Nektar Announces Closing of Aerogen Acquisition.

SAN CARLOS, Calif. -- Nektar Therapeutics (Nasdaq:NKTR) announced today that it has closed the acquisition of Aerogen, Inc. (OTCBB:AEGN) under the definitive merger agreement announced on August 15, 2005. Aerogen stockholders approved the acquisition during a special meeting held October 19, 2005.

The acquisition will broaden Nektar's pulmonary technology base by adding capabilities in aerosolized liquid drugs to Nektar's leadership position with inhaleable powdered drugs. Initially, Nektar will incorporate Aerogen technology into its proprietary inhaled ICU antibiotics product, which is in clinical trials for the prevention of pneumonia in mechanically-ventilated patients. Nektar's inhaled ICU antibiotics program is designed to lower morbidity and mortality in ventilated patients and reduce the cost of care. The addition of Aerogen's technologies, people, products, and intellectual property, including a patent portfolio of more than 35 patents, will strengthen Nektar's pulmonary leadership position.

"We welcome and look forward to supporting Aerogen customers and to working with the Aerogen team to advance important therapies for intensive-care unit (ICU) patients," said Ajit S. Gill, Nektar president and CEO.

Aerogen products are based on its OnQ(R) Aerosol Generator technology to improve the treatment of respiratory disorders in the acute care setting. Aerogen has commercialized its Aeroneb(R) Micropump Nebulizer products for hospital, home and pre-clinical use through a network of world-class respiratory distribution partners that includes Puritan-Bennett, Respironics, Maquet, Cardinal Health, Evo Medical Solutions, and Drager Medical. The Aeroneb Professional Nebulizer is currently used in hospitals in more than 30 countries. Aerogen also has development collaborations with pharmaceutical and biotechnology companies for use of its technology in the delivery of novel compounds that treat respiratory and other disorders. In 2004, Aerogen reported revenue of $6.2 million and net loss of $10.1 million.

Former Aerogen stockholders who have questions about exchanging their shares of Aerogen capital stock for their portion of the merger consideration are advised to contact Mellon Investor Services LLC, the exchange agent for the merger, at [phone] (U.S.) toll free; or [phone] (outside the U.S.) collect.

About Nektar

Nektar Therapeutics enables high-value, differentiated therapeutics with its industry-leading drug delivery technologies, expertise and manufacturing capabilities. The world's top biotechnology and pharmaceutical companies are developing new and better therapeutics using Nektar's advanced technologies and know-how. Nektar also develops its own products by applying its drug delivery technologies and its expertise to existing medicines to enhance performance, such as improving efficacy, safety and compliance. For more information, visit www.nektar.com.

This release contains forward-looking statements that reflect management's current views as to Nektar's business strategy, product and technology development plans and funding, collaborative arrangements, clinical trