The following table presents selected financial data derived from Tekmira’s audited consolidated financial statements for the fiscal years ended December 31, 2011, 2010, 2009, 2008, and 2007. You should read this information in conjunction with our financial statements for the periods presented, as well as Item 4 “ Information on the Company ” and Item 5 “ Operating and Financial Review and Prospects ” included elsewhere in this Annual Report.

Notes:

-6-

Table of Contents

We have never declared or paid any cash dividends.

Exchange Rate

The closing exchange rate between the Canadian dollar and the U.S. dollar was CDN$0.9987 per US$1.00 (or US$1.0013 per CDN$1.00) using the Bank of Canada exchange rate on March 23, 2012.

The average exchange rates for the financial periods of Tekmira listed above (based on the average exchange rate for each period using the average of the closing exchange rates on the last day of each month during the period in accordance with the exchange rates provided by the Bank of Canada) are as follows:

The high and low exchange rates between the Canadian dollar and the U.S. dollar for the past six months (provided by the Bank of Canada) are as follows:

Not applicable.

Not applicable.

An investment in our common shares is highly speculative and involves a high degree of risk. We may face a variety of risks that may affect our operations or financial results, and many of those risks are driven by factors that we cannot control or predict. Before investing in our common shares, investors should carefully consider the following risks. If any of the following risks actually occurs, our business, prospects, financial condition and results of operations could be materially adversely affected. In that case, investors may lose all or a part of their investment. You should not consider an investment in our common shares unless you are capable of sustaining an economic loss of the entire investment.

Risks Related to Our Business

We are in the early stages of our development and because we have a short development history with ribonucleic acid interference (RNAi), there is a limited amount of information about us upon which you can evaluate our RNAi business and prospects.

We have not begun to market or generate revenues from the commercialization of any products. We have only a limited history upon which one can evaluate our RNAi business and prospects as our RNAi therapeutic products are still at an early stage of development and thus we have limited experience and have not yet demonstrated an ability to successfully overcome many of the risks and uncertainties frequently encountered by companies in new and rapidly evolving fields, particularly in the biopharmaceutical area. For example, to execute our business plan, we will need to successfully:

-7-

Table of Contents

If we are unsuccessful in accomplishing these objectives, we may not be able to develop products, raise capital, expand our business or continue our operations.

The approach we are taking to discover and develop novel drug products is unproven and may never lead to marketable drug products.

We intend to concentrate our internal research and development efforts in the future on RNAi technology, and our future success depends in part on the successful development of RNAi technology and products based on RNAi technology. While RNAi technology is based on a naturally occurring process that takes place inside cells, which can suppress the production of specific proteins, and has the potential to generate therapeutic drugs that take advantage of that process, neither we nor any other company has received regulatory approval to market a therapeutic product based on RNAi technology. The scientific discoveries that form the basis for our efforts to discover and develop new products are relatively new. While there are a number of RNAi therapeutics in development, very few product candidates based on these discoveries have ever been tested in humans and there can be no assurance that any RNAi therapeutic product will be approved for commercial use.

Further, our focus solely on RNAi technology for developing products, as opposed to multiple, more proven technologies for product development, increases our risks. If we are not successful in developing a product candidate using RNAi technology, we may be required to change the scope and direction of our product development activities. In that case, we may not be able to identify and implement successfully an alternative product development strategy.

Risks Related to Our Financial Results and Need for Financing

We will require substantial additional capital to fund our operations. If additional capital is not available, we may need to delay, limit or eliminate our research, development and commercialization processes and may need to undertake a restructuring.

At December 31, 2011 we had $7.2 million in working capital excluding deferred revenue and expense balances. We believe that our current funds on hand, including funds from a recently completed equity private placement and access to a term loan, plus expected income including funds from our collaborative partners and the U.S. Government will be sufficient to extend our cash runway into the second half of 2013. Substantial additional funds will be required to continue with the active development of our pipeline products and technologies. In particular, our funding needs may vary depending on a number of factors including:

We will seek to obtain funding to maintain and advance our business from a variety of sources including public or private equity or debt financing, collaborative arrangements with pharmaceutical companies and government grants and contracts. There can be no assurance that funding will be available at all or on acceptable terms to permit further development of our products especially in light of the current difficult climate for investment in early stage biotechnology companies and our ongoing litigation with Alnylam.

If adequate funding is not available, we may be required to delay, reduce or eliminate one or more of our research or development programs or reduce expenses associated with non-core activities. We may need to obtain funds through arrangements with collaborators or others that may require us to relinquish most or all of our rights to product candidates at an earlier stage of development or on less favorable terms than we would otherwise seek if we were better funded. Insufficient financing may also mean failing to prosecute our patents or relinquishing rights to some of our technologies that we would otherwise develop or commercialize.

-8-

Table of Contents

We have incurred losses in nearly every year since our inception and we anticipate that we will not achieve sustained profits for the foreseeable future. To date, we have had no product revenues.

With the exception of the year ended December 31, 2006, we have incurred losses since inception and have not received any revenues other than from research and development collaborations, license fees and milestone payments. From inception to December 31, 2011, we have an accumulated net deficit of $258.8 million. As we continue our research and development and clinical trials and seek regulatory approval for the sale of our product candidates, we do not expect to attain sustained profitability for the foreseeable future. We do not expect to achieve sustained profits until such time as strategic alliance payments, product sales and royalty payments, if any, generate sufficient revenues to fund our continuing operations. We cannot predict if we will ever achieve profitability and, if we do, we may not be able to remain consistently profitable or increase our profitability.

A determination that we have defaulted under the terms of our term loan debt would have a material adverse effect on our business and financial condition.

