Exhibit 99.1

Contact:

Jim Goff, InterMune, Inc., 415-466-2228, jgoff@intermune.com

INTERMUNE REPORTS THIRD QUARTER 2009 FINANCIAL RESULTS AND BUSINESS HIGHLIGHTS

BRISBANE, Calif., November 5, 2009 — InterMune, Inc. (Nasdaq: ITMN) today announced results from operations for the third quarter and nine months ended September 30, 2009. InterMune reported a net loss for the third quarter of 2009 of $8.8 million, or $0.19 per share, compared with a net loss of $14.0 million, or $0.36 per share, in the third quarter of 2008.

Dan Welch, Chairman, Chief Executive Officer and President of InterMune, said, “The third quarter and recent weeks have been a period of exceptional progress and accomplishment for InterMune. As announced yesterday, we submitted our New Drug Application (NDA) for pirfenidone, the first NDA ever submitted for a medicine for patients who suffer from idiopathic pulmonary fibrosis (IPF). We also made excellent progress on our hepatitis C virus (HCV) protease inhibitor ITMN-191 (RG7227) including the initiation of our Phase 2b clinical study and the presentation of the promising results of our novel clinical study of two direct antiviral agents, INFORM-1, at the AASLD meeting earlier this week.” Mr. Welch continued, “Our efforts are now focused on the submission of the MAA for pirfenidone, the support of the NDA and the work to be prepared to bring pirfenidone to patients, should our NDA and/or MAA be granted approval by the regulatory authorities in the United States and Europe, respectively.”

Results for the Three Months Ended September 30, 2009

InterMune reported total revenue in the third quarter of 2009 of $27.3 million, compared with total revenue of $23.3 million in the third quarter of 2008. Total revenue in the third quarter of 2009 primarily consisted of revenue from the collaboration with Roche for the development of protease inhibitors, including ITMN-191, which totaled $20.8 million in the third quarter of 2009, compared with $15.8 million in the third quarter of 2008. Third quarter 2009 collaboration revenue included a $20.0 million milestone payment from Roche associated with initiation of the Phase 2b clinical trial of ITMN-191 in patients chronically infected with HCV. Collaboration revenue in the third quarter a year earlier included a $15.0 million development milestone payment from Roche.

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InterMune reported Actimmune^® (interferon gamma-1b) revenue in the third quarter of 2009 of $6.5 million, compared with $7.5 million in the same quarter of 2008, a decrease of approximately 15 percent, reflecting lower off-label physician prescriptions of Actimmune for the treatment of IPF, which InterMune does not promote.

Research and development (R&D) expenses in the third quarter of 2009 were $20.6 million compared with $25.6 million in the third quarter of 2008, a decrease of approximately 20 percent, reflecting completion of the CAPACITY clinical trials in early 2009, partially offset by expenses associated with the RECAP extension study and the preparation of the NDA and MAA for pirfenidone. General and administrative (G&A) expenses were $9.9 million in the third quarter of 2009, compared with $8.2 million in the same period a year earlier, an increase of approximately 20 percent, primarily attributed to costs related to preparation for the potential commercialization of pirfenidone, which is subject to regulatory approvals.

InterMune recorded a non-cash loss on extinguishment of debt of $0.7 million in the third quarter of 2009 in connection with the September 2009 exchange of approximately $3.8 million of its 0.25% Convertible Senior Notes due 2011 held by certain of its debt holders for shares of the company’s common stock. A total of approximately 250,000 shares of common stock were issued in connection with the transaction.

As of September 30, 2009, InterMune had cash, cash equivalents and available-for-sale securities of approximately $139.7 million, compared with $154.7 million as of December 31, 2008.

Results for the Nine Months Ended September 30, 2009

InterMune also reported results from operations for the nine months ended September 30, 2009. The net loss for the period was $87.4 million, or $2.00 per share, compared with a net loss of $72.7 million, or $1.87 per share, in the first nine months of 2008.

