Forward-Looking Statements

      This Quarterly Report on Form 10-Q (the “Report”) contains certain information regarding our financial projections, plans and strategies that are forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. These statements involve substantial risks and uncertainty. You can identify these statements by forward-looking words such as “may,” “will,” “expect,” “intend,” “anticipate,” “believe,” “estimate,” “plan,” “could,” “should,” “continue” or the negative of such terms or similar words or expressions. These forward-looking statements may also use different phrases.

      We have based these forward-looking statements on our current expectations and projections about future events. These forward-looking statements, which are subject to risks, uncertainties and assumptions about us, may include, among other things, statements which address our strategy and operating performance and events or developments that we expect or anticipate will occur in the future, including, but not limited to, statements in the discussions about:

      You should also consider carefully the statements under the heading “Risk Factors” below, which address additional factors that could cause our results to differ from those set forth in the forward-looking statements. Any forward-looking statements are qualified in their entirety by reference to the factors discussed in this Report, including those discussed in this Report under the heading “Risk Factors” below. Because of the factors referred to above, as well as the factors discussed in this Report under the heading “Risk Factors” below, could cause actual results or outcomes to differ materially from those expressed in any forward-looking statements made by us or on our behalf, you should not place undue reliance on any forward-looking statement. Further, any forward-looking statement speaks only as of the date on which it is made, and we undertake no obligation to update any forward-looking statement to reflect events or circumstances after the date on which the statement is made or to reflect the occurrence of unanticipated events. New factors emerge from time to time, and it is not possible for us to predict which factors will arise. In addition, we cannot assess the impact of each factor on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements. When used in the Report, unless otherwise indicated, “InterMune,” “we,” “our” and “us” refers to InterMune, Inc.

Critical Accounting Policies

      Our discussion and analysis of our financial condition and results of operations are based upon our consolidated financial statements, which have been prepared in accordance with U.S. generally accepted accounting principles. The preparation of these financial statements requires us to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenue and expenses, and related disclosure of contingent assets and liabilities. We base our estimates on historical experience and on various other assumptions that we believe are reasonable. These estimates are the basis for our judgments about the carrying values of assets and liabilities, which in turn may impact our reported revenue and expenses. Actual results may differ from these estimates under different assumptions or conditions.

      An accounting policy is deemed to be critical if it requires an accounting estimate to be made based on assumptions about matters that are highly uncertain at the time the estimate is made, and if different

estimates that reasonably could have been used, or changes in the accounting estimate that are reasonably likely to occur periodically, could materially change the financial statements. We believe there have been no significant changes during the three-and nine-month periods ended September 30, 2005 to the items that we disclosed as our critical accounting policies and estimates under Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” in our Annual Report on Form 10-K for the year ended December 31, 2004.

Executive Overview

      We are an independent biopharmaceutical company focused on the research, development and commercialization of innovative therapies in pulmonology and hepatology. Pulmonology is the field of medicine concerned with the diagnosis and treatment of pulmonary, or lung, conditions. Hepatology is the field of medicine concerned with the diagnosis and treatment of disorders of the liver. We were incorporated in California in 1998 and reincorporated in Delaware in 2000 upon becoming a public company. Our revenue base is provided primarily from sales of our two core products, Actimmune and Infergen. Since 2003, sales of Actimmune have been declining on a year to year basis. Significant resources have been applied to the marketing of Infergen contributing to its recent growth. We also have a number of advanced-stage clinical programs addressing a range of unmet medical needs with attractive potential commercial markets as well as one non-core asset, oritavancin, that we are seeking to divest. We have sustained losses in every year since inception and, as of September 30, 2005, we had an accumulated deficit of $520.5 million and a capital deficit of $30.5 million.

Approved Products

      Our two marketed products are Actimmune® (interferon gamma-1b), approved for the treatment of patients with severe, malignant osteopetrosis and chronic granulomatous disease (“CGD”) and Infergen® (consensus interferon alfacon-1), approved for the treatment of patients with compensated liver disease who have chronic hepatitis C virus (“HCV”) infections. For the nine months ended September 30, 2005, Actimmune accounted for approximately 74% of our product revenues, and substantially all of those revenues were derived from physicians’ prescriptions for the off-label use of Actimmune in the treatment of idiopathic pulmonary fibrosis (“IPF”).

Research Programs

      We have a preclinical research program in the hepatology area. In September 2002, we entered into a drug discovery collaboration agreement with Array BioPharma, Inc. (“Array”) to discover certain novel small molecule NS-3 protease inhibitors for the treatment of hepatitis C. In late 2004, we amended the Array agreement to provide for the acquisition of certain intellectual property rights from Array. In April 2005, we initiated a second research collaboration with Array with respect to a new hepatology target.

      Results presented at the Digestive Disease Weekly medical conference in May 2005 have identified protease inhibitors as a promising therapeutic class. We are advancing our own HCV protease inhibitor program and have completed several preclinical studies on a series of compounds. We have selected one compound for toxicology studies in support of a potential IND submission. We are in the process of determining whether or not we will enter into a partnership to help us develop this protease inhibitor program. Pending discussions with the FDA and irrespective of whether or not we enter into a partnership for this program, we expect to file an IND for this protease inhibitor in 2006.

      In addition, we are pursuing research related to other small molecules for unspecified hepatology targets.

      We have a preclinical research program in pulmonology focused on the discovery of small molecule therapeutics.

Development Programs

      We have a late-stage development pipeline in the areas of pulmonology, hepatology and ovarian cancer.

      In hepatology, we are focused on expanding treatment options for patients suffering from chronic HCV infections. Patients who have never been treated with interferons are referred to as “naïve” patients. We are developing once-daily Infergen in combination with ribavirin therapy for the re-treatment of patients suffering from chronic HCV infections who are reported to have detectable HCV after at least twelve weeks of previous pegylated interferon alpha 2 in combination with ribavirin therapy. Approximately 50% of naïve patients show a sufficient and sustained virologic response (the most commonly used measure of treatment effectiveness) to this initial treatment. The remaining patients that do not show a sufficient and sustained virologic response to pegylated interferons plus ribavirin are referred to as hepatitis C “PEG nonresponders.” We believe that there are approximately 200,000 hepatitis C PEG non-responder patients in the United States. We initiated a Phase III trial of once-daily treatment with Infergen in combination with ribavirin therapy for hepatitis C PEG nonresponder patients (the “DIRECT trial”) in June 2004 and announced in July 2005 that patient enrollment was completed. Results from independent investigator studies of daily Infergen plus ribavirin in the U.S. and Europe suggest sustained virologic response rates that are substantially higher than alternative treatments for PEG nonresponders. We hope to confirm these findings in the DIRECT trial. The DIRECT trial is progressing on schedule through the treatment stage of the study. We met with the FDA on October 24, 2005 to discuss our proposed plan to complete the additional clinical work that we believe would satisfy the requirements for the registration of once-daily Infergen in combination with ribavirin therapy. We plan to provide more specifics around the details and timing of our registration plan once we receive written feedback from the FDA from this meeting. We anticipate obtaining top-line data from the DIRECT trial in the first half of 2007.

      We have been developing once-daily Infergen in combination with Actimmune, with and without ribavirin, for the treatment of hepatitis C PEG nonresponder patients. We initiated a Phase IIb clinical trial of this combination in May 2004. Although an independent Data Safety Monitoring Board has approved the continuation of the first three cohorts already enrolled, our decision regarding the future of this trial will depend on data from the first phase of the Phase IIb trial.

      We completed our Phase I trial of a pegylated form of Infergen, PEG-Alfacon-1, for the treatment of chronic HCV infections in 2003. The PEG-Alfacon-1 development program will be lengthy and very expensive, and the duration and expense carry significant risk. We do not currently expect to develop this program unless a suitable development partner for this program can be found.

      In pulmonology, we are developing two therapies for the treatment of IPF. IPF is a fatal disease characterized by progressive scarring, or fibrosis, of the lungs, which leads to the deterioration and destruction of lung function. There is no FDA approved therapy for IPF. Based on available data, we believe that there are approximately 83,000 patients with IPF in the United States. We are developing two clinically advanced compounds for the treatment of IPF, Actimmune and pirfenidone.

      We initiated a second Phase III clinical trial of Actimmune for the treatment of patients with IPF (the “INSPIRE” trial) in December 2003. The INSPIRE trial required the enrollment of approximately 600 patients which we anticipate will be completed by the end of 2005. However, to ensure the trial has adequate statistical power, we recently conducted a sample size re-evaluation and determined that the overall mortality rate observed at this early point in the trial was somewhat lower than forecast in the study protocol. Consequently, as provided in the protocol, we made the decision in October 2005 to increase the sample size of the trial by an additional 200 patients to increase the likelihood that the protocol-specified number of events will have occurred by the time the trial is scheduled to conclude by the end of 2007. These additional patients bring the total size to approximately 800 patients. We expect to receive top-line data from the INSPIRE trial in early 2008.

      We have rights to develop and commercialize Actimmune for a broad range of diseases in the United States, Canada and Japan. We are collaborating with BI, which has similar rights in Europe and the rest of the world, to develop and commercialize interferon gamma-1b under the trade name Imukin®. Actimmune has been granted orphan drug designation for IPF in the United States. Under the Orphan Drug Act, the FDA may grant orphan drug designation to drugs intended to treat a rare disease or condition, which is generally a disease or condition that affects fewer than 200,000 individuals in the United States. This designation provides seven years of market exclusivity in the United States upon the FDA’s first approval of the product for the orphan designation provided that the sponsor complies with certain FDA specified conditions. EMEA orphan drug designation provides for ten years of market exclusivity in Europe.

      We are developing pirfenidone for the treatment of IPF and we currently plan to initiate a Phase III clinical program for pirfenidone in this regard. This program will involve approximately 550 patients, will include two separate multi-national Phase III trials and will have lung function as the primary endpoint. We expect to initiate this program in the first half of 2006. In 2004, the FDA and the European Medicines Agency (“EMEA”) granted us orphan drug designation for pirfenidone for the treatment of IPF. We are also supporting the development of pirfenidone for pulmonary fibrosis associated with Hermansky-Pudlak Syndrome, a fatal, fibrotic lung disease caused by genetic factors for which there is no FDA approved therapy, by providing free drug product to the National Institute of Health for continuing clinical work.

      We are also evaluating Actimmune in patients with ovarian cancer in an ongoing Phase III trial (the “GRACES trial”). We will review this program based on the outcome of a planned interim analyses of progression-free survival and overall survival. These are event driven analyses performed by an independent Data Safety Monitoring Board that we anticipate will occur in late 2005 or the first quarter of 2006.