In December 2011, we secured a US$3.0 million term loan from Silicon Valley Bank (SVB). The loan may limit our access to additional capital and the loan is subject to specific non-financial covenants, which include ongoing reporting obligations and restrictions on Tekmira’s ability to incur further indebtedness, dispose of its assets, encumber its property, and enter into a merger or amalgamation. The loan is secured by the assets and intellectual property of Tekmira. At December 31, 2011 we had not drawn down on the loan facility. If we fail to meet our ongoing obligations and covenants under the loan facility prior to drawing down on the loan, we may not be able to draw down on the loan as the need arises. Additionally, should we draw down on the loan and fail to meet our obligations and covenants under the loan, we could default on the loan, which may prevent us from drawing down further on the loan and place at risk the assets and intellectual property of Tekmira that are granted as collateral for the loan.

Risks Related to Our Dependence on Third Parties

We expect to depend on our existing and new collaborators for a significant portion of our revenues and to develop, conduct clinical trials with, obtain regulatory approvals for, and manufacture, market and sell some of our product candidates. If these collaborations are unsuccessful, our business could be adversely affected.

We expect that we will depend in part on our Alnylam and U.S. Government collaborations to provide revenue to fund our operations, especially in the near term. These collaborations represented 25% and 69%, respectively, of our operating revenue for the fiscal year 2011. Furthermore, our strategy is to enter into various additional arrangements with corporate and academic collaborators, licensors, licensees and others for the research, development, clinical testing, manufacturing, marketing and commercialization of our products. We may be unable to continue to establish such collaborations, and any collaborative arrangements we do establish may be unsuccessful.

Should any collaborative partner fail to develop or ultimately successfully commercialize any of the products to which it has obtained rights, our business may be adversely affected. In addition, once initiated, there can be no assurance that any of these collaborations will be continued or result in successfully commercialized products. In particular, there is now a risk that our collaboration with Alnylam could be adversely affected, following our initiation of a lawsuit with Alnylam. Failure of a collaborative partner to continue funding any particular program could delay or halt the development or commercialization of any products arising out of such program. In addition, there can be no assurance that the collaborative partners will not pursue alternative technologies or develop alternative products either on their own or in collaboration with others, including our competitors, as a means for developing treatments for the diseases targeted by our programs.

We expect the U.S. Government to fund our TKM-Ebola program through to completion of a Phase 1 human safety clinical trial and possibly beyond that to FDA drug approval. The quantum and timing of funding may not be what we have projected and the U.S. Government could cancel this funding at any time.

The contract we signed with the U.S. Government on July 14, 2010 is for funding of up to US$34.7 million for our TKM-Ebola program through to the completion of a Phase 1 human safety clinical trial and certain manufacturing objectives. The U.S. Government may later extend the contract to cover the entire TKM-Ebola program through to FDA drug approval.

This is our first U.S. Government contract of any notable size. Our lack of experience in dealing with the U.S. Government brings uncertainty into our cash flow projections and uncertainty into our ability to execute the contract within U.S. Government requirements. Furthermore, there is inherent risk in projecting cash flows years ahead for such a complex program.

The quantum and timing of funding for the TKM-Ebola program may not be what we have projected and under the terms of the contract the U.S. Government could cancel this funding, which is paid through monthly reimbursements, at any time.

We rely on third parties to conduct our clinical trials, and if they fail to fulfill their obligations, our development plans may be adversely affected.

We rely on independent clinical investigators, contract research organizations and other third-party service providers to assist us in managing, monitoring and otherwise carrying out our clinical trials. We have contracted with, and we plan to

-9-

Table of Contents

continue to contract with, certain third parties to provide certain services, including site selection, enrolment, monitoring and data management services. Although we depend heavily on these parties, we do not control them and therefore, we cannot be assured that these third parties will adequately perform all of their contractual obligations to us. If our third-party service providers cannot adequately fulfill their obligations to us on a timely and satisfactory basis or if the quality or accuracy of our clinical trial data is compromised due to failure to adhere to our protocols or regulatory requirements, or if such third parties otherwise fail to meet deadlines, our development plans may be delayed or terminated. One of the contract research organizations we are currently working with is undergoing a financial restructuring. The outcome of the restructuring is not currently determinable and may impact timelines in the development of TKM-Ebola.

We have no sales, marketing or distribution experience and would have to invest significant financial and management resources to establish these capabilities.

We have no sales, marketing or distribution experience. We currently expect to rely heavily on third parties to launch and market certain of our products, if approved. However, if we elect to develop internal sales, distribution and marketing capabilities, we will need to invest significant financial and management resources. For products where we decide to perform sales, marketing and distribution functions ourselves, we could face a number of additional risks, including:

If we are unable to develop our own sales, marketing and distribution capabilities, we will not be able to successfully commercialize our products, if approved, without reliance on third parties.

We will rely on third-party manufacturers to manufacture our products (if approved) in commercial quantities, which could delay, prevent or increase the costs associated with the future commercialization of our products.

Our product candidates have not yet been manufactured for commercial use. If any of our product candidates becomes approved for commercial sale, in order to supply our or our collaborators’ commercial requirements for such an approved product, we will need to establish third-party manufacturing capacity. Any third-party manufacturing partner may be required to fund capital improvements to support the scale-up of manufacturing and related activities. The third-party manufacturer may not be able to establish scaled manufacturing capacity for an approved product in a timely or economic manner, if at all. If a manufacturer is unable to provide commercial quantities of such an approved product, we will have to successfully transfer manufacturing technology to a new manufacturer. Engaging a new manufacturer for such an approved product could require us to conduct comparative studies or utilize other means to determine bioequivalence of the new and prior manufacturers’ products, which could delay or prevent our ability to commercialize such an approved product. If any of these manufacturers is unable or unwilling to increase its manufacturing capacity or if we are unable to establish alternative arrangements on a timely basis or on acceptable terms, the development and commercialization of such an approved product may be delayed or there may be a shortage in supply. Any inability to manufacture our products in sufficient quantities when needed would seriously harm our business.