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Total revenue in the first nine months of 2009 was $42.1 million, compared with total revenue of $40.8 million in the same period of 2008, an increase of 3 percent. Actimmune revenue totaled $19.6 million in the first nine months of 2009, compared with $23.3 million of Actimmune revenue in the first nine months of 2008, a decrease of approximately 16 percent, reflecting lower off-label sales of Actimmune for the treatment of IPF, which InterMune does not promote. Revenue from the collaboration with Roche was $22.5 million in the first nine months of 2009, compared with $17.5 million in the same period of 2008. Collaboration revenue in the first nine months of 2009 included a $20.0 million milestone payment from Roche in connection with the start of the Phase 2b clinical trial program of ITMN-191, which was initiated in August. Collaboration revenue in the first nine months of 2008 included a $15.0 million development milestone payment received in the third quarter of 2008.

R&D expenses were $68.0 million in the first nine months of 2009, a 13 percent decrease compared to $78.0 million in the same period of 2008. This decrease in R&D expenses was primarily due to the completion of the Phase 3 CAPACITY program in early 2009, partially offset by increased expenses associated with: the RECAP pirfenidone study, the INFORM-1 and Phase 2b studies with ITMN-191 and the preparation of the NDA and MAA for pirfenidone. G&A expenses of $26.9 million in the first nine months of 2009 were approximately 19 percent higher than $22.7 million in the first nine months of 2008, primarily reflecting costs related to preparation for the potential commercialization of pirfenidone, which is subject to regulatory approvals. Expenses in the first nine months of 2009 included a milestone payment of $13.5 million for pirfenidone made to Marnac/KDL in accordance with the pirfenidone purchase agreement and InterMune’s decision to submit NDA and MAA filings for pirfenidone.

On January 1, 2009, the company adopted guidance in the Debt Topic of the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”), formerly FASB Staff Position APB 14-1, “Accounting for Convertible Debt Instruments That May Be Settled In Cash Upon Conversion (Including Partial Cash Settlement),” and recorded additional interest expense for the third quarter of 2009 of $1.0 million and $3.7 million for the first nine months of 2009. This guidance requires retrospective application upon adoption; therefore, net losses attributable to InterMune for the third quarter and first nine months of 2008 have been adjusted from those which were previously reported to reflect additional interest expense of $1.5 million and $6.0 million, respectively.

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Clinical Development Highlights – Third Quarter and Recent Events

Pirfenidone:

ITMN-191 (RG7227)

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Leadership Additions – Preparation for Potential Pirfenidone Launch

The company today announced in a separate press release the expansion of its senior leadership team that will prepare the company to bring pirfenidone to patients, should InterMune’s NDA and/or MAA be granted approval by the regulatory authorities in the United States and Europe, respectively:

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Further expansion of InterMune’s commercial infrastructure will be made upon the successful outcome of key regulatory events related to the NDA and MAA, expected in 2010.

2009 Key Project Guidance

The company provided the following guidance on its key development projects, pirfenidone and ITMN-191 (RG7227).

Guidance for 2009 Revenue and Expenses

The company updated its 2009 financial guidance for revenue and operating expenses from the guidance initially provided on February 26, 2009.

Revenue: 2009 revenue, including Actimmune^® and milestone payments from Roche, is expected to be in a range of approximately $45 to $50 million. Actimmune revenue represents approximately 50 percent of this revenue range.

Operating Expenses

Approximately 35 percent of the R&D expense is attributed to the company’s one-third share of all development expenses incurred by the collaboration with Roche on ITMN-191. The balance of 2009 R&D expense is related to the advancement of a named pirfenidone analog compound, ITMN-520, toward an expected IND filing in 2010.

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Conference Call and Webcast Details

InterMune will host a conference call today at 4:30 p.m. EST to discuss its financial results for its third quarter and first nine months of 2009, its forward-looking financial guidance and its clinical development programs. Interested investors and others may participate in the conference call by dialing 888-799-0528 (U.S.) or 973-200-3372 (international), conference ID# 37626791. A replay of the webcast and teleconference will be available approximately three hours after the call.

To access the webcast, please log on to the company’s website at www.intermune.com at least 15 minutes prior to the start of the call to ensure adequate time for any software downloads that may be required.

The teleconference replay will be available approximately three hours after the call. The teleconference replay will be available for 10 business days following the call and can be accessed by dialing 800-642-1687 (U.S.) or 706-645-9291 (international), and entering the conference ID# 37626791. The webcast will remain available on the company’s website until the next earnings call.

About InterMune

InterMune is a biotechnology company focused on the research, development and commercialization of innovative therapies in pulmonology and hepatology. InterMune has an R&D portfolio addressing idiopathic pulmonary fibrosis (IPF) and hepatitis C virus (HCV) infections. The pulmonology portfolio includes pirfenidone for which InterMune has completed a Phase 3 program in patients with IPF (CAPACITY) and has submitted a New Drug Application (NDA) to the FDA. The hepatology portfolio includes the HCV protease inhibitor compound RG7227 (ITMN-191) which entered Phase 2b in August of 2009 and a second-generation HCV protease inhibitor research program. For additional information about InterMune and its R&D pipeline, please visit www.intermune.com.

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Forward-Looking Statements

This news release contains forward-looking statements within the meaning of section 21E of the Securities Exchange Act of 1934, as amended, that reflect InterMune’s judgment and involve risks and uncertainties as of the date of this release, including without limitation the statements related to anticipated product development timelines and the likelihood of regulatory success. All forward-looking statements and other information included in this press release are based on information available to InterMune as of the date hereof, and InterMune assumes no obligation to update any such forward-looking statements or information. InterMune’s actual results could differ materially from those described in InterMune’s forward-looking statements. Pirfenidone failed to achieve statistical significance on the primary endpoint in one of its two pivotal clinical trials and there can be no assurance that the regulatory authorities in either the United States or Europe will grant regulatory approval based upon this data, in combination with the other efficacy and safety results the company currently has submitted in support of its NDA file and plans to submit in support of its MAA filing. Other factors that could cause or contribute to such differences include, but are not limited to, those discussed in detail under the heading “Risk Factors” in InterMune’s most recent annual report on Form 10-K filed with the SEC on March 16, 2009 (the “Form 10-K”) and other periodic reports filed with the SEC, including the following: (i) the fact that physician prescriptions of Actimmune for the treatment of IPF, an indication for which Actimmune has not been approved by the FDA, have declined significantly following the March 2007 termination of the Phase 3 INSPIRE trial of Actimmune in IPF and the risk that InterMune’s revenue will continue to decline as expected; (ii) risks related to regulation by the FDA and other agencies with respect to InterMune’s communications with physicians concerning Actimmune for the treatment of IPF; (iii) reimbursement risks associated with third-party payors; (iv) risks related to whether InterMune is able to obtain, maintain and enforce patents and other intellectual property; (v) risks related to significant regulatory, supply and competitive barriers to entry; (vi) risks related to the uncertain, lengthy and expensive clinical development and regulatory process, including having no unexpected safety, toxicology, clinical or other issues; (vii) risks related to achieving positive clinical trial results; (viii) risks related to timely patient enrollment and retention in clinical trials; (ix) the results of the InterMune CAPACITY trials of pirfenidone differ in some respects from those of the Shionogi & Co., Ltd. Phase 3 trial of pirfenidone and there can be no assurance that the U.S. or European regulatory authorities will approve the use of pirfenidone for the treatment of IPF; (x) the results as reported by Shionogi concerning their Phase 3 trial may differ from those published or presented in a peer-reviewed forum; and (xi) risks related to the company’s manufacturing strategy, which relies on third-party manufacturers and which exposes InterMune to additional risks where it may lose potential revenue. The risks and other factors discussed above should be considered only in connection with the fully discussed risks and other factors discussed in detail in the Form 10-K and InterMune’s other periodic reports filed with the SEC, all of which are available via InterMune’s web site at www.intermune.com.

Actimmune® is a registered trademark of InterMune, Inc. Pegasys® and Copegus® are registered trademarks of Roche.

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Financial tables follow

InterMune, Inc.

PRELIMINARY CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

(unaudited, in thousands, except per share amounts)

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InterMune, Inc.

PRELIMINARY CONDENSED CONSOLIDATED BALANCE SHEETS

(unaudited, in thousands)

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