      Our oritavancin asset does not fit within our core focus areas of pulmonology and hepatology. Therefore, we have been attempting to divest this non-core asset for the past two years.

Product Development Status

      The following chart shows the status of our product development programs as of September 30, 2005:

Results of Operations

      Total product revenues were $36.6 million and $37.5 million for the three-month periods ended September 30, 2005 and 2004, respectively, representing a decrease of 2%. This decrease was primarily attributable to decreases in sales of Actimmune and Amphotec, a product line we divested in May 2005, partially offset by an increase in Infergen sales. For the three-month periods ended September 30, 2005 and 2004, Actimmune accounted for approximately 70% and 80%, respectively, of our net product revenues, and substantially all of these revenues were derived from physicians’ prescriptions for the off-label use of Actimmune in the treatment of IPF.

      Total product revenues were $106.8 million and $111.5 million for the nine-month periods ended September 30, 2005 and 2004, respectively, representing a decrease of 4%. This decrease was primarily attributable to decreases in sales of Actimmune and Amphotec partially offset by increased sales of Infergen. For the nine-month periods ended September 30, 2005 and 2004, Actimmune accounted for 74% and 85%, respectively, of our net product sales, and substantially all of these sales were derived from physicians’ prescriptions for the off-label use of Actimmune in the treatment of IPF.

      There are a number of variables that impact Actimmune revenue including, but not limited to, the level of U.S. enrollment in our INSPIRE Trial, new patients started on therapy, average duration of therapy, new data presented at medical conferences and publications in medical journals, reimbursement and patient referrals from physicians. In the third quarter of 2005, Actimmune revenues declined 14% to $25.8 million from $30.1 million during the same period in 2004.

      In the third quarter of 2005, Infergen revenue increased 63% to $10.2 million from $6.2 million in the same period in 2004. We continue to see strong growth in Infergen demand as measured by prescriptions written for vials. For the three months ended September 30, 2005, Infergen demand, as measured by the number of prescribed vials, grew 123% from the same period of 2004.

      Cost of goods sold included product manufacturing costs, royalties and distribution costs. Cost of goods sold were $16.5 million and $12.3 million for the three-month periods ended September 30, 2005 and 2004, respectively. The gross margin percentage for our products was 55% and 67% for these periods in 2005 and 2004, respectively. The increase as a percentage of sales in the cost of goods sold for the third quarter of 2005, when compared to the same period in 2004, was primarily the result of a charge of $7.2 million, or $0.22 per share, to cost of goods sold for excess inventory from previous years’ contractual purchases.

      In 2003 and 2004, we had contractual obligations to purchase approximately 1.0 million and 1.8 million vials of commercial Actimmune, respectively, from BI. During the quarter ended September 30, 2005, we amended our contractual obligation with BI to eliminate previously required purchases for 2005 and reduce the obligation for future purchases. As part of our regular quarterly forecast process and following this amendment, an analysis of existing Actimmune inventory from previous years’ contractual purchases was completed and compared to current and projected sales trends. As a result of this analysis, we charged $7.2 million to cost of goods sold during the quarter ended September 30, 2005 for excess inventory from previous years’ contractual purchases. In accordance with the terms of our amended agreement with BI, we have guaranteed a minimum annual dollar purchase amount in 2007 and through the remainder of the term of the agreement. In the event that we do not order a sufficient quantity of vials based on forecasted demand such that we do not meet the minimum annual dollar purchase amount, we are required to pay to BI the difference. In any given year that we are required to make this payment, our gross margin percentage would be adversely affected.

      Cost of goods sold was $36.8 million and $30.8 million for the nine-month periods ended September 30, 2005 and 2004, respectively. The gross margin for our products was 66% and 72%, respectively, for these periods in 2005 and 2004. This increase in cost of goods sold is attributable to the same reason noted above for the increase in cost of goods sold for the three month period.

      Exchange rate fluctuations between the U.S. dollar and the Euro may adversely affect cost of goods sold on Actimmune purchased from BI. We have, in the past, utilized forward exchange contracts to partially offset the effect of exchange rate fluctuations on purchases. However, no forward exchange contracts have been established to date in 2005.

      We recorded amortization of acquired product rights of $0.7 million for the three-month period ended September 30, 2005 and $0.8 million for the three-month period ended September 30, 2004. The amounts recorded for the three-month periods ending September 30, 2005 and 2004 were comprised of the amortization charges related to the acquisition of Amphotec (until its May 2005 divestiture), Infergen and interferon gamma-1b patents.

      We recorded amortization of acquired product rights of $2.8 million and $2.3 million for the nine-month periods ended September 30, 2005 and 2004, respectively. The amortization charges for both 2005 and 2004 were related to the acquisition of Amphotec, Infergen and interferon gamma-1b patents. The increase for the 2005 period compared to the same period in 2004 was due to a charge of $0.8 million taken in the first half of 2005 for the impairment of Amphotec/ Amphocil product rights in connection with the divestiture of this brand, which was completed in May 2005.

      Research and development expenses were $22.0 million and $16.3 million for the three-month periods ended September 30, 2005 and 2004, respectively, representing an increase of $5.7 million or 35%. The increase in spending for the three-month period ended September 30, 2005 compared with the same period in 2004 was primarily due to progress made on our three ongoing Phase III clinical trials and the advancement of our pre-clinical HCV protease inhibitor program. Research and development expenses were $64.3 million and $54.9 million for the nine-month periods ended September 30, 2005 and 2004, respectively, representing an increase of $9.4 million, or 17%. The increase for the nine-month period ended September 30, 2005 compared with the same period in 2004 was primarily due to a $7.4 million increase for the pulmonology development program and a $9.3 million increase for the hepatology development program. These increases in development programs were offset by a decrease of $2.6 million for the oncology development program; a $1.8 million decrease in our non-core oritavancin and Amphotec programs (a substantial majority of the expenses related to oritavancin); and a $2.9 million decrease in non-specific research and development programs.

      The following table lists our current product development programs and the research and development expenses recognized in connection with each program during the indicated periods. The category title “Programs-Non specific” is comprised of facilities and personnel costs that are not allocated to a specific development program or discontinued programs. Our management reviews each of these program categories in evaluating our business. For a discussion of the risks and uncertainties associated with developing our products, as well as the risks and uncertainties associated with potential commercialization of our product candidates, see the Risk Factors below including those under the headings “Risks Related to the Development of Our Products and Product Candidates” and “Risks Related to Manufacturing and Our Dependence on Third Parties.”

      Our development program expenses for the nine-months ended September 30, were as follows (in thousands):

      A significant component of our total operating expenses is our ongoing investments in research and development and, in particular, the clinical development of our product pipeline. The process of conducting the clinical research necessary to obtain FDA approval is costly, time consuming, and variable with respect to the timing of expense recognition. Current FDA requirements for a new human drug to be marketed in the United States include:

      In light of the factors mentioned above, we consider the active management and development of our clinical pipeline to be crucial to our long-term success. The actual probability of success for each candidate and clinical program may be impacted by a variety of factors, including, among others, the quality of the candidate, the validity of the target and disease indication, early clinical data, investment in the program, competition, manufacturing capability and commercial viability. Due to these factors, it is not possible to give accurate guidance on the anticipated proportion of our research and development investments by program or the future cash inflows from these programs.

      Selling, general and administrative expenses were $22.2 million and $17.1 million for the three-month periods ended September 30, 2005 and 2004, respectively, representing an increase of $5.1 million or 30%. The increased spending for the three-month period ended September 30, 2005 compared with the same period in 2004 was primarily related to an increased level of sales and marketing expenses supporting Infergen, including the 31-representative Infergen sales force hired in the fourth quarter of 2004, and approximately

$1.8 million of legal expenses related to litigation and ongoing legal matters. The legal matters are described in Part II, Item 1 of this Report.

      Selling, general and administrative expenses were $70.7 million and $51.8 million for the nine-month periods ended September 30, 2005 and 2004, respectively, representing an increase of $18.9 million or 36%. The increased spending for the nine-month period ended September 30, 2005, versus the same period in 2004, was primarily related to an increased level of sales and marketing expenses supporting Infergen, $2.0 million of legal expense associated with the settlement of the shareholder class action lawsuit and employee lawsuit and $3.4 million of legal expenses related to litigation and ongoing legal matters. The legal matters are described in Part II, Item 1 of this Report.

      Interest income increased to $1.0 million for the three-month period ended September 30, 2005, compared to $0.8 million for the three-month period ended September 30, 2004. Interest income increased to $3.1 million for the nine-month period ended September 30, 2005, compared to $2.6 million for the nine-month period ended September 30, 2004. The increase in interest income in the three-month and nine-month periods ended September 30, 2005 reflects increasing investment yields on our cash and short-term investments resulting from higher market interest rates, partially offset by lower cash and investment balances.

      Interest expense decreased to $0.3 million for the three-month period ended September 30, 2005, compared to $0.6 million for the three-month period ended September 30, 2004. Interest expense decreased to $0.9 million for the nine-month period ended September 30, 2005, compared to $4.8 million for the nine-month period ended September 30, 2004. The decrease in interest expense in the three-month and nine-month periods ended September 30, 2005, reflects the 2004 repurchase of all of our $149.5 million 5.75% convertible subordinated notes due in July 2006 and the impact of the issuance of our $170 million 0.25% convertible senior notes due in March 2011.

      Other income (expense) was $0.3 million income for the three-month period ended September 30, 2005 compared to other expense of $4.1 million for the three-month period ended September 30, 2004. Other expense of $4.1 million for the three-month period ended September 30, 2004 included a charge of $2.8 million for the repurchase of all of the remaining $97.0 million of the 5.75% convertible subordinated notes due in July 2006 and the acceleration of $1.3 million of the deferred debt issuance costs associated with these notes. Other income (expense) reflected income of $0.8 million for the nine-month period ended September 30, 2005, comprised of a gain on currency exchange partially offset by the loss on the Amphotec divestiture. This compares to $7.1 million expense for the nine-months ended September 30, 2004. Other expense of $7.1 million for the nine-month period ended September 30, 2004 included a charge of $5.0 million for the repurchase of all $149.5 million of our 5.75% convertible subordinated notes due in July 2006 and the acceleration of $2.1 million of the deferred debt issuance costs associated with these notes.

Liquidity and Capital Resources

      At September 30, 2005, we had available cash, cash equivalents and available-for-sale securities of $120.1 million. The primary objective of our investment activities is to preserve principal while at the same time maximizing yields without significantly increasing risk. To achieve this objective, we invest our excess cash in debt instruments of the U.S. federal and state governments and their agencies and high-quality corporate issuers, and, by policy, restrict our exposure to any single corporate issuer by imposing concentration limits.

      Operating activities used $62.0 million in cash during the nine-month period ended September 30, 2005, primarily due to the loss from operations of $64.9 million and a decrease in accounts payable and accrued compensation of approximately $9.9 million. This use of cash was partially offset by a decrease in inventories

of $11.1 million. The decrease in accounts payable and accrued compensation was primarily a result of payments made during the second quarter of 2005 for inventories received during the fourth quarter of 2004. The decrease in inventories is primarily due to a $7.2 million charge recorded to cost of goods sold for excess inventory from previous years’ contractual purchases. Details concerning the loss from operations can be found above in this Report under the heading “Results of Operations.”

      Investing activities provided $61.1 million in cash during the nine-month period ended September 30, 2005, due in part to maturities and sales of short-term investments totaling $133.3 million, offset by $70.3 million of short-term investment purchases and purchases of property and equipment of $1.9 million. Cash provided by investing activities increased by $7.7 million for the 2005 period, compared to the same period in 2004, primarily due to a reduction in purchases of available-for-sale securities.

      Cash provided by financing activities of $1.0 million for the nine-month period ended September 30, 2005 was primarily due to the receipt of proceeds from issuance of common stock. Cash provided by financing activities of $11.5 million for the nine-month period ended September 30, 2004 was primarily due to the receipt of net proceeds of $164.2 million related to the issuance of $170.0 million in 0.25% convertible senior notes due March 2011. These proceeds were offset by the repurchase of $154.5 million in principal amount of our outstanding 5.75% convertible subordinated notes due July 2006.

      We do not have any “special purpose” entities that are unconsolidated in our financial statements as of September 21, 2005. We have no commercial commitments with related parties. We have no loans with related parties, except for an executive loan of $0.2 million to Dr. Marianne Armstrong, our Senior Vice President of Regulatory/ Medical Affairs and Drug Safety, and an executive loan of $0.2 million to Dr. Lawrence Blatt, our Senior Vice President of Preclinical and Applied Research. Both of these loans were in place prior to the enactment of the Sarbanes-Oxley Act in 2002.

      We believe that we will continue to require substantial additional funding in order to complete the research and development activities currently contemplated and to commercialize our product candidates. We believe our existing cash, cash equivalents and available-for-sale securities, together with anticipated cash flows from our operations, will be sufficient to fund our operating expenses, debt obligations and capital requirements under our current business plan through at least the end of 2006. However, this forward-looking statement is based upon the risks identified in this report; our current plans and assumptions, which may change; and our capital requirements, which may increase in future periods. Our future capital requirements will depend on many factors, including, but not limited to:

      As a result, we will require additional funds and plan to attempt to raise additional funds through equity or debt financings, collaborative arrangements with corporate partners or from other sources. We have no commitments for such fund raising activities. Additional funding may not be available to finance our operations when needed or, if available, the terms for obtaining such funds may not be favorable or may result in dilution to our stockholders.

RISK FACTORS

      An investment in our common stock is risky. Stockholders and potential investors in shares of our stock should carefully consider the following risk factors, which hereby update those risks contained in the “Risk Factors” section of our Quarterly Report on Form 10-Q for the period ended June 30, 2005, in addition to other information and risk factors in this Report. We are identifying these risk factors as important factors that could cause our actual results to differ materially from those contained in any written or oral forward-looking statements made by or on behalf of InterMune. We are relying upon the safe harbor for all forward-looking statements in this Report, and any such statements made by or on behalf of InterMune are qualified by reference to the following cautionary statements, as well as to those set forth elsewhere in this Report.

Risks Related to the Development of Our Products and Product Candidates

      We commenced operations in 1998 and have incurred significant losses to date. Our revenues have been limited primarily to sales of Actimmune derived from physicians’ prescriptions for the off-label use of Actimmune in the treatment of IPF. Although we are developing Actimmune for the treatment of IPF and ovarian cancer, Actimmune may not be marketed for IPF before 2008, if at all, and will not be marketed for ovarian cancer before 2007, if at all. We market Infergen for the treatment of HCV infections, but Infergen revenues may fail to grow significantly. We are developing pirfenidone for the treatment of IPF, but pirfenidone will not be marketed for any diseases before 2010, if at all. The development of PEG-Alfacon-1, a pegylated form of Infergen, for the treatment of chronic HCV infections will be lengthy and very expensive and carries significant risk. We do not currently expect to develop the PEG-Alfacon-1 program unless a suitable development partner is found. We have determined that continued development of oritavancin is non-strategic and therefore we are attempting to divest oritavancin. We may be unable to conclude a sale of oritavancin in the near term or on favorable terms, if at all.

      We may fail to develop our products on schedule, or at all, for the reasons stated in this “Risks Related to the Development of Our Products and Product Candidates” section of this Report. If this were to occur, our costs would increase and our ability to generate revenue could be impaired. In addition, we may need to raise capital in amounts greater than we anticipate in order to continue our development activities as planned. If additional capital is not available, we may be forced to curtail our development activities or cease operations.

      To gain approval to market a product for treatment of a specific disease, we must provide the FDA and foreign regulatory authorities with clinical data that demonstrate the safety and statistically significant efficacy of that product for the treatment of the disease. Clinical development is a long, expensive and uncertain process, and delay or failure can occur at any stage of any of our clinical trials. A number of companies in the pharmaceutical industry, including biotechnology companies, have suffered significant setbacks in advanced clinical trials, even after promising results in earlier trials. Success in preclinical testing and early clinical trials does not ensure that later clinical trials will be successful. For example, we reported that our exploratory Phase II clinical trial evaluating Actimmune for the potential treatment of advanced liver fibrosis caused by HCV in patients who have failed standard antiviral therapy failed to meet its primary endpoint. As a result, we do not intend to conduct further development of Actimmune for the treatment of liver fibrosis.

      We are conducting a second Phase III clinical trial of Actimmune as a treatment for IPF, our INSPIRE trial. However, Actimmune may not demonstrate safety or statistically significant efficacy with respect to the primary or secondary endpoints of the protocol of that clinical trial or any additional clinical trial. If the Phase III clinical trial were to fail to demonstrate statistically significant efficacy, we would likely abandon the development of Actimmune for the treatment of IPF, which would seriously harm our business and would result in a significant decline in our expected Actimmune revenue.

      The commencement or completion of any of our clinical trials may be delayed or halted for numerous reasons, including, but not limited to, the following:

      Our development costs will increase if we have material delays in our clinical trials or if we need to perform more or larger clinical trials than planned. For example, our development costs related to Actimmune as a treatment for IPF increased due to our need to conduct an additional Phase III clinical trial, as our first Phase III clinical trial of Actimmune for the treatment of IPF failed to show a significant effect on the primary endpoint of progression-free survival or on secondary endpoints of lung function and quality of life. In addition, we recently conducted a blinded pre-specified sample size re-evaluation in the INSPIRE trial that was a part of the original study protocol to determine if the observed aggregate mortality rate to date was consistent with the mortality assumptions underlying the trial design. At this early stage of the trial, the aggregate mortality rate observed was somewhat lower than the projections used in designing the trial. To increase the likelihood of reaching the total number of deaths upon which the trial is powered by the time the trial is scheduled to conclude in late 2007, we decided to increase the trial size by an additional 200 patients, bringing the total trial size to approximately 800 patients. However, there is no guarantee that this increase in patient numbers will in fact result in an aggregate mortality rate necessary to reach the mortality projections. In this event, the scheduled completion of this trial would extend past late 2007. If there are any significant delays for this or any of our other current or planned clinical trials, our financial results and the commercial prospects for our products and product candidates will be harmed, and our prospects for profitability will be impaired.

      We may determine that certain preclinical product candidates or programs do not have sufficient potential to warrant the allocation of resources toward them. Accordingly, we may elect to terminate our

programs for and, in certain cases, our licenses to, such product candidates or programs. If we terminate a preclinical program in which we have invested significant resources, we will have expended resources on a program that will not provide a full return on our investment and missed the opportunity to have allocated those resources to potentially more productive uses. In this regard, we did not recover the resources spent on the development of Amphotec when we divested Amphotec in May 2005.

      In 2003, we refocused our business by curtailing investment in non-core areas and focusing our commercial and development efforts in pulmonology and hepatology. As a result, we have divested Amphotec and are in the process of attempting to divest oritavancin. We are also evaluating Actimmune in patients with ovarian cancer in our ongoing GRACES Phase III trial. We will review this program based on the outcome of a planned interim analyses of progression-free survival and overall survival. These are event driven analyses performed by an independent Data Safety Monitoring Board that we anticipate will occur in late 2005 or the first quarter of 2006. We have spent significant resources in the acquisition and development of these assets. We may in the future determine that additional product candidates or programs are not consistent with our future business strategy. We may not be able to recover our investment in some or all of these assets in full. In such event, we will have expended resources on programs that will not provide a full return on our investment and missed the opportunity to have allocated those resources to potentially more productive uses.

Risks Related to Government Regulation and Approval of our Products and Product Candidates

      Physicians may prescribe commercially available drugs for uses that are not described in the product’s labeling and that differ from those uses tested by us and approved by the FDA. Such off-label uses are common across medical specialties. For example, even though the FDA has not approved the use of Actimmune for the treatment of IPF, we are aware that physicians are prescribing Actimmune for the treatment of IPF. Substantially all of our Actimmune revenues are derived from physicians’ prescriptions for off-label use. We are also aware that physicians are prescribing Infergen in combination with ribavirin therapy and prescribing daily administration of Infergen for the treatment of chronic HCV infections, even though the FDA has not approved this combination or dosing regimen for the treatment of chronic HCV infections. The FDA does not regulate the behavior of physicians in their choice of treatments. The FDA and other governmental agencies do, however, restrict manufacturers’ communications on the subject of off-label use. Companies may not promote FDA approved drugs for off-label uses. Accordingly, we may not promote Actimmune for the treatment of IPF, or Infergen in combination with ribavirin therapy, or the daily Infergen regimen for the treatment of chronic HCV infections. The FDA and other governmental authorities actively enforce regulations prohibiting promotion of off-label uses and the promotion of products for which marketing approval has not been obtained. The federal government has levied large civil and criminal fines against manufacturers for alleged improper promotion, and the FDA has enjoined several companies from engaging in off-label promotion. The FDA has also requested that companies enter into consent decrees or permanent injunction under which certain promotional conduct is changed or curtailed. We are aware of at least one instance in which the Office of the Inspector General has sought criminal penalties and a corporate integrity agreement against a pharmaceutical manufacturer requiring that company to pay substantial fines and to monitor certain promotional activities to ensure compliance with FDA regulations. We engage in medical education activities that are subject to scrutiny under the FDA’s regulations relating to off-label promotion. While we believe we are currently in compliance with these regulations, the regulations are subject to varying interpretations, which are evolving.

