Tekmira Pharmaceuticals and Protiva Biotherapeutics Announce Completion of Business Combination

Vancouver, B.C. — Tekmira Pharmaceuticals Corporation ("Tekmira"; TSX: TKM) and Protiva Biotherapeutics Inc. ("Protiva") announced today that they have completed the business combination between the two companies. The combined company, which will retain the name Tekmira, will be a global leader in the field of RNA interference ("RNAi") therapeutics.

As part of the business combination, a $10.0 million private placement with Alnylam Pharmaceuticals, Inc. ("Alnylam"; Nasdaq: ALNY) and an affiliate of F. Hoffman-La Roche Ltd. ("Roche"; SWX: ROG) has also been completed at a price of $2.40 per Tekmira share.

The new Tekmira will focus its business on advancing a pipeline of novel therapeutic products, including its lead RNAi therapeutic candidate, ApoB SNALP, as a treatment for hypercholesterolemia. The company will have rights to develop a total of seven RNAi therapeutic products based on access to Alnylam’s intellectual property. The company expects to file an Investigational New Drug application for ApoB SNALP in the next 12 months.

The new Tekmira will also continue to support its alliance partners that have licensed the company’s lipid-based nanoparticle delivery technology in the field of RNAi therapeutics.

Alnylam has taken a broad license to the new Tekmira’s intellectual property and has sub-licensed the technology to Roche and has provided access to the technology to other companies, including Regulus Therapeutics. The new Tekmira is eligible to receive up to US$16.0 million in milestones on each and every RNAi therapeutic advanced by Alnylam or its partners, including Roche, that utilizes the company’s technology, as well as royalties on product sales. Merck & Co., Inc. has also taken a license to certain of the company’s intellectual property and Tekmira has the opportunity to form new alliances in the RNAi field.

Dr. Mark J. Murray, Tekmira’s President and CEO said, "The new Tekmira has a tremendous opportunity to be a leader in the advancement of novel RNAi therapeutic products. We will also continue to support and build upon our world-class alliance partners as they advance products based on our lipid nanoparticle delivery technology."

RNAi drugs have the potential to treat human disease by "switching-off" genes that cause disease. The technology represents one of the most promising and rapidly advancing frontiers in biology and drug discovery and was awarded the 2006 Nobel Prize for Physiology or Medicine.

Business Combination Summary and Financial Resources

Tekmira has purchased all of the outstanding equity of Protiva by issuing approximately 22.8 million Tekmira shares and reserving approximately 1.8 million shares for issuance upon the exercise of Protiva stock options. Protiva is now a wholly-owned subsidiary of Tekmira.

Pursuant to the private placement, Tekmira has issued approximately 2.1 million shares to each of Alnylam and Roche at a price of $2.40 per share, for total proceeds of approximately $10.0 million. Tekmira now has working capital of greater than $35.0 million.

Ian C. Mortimer, Executive Vice President and Chief Financial Officer of Tekmira said, "With the strong support of Alnylam and Roche, the new Tekmira has sufficient financial resources to fund our development plan for at least the next two years."

Tekmira now has approximately 51.6 million shares outstanding and approximately 5.7 million options outstanding.

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. In addition, this press release may contain forward-looking statements attributed to third party industry sources.

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. The assumptions made by Tekmira include expectations concerning Tekmira’s cash burn rate and the estimate of the length of time that Tekmira’s development plan will be funded by its anticipated financial resources; the development of products; the actions of collaborative partners; the timing of receipt of regulatory approvals; the sufficiency of budgeted capital expenditures in carrying out planned activities; and the availability and cost of labour and services.

More particularly and without limitation, this press release contains forward-looking statements and information concerning the business combination of Tekmira and Protiva; the potential of Tekmira; the potential of RNAi therapeutics and nucleic acids as a treatment for diseases such as cancer; and the number and timing of advancement of its lead product into clinical development. There are also risks inherent in the nature of the business combination, principally risks regarding the integration of the two entities.

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.

About Tekmira

Tekmira Pharmaceuticals Corporation is a Canadian biopharmaceutical company developing and commercializing proprietary drugs and drug delivery systems to improve the treatment of cancer and other diseases. Further information about Tekmira can be found at www.tekmirapharm.com. Tekmira is based in Vancouver, B.C.

Contact Information

Investors
Ian Mortimer
Executive Vice President and Chief Financial Officer
Phone: 604-419-3200

Media
Karen Cook
James Hoggan & Associates Inc.
Phone: 604-739-7500
Email: kcook@hoggan.com

David Ryan
Longview Communications Inc.
Phone: 604-694-6031
Email: dryan@longviewcomms.ca