a certain population of cells thought to be cancer stem cells. Research suggests that it is critical to destroy this population of cancer stem cells within a tumor to prevent the re-growth of the tumor. Dr. Mark J. Murray, Tekmira's President and CEO, said, "We have had a very successful collaboration with NCI over the past two years. By combining their expertise in identifying novel cancer genes and our expertise in designing and delivering siRNA molecules, we have been able to generate this promising data targeting the CSN5 gene."

Tekmira and NCI are continuing to collaborate on identifying novel cancer genes and demonstrating anti-tumor activity by silencing these genes through RNA interference.

Presentation at Charles River Biotech Symposium

In addition to the NCI presentation at the ILCA meeting, Tekmira is also presenting data at the Charles River Biotech Symposium (CRBS). Dr. Ian MacLachlan, Tekmira's Chief Scientific Officer, is presenting at CRBS September 9, 2008.

Dr. MacLachlan's presentation will focus on Tekmira's advancement of its SNALP delivery technology and its chemical modification technology that can minimize the immune stimulatory effects of siRNA. Tekmira's SNALP technology is designed to overcome the challenges of systemic delivery of siRNA by designing lipid nanoparticles with the appropriate characteristics to deliver siRNA to target tissues and into cells.

Tekmira's first two product candidates, ApoB SNALP and PLK1 SNALP, are based on its SNALP technology. Tekmira has also licensed its SNALP technology to leading industry partners including Alnylam Pharmaceuticals, Inc. (NASDAQ:ALNY), Roche (SWX:ROG) and Merck & Co. (NYSE:MRK). Alnylam has also provided access to Tekmira's technology to certain of its partners, including Regulus Therapeutics and Takeda Pharmaceutical Company Limited.

About RNAi and SNALP

RNAi drugs have the potential to treat human diseases by "switching-off" disease causing genes. The technology, representing one of the most promising and rapidly advancing frontiers in biology and drug discovery, was awarded the 2006 Nobel Prize for Physiology or Medicine. RNAi drugs, such as siRNA, require delivery technology to be administered systemically. In preclinical studies, Tekmira's SNALP (stable nucleic acid-lipid particles) technology has been shown to be a safe and effective way to deliver RNAi drugs to disease sites. Tekmira believes it has a leading intellectual property position in the field of siRNA delivery.

About Tekmira

Tekmira Pharmaceuticals Corporation is a biopharmaceutical company focused on advancing novel RNAi products and providing its leading lipid nanoparticle delivery technology to pharmaceutical partners. Further information about Tekmira can be found at www.tekmirapharm.com. Tekmira is based in Vancouver, B.C.

Forward-Looking Statements and Information

There are forward-looking statements and information contained herein that are not based on historical fact, including, without limitation, statements containing the words "believes", "may", "plans", "will", "estimate", "continue", "anticipates", "intends", "expects", and similar expressions, and the negative of such expressions. These statements are only predictions.

Forward-looking statements and information should be considered carefully. Undue reliance should not be placed on forward-looking statements and information as there can be no assurance that the plans, intentions or expectations upon which they are based will occur. By their nature, forward-looking statements and information involve numerous assumptions, known and unknown risks and uncertainties, both general and specific, which contribute to the possibility that the predictions, forecasts, projections and other forward-looking statements and information will not occur and may cause actual results or events to differ materially from those anticipated in such forward-looking statements and information.

There are also other factors that may cause the actual results, events or developments to be materially different from any future results, events or developments expressed or implied by such forward-looking statements and information. Such factors include, among others, the stage of development of Tekmira, lack of product revenues, additional capital requirements, the need to obtain regulatory approval to commence clinical trials, risks associated with the completion of clinical trials and obtaining regulatory approval to market Tekmira's products, the safety and efficacy of Tekmira's products, the ability to protect Tekmira's intellectual property and dependence on collaborative partners.

A more complete discussion of the risks and uncertainties facing Tekmira appears in Tekmira's management information circular dated May 1, 2008 available at www.sedar.com. Tekmira disclaims any obligation to update any such factors or to publicly announce the result of any revisions to any of the forward-looking statements or information contained herein to reflect future results, events or developments, except as required by law.

SOURCE: Tekmira Pharmaceuticals Corporation

Tekmira Pharmaceuticals Corporation - Investors Ian Mortimer Executive Vice President and Chief Financial Officer (604) 419-3200 Website: www.tekmirapharm.com Longview Communications Inc. - Media Josh Pekarsky (604) 694-6030 Email: This email address is being protected from spambots. You need JavaScript enabled to view it.