      If the FDA or any other governmental agency initiates an enforcement action against us and it is determined that we violated prohibitions relating to off-label promotion in connection with past or future

activities, we could be subject to civil and/or criminal sanctions such as those noted above in this risk factor, any of which would have an adverse effect on our revenues, business and financial prospects. On November 9, 2004, we received a subpoena from the U.S. Department of Justice requiring us to provide the Department of Justice with certain information relating to Actimmune, including information regarding the promotion and marketing of Actimmune. We are cooperating with the Department of Justice in this inquiry. Although we cannot predict whether the outcome of this inquiry will have a material adverse effect on our business, it is possible that we will be required to pay a substantial civil fine in connection with the settlement of this matter. At this time we cannot predict the magnitude of such a fine or the impact the payment of such a fine may have on our future business operations.

      In addition, some of the agreements pursuant to which we license our products, including our license agreement relating to Actimmune, contain provisions requiring us to comply with applicable laws and regulations, including the FDA’s restriction on the promotion of FDA approved drugs for off-label uses. As a result, if it were determined that we violated the FDA’s rules relating to off-label promotion in connection with our marketing of Actimmune, we may be in material breach of our license agreement for Actimmune. If we failed to cure a material breach of this license agreement, we could lose our rights to Actimmune under the agreement.

      The FDA and foreign regulatory authorities may impose significant restrictions on the use or marketing of our products or impose additional requirements for post-approval studies. Later discovery of previously unknown problems with any of our products or their manufacture may result in further restrictions, including withdrawal of the product from the market. In this regard, the FDA has conducted routine inspections of our manufacturing contractors, and some were issued a standard “notice of observations.” While we believe that all of these observations are being appropriately corrected, failure to correct any deficiency could result in manufacturing delays. Our existing approvals for diseases, and any new approval for any other disease that we target, if granted, could be withdrawn for failure to comply with regulatory requirements or to meet our post-approval commitments. For example, we have ongoing Phase IV post-marketing commitments to the FDA relating to Actimmune for the treatment of osteopetrosis and Infergen for the treatment of HCV. Our failure to adequately address these ongoing Phase IV commitments could result in a regulatory action or restriction, such as withdrawal of the relevant product’s approval by the FDA. If approval for a disease is withdrawn, we could no longer market the affected product for that disease. In addition, governmental authorities could seize our inventory of such product, or force us to recall any product already in the market, if we fail to comply with FDA or other governmental regulations.

      For a description of restrictions relating to the off-label promotion of our products, please see the risk factor titled, “If we fail to comply with FDA or other government regulations prohibiting the promotion of off-label uses and the promotion of products for which marketing approval has not been obtained, it could result in regulatory enforcement action by the FDA or other governmental authorities, which would harm our business” above.

      Our failure to adequately demonstrate the safety and effectiveness of any of our products or product candidates for the treatment of particular diseases will delay or prevent our receipt of the FDA’s and foreign regulatory authorities’ approval and, ultimately, may prevent commercialization of our products and product candidates for those diseases. The FDA and foreign regulatory authorities have substantial discretion in deciding whether, based on the benefits and risks in a particular disease, any of our products or product candidates should be granted approval for the treatment of that particular disease. Even if we believe that a

clinical trial has demonstrated the safety and statistically significant efficacy of any of our products or product candidates for the treatment of a disease, the results may not be satisfactory to the FDA or foreign regulatory authorities. Preclinical and clinical data can be interpreted by the FDA and foreign regulatory authorities in different ways, which could delay, limit or prevent regulatory approval. If regulatory delays are significant or regulatory approval is limited or denied altogether, our financial results and the commercial prospects for those of our products or product candidates involved will be harmed, and our prospects for profitability will be impaired.

      For example, we reported results from our confirmatory pivotal Phase III clinical trial of oritavancin for the treatment of complicated skin and skin-structure infections (“CSSSIs”). However, in two additional small clinical pharmacology trials, we observed adverse events, primarily phlebitis and rash, that were inconsistent with the safety profile observed in prior clinical trials of oritavancin. Since the cause of the inconsistency is unknown, the FDA has requested an additional clinical safety trial be completed prior to the submission of a New Drug Application (“NDA”), for oritavancin. Because of the need to perform an additional clinical trial, further development of oritavancin for the treatment of CSSSIs will require additional investment. We are seeking to divest oritavancin.

      The continuing efforts of governmental and other third-party payors to contain or reduce the cost of healthcare through various means may adversely affect our ability to successfully commercialize our products. For example, in most foreign markets, the pricing and/or profitability of prescription pharmaceuticals are subject to governmental control. In the United States, we expect that there will continue to be federal and state proposals to implement similar governmental control. For example, federal legislation was enacted on December 8, 2003 that provides a new Medicare prescription drug benefit beginning in 2006 and mandates other reforms. Although we cannot predict the full effects on our business of the implementation of this new legislation, it is possible that the new Medicare benefit, which will be managed by private health insurers, pharmacy benefit managers and other managed care organizations, will result in decreased reimbursement for prescription drugs, which may further exacerbate industry-wide pressure to reduce the prices charged for prescription drugs. In addition, increasing emphasis on managed care in the United States will continue to put pressure on the pricing of pharmaceutical products. These new and any future cost-control initiatives could decrease the price that we would receive for Actimmune, Infergen or any other products we may develop in the future, which would reduce our revenues and potential profitability.

      We are subject to various federal and state laws pertaining to health care “fraud and abuse,” including anti-kickback laws and false claims laws. Subject to certain exceptions, the anti-kickback laws make it illegal for a prescription drug manufacturer to knowingly and willfully solicit, offer, receive or pay any remuneration in exchange for, or to induce, the referral of business, including the purchase or prescription of a particular drug. The federal government has published regulations that identify “safe harbors” or exemptions for certain payment arrangements that do not violate the anti-kickback statutes. Due to the breadth of the statutory provisions and the absence of guidance in the form of regulations or court decisions addressing some of our practices, it is possible that our practices might be challenged under anti-kickback or similar laws. False claims laws prohibit anyone from knowingly presenting, or causing to be presented, for payment to third party payors (including Medicare and Medicaid) claims for reimbursed drugs or services that are false or fraudulent, claims for items or services not provided as claimed or claims for medically unnecessary items or services. Our activities relating to the reporting of wholesaler or estimated retail prices for our products, the reporting of Medicaid rebate information and other information affecting federal and state and third-party payment for our products, and the sale and marketing of our products, could become subject to scrutiny under these laws.

      In addition, pharmaceutical companies have been prosecuted under the False Claims Act in connection with their “off-label” promotion of drugs. For information regarding allegations with respect to “off-label” promotion by us, please see “If we fail to comply with FDA or other government regulations prohibiting the promotion of off-label uses and the promotion of products for which marketing approval has not been obtained, it could result in regulatory enforcement action by the FDA or other governmental authorities, including a substantial fine, either of which could harm our business” above.

      If the government were to allege that we were, or convict us of, violating these laws, there could be a material adverse effect on us, including a substantial fine, decline in our stock price, or both. Our activities could be subject to challenge for the reasons discussed above and due to the broad scope of these laws and the increasing attention being given to them by law enforcement authorities.

Risks Related to Manufacturing and Our Dependence on Third Parties

      The manufacturing and manufacturing development of pharmaceuticals, and, in particular, biologicals, are technologically and logistically complex and heavily regulated by the FDA and other governmental authorities. The manufacturing and manufacturing development of our products and product candidates present many risks, including, but not limited to, the following:

      Any of these factors could delay clinical trials, regulatory submissions and/or commercialization of our products for particular diseases, interfere with current sales, entail higher costs and result in our being unable to effectively sell our products.

      We do not have the resources, facilities or experience to manufacture any of our products or product candidates ourselves. Completion of our clinical trials and commercialization of our products requires access to, or development of, manufacturing facilities that meet FDA standards to manufacture a sufficient supply of our products. The FDA must approve facilities that manufacture our products for commercial purposes, as well as the manufacturing processes and specifications for the product. We depend on third parties for the manufacture of our product candidates for preclinical and clinical purposes, and we rely on third parties with FDA approved manufacturing facilities for the manufacture of our products for commercial purposes. These third parties include BI, Amgen and Cardinal Health. We have long-term supply contracts with BI for Actimmune, with Amgen for Infergen and with Cardinal for pirfenidone. However, if we do not perform our obligations under these agreements, they may be terminated.

      Our manufacturing strategy for our products and product candidates presents many risks, including, but not limited to, the following:

      Any of these factors could delay clinical trials, regulatory submissions or commercialization of our products for particular diseases, interfere with current sales, entail higher costs and result in our being unable to effectively sell our products.

      Our key supply agreements provide that the manufacturer is our exclusive source of supply for the product, except under certain circumstances. For example, BI is currently our exclusive manufacturer for Actimmune. Under our agreement with BI, we cannot seek a secondary source to manufacture Actimmune until BI has indicated to us its inability or unwillingness to meet our requirements. Amgen is currently our exclusive manufacturer of Infergen. In December 2004, we amended our Licensing and Commercialization Agreement with Amgen to allow us to transfer the manufacturing of Infergen from Amgen to a new supplier. Even if we were to begin working with a new supplier to manufacture Infergen, it could take several

years to transfer the Infergen manufacturing process to a secondary source. If we are delayed in establishing a secondary supply source for Actimmune or Infergen, or cannot do so at an acceptable cost, we may suffer a shortage of commercial supply of that product or a higher cost of product, either of which would have a material and adverse effect on our revenues, business and financial prospects.

      If our third-party contractors do not successfully carry out their contractual duties or meet expected deadlines, we may be delayed in or prevented from obtaining regulatory approvals for our products and product candidates, and may not be able to successfully commercialize our products and product candidates for targeted diseases. We do not have the ability to independently conduct clinical trials for all of our products and product candidates, and we rely on third parties such as contract research organizations, medical institutions and clinical investigators to perform this function. Our ability to monitor and audit the performance of these third parties is limited. If these third parties do not perform satisfactorily, our clinical trials may be extended or delayed, resulting in potentially substantial cost increases to us and other adverse impacts on our product development efforts. We may not be able to locate any necessary acceptable replacements or enter into favorable agreements with them, if at all.