Manufacturers of our approved products, if any, must comply with cGMP requirements enforced by the FDA and Health Canada through facilities inspection programs. These requirements include quality control, quality assurance, and the maintenance of records and documentation. Manufacturers of our approved products, if any, may be unable to comply with these cGMP requirements and with other FDA, Health Canada, state, and foreign regulatory requirements. We have little control over our manufacturers’ compliance with these regulations and standards. A failure to comply with these requirements may result in fines and civil penalties, suspension of production, suspension or delay in product approval, product seizure or recall, or withdrawal of product approval. If the safety of any quantities supplied is compromised due to our manufacturer’s failure to adhere to applicable laws or for other reasons, we may not be able to obtain regulatory approval for or successfully commercialize our products, which would seriously harm our business.

Risks Related to Managing Our Operations

We are dependent on certain members of our management and scientific staff. The loss of services of one or more of these staff members could adversely affect us.

We depend on our senior executive officers as well as key scientific, management and other personnel. The competition for qualified personnel in the biotechnology field is intense. We rely heavily on our ability to attract and retain qualified managerial, scientific and technical personnel. While we currently have employment contracts with our key personnel and are not aware that any are planning to leave or retire, we may not be able to successfully attract and retain skilled and experienced personnel in the future. In particular, we rely on our President and Chief Executive Officer, Mark J. Murray, Ph.D., and our Executive Vice President and Chief Science Officer, Ian MacLachlan, Ph.D. Dr. Murray has over 20 years of experience in both the R&D and business development and management facets of the biotechnology industry and Dr. MacLachlan has been active in molecular therapeutics for more than a decade. If we were to lose either of their services, our ability to develop our technology, add to our pipeline, advance our product candidates and manage our operations and relationships with third parties would be adversely affected.

-10-

Table of Contents

We may have difficulty managing our growth and expanding our operations successfully as we seek to evolve from a company primarily involved in discovery and preclinical testing into one that develops products through clinical development and commercialization.

As product candidates we develop enter and advance through clinical trials, we will need to expand our development, regulatory, manufacturing, clinical and medical capabilities or contract with other organizations to provide these capabilities for us. As our operations expand, we expect that we will need to manage additional relationships with various collaborators, suppliers and other organizations. Our ability to manage our operations and growth will require us to continue to improve our operational, financial and management controls, reporting systems and procedures. We may not be able to implement improvements to our management information and control systems in an efficient or timely manner and may discover deficiencies in existing systems or controls.

We could face liability from our controlled use of hazardous and radioactive materials in our research and development processes.

We use certain radioactive materials, biological materials and chemicals, including organic solvents, acids and gases stored under pressure, in our research and development activities. Our use of radioactive materials is regulated by the Canadian Nuclear Safety Commission for the possession, transfer, import, export, use, storage, handling and disposal of radioactive materials. Our use of biological materials and chemicals, including the use, manufacture, storage, handling and disposal of such materials and certain waste products is regulated by a number of federal, provincial and local laws and regulations. Although we believe that our safety procedures for handling such materials comply with the standards prescribed by such laws and regulations, the risk of accidental contamination or injury from these materials cannot be completely eliminated. In the event of such an accident, we could be held liable for any damages that result and any such liability could exceed our resources. We are not specifically insured with respect to this liability.

Our business and operations could suffer in the event of information technology system failures.

Despite the implementation of security measures, our internal computer systems and those of our contractors and consultants are vulnerable to damage from computer viruses, unauthorized access, natural disasters, terrorism, war, and telecommunication and electrical failures. Such events could cause interruption of our operations. For example, the loss of pre-clinical trial data or data from completed or ongoing clinical trials for our product candidates could result in delays in our regulatory filings and development efforts and significantly increase our costs. To the extent that any disruption or security breach were to result in a loss of or damage to our data, or inappropriate disclosure of confidential or proprietary information, we could incur liability and the development of our product candidates could be delayed.

Our independent auditors have not assessed our internal control over financial reporting. If our internal control over financial reporting is not effective, it could have a material adverse effect on our stock price and our ability to raise capital.

As disclosed in Item 15 of this annual report, our management has evaluated, and provided a report with respect to, the effectiveness of our internal control over financial reporting as of December 31, 2011. However, because we are a “non-accelerated filer” within the meaning of Rule 12b-2 under the Securities Exchange Act of 1934, our independent auditors are not required to assess our internal control over financial reporting or to provide a report thereon. Although our management has determined that our internal control over financial reporting was effective as of the evaluation date, there can be no assurance that our independent auditors would agree with our management’s conclusion. Furthermore, if our market capitalization, excluding affiliated stockholders, at June 30 of any fiscal year is greater than US$75 million, then we will be required to obtain independent auditor certification on the adequacy of our internal control over financial reporting for that fiscal year. If our internal control over financial reporting is determined in the future to not be effective, whether by our management or by our independent auditors, there could be an adverse reaction in the financial markets due to a loss of confidence in the reliability of our financial statements, which could materially adversely affect our stock price and our ability to raise capital necessary to operate our business. In addition, we may be required to incur costs in improving our internal control system and hiring additional personnel.

Risks Related to Our Industry

Risks Related to Development, Clinical Testing and Regulatory Approval of Our Product Candidates

The manufacture and sale of human therapeutic products are governed by a variety of statutes and regulations. There can be no assurance that our product candidates will obtain regulatory approval.

