Aventis Behring and Inhale Announce Promising Results of a Phase IB Clinical Trial for Inhaleable Alpha1 Proteinase Inhibitor for Hereditary Emphysema Patients.

Business Editors, Medical/Technology Writers

KING OF PRUSSIA, Pa. & SAN CARLOS, Calif.--(BUSINESS WIRE)--April 10, 2001

Inhale Therapeutic Systems, Inc. (Nasdaq:INHL) and Aventis Behring L.L.C. announced today the successful completion of a Phase IB clinical trial of a novel, inhaleable form of Alpha1 Proteinase Inhibitor (API) (Human) currently under investigation for an inherited form of emphysema caused by alpha one antitrypsin deficiency.

All doses were well tolerated including the maximum amount administered. Dose related response was achieved. Further, doses were measurable in the deep lung where API bound to the neutrophil elastase. Neutrophil elastase, if left uncontrolled, leads to excessive inflammation and progressive emphysema. All patients were tested for antibodies to the drug, and no antibodies were detected to this natural human protein. Further, patients indicated in a post study survey that the Inhale delivery system is easy to use.

"Aventis Behring is pleased to be working with Inhale to develop this revolutionary, inhaleable formulation of Alpha1 Proteinase Inhibitor, which may provide a major breakthrough for the Alpha One community. Additionally, our newly constructed Alpha1 Proteinase Inhibitor manufacturing facility in Kankakee, Illinois is now in the validation phase," said Gail Schulze, COO of Aventis Behring L.L.C. "Completion of these two steps moves us closer towards our goal of providing the Alpha One community with a novel treatment option for this under-recognized disease."

"Inhale has been working to provide an easy-to-use portable delivery system for the Alpha One community. A dry powder inhalation form of Alpha1 Proteinase Inhibitor may increase the efficiency of drug dosing compared to the current infusion therapy of Alpha1 Proteinase Inhibitor. Further, its shorter dosing time and more patient-friendly delivery mode could potentially improve patients' quality of life," said Robert Chess, Chairman, Inhale Therapeutic Systems, Inc.

Alpha one antitrypsin deficiency affects approximately 100,000 Americans, according to the Alpha One Foundation, a not-for-profit organization dedicated to increasing the awareness and early diagnosis of this life-threatening genetic disorder. Unlike emphysema that develops as a result of smoke inhalation, emphysema caused by alpha one antitrypsin deficiency is an inherited condition that may affect both the structure and the function of the lungs and can lead to chronic emphysema and premature death if left untreated. Current treatment involves weekly intravenous infusions that may take up to two hours.

The US Food and Drug Administration (FDA) has granted orphan drug designation to this inhaled formulation of Alpha1 Proteinase Inhibitor. Orphan drug designation could provide for U.S. market exclusivity for seven years if the drug is approved by the FDA. The status also provides certain tax benefits and exempts the registrant from certain FDA application fees.

Under the collaboration between the two companies, Aventis Behring manufactures the active substance for treatment of alpha one antitrypsin deficiency, Alpha1 Proteinase Inhibitor. Inhale produces the dry powder formulation for use with its proprietary inhalation system and processes and packages the powder for clinical supplies. Aventis Behring oversees the clinical program and will be responsible for the worldwide commercialization of any approved products resulting from the collaboration.

Aventis Behring L.L.C. is a global leader in the plasma protein industry, providing a wide range of innovative, high quality therapies and unique support services to patients worldwide. Aventis Behring is dedicated to the research and development of proteins from human blood plasma and emerging technologies. For more information about the company, visit its WEBSITE at www.aventisbehring.com.

Aventis (NYSE:AVE), a world leader in pharmaceuticals and agriculture, is dedicated to improving life through the discovery and development of innovative products in the fields of prescription drugs, vaccines, therapeutic proteins, crop production and protection, animal health and nutrition. Aventis announced in November 2000 that it intends to focus on pharmaceuticals and plans to divest its activities in agriculture. With its global corporate headquarters in Strasbourg, France, Aventis employs approximately 95,000 people in more than 120 countries and recorded pro forma sales in 1999 of 20.5 billion Euros. Aventis was launched in December 1999 through the merger of Hoechst AG of Germany and Rhone-Poulenc SA of France. For more information: www.aventis.com.

Inhale Therapeutic Systems, Inc. develops advanced drug delivery solutions for the biopharmaceutical industry. Inhale is pioneering inhaler technologies for pulmonary delivery as well as drug powder formulations and processing for oral, injectable and inhaleable drug delivery. The Company is collaborating with major pharmaceutical and biotechnology companies, including, AstraZeneca, Aventis Behring, Biogen, Bristol-Myers Squibb, GlaxoSmithKine, Lilly and Pfizer. Inhale's most advanced program is inhaleable insulin, sponsored by Pfizer and its collaborator Aventis Pharma, which is in Phase III clinical trials.

This release contains forward-looking statements that reflect Inhale management's current views as to its future products, product developments, manufacturing scale-up, and other future events and operations. These forward-looking statements involve uncertainties and other risks that are detailed in Inhale's reports and other filings with the Securities and Exchange Commission, including its Form 10-K for the year ending Dec. 31, 2000. Actual results could differ materially from these forward-looking statements.

Statements in this news release other than historical information are forward-looking statements subject to risks and uncertainties. Actual results could differ materially depending on factors such as the availability of resources, the timing and effects of regulatory actions, the strength of competition, the outcome of litigation and the effectiveness of patent protection. Additional information regarding risks and uncertainties is set forth in the current Annual Report on Form 20-F of Aventis on file with the Securities and Exchange Commission.