Risks Related to the Commercialization of Our Products and Product Candidates

      We believe that market acceptance of and demand for Infergen for the treatment of chronic HCV infections may depend upon our ability to change Infergen’s label to provide for daily dosing and to market Infergen in combination therapy with ribavirin for Hepatitis C re-treatment patients. Before we may change Infergen’s label or market Infergen for use in combination therapy with ribavirin for Hepatitis C re-treatment patients, we would need to obtain FDA approval. To seek and obtain such approval, we would need to supplement Infergen’s current FDA license with data that support daily use of Infergen and the combination use of Infergen and ribavirin or another anti-viral drug for increased effectiveness in treating chronic HCV infections. We cannot be certain how long it would take us to submit such data and obtain such an approval from the FDA, if at all. In June 2004, we initiated a Phase III clinical trial designed to evaluate the safety and efficacy of daily Infergen in combination with ribavirin for the re-treatment of patients chronically infected with HCV who are reported to have detectible HCV after at least 12 weeks of previous pegylated interferon alfa-2 plus ribavirin therapy. However, we cannot provide assurance that this trial will be successful. In addition, if we are able to gain FDA approval for Infergen and ribavirin combination therapy, we may become involved in litigation involving patents held by third parties covering use of interferon alpha and ribavirin combination therapy. If we are unable to obtain FDA approval of daily dosing of Infergen and for these new uses for Infergen, we will be unable to market Infergen in combination with ribavirin or other anti-viral drugs, and our revenues, business and financial prospects would be adversely affected.

      Amgen is currently our exclusive manufacturer of Infergen. In December 2004, we amended our Licensing and Commercialization Agreement with Amgen to allow us to transfer the manufacturing of Infergen from Amgen to a new supplier. Even if we were to begin working with a new supplier to manufacture Infergen, it could take several years to transfer the Infergen manufacturing process to a secondary source. If Amgen is unable or refuses to meet our requirements for the manufacture of Infergen, we would be unable to meet market demand for Infergen, which would harm our ability to generate revenue. In addition, we have limited control over the cost of goods for Infergen. If we are unable to purchase Infergen at

an acceptable cost, it would have a material and adverse effect on our revenues, business and financial prospects.

      Our competitors and their strategic partners have substantial and extensive patent rights related to combination therapy of interferon alpha and ribavirin for the treatment of chronic HCV infections. For example, we are aware of three U.S. patents that relate to the use of interferon alpha and ribavirin to treat chronic HCV infections. These patents expire in 2015, 2016 and 2017, respectively. It is possible that these patents could adversely impact or prevent our efforts to market Infergen in combination therapy with ribavirin. If these patents adversely impact our ability to market Infergen or PEG-Alfacon-1 with ribavirin, it is possible that the commercial prospects for Infergen or PEG-Alfacon-1 could be reduced and our prospects for profitability may be impaired. Further, it is possible that our competitors and their strategic partners may obtain additional patent rights in connection with filed patent applications for combination therapy of interferon alpha and other anti-viral drugs for the treatment of chronic HCV infections. If those patent applications were to issue, we may be unable to market Infergen or PEG-Alfacon-1 with ribavirin or with another anti-viral drug, reducing the commercial prospects for Infergen and PEG-Alfacon-1 and our prospects for profitability.

      In addition, we are aware of a U.S. patent that relates to the use of pegylated interferon alpha to treat chronic HCV infections. This patent expires in 2016. It is possible that this patent could adversely impact or prevent us from marketing PEG-Alfacon-1 for the treatment of chronic HCV infections. If this patent impacts our ability to market PEG-Alfacon-1 for the treatment of chronic HCV infections, the commercial prospects for PEG-Alfacon-1 could be reduced. Our competitors and their strategic partners may have patent rights relating to pegylation technology in general and the use of pegylated interferon alpha for the treatment of chronic HCV infections in particular. These patents may adversely impact the commercial prospects for PEG-Alfacon-1.

      Although we have licensed from Amgen rights to PEG-Alfacon-1, we may not have, and may not be able to license on commercially reasonable terms, if at all, sufficient rights to all the intellectual property necessary for us to commercialize PEG-Alfacon-1 for the treatment of chronic HCV infections. For example, our competitors and their strategic partners have substantial and extensive patent rights in connection with interferon alpha and its recombinant production.

      Pegylated interferon alpha products may have an advantage over non-pegylated products because they circulate longer in the body, permitting a less frequent dosing schedule and enhancing efficacy in some patients infected with the HCV virus. Because our competitors Schering-Plough Corporation and Roche Laboratories have commenced marketing their respective pegylated interferon alpha products, Infergen, which is a non-pegylated interferon alpha product, may be at a significant disadvantage. As a result, these competing products may impede Infergen’s ability to gain acceptance with physicians and patients and thus our ability to generate revenue. In addition, both of these companies have obtained and it is likely they will continue to obtain significant patent protection relating to their respective products.

      Specific targeted agents directed against HCV may be effective in reducing the amount of virus in infected chronic HCV patients. Results presented at the Digestive Disease Weekly medical conference in May 2005 have provided additional support of protease inhibitors as a promising target against HCV. If the use of

the protease inhibitor or other specific targeted anti-HCV agents proves to be effective in the treatment of chronic HCV infections, the use of interferon-based therapies, like Infergen for chronic HCV infections may diminish, which would harm our business.

      If the use of interferon-based therapies, including Infergen, for chronic HCV infections were to diminish or not grow as we expect, this could impact the recoverability of the Infergen-related intangible asset, which was $13.5 million as of September 30, 2005. We have conducted detailed assessments of the current and future market potential of Infergen and PEG-Alfacon-1, including, but not limited to, the impact of competing products on the market potential of these interferon-based therapies. These assessments resulted in no reduction of the carrying value of the Infergen-related intangible asset. If we are unable to achieve results consistent with those assumed in our detailed assessment, it may be necessary to perform a future detailed assessment, which could result in a reduction of the carrying value of the Infergen-related intangible asset. This could have a material adverse effect on our financial condition and results of operations during the period in which we recognize a reduction.

      During the nine months ended September 30, 2005, Priority Healthcare Corporation accounted for approximately 45% of our total product sales and 41% of our outstanding receivables. If Priority Healthcare Corporation or any other customer that sells a significant portion of our products were to experience financial difficulties, or otherwise became unable or unwilling to sell our products, our business would be harmed. Additionally, any reduction, delay or loss of orders from our key customers could harm our revenues in any period or harm our business generally. On October 14, 2005, Express Scripts, Inc. announced that it had acquired Priority Healthcare Corporation. We are uncertain what implications, if any, this may have on our business.

      Our success depends on the continued customer support efforts of our network of specialty pharmacies and distributors. A specialty pharmacy is a pharmacy that specializes in the dispensing of injectable or infused medications for complex or chronic conditions, which often require a high level of patient education and ongoing management. The use of specialty pharmacies and distributors involves certain risks, including, but not limited to, risks that these specialty pharmacies and distributors will:

Any such failure may result in decreased product sales and lower product revenues, which would harm our business.

      Our products and product candidates are expensive, and we anticipate that the annual cost for treatment for each of the diseases for which we are seeking approval will be significant. These costs will vary for different diseases based on the dosage and method of administration. Accordingly, we may decide not to market any of our products or product candidates for an approved disease because we believe that it may not be commercially successful. Market acceptance of and demand for our products and product candidates will depend on many factors, including, but not limited to:

      Our ability to commercialize our products or product candidates for particular diseases is highly dependent on the extent to which coverage and reimbursement for our products is available from:

      Significant uncertainty exists as to the coverage and reimbursement status of pharmaceutical products, particularly with respect to products that are prescribed by physicians for off-label use. If governmental and other third-party payors do not provide adequate coverage and reimbursement levels for our products, market acceptance of our products will be reduced, and our sales will suffer. Many third-party payors provide coverage or reimbursement only for FDA approved indications. If any large or many third-party payors decide to deny reimbursement for Actimmune used to treat IPF, sales of Actimmune would decline, and our revenues would suffer.

      Often, third-party payors make the decision to reimburse an off-label prescription based on whether that product has a compendium listing. The drug compendia list approved indications that products have received from the FDA. The compendia also evaluate the body of clinical evidence to determine whether an off-label use of products should be listed in the compendia as medically appropriate. A compendium listing of an off-label use is many times a requirement by payors, such as Medicare and private payors, to approve that use. To receive a compendium listing for the use of Actimmune in the treatment of IPF, we would have to complete an application and submit clinical data regarding the use of Actimmune in the treatment of IPF. We will evaluate whether we apply for a compendium listing based upon the publication of certain data in peer reviewed journals whose publication is outside of our control. If we file for a compendium listing and are unable to acquire a compendium listing for Actimmune for the treatment of IPF, additional third-party payors may decide to deny reimbursement for Actimmune for the treatment of IPF, and fewer physicians may prescribe Actimmune for such treatment. If either of these were to occur, sales of Actimmune would decline and our revenues would suffer.

      Some third-party payors have denied coverage for Actimmune for the treatment of IPF for a variety of reasons, including the cost of Actimmune, the fact that IPF is not an FDA approved indication for Actimmune or a third-party payor’s assessment that a particular patient’s case of IPF has advanced to a stage at which treatment with Actimmune would not have a significant effect. We believe that approximately 60-70% of the patients who seek coverage for Actimmune for the treatment of IPF from private third-party payors are able to obtain coverage. While coverage trends have not changed significantly in the last two years, major health plans could further restrict coverage or adopt a policy of no coverage.

      Medicare generally does not provide coverage for drugs, like Actimmune, that are administered by injection in the home. However, in connection with the Medicare Prescription Drug Improvement and Modernization Act of 2003, Medicare has recently discussed the possibility of refusing to provide coverage for products for a specific indication unless the product has been approved by the FDA for that indication. If Medicare were to make a formal decision not to cover the off-label use of products, it may have a negative impact on the willingness of private third-party payors to provide coverage for the off-label use of products such as Actimmune.