To obtain marketing approval, U.S. and Canadian laws require:

-11-

Table of Contents

The product candidates we currently have under development will require significant development, pre-clinical and clinical testing and investment of significant funds before their commercialization. Some of our product candidates, if approved, will require the completion of post-market studies. There can be no assurance that such products will be developed. The process of completing clinical testing and obtaining required approvals is likely to take a number of years and require the use of substantial resources. If we fail to obtain regulatory approvals, our operations will be adversely affected. Further, there can be no assurance that future product candidates will be shown to be safe and effective in clinical trials or receive applicable regulatory approvals.

Other markets have regulations and restrictions similar to those in the U.S. and Canada. Investors should be aware of the risks, problems, delays, expenses and difficulties which we may encounter in view of the extensive regulatory environment which affects our business in any jurisdiction where we develop product candidates.

If testing of a particular product candidate does not yield successful results, then we will be unable to commercialize that product candidate.

We must demonstrate our product candidates’ safety and efficacy in humans through extensive clinical testing. Our research and development programs are at an early stage of development. We may experience numerous unforeseen events during, or as a result of, the testing process that could delay or prevent commercialization of any products, including the following:

Clinical testing is very expensive, can take many years, and the outcome is uncertain. The data collected from our clinical trials may not be sufficient to support approval of our product candidates by the regulatory authorities. The clinical trials of our product candidates may not be completed on schedule, and the regulatory authorities may not ultimately approve any of our product candidates for commercial sale. If we fail to adequately demonstrate the safety and efficacy of a product candidate, this would delay or prevent regulatory approval of the product candidate, which could prevent us from achieving profitability.

It may take us longer than we are currently projecting to complete our clinical trials, and we may not be able to complete them at all.

Although for planning purposes we project the commencement, continuation and completion of our clinical trials, a number of factors, including scheduling conflicts with participating clinicians and clinical institutions, and difficulties in identifying or enrolling patients who meet trial eligibility criteria, may cause significant delays. We may not commence or complete clinical trials involving any of our product candidates as projected or may not conduct them successfully.

We rely on academic institutions, hospitals, medical clinics and/or clinical research organizations to conduct, supervise or monitor some or all aspects of clinical trials involving our product candidates. We will have less control over the timing and other aspects of these clinical trials than if we conducted them entirely on our own. If we fail to commence or complete, or if we experience delays in, any of our planned clinical trials, our ability to conduct business as currently planned could be harmed.

Even if we achieve regulatory approval, future regulatory reviews or inspections may result in the suspension or withdrawal of one or more of our products, closure of a facility or enforcement of substantial fines.

If regulatory approval to sell any of our product candidates is received, regulatory agencies may, nevertheless, limit the categories of patients who can use them. In addition, regulatory agencies subject a marketed product, its manufacture and the manufacturers’ facilities to continual review and periodic inspection. If previously unknown problems with a product or manufacturing and laboratory facility are discovered or we fail to comply with applicable regulatory approval requirements, a regulatory agency may impose restrictions on that product or on us. The agency may require the withdrawal of the product from the market, closure of the facility or enforcement of substantial fines.

Our ability to successfully commercialize human therapeutic products may depend in part on reimbursement for the cost of such products and related treatments from government health administration authorities, private health coverage insurers and other organizations.

Third-party payers are increasingly challenging the price of medical products and services. Significant uncertainty exists as to the reimbursement status of newly approved healthcare products, and adequate third-party coverage may not be

-12-

Table of Contents

available to establish price levels sufficient for us to realize an appropriate return on our investment in product development. When we partner our product candidates we will typically be relying on that partner to obtain cost reimbursement from third parties for the product candidate.

Product candidates we develop, if approved for marketing, may be slow to achieve market acceptance or gain market acceptance at all.

The product candidates that we are trying to develop will compete with a number of drugs and therapies currently on the market, as well as products currently under development. The rate and degree of market acceptance of our products will depend on a number of factors, including the establishment and demonstration in the medical community of the clinical efficacy and safety of our products and their potential advantage over alternative treatments. There is no assurance that physicians, patients or the medical community in general will accept and utilize any products that we may develop.

We face potential product liability exposure, and if successful claims are brought against us, we may incur substantial liability for a product candidate and may have to limit its commercialization.

The use of our product candidates in clinical trials and the sale of any products for which we obtain marketing approval expose us to the risk of product liability claims. Product liability claims might be brought against us by consumers, health-care providers, pharmaceutical companies, or others selling our products. If we cannot successfully defend ourselves against these claims, we will incur substantial liabilities. Regardless of merit or eventual outcome, product liability claims may result in:

Although we currently have product liability insurance coverage for our clinical trials for expenses or losses, our insurance coverage is limited to US$10 million per occurrence, and US$10 million in the aggregate, and may not reimburse us or may not be sufficient to reimburse us for any or all expenses or losses we may suffer. Moreover, insurance coverage is becoming increasingly expensive and, in the future, we may not be able to maintain insurance coverage at a reasonable cost or in sufficient amounts to protect us against losses due to liability. We intend to expand our insurance coverage to include the sale of commercial products if we obtain marketing approval for our product candidates in development, but we may be unable to obtain commercially reasonable product liability insurance for any products approved for marketing. On occasion, large judgments have been awarded in class action lawsuits based on products that had unanticipated side effects. A successful product liability claim or series of claims brought against us could cause our stock price to fall and, if judgments exceed our insurance coverage, could decrease our cash and adversely affect our business.

The Animal Rule is a new and seldom-used approach to seeking approval of a new drug, and our TKM-Ebola program may not meet the requirements for this path to regulatory approval.

We plan to develop the TKM-Ebola therapeutic product candidate to treat Ebola virus using the “Animal Rule” regulatory mechanism. Pursuant to the Animal Rule, we must demonstrate efficacy in animal models and safety in humans. There is no guarantee that the FDA will agree to this approach to the development of TKM-Ebola, considering that no validated animal model has been established as predicting human outcomes in the prevention or treatment of the Ebola virus. The FDA may decide that our data are insufficient for approval and require additional pre-clinical, clinical, or other studies, or refuse to approve our products, or place restrictions on our ability to commercialize those products. Animal models represent, at best, a rough approximation of efficacy in humans, and, as such, countermeasures developed using animal models will be untested until their use in humans during an emergency.

Risks Related to Patents, Licenses and Trade Secrets

Other companies or organizations may assert patent rights that prevent us from developing or commercializing our products.

RNA interference is a relatively new scientific field that has generated many different patent applications from organizations and individuals seeking to obtain patents in the field. These applications claim many different methods, compositions and processes relating to the discovery, development and commercialization of RNAi therapeutic products. Because the field is so new, very few of these patent applications have been fully processed by government patent offices around the world, and there is a great deal of uncertainty about which patents will be issued, when, to whom, and with what claims. It is likely that there will be litigation and other proceedings, such as interference and opposition proceedings in various patent offices, relating to patent rights in the RNAi field.

In addition, there are many issued and pending patents that claim aspects of small interfering RNA (siRNA) chemistry technology that we may need to apply to our product candidates. There are also many issued patents that claim genes or

-13-

Table of Contents

portions of genes that may be relevant for siRNA drug products we wish to develop. Thus, it is possible that one or more organizations will hold patent rights to which we will need a license. If those organizations refuse to grant us a license to such patent rights on reasonable terms, we will not be able to market products or perform research and development or other activities covered by these patents.

Our patents and patent applications may be challenged and may be found to be invalid, which could adversely affect our business.

Certain Canadian, U.S. and international patents and patent applications we own involve complex legal and factual questions for which important legal principles are largely unresolved. For example, no consistent policy has emerged for the breadth of biotechnology patent claims that are granted by the U.S. Patent and Trademark Office or enforced by the U.S. federal courts. In addition, the coverage claimed in a patent application can be significantly reduced before a patent is issued. Also, we face the following intellectual property risks:

A number of industry competitors, including Alnylam, and institutions have developed technologies, filed patent applications or received patents on various technologies that may be related to or affect our business. Some of these technologies, applications or patents may conflict with our technologies or patent applications. Such conflict could limit the scope of the patents, if any, that we may be able to obtain or result in the denial of our patent applications. In addition, if patents that cover our activities are issued to other companies, there can be no assurance that we would be able to obtain licenses to these patents at a reasonable cost or be able to develop or obtain alternative technology. If we do not obtain such licenses, we could encounter delays in the introduction of products, or could find that the development, manufacture or sale of products requiring such licenses is prohibited. In addition, we could incur substantial costs in defending patent infringement suits brought against us or in filing suits against others to have such patents declared invalid.

As publication of discoveries in the scientific or patent literature often lags behind actual discoveries, we cannot be certain we or any licensor was the first creator of inventions covered by pending patent applications or that we or such licensor was the first to file patent applications for such inventions. For example, we are currently involved in a patent interference proceeding declared by the U.S. Patent and Trademark Office to determine priority of invention to subject matter of Alnylam’s U.S. Patent No. 7,718,629 in light of Tekmira’s U.S. Patent Application 11/807,872. This proceeding, and any future proceedings, could result in substantial costs, even if the eventual outcomes are favorable. There can be no assurance that our patents, if issued, will be held valid or enforceable by a court or that a competitor’s technology or product would be found to infringe such patents.

Our business depends on our ability to use RNAi technology that we have licensed or will in the future license from third parties, including Alnylam, and, if these licenses were terminated or if we were unable to license additional technology we may need in the future, our business will be adversely affected.

We currently hold licenses for certain technologies that are or may be applicable to our current and subsequent product candidates. These include licenses to core siRNA patents held or applied for by Alnylam. The Alnylam licenses are subject to termination in the event of a breach by us of the licenses or of certain of our other agreements with Alnylam, if we fail to cure the breach following notice and the passage of a cure period. The UBC license, which is sublicensed to Alnylam, is subject to termination with respect to one or more particular patents if we and Alnylam were to cease patent prosecution or maintenance activities with respect to such patent(s), or in the event of a breach by us of the license, if we fail to cure the breach following notice and the passage of a cure period. There can be no assurance that these licenses will not be terminated, especially in light of our ongoing lawsuit with Alnylam. Alnylam has also provided us notice that certain intellectual property to which they have an exclusive license, under the UBC sublicense agreement, has not been granted to us for all of our product candidates. We may need to acquire additional licenses in the future to technologies developed by others, including Alnylam. For example, Alnylam has granted us a worldwide license for the discovery, development and commercialization of RNAi products directed to eight gene targets (three exclusive and five non-exclusive licenses). Licenses for the five non-exclusive targets and one exclusive target have already been granted. We have rights to select the gene targets for up to two more exclusive licenses from Alnylam, which would only be made available to us only if they have not been previously selected by Alnylam or one of its other partners. This will limit the targets available for selection by us, and we may never be able to select gene targets or may be required to make our selection from gene targets that have minimal commercial potential. Furthermore, future license agreements may require us to make substantial milestone payments. We will also be obligated to make royalty payments on the sales, if any, of products resulting from licensed RNAi technology. For some of our licensed RNAi technology, we are responsible for the costs of filing and prosecuting patent applications. The termination of a license or the inability to license future technologies on acceptable terms may adversely affect our ability to develop or sell our products.

-14-

Table of Contents

We may incur substantial costs as a result of litigation or other proceedings relating to patent and other intellectual property rights which could have a material adverse effect on our business, financial condition and results of operations and could cause the market value of our common shares to decline.

There has been significant litigation in the biotechnology industry over patents and other proprietary rights, and we are or may become involved in various types of litigation that arise from time to time. Involvement in litigation could consume a substantial portion of our resources, regardless of the outcome of the litigation. Counterparties in litigation may be better able to sustain the costs of litigation because they have substantially greater resources. If claims against us are successful, in addition to any potential liability for damages, we could be required to obtain a license, grant cross-licenses, and pay substantial royalties in order to continue to manufacture or market the affected products. Involvement and continuation of involvement in litigation may result in significant and unsustainable expense, and divert management’s attention from ongoing business concerns and interfere with our normal operations. Litigation is also inherently uncertain with respect to the time and expenses associated therewith, and involves risks and uncertainties in the litigation process itself, such as discovery of new evidence or acceptance of unanticipated or novel legal theories, changes in interpretation of the law due to decisions in other cases, the inherent difficulty in predicting the decisions of judges and juries and the possibility of appeals. Ultimately we could be prevented from commercializing a product or be forced to cease some aspect of our business operations as a result of claims of patent infringement or violation of other intellectual property rights and the costs associated with litigation, which could have a material adverse effect on our business, financial condition, and operating results and could cause the market value of our common shares to decline.

We have ongoing litigation with Alnylam and AlCana where we have alleged misappropriation of our proprietary lipid nanoparticle delivery technology, resulting in damage to our intellectual property and business interests. Alnylam and AlCana have responded to our complaint and have also filed counterclaims. In addition, Alnylam has filed a patent infringement lawsuit against us arising from our research activities with a pharmaceutical collaborator. Isis Pharmaceuticals, Inc. is named as a co-plaintiff in the patent infringement suit. Litigation is subject to inherent uncertainty and if we are unsuccessful in defending ourselves we could be required to pay significant damages, costs and attorney fees. We also continue to incur significant costs in the litigation and the litigation has diverted the attention of management and other resources that could otherwise be engaged in other activities. See “Item 8A Legal Proceedings” section of this Annual Report for more information.

Confidentiality agreements with employees and others, including collaborators, may not adequately prevent disclosure of trade secrets and other proprietary information.

Much of our know-how and RNAi technology may constitute trade secrets. There can be no assurance, however, that we will be able to meaningfully protect our trade secrets. In order to protect our proprietary RNAi technology and processes, we rely in part on confidentiality agreements with our collaborators, employees, vendors, consultants, outside scientific collaborators and sponsored researchers, and other advisors. These agreements may not effectively prevent disclosure of confidential information and may not provide an adequate remedy in the event of unauthorized disclosure of confidential information. In addition, others may independently discover trade secrets and proprietary information, and in such cases we could not assert any trade secret rights against such party. Costly and time-consuming litigation, including our ongoing litigation with Alnylam and AlCana, could continue to be necessary to enforce and determine the scope of our proprietary rights, and failure to obtain or maintain trade secret protection could adversely affect our competitive business position. In addition, we have sued certain individuals from AlCana for theft of confidential documents containing our confidential information and trade secrets. See “Item 8A Legal Proceedings” section of this Annual Report for more information.

Risks Related to Competition

The pharmaceutical market is intensely competitive. If we are unable to compete effectively with existing drugs, new treatment methods and new technologies, we may be unable to successfully commercialize any product candidates that we develop.

The pharmaceutical market is intensely competitive and rapidly changing. Many large pharmaceutical and biotechnology companies, academic institutions, governmental agencies and other public and private research organizations are pursuing the development of novel drugs for the same diseases that we are targeting or expect to target. Many of our competitors have:

-15-

Table of Contents

We will face intense competition from products that have already been approved and accepted by the medical community for the treatment of the conditions for which we are currently developing products. We also expect to face competition from new products that enter the market. We believe a significant number of products are currently under development, and may become commercially available in the future, for the treatment of conditions for which we may try to develop products. These products, or other of our competitors’ products, may be more effective, safer, less expensive or marketed and sold more effectively, than any products we develop.

There are a large number of companies that are developing new agents for use in cancer therapy including RNAi therapeutics, and there are other companies developing small molecule drugs designed to inhibit the PLK1 target, including Boehringer Ingelheim. These agents may be competitive with our product candidate TKM-PLK1.

We are also aware of other companies developing drugs to treat high cholesterol, some with compounds at a later stage of development than our product candidate TKM-ApoB. There are several drugs currently approved for treatment of high cholesterol including the statins, such as Lipitor and Crestor, fibrates and bile acid sequestrant drugs. Many new agents are in development for the treatment of high cholesterol including an antisense drug targeting ApoB (Kynamro) which is being developed by Isis Pharmaceuticals, Inc. and Genzyme Corporation, a wholly-owned subsidiary of Sanofi-aventis. Kynamro has shown promising clinical activity in recently completed Phase 3 studies and Genzyme is seeking drug approval. There are also a number of drugs in development that target the gene proprotein convertase subtilisn/kexin type 9 (PCSK9) to treat hypercholesterolemia including Alnylam’s ALN-PCS, as well as antibodies being developed by Regeneron Pharmaceuticals Inc., Amgen Inc., and Pfizer.

In addition, there are organizations working on treatments for hemorrhagic fever viruses. AVI BioPharma Inc. has a drug candidate (AVI-6002) in active clinical development which is competitive with our TKM-Ebola product candidate. AVI BioPharma commenced initial human safety studies of its therapeutic candidate against the Ebola virus in May 2011. Since AVI BioPharma’s development efforts are presently ahead of TKM-Ebola, AVI BioPharma may gain marketing approval before our product candidate. Furthermore, if U.S. Government funding is constrained, funding could be limited or discontinued for two competing products treating the same disease.

If we successfully develop product candidates, and obtain approval for them, we will face competition based on many different factors, including:

Our competitors may develop or commercialize products with significant advantages over any products we develop based on any of the factors listed above or on other factors. Our competitors may therefore be more successful in commercializing their products than we are, which could adversely affect our competitive position and business. Competitive products may make any products we develop obsolete or noncompetitive before we can recover the expenses of developing and commercializing our product candidates. Such competitors could also recruit our employees, which could negatively impact our level of expertise and the ability to execute on our business plan. Furthermore, we also face competition from existing and new treatment methods that reduce or eliminate the need for drugs, such as the use of advanced medical devices. The development of new medical devices or other treatment methods for the diseases we are targeting and may target could make our product candidates noncompetitive, obsolete or uneconomical.

We face competition from other companies that are working to develop novel products using technology similar to ours. If these companies develop products more rapidly than we do or their technologies, including delivery technologies, are more effective than ours, then our ability to successfully commercialize products will be adversely affected.

In addition to the competition we face from competing products in general, we also face competition from other companies working to develop novel products using technology that competes more directly with our own. There are multiple companies that are working in the field of RNAi, including major pharmaceutical companies such as Novartis International AG, Takeda Pharmaceutical Company Limited, and Merck, and biotechnology companies such as Alnylam, Quark Pharmaceuticals, Inc., Silence Therapeutics plc, Arrowhead Research Corporation and its subsidiary, Calando, Marina Biotech, Inc., RXi Pharmaceuticals Corporation, Dicerna Pharmaceuticals, Inc., Sylentis S.A., Santaris Pharma A/S, Benitec Ltd and Opko Health, Inc., among others. Any of these companies may develop its RNAi technology more rapidly and more effectively than we do or may develop products against the same target or disease indication that we are pursuing.

We also compete with companies working to develop antisense-based drugs, such as Isis and AVI BioPharma. Like RNAi therapeutic products, antisense drugs target messenger RNAs, or mRNAs, in order to suppress the activity of specific

-16-

Table of Contents

genes. Isis is the developer of a currently approved antisense drug and has several antisense product candidates in clinical trials. Isis has also licensed its antisense technology to a number of other companies that are developing antisense-based drugs. The development of antisense drugs is more advanced than that of RNAi therapeutic products, and antisense technology may become the preferred technology for products that target mRNAs to silence specific genes.

In addition to competition with respect to RNAi and with respect to specific products, we face substantial competition to discover and develop safe and effective means to deliver siRNAs to the relevant cell and tissue types. Our competitors may develop safer and more effective means to deliver siRNAs to the relevant cell and tissue types than our existing lipid nanoparticle delivery technology, and our ability to successfully commercialize our products would be adversely affected. In addition, substantial resources are being expended by third parties in the effort to discover and develop alternative means of delivering siRNAs into the relevant cell and tissue types, both in academic laboratories and in the corporate sector. Some of our competitors have substantially greater resources than we do, and if our competitors are able to negotiate exclusive access to those delivery solutions developed by third parties, we may be unable to successfully commercialize our product candidates.

Risks Related to the Ownership of our Stock

If our stock price fluctuates, our investors could incur substantial losses.

The market price of our common shares may fluctuate significantly in response to factors that are beyond our control. The stock market in general has recently experienced extreme price and volume fluctuations. The market prices of securities of pharmaceutical and biotechnology companies have been extremely volatile, and have experienced fluctuations that often have been unrelated or disproportionate to the operating performance of these companies. These broad market fluctuations could result in extreme fluctuations in the price of our common shares, which could cause our investors to incur substantial losses.

There is no assurance that an active trading market in our common shares will be sustained.

Our common shares are listed for trading on the NASDAQ and the TSX exchanges. However, there can be no assurances that an active trading market in our common shares on these stock exchanges will be sustained.

We are incorporated in Canada and all of our assets, the majority of our officers and a significant number of our directors reside outside the United States, with the result that it may be difficult for investors to enforce any judgments obtained against us or some of our directors or officers.

We and our wholly-owned subsidiary, Protiva, are each incorporated under the laws of the Province of British Columbia and all of our assets are located outside the United States. In addition, the majority of our officers and a significant number of our directors are nationals or residents of countries other than the United States, and all or a substantial portion of such persons’ assets are located outside the United States. While we have appointed National Registered Agents, Inc. as our agent for service of process to effect service of process within the United States upon us, it may not be possible for you to enforce against us or those persons in the United States, judgments obtained in U.S. courts based upon the civil liability provisions of the U.S. federal securities laws or other laws of the United States. In addition, there is doubt as to whether original action could be brought in Canada against us or our directors or officers based solely upon U.S. federal or state securities laws and as to the enforceability in Canadian courts of judgments of U.S. courts obtained in actions based upon the civil liability provisions of U.S. federal or state securities laws.

As a foreign private issuer, we are subject to different United States securities laws and rules than a domestic United States issuer, which may limit the information publicly available to our shareholders.

We are a “foreign private issuer” as defined under U.S. securities laws. As a result, even though we are subject to the informational requirements of the Exchange Act, as a foreign private issuer, we are exempt from certain informational requirements of the Exchange Act which domestic U.S. issuers are subject to, including, the annual report on Form 10-K, quarterly report on Form 10-Q, current reports on Form 8-K upon the occurrence of certain material events and the proxy rules under Section 14 of the Exchange Act. In addition, as a foreign private issuer we are exempt from the proxy solicitation rules under the Exchange Act. Furthermore, the insider reporting and short-profit provisions under Section 16 of the Exchange Act are not be applicable to us, therefore, our shareholders may not know on as timely a basis when our officers, directors and principal shareholders purchase or sell our common shares, as the reporting periods under the corresponding Canadian insider reporting requirements are longer. We intend to fulfill all informational requirements that do apply to us as a foreign private issuer under the Exchange Act by filing the more limited version of the annual report for foreign private issuers on Form 20-F and current reports on Form 6-K with the SEC, which contains information disclosed in response to the informational requirements of the securities commissions in all provinces of Canada.

We may lose our foreign private issuer status in the future, which could result in significant additional costs and expenses to us.

In order to maintain our current status as a foreign private issuer, a majority of our common shares must be either directly or indirectly owned by non-residents of the United States, unless we satisfy all of the additional requirements necessary to preserve this status. We may in the future lose our foreign private issuer status if a majority of our common shares are held in the United States and we fail to meet the additional requirements necessary to avoid loss of foreign private

-17-

Table of Contents

issuer status. If we are not a foreign private issuer, we would not be eligible to use certain foreign issuer forms and would be required to file periodic and current reports and registration statements on United States domestic issuer forms with the SEC, which are more detailed and extensive than the forms available to a foreign private issuer. In addition, we may lose the ability to rely upon exemptions from NASDAQ corporate governance requirements that are available to foreign private issuers. Further, if we engage in capital raising activities after losing our foreign private issuer status, there is a higher likelihood that investors may require us to file resale registration statements with the SEC as a condition to any such financing.

We believe we were classified as a passive foreign investment company for United States tax purposes for the fiscal year ended December 31, 2008 and for certain prior years. This may have adverse tax consequences for U.S. holders of our shares.

For the fiscal year ended December 31, 2008 and certain prior years we believe we were classified for United States income tax purposes as a passive foreign investment company (PFIC). We do not believe we are classified as a PFIC for the fiscal years ended December 31, 2009, 2010, and 2011, although we have not requested or received an opinion from a U.S. tax advisor. We could be classified as a PFIC in certain fiscal years. If you are a U.S. holder of our shares and you purchased your shares in 2008 or certain prior years then any dividends we pay you may be taxed as ordinary income and not at preferential qualifying dividend tax rates, and upon any sale of our common shares, any capital gain may be taxed as ordinary income and not at preferential capital gains rates. The U.S. federal income tax consequences to a U.S. holder on the acquisition, ownership and disposition of common shares will also depend on whether such U.S. holder makes an election to treat us as a qualified electing fund, or QEF, under Section 1295 of the U.S. internal revenue code or a mark-to-market election under Section 1296 of the U.S. internal revenue code.

Our articles and certain Canadian laws could delay or deter a change of control.

Our preferred shares are available for issuance from time to time at the discretion of our board of directors, without shareholder approval. Our articles allow our board, without shareholder approval, to determine the special rights to be attached to our preferred shares, and such rights may be superior to those of our common shares.

In addition, limitations on the ability to acquire and hold our common shares may be imposed by the Competition Act in Canada. This legislation permits the Commissioner of Competition of Canada to review any acquisition of a significant interest in us. This legislation grants the Commissioner jurisdiction to challenge such an acquisition before the Canadian Competition Tribunal if the Commissioner believes that it would, or would be likely to, result in a substantial lessening or prevention of competition in any market in Canada. The Investment Canada Act subjects an acquisition of control of a company by a non-Canadian to government review if the value of our assets, as calculated pursuant to the legislation, exceeds a threshold amount. A reviewable acquisition may not proceed unless the relevant minister is satisfied that the investment is likely to result in a net benefit to Canada. Any of the foregoing could prevent or delay a change of control and may deprive or limit strategic opportunities for our shareholders to sell their shares.

The exercise of all or any number of outstanding stock options, the award of any additional options, bonus shares or other stock-based awards or any issuance of shares to raise funds or acquire a business may dilute your common shares.

We have in the past and may in the future grant to some or all of our directors, officers and employees options to purchase our common shares and other stock-based awards as non-cash incentives to those persons. The issuance of any equity securities could, and the issuance of any additional shares will, cause our existing shareholders to experience dilution of their ownership interests.

Any additional issuance of shares or a decision to acquire other businesses through the sale of equity securities, may dilute our investors’ interests, and investors may suffer dilution in their net book value per share depending on the price at which such securities are sold. Such issuance may cause a reduction in the proportionate ownership and voting power of all other shareholders. The dilution may result in a decline in the price of our common shares or a change in control.

We do not expect to pay dividends for the foreseeable future.

We have not paid any dividends to date and we do not intend to declare dividends for the foreseeable future, as we anticipate that we will reinvest future earnings, if any, in the development and growth of our business. Therefore, investors will not receive any funds unless they sell their common shares, and shareholders may be unable to sell their shares on favourable terms or at all. We cannot assure you of a positive return on investment or that you will not lose the entire amount of your investment in our common shares. Prospective investors seeking or needing dividend income or liquidity should not purchase our common shares.

The value of our securities, including our common shares, might be affected by matters not related to our operating performance and could subject us to securities litigation.

The value of our common shares may be reduced for a number of reasons, many of which are outside our control, including:

-18-

Table of Contents

In the past, companies that have experienced volatility in their value have been the subject of securities class action litigation. There can be no assurance that we will not become involved in securities class action litigation in the future. Such litigation often results in substantial costs and diversion of management’s attention and resources.