InterMune Initiates Phase III Trial of ACTIMMUNE in the Treatment of Idiopathic Pulmonary Fibrosis.

Business/Medical Editors

BURLINGAME, Calif.--(BW HealthWire)--Oct. 3, 2000

InterMune Pharmaceuticals (Nasdaq: ITMN) today announced that it has started a Phase III clinical trial evaluating the safety and efficacy of ACTIMMUNE(R) (Interferon gamma-1b) Injection for the treatment of idiopathic pulmonary fibrosis (IPF).

"This is a significant milestone in the development of ACTIMMUNE(R) for IPF, a deadly disease for which there previously has been no effective therapy," said W. Scott Harkonen, M.D., CEO and President of InterMune. "ACTIMMUNE(R) is now in three late stage clinical trials, including multidrug-resistant tuberculosis and systemic fungal disease. We have additional trials planned for ovarian cancer, cystic fibrosis and non-tuberculous mycobacterial infections as well."

InterMune initiated the Phase III trial following positive clinical results in a Phase II trial published in The New England Journal of Medicine in October 1999, and a reanalysis of those results presented in a monograph published by the American Thoracic Society (ATS) in September 2000. The Phase II trial demonstrated that interferon gamma-1b may be effective in treating IPF, and the reanalysis confirmed those results.

IPF is a life-threatening disease characterized by progressive scarring, or fibrosis of the lungs, which ultimately leads to respiratory failure. The prognosis is poor for patients with IPF and the median life span is three to five years from the time of diagnosis. IPF occurs primarily in persons 40 to 70 years old, and InterMune believes that there are approximately 50,000 patients in the United States with this disease. Interferon gamma-1b is the first and only drug to have shown promise as a treatment for IPF in a Phase II clinical trial.

InterMune Pharmaceuticals, Inc. is a biotechnology company dedicated to the development and commercialization of innovative products for the treatment of serious pulmonary and infectious diseases and cancer. InterMune currently markets ACTIMMUNE(R) (Interferon gamma-1b) Injection in the United States for the treatment of chronic granulomatous disease (CGD) and severe, malignant osteopetrosis. For more information about InterMune and ACTIMMUNE(R), please visit InterMune's web sites at www.intermune.com and www.actimmune.com, or send e-mail to [e-mail].

Except for the historical information contained herein, this press release contains certain forward-looking statements, concerning the possible benefits of interferon gamma for treating idiopathic pulmonary fibrosis, that involve risks and uncertainties. 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. Factors that could cause or contribute to such differences include, but are not limited to the following: even if InterMune's potential idiopathic pulmonary fibrosis products appear promising at an early stage of development, they may not reach the market for a number of reasons. Such reasons include, but are not limited to, the possibilities that the potential products will be found ineffective during clinical trials, fail to receive the necessary regulatory approvals, be difficult to manufacture on a large scale, be uneconomical to market, be precluded from commercialization by the proprietary rights of third parties; or fail to be as safe or effective and/or cost more than competitors' IPF products that may be approved by the U.S. FDA. Although the FDA approves products based upon a single Phase III clinical trial, generally, these FDA approvals are for those trials that demonstrate a clinically meaningful effect on mortality, irreversible morbidity, or prevention of a disease with potentially serious outcome, and confirmation of the result in a second trial would present practical or ethical concerns. Other factors that could cause or contribute to such differences include, but are not limited to those discussed under the heading "Risk Factors" and the risks and factors discussed in InterMune's Registration Statement on Form S-1, declared effective on September 20, 2000 by the Securities and Exchange Commission (File No. 333-45460), and InterMune's most recent 10-Q filed with the SEC. In sum, these significant risks include, but are not limited to: the uncertainty of success of InterMune's efforts in research, development, commercialization, product acceptance, third-party manufacturing and capital raising; product liability lawsuits; uncertainties associated with: obtaining and enforcing patents important to its business, being an early-stage company and relying on third-party payors' reimbursement policies; the uncertain, lengthy and expensive regulatory process; and competition from other products.