      Our commercial opportunities will be reduced or eliminated if our competitors develop or market products that, compared to our products or product candidates:

      Even if we are successful in developing effective drugs, our products may not compete effectively with our competitors’ current or future products. Our competitors include larger, more established, fully integrated pharmaceutical companies and biotechnology companies that have substantially greater capital resources, existing competitive products, larger research and development staffs and facilities, greater experience in drug development and in obtaining regulatory approvals and greater marketing capabilities than we do.

Risks Related to Our Intellectual Property Rights

      Our commercial success will depend in part on obtaining and maintaining patent protection on our products and product candidates and successfully defending these patents against third-party challenges. Our ability to commercialize our products will also depend in part on the patent positions of third parties, including those of our competitors. The patent positions of pharmaceutical and biotechnology companies can be highly uncertain and involve complex legal and factual questions. No consistent policy regarding the breadth of claims allowed in biotechnology patents has emerged to date. Accordingly, we cannot predict with certainty the scope and breadth of patent claims that may be afforded to other companies’ patents. We could incur

substantial costs in litigation if we are required to defend against patent suits brought by third parties, or if we initiate suits to protect our patent rights.

      The degree of future protection for our proprietary rights is uncertain, and we cannot ensure that:

      Others have filed and in the future may file patent applications covering uses and formulations of interferon gamma-1b, interferon alpha, pegylated versions of these products and other products in our development program. If a third party has been or is in the future issued a patent that blocked our ability to commercialize any of our products, alone or in combination, for any or all of the diseases that we are targeting, we would be prevented from commercializing that product or combination of products for that disease or diseases unless we obtained a license from the patent holder. We may not be able to obtain such a license to a blocking patent on commercially reasonable terms, if at all. If we cannot obtain, maintain and protect the necessary proprietary rights for the development and commercialization of our products or product candidates, our business and financial prospects will be impaired.

      We license certain patents and trade secrets relating to Actimmune from Genentech, Inc; relating to Infergen from Amgen; relating to pirfenidone from Marnac and KDL; and relating to oritavancin from Eli Lilly. If we breach any of our agreements with Genentech, Amgen, Marnac and KDL or Eli Lilly, any of these licensors may be able to terminate the respective license, and we would have no further rights to utilize the licensed patents or trade secrets to develop and market the corresponding products, which could adversely affect our revenues and financial prospects.

      Composition of matter patent protection for pirfenidone molecule has expired in the United States and elsewhere. Marnac and others have obtained patents in the United States and elsewhere relating to methods of use of pirfenidone for the treatment of certain diseases. We have licensed from Marnac and KDL rights to a U.S. patent related to the use of pirfenidone for the treatment of fibrotic disorders, including the use of pirfenidone for the treatment of IPF. Marnac has retained rights under other U.S. and foreign patents for the use of pirfenidone to treat diseases other than fibrotic disorders. It is possible that Marnac will license these patent rights to third parties to develop, market, sell and distribute pirfenidone for these indications in the United States and elsewhere. It is also possible that a third party may develop pirfenidone for the treatment of certain diseases that are not covered by patents held by Marnac or those we licensed from Marnac. If Marnac or others were to license their method of use patents for non anti-fibrotic indications to a third party, or if a third party were to develop pirfenidone for a use that is not covered by any patents and such third parties successfully developed pirfenidone for non-fibrotic indications, we could face competition from third party products with the same active pharmaceutical ingredient as our product candidate. If a third party were to

obtain FDA approval for the use of pirfenidone for an indication before we did, such third party would be first to market and could establish the price for pirfenidone. This could adversely impact our ability to implement our pricing strategy for the product and may limit our ability to maximize the commercial potential of pirfenidone. The presence of a lower priced competitive product with the same active pharmaceutical ingredients as our product could lead to use of the competitive product for our anti-fibrotic indications. This could lead to pricing pressure for pirfenidone, which would adversely affect our ability to generate revenue from the sale of pirfenidone for anti-fibrotic indications.

      We have licensed certain patents relating to interferon gamma-1b, the active ingredient in Actimmune, from Genentech. A U.S. patent relating to the composition of interferon gamma-1b expires in 2014. Other material U.S. patents relating to interferon gamma-1b expire between 2009 and 2013. We also previously purchased certain patents relating to interferon gamma analogs from Amgen in 2002 including a U.S. patent issued August 30, 2005 which will expire on August 30, 2022. When these various patents expire, we will be unable to use these patents to try to block others from marketing interferon gamma-1b in the United States.

      We have licensed U.S. and Canadian patent rights relating to Infergen, a type of interferon alpha, from Amgen. Two of Amgen’s U.S. patents relating to Infergen’s active ingredient, the interferon alfacon-1 molecule, expired in 2004. However, the U.S. Patent and Trademark Office recently issued a Certificate of Extension of Patent Term, officially extending the term of one of these patents by five years, to 2009. After expiration of the extended patent term in 2009, we would rely on a U.S. patent related to the use of interferon alfacon-1 for the treatment of HCV infections while reducing the occurrence of Grade 3 or Grade 4 toxicities to block others from marketing interferon alfacon-1 for the treatment of chronic HCV infections at these doses. When this patent expires in 2011, we will not be able to use this patent to block others from marketing Infergen or other forms of interferon alfacon-1 for the treatment of HCV infections in the United States. Another U.S. patent that we have licensed from Amgen covers the use of interferon alfacon-1 for the treatment of HCV patients who have failed to respond to previous interferon treatment. This patent expires in 2016.

      We have licensed from Marnac and KDL rights to a U.S. patent related to the use of pirfenidone for the treatment of fibrotic disorders, including the use of pirfenidone for the treatment of IPF. After the U.S. patent expires in 2011, we will not be able to use this patent to block others from marketing pirfenidone for fibrotic disorders, including IPF although we may be able to extend our U.S. exclusivity for IPF if we gain FDA approval for IPF under orphan drug designation. The pirfenidone molecule itself has no composition of matter patent protection in the United States or elsewhere. Therefore, we have no ability to prevent others from commercializing pirfenidone for (i) uses covered by the other patents held by Marnac and third parties, or (ii) other uses in the public domain for which there is no patent protection. We are relying on exclusivity granted from orphan drug designation in IPF to protect pirfenidone from competitors in this indication. The exclusivity period in the United States begins on first NDA approval for this product in IPF and ends seven years thereafter. In addition, a third party could develop pirfenidone for another non-fibrotic disease that also qualifies for orphan drug designation and could be granted seven years exclusivity in that indication. Additionally, in Europe we have already been granted orphan drug designation by the EMEA. We anticipate having ten years of exclusivity in Europe for pirfenidone for the treatment of IPF following first marketing approval in Europe. We cannot provide any assurance that we will be able to maintain this orphan drug designation.

      We have licensed certain patents throughout the world relating to oritavancin from Eli Lilly. After patents related to the composition of oritavancin expire in 2015, we will not be able to use such patents to block others from marketing oritavancin.

      Once our patents expire, we will be subject to competition from third parties who will be able to use the intellectual property covered by these patents, which could impair our ability to generate revenues.

      Our competitors and their strategic partners have substantial and extensive patent rights in connection with the use of interferon alpha to treat a variety of diseases. It is possible that our competitors and their strategic partners may obtain additional patent rights in connection with filed patent applications for interferon alpha. We are uncertain of the extent to which the currently issued patents and any additional patents of our competitors that may issue will prevent us from marketing Infergen for the treatment of certain diseases. If these patents adversely impact our ability to market, or prevent us from marketing, Infergen for a range of diseases, the commercial prospects for Infergen will be reduced and our prospects for profitability may be impaired. In addition, our competitors and their strategic partners have substantial and extensive patent rights in connection with the use of pegylated interferon alpha to treat a variety of diseases. Although we have licensed from Amgen rights to PEG-Alfacon-1, we may not have, and may not be able to license on commercially reasonable terms, if at all, sufficient rights to all the intellectual property necessary for us to commercialize PEG-Alfacon-1.

      We are aware of the settlement of a lawsuit involving Infergen filed in 1997 by Biogen, Inc. against Amgen in the U.S. District Court for the District of Massachusetts. The suit alleged that the manufacture of Infergen infringed three Biogen U.S. patents relating to vectors for expressing cloned genes, methods of making vectors and expressing cloned genes, and host cells. All claims in the lawsuit were dismissed with prejudice by order of the court in December 2001 under a confidential settlement agreement entered into between Biogen and Amgen. Although Amgen has informed us that the settlement agreement applies to Infergen, we do not know the terms of the settlement agreement or how the terms of the settlement may affect our ability to commercialize Infergen in the United States. The settlement agreement may have a material adverse effect on our ability to commercialize Infergen in the United States.

      The combination of our products with other drugs may have a greater therapeutic effect in treating certain diseases than our products alone. In some cases, third parties hold patents either on the potential companion drugs or on combination therapies that include our products. We may not be able to negotiate licenses or other rights to potential companion drugs on reasonable terms, or at all. If we are not able to negotiate these licenses or other rights, the market for our products may be diminished.

      Our commercial success depends in part on our ability and the ability of our collaborators to avoid infringing patents and proprietary rights of third parties. As noted in the immediately preceding risk factor, third parties may accuse us or our collaborators of employing their proprietary technology in our products, or in the materials or processes used to research or develop our products, without authorization. Any legal action against our collaborators or us claiming damages and/or seeking to stop our commercial activities relating to the affected products, materials and processes could, in addition to subjecting us to potential liability for damages, require our collaborators or us to obtain a license to continue to utilize the affected materials or processes or to manufacture or market the affected products. We cannot predict whether we, or our collaborators, would prevail in any of these actions or whether any license required under any of these patents would be made available on commercially reasonable terms, if at all. If we are unable to obtain such a license, we, or our collaborators, may be unable to continue to utilize the affected materials or processes or manufacture or market the affected products or we may be obligated by a court to pay substantial royalties and/or other damages to the patent holder. Even if we are able to obtain such a license, the terms of such a license could substantially reduce the commercial value of the affected product or products and impair our prospects for profitability. Accordingly, we cannot predict whether or to what extent the commercial value of the affected product or products or our prospects for profitability may be harmed as a result of any of the liabilities discussed above. Furthermore, infringement and other intellectual property claims, with or without merit, can be expensive and time-consuming to litigate and can divert management’s attention from our core business.

      We generally do not control the patent prosecution of technology that we license from others. Accordingly, we are unable to exercise the same degree of control over this intellectual property as we would exercise over technology that we own. For example, if Genentech fails to maintain the intellectual property licensed to us, we may lose our rights to develop and market Actimmune and may be forced to incur substantial additional costs to maintain or protect the intellectual property or to compel Genentech to do so.

      We rely on trade secrets to protect technology where it is possible that patent protection is not appropriate or obtainable. However, trade secrets are difficult to protect. We protect these rights mainly through confidentiality agreements with our corporate partners, employees, consultants and vendors. These agreements generally provide that all confidential information developed or made known to an individual or company during the course of their relationship with us will be kept confidential and will not be used or disclosed to third parties except in specified circumstances. In the case of employees and consultants, our agreements generally provide that all inventions made by the individual while engaged by us will be our exclusive property. We cannot be certain that these parties will comply with these confidentiality agreements, that we will have adequate remedies for any breach, or that our trade secrets will not otherwise become known or be independently discovered by our competitors. If our trade secrets become known, we may lose a competitive advantage and our ability to generate revenue may therefore be impaired.

      Under some of our research and development agreements, inventions discovered in certain cases become jointly owned by our corporate partner and us and in other cases become the exclusive property of one of us. It can be difficult to determine who owns a particular invention, and disputes could arise regarding those inventions. These disputes could be costly and could divert management’s attention from our business. Our research collaborators and scientific advisors have some rights to publish our data and proprietary information in which we have rights. Such publications may impair our ability to obtain patent protection or protect our proprietary information, which could impair our ability to generate revenues.

Risks Related to Our Financial Results and Other Risks Related to Our Business

      Physicians may choose not to prescribe Actimmune or provide fewer patient referrals for Actimmune for the treatment of IPF because:

      Net sales of Actimmune for the nine months ended September 30, 2005 were $79.4 million, compared to $94.3 million for the nine months ended September 30, 2004, a decline of 16%. Net sales of Actimmune for the quarter ended September 30, 2005 were $25.8 million, compared to $30.1 million for the quarter ended September 30, 2004 representing a decrease of 14%. If physicians do not prescribe Actimmune for the treatment of IPF for the above reasons or any other reasons, our Actimmune revenues will continue to decline. Revenues for Actimmune may have been adversely affected by the publication of an article and a related editorial in the January 8, 2004 issue of the New England Journal of Medicine regarding the results of our initial Phase III trial of Actimmune for the treatment of IPF. The article concluded that “(i)n a well-defined population of patients with idiopathic pulmonary fibrosis, (Actimmune) did not affect progression-free survival, pulmonary function, or the quality of life. Owing to the size of and duration of the trial, a clinically significant survival benefit could not be ruled out.” The related editorial that appeared in the January 8, 2004 New England Journal of Medicine, among other things, cast doubt on our study’s indication of “increased survival among patients who were compliant with interferon gamma-1b treatment” by stating, “(i)t should be emphasized that survival data based on one year of observation in a disease with an unknown date of onset and a life expectancy of two to five years after diagnosis may be very misleading.” The editorial concluded by stating, “(s)tudies of other promising agents ... are indicated, since interferon gamma-1b has not proved to be the answer.”

      We believe our existing cash, cash equivalents and available-for-sale securities, together with anticipated cash flows from our operations, will be sufficient to fund our operating expenses, debt obligations and capital requirements under our current business plan through at least the end of 2006. However, our current plans and assumptions may change, and our capital requirements may increase in future periods. We have no committed sources of capital and do not know whether additional financing will be available when needed, or, if available, that the terms will be favorable to our stockholders or us. If additional funds are not available, we may be forced to delay or terminate clinical trials, curtail operations or obtain funds through collaborative and licensing arrangements that may require us to relinquish commercial rights or potential markets, or grant licenses on terms that are not favorable to us. If adequate funds are not available, we will not be able to successfully execute our business plan.

      We have lost money since inception, and our accumulated deficit was approximately $520.5 million at September 30, 2005. We expect to incur substantial additional net losses prior to achieving profitability, if ever. The extent of our future net losses and the timing of our profitability are highly uncertain, and we may never achieve profitable operations. We are planning to expand the number of diseases for which our products may be marketed, and this expansion will require significant expenditures. To date, we have generated revenues primarily through the sale of Actimmune. However, Actimmune sales have decreased in recent periods. We have not generated operating profits to date from our products. If the time required for us to achieve profitability is longer than we anticipate, we may not be able to continue our business.

      We base many of our operating decisions on anticipated revenue trends and competitive market conditions, which are difficult to predict. Based on projected revenue trends, we acquired inventories and

entered into non-cancelable purchase obligations in order to meet anticipated increases in demand for our products. However, more recent projected revenue trends resulted in us recording charges of $7.2 million for the three months ended September 30, 2005 for excess inventories from previous years’ contractual purchases. If revenue levels experienced in future quarters are substantially below our expectations, especially those revenues from sales of Actimmune and/or Infergen, we could be required to record additional charges for excess inventories and/or non-cancelable purchase obligations. For additional information relating to difficulties we have experienced forecasting revenues, see the risk factor titled, “We may fail to meet our publicly announced revenue and/or expense projections and/or other financial guidance, which would cause our stock to decline in value” below.

      The testing, marketing and sale of medical products entail an inherent risk of product liability. If product liability costs exceed our liability insurance coverage, we may incur substantial liabilities. Whether or not we were ultimately successful in product liability litigation, such litigation would consume substantial amounts of our financial and managerial resources, and might result in adverse publicity, all of which would impair our business. While we believe that our clinical trial and product liability insurance currently provides adequate protection to our business, we may not be able to maintain our clinical trial insurance or product liability insurance at an acceptable cost, if at all, and this insurance may not provide adequate coverage against potential claims or losses.

      Our research and development activities involve the controlled use and disposal of hazardous materials, chemicals, infectious disease agents and various radioactive compounds. Although we believe that our safety procedures for handling and disposing of such materials comply with the standards prescribed by state and federal regulations, we cannot completely eliminate the risk of accidental contamination or injury from these materials. In the event of such an accident, we could be held liable for significant damages or fines, which may not be covered by or may exceed our insurance coverage.

      On November 9, 2004, we received a subpoena from the U.S. Department of Justice requiring us to provide the Department of Justice with certain information relating to Actimmune, including information regarding the promotion and marketing of Actimmune. We are cooperating with the Department of Justice in this inquiry. Although we cannot predict whether the outcome of this inquiry will have a material adverse effect on our business, it is possible that we will be required to pay a substantial civil fine in connection with the settlement of this matter. At this time we cannot predict the magnitude of such a fine or the impact the payment of such a fine may have on our future business operations.

      While we currently maintain clinical trial and product liability insurance, directors’ and officers’ liability insurance, general liability insurance, property insurance and warehouse and transit insurance, first- and third-party insurance is increasingly more costly and narrower in scope, and we may be required to assume more risk in the future. If we are subject to third-party claims or suffer a loss or damage in excess of our insurance coverage, we may be required to share that risk in excess of our insurance limits. Furthermore, any first- or third-party claims made on our insurance policies may impact our future ability to obtain or maintain insurance coverage at reasonable costs, if at all.

      Because we are an emerging company with limited resources, and because research and development is an expensive process, we must regularly assess the most efficient allocation of our research and development resources. Accordingly, we may choose to delay our research and development efforts for a promising product candidate to allocate those resources to another program, which could cause us to fall behind our initial timetables for development. As a result, we may not be able to fully realize the value of some of our product candidates in a timely manner, since they will be delayed in reaching the market, or may not reach the market at all.

      We had 356 employees as of October 31, 2005, and our success depends on our continued ability to attract, retain and motivate highly qualified management and scientific personnel and on our ability to develop relationships with leading academic scientists. Competition for personnel and academic collaborations is intense. We are highly dependent on our current management and key scientific and technical personnel, including Daniel G. Welch, our Chief Executive Officer and President, as well as the other principal members of our management. None of our employees, including members of our management team, has a long-term employment contract, and any of our employees can leave at any time. Our success will depend in part on retaining the services of our existing management and key personnel and attracting and retaining new highly qualified personnel. In addition, we may need to hire additional personnel and develop additional academic collaborations as we continue to expand our research and development activities. We do not know if we will be able to attract, retain or motivate personnel or cultivate academic collaborations. Our inability to hire, retain or motivate qualified personnel or cultivate academic collaborations would harm our business.

      In connection with management’s assessment of our internal control over financial reporting (as defined in Rule 13a-15(f) of the Exchange Act) as of December 31, 2004, we determined that we had a material weakness in our financial statement close process, primarily related to the accurate presentation of disclosures in the notes to our financial statements in accordance with U.S. Generally Accepted Accounting Principles and the rules and regulations of the SEC. This material weakness in our financial statement close process arose from the lack of sufficient finance staff with proficiency to interpret such principles and rules and inadequate review and approval procedures. As a result of the material weakness noted above, our management concluded that our internal control over financial reporting and disclosure controls and procedures (as defined in Rule 13a-15(e) of the Exchange Act) was not effective as of December 31, 2004.

      While audit and other procedures can compensate for problems with internal control over financial reporting and disclosure controls and procedures, our ability to provide reliable financial and other information to investors depends upon the effectiveness of our internal control over financial reporting and disclosure controls and procedures. We have implemented and continue to implement remedial measures to improve our internal control over financial reporting. However, if we are not successful in improving our internal control over financial reporting and disclosure controls and procedures, investors and current and potential collaborative partners could lose confidence in the reports we file with the SEC, which could harm the market price of our common stock and our business.

Risks Related to our Common Stock

      There are a number of reasons why we might fail to meet our revenue and/or expense projections and/or other financial guidance, including, but not limited to, the following:

      If we fail to meet our revenue and/or expense projections and/or other financial guidance for any reason, our stock could decline in value. In this regard, as a result of changing market dynamics for Actimmune, on April 29, 2004, we removed our Actimmune and total revenue guidance for the year ending December 31, 2004 that was provided on January 29, 2004. Our stock price decreased by $3.30, or 18%, to $14.71 by the close of business on April 30, 2004, the day after we removed this guidance.

      The trading price of our common stock has been and is likely to continue to be extremely volatile. During the twelve-month period ended September 30, 2005, the closing price of our common stock on the Nasdaq National Market ranged from $9.99 to $18.14. Our stock price could be subject to wide fluctuations in response to a variety of factors, including, but not limited to all the factors discussed in this “Risk Factors” section.

      In addition, the stock market in general, and the NASDAQ National Market and biotechnology companies in particular, have experienced extreme price and volume fluctuations that have often been unrelated or disproportionate to the operating performance of these companies. Broad market and industry factors may negatively affect the market price of our common stock, regardless of actual operating performance. Periods of volatility in the market price of a company’s securities frequently results in securities class action and shareholder derivative litigation against that company. This type of litigation can result in substantial costs and a diversion of management’s attention and resources, as discussed in more detail above.

We have recently had several lawsuits filed against us, as discussed under the risk factor titled, “We face certain litigation risks that could harm our business.”

      At September 30, 2005, our directors, executive officers and greater than 5% stockholders and their affiliates beneficially owned approximately 45% of our issued and outstanding common stock. Accordingly, they collectively may have the ability to significantly influence the election of all of our directors and to significantly influence the outcome of corporate actions requiring stockholder approval, such as mergers or a financing in which we sell more than 20% of our voting stock at a discount to market price. They may exercise this ability in a manner that advances their own best interests and not necessarily those of other stockholders. This concentration of ownership could also depress our stock price.

      If our stockholders sell substantial amounts of our common stock, including shares issued upon the exercise of outstanding options or conversion of our outstanding convertible notes the market price of our common stock may decline. In addition, the existence of our outstanding convertible notes may encourage short selling by market participants. These sales also might make it more difficult for us to sell equity or equity related securities in the future at a time and price that we deem appropriate. We are unable to predict the effect that sales may have on the then-prevailing market price of our common stock.

      We have filed registration statements covering the approximately 9,340,737 shares of common stock that are either issuable upon the exercise of outstanding options or reserved for future issuance pursuant to our stock plans as of September 30, 2005. We have also filed a shelf registration statement covering the resale of our 0.25% convertible senior notes due in 2011 and the 7,858,811 shares of common stock issuable upon conversion of those notes. In addition, some of the holders of common stock that are parties to our amended and restated investor rights agreement are entitled to registration rights with respect to approximately 6,500,000 shares of our common stock as of September 30, 2005.

      On October 29, 2004, we entered into an Amended and Restated Standstill Agreement with Warburg Pincus Equity Partners, L.P. and certain of its affiliates (“Warburg Pincus”) that permits Warburg Pincus to acquire up to 25% of our outstanding common stock in the open market. Under this agreement, Warburg Pincus may acquire up to 25% of our outstanding common stock and we have granted Warburg Pincus certain registration rights with respect to its holdings. The restriction on Warburg Pincus’ acquisition of additional shares of our common stock expires on October 29, 2007. In exchange for allowing Warburg Pincus to increase its ownership stake, Warburg Pincus has granted the independent members of our board of directors the right to vote the shares of InterMune common stock owned by Warburg Pincus in excess of 19.9%. In addition, Warburg Pincus has agreed to certain limitations on the manner in which it may dispose of its ownership interest in InterMune. In connection with this transaction, we also amended our stockholder Rights Plan to allow Warburg Pincus to acquire up to 25% of our outstanding common stock. Jonathan S. Leff, a member of our board of directors, is a managing director of Warburg Pincus LLC and a partner of Warburg Pincus & Co., which are affiliates of Warburg Pincus Equity Partners, L.P.

      The existence of our stockholder Rights Plan and provisions of our Amended and Restated Certificate of Incorporation and Bylaws, as well as provisions of Delaware law, could make it more difficult for a third party to acquire us, even if doing so would benefit our stockholders. In addition, these provisions may frustrate or prevent any attempts by our stockholders to replace or remove our current management by making it more difficult for stockholders to replace members of our board of directors. Because our board of directors is

responsible for appointing the members of our management team, these provisions could in turn affect any attempt by our stockholders to replace current members of our management team. These provisions:

      In addition, Section 203 of the Delaware General Corporation Law, which prohibits business combinations between us and one or more significant stockholders unless specified conditions are met, may discourage, delay or prevent a third party from acquiring us.

Risks Related to our Outstanding Notes

      As of September 30, 2005, our annual debt service obligation on the $170.0 million in aggregate principal amount of our 0.25% convertible senior notes due March 1, 2011 was $0.4 million. We intend to fulfill our current debt service obligations, including repayment of the principal, both from cash generated by our operations and from our existing cash and investments. If we are unable to generate sufficient cash to meet these obligations and need to use existing cash or liquidate investments in order to fund our current debt service obligations, including repayment of the principal, we may have to delay or curtail research and development programs.

      We may add additional lease lines to finance capital expenditures and may obtain additional long-term debt and lines of credit. If we issue other debt securities in the future, our debt service obligations will increase further.

      Our indebtedness could have significant additional negative consequences, including, but not limited to:

      If a designated event, such as the termination of trading of our common stock on the Nasdaq National Market or a specified change of control transaction, occurs prior to maturity, we may be required to redeem all or part of our 0.25% convertible senior notes due 2011. We may not have enough funds to pay the redemption price for all tendered notes. Although the indenture governing the 0.25% convertible senior notes due 2011 allows us in certain circumstances to pay the applicable redemption prices in shares of our common stock, if a

designated event were to occur, we may not have sufficient funds to pay the redemption prices for all the notes tendered.

      We have not established a sinking fund for payment of our outstanding notes, nor do we anticipate doing so. In addition, any future credit agreements or other agreements relating to our indebtedness may contain provisions prohibiting redemption of our outstanding notes under certain circumstances, or expressly prohibit our redemption of our outstanding notes upon a designated event or may provide that a designated event constitutes an event of default under that agreement. If a designated event occurs at a time when we are prohibited from purchasing or redeeming our outstanding notes, we could seek the consent of our lenders to redeem our outstanding notes or attempt to refinance this debt. If we do not obtain consent, we would not be permitted to purchase or redeem our outstanding notes. Our failure to redeem tendered notes would constitute an event of default under the indenture for the notes, which might constitute a default under the terms of our other indebtedness.

      The securities in our investment portfolio are not leveraged, are classified as available-for-sale and are, due to their short-term nature, subject to minimal interest rate risk. We currently do not hedge interest rate exposure. Because of the short-term maturities of our investments, we do not believe that a change in market rates would have a significant negative impact on the value of our investment portfolio.

      The primary objective of our investment activities is to preserve principal while at the same time maximizing yields without significantly increasing risk. To achieve this objective, we invest our excess cash in debt instruments of the U.S. federal and state governments and its agencies and high-quality corporate issuers, and, by policy, restrict our exposure to any single corporate issuer by imposing concentration limits. To minimize the exposure due to adverse shifts in interest rates we maintain investments of shorter effective maturities.

      The table below presents the principal amounts and weighted-average interest rates by year of maturity for our investment portfolio as of September 30, 2005 by effective maturity (in millions, except percentages):

Foreign Currency Market Risk

      We have obligations denominated in Euros for the purchase of Actimmune inventory. In the nine months ended September 30, 2005, we used foreign currency forward contracts to partially mitigate this exposure. We regularly evaluate the cost-benefit of entering into such arrangements and had no foreign currency hedge agreements outstanding at September 30, 2005.

Evaluation of Disclosure Controls and Procedures.

      As of the end of the period covered by this quarterly report on Form 10-Q, we evaluated the effectiveness of the design and operation of our disclosure controls and procedures, or “disclosure controls.” This controls evaluation was performed under the supervision and with the participation of management, including our CEO and CFO. Disclosure controls are controls and procedures designed to reasonably assure that information

required to be disclosed in our reports filed under the Exchange Act, such as this Report, is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms. Disclosure controls are also designed to reasonably ensure that such information is accumulated and communicated to our management, including the CEO and CFO, as appropriate, to allow timely decisions regarding required disclosure. Based upon the controls evaluation, our CEO and CFO have concluded that, as a result of the matters discussed below with respect to our internal control over financial reporting, our disclosure controls were effective as of the end of the period covered by this Report.

Internal Control Over Financial Reporting

      Management assessed our internal control over financial reporting as of December 31, 2004, the end of our fiscal year. As previously disclosed in the Annual Report on Form 10-K for the year ended December 31, 2004, as a result of this assessment, we identified a material weakness in our financial statement close process. Management identified this material weakness as being due to insufficient controls related to the preparation and review of our annual consolidated financial statements and accompanying footnote disclosures in accordance with U.S. generally accepted accounting principles and the rules and regulations of the SEC. The insufficient controls identified included a lack of finance staff with the proficiency to interpret such principles and rules, and inadequate review and approval procedures to prepare external financial statements in accordance with U.S. generally accepted accounting principles and the rules and regulations of the SEC.

Remediation Actions to Address Material Weaknesses in Internal Control over Financial Reporting

      Management believes that actions that we have taken since December 31, 2004 have addressed the material weaknesses in our financial statement close process. We intend to continue to monitor our internal control over financial reporting, and if further improvements or enhancements are needed, we will take steps to implement such improvements or enhancements.

Changes in Internal Control Over Financial Reporting

      There have been no changes to our internal controls over financial reporting during the three months ended September 30, 2005 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

CEO and CFO Certifications

      Attached as exhibits to this Report, there are “Certifications” of the CEO and the CFO required by Rule 13a-14(a) of the Securities Exchange Act of 1934, or the Rule 13a-14(a) Certifications. This Controls and Procedures section of the Report includes the information concerning the controls evaluation referred to in the Rule 13a-14(a) Certifications and it should be read in conjunction with the Rule 13a-14(a) Certifications for a more complete understanding of the topics presented.

Limitations on the effectiveness of controls.

      Our management, including our CEO and CFO, does not expect that our control systems will prevent all error and all fraud. A control system, no matter how well conceived and operated, can provide only reasonable, not absolute, assurance that the objectives of the control system are met. Further, the design of a control system must reflect the fact that there are resource constraints, and the benefits of controls must be considered relative to their costs. Because of the inherent limitations in all control systems, no evaluation of controls can provide absolute assurance that all control issues and instances of fraud, if any, within InterMune have been detected. These inherent limitations include the realities that judgments in decision-making can be faulty, and that breakdowns can occur because of simple error or mistake. Additionally, controls can be circumvented by the individual acts of some persons, by collusion of two or more people or by management override of the control. The design of any system of controls also is based in part upon certain assumptions about the likelihood of future events, and there can be no assurance that any design will succeed in achieving its stated goals under all potential future conditions. Over time, controls may become inadequate because of changes in

conditions, or the degree of compliance with the policies or procedures may deteriorate. Because of the inherent limitations in a cost-effective control system, misstatements due to error or fraud may occur and not be detected. Accordingly, our disclosure controls and procedures are designed to provide reasonable, not absolute, assurance that the objectives of our disclosure control system are met and, as set forth above, our CEO and CFO have concluded, based on their evaluation as of the end of the period covered by this Report, that our disclosure controls and procedures were effective to provide reasonable assurance that the objectives of our disclosure control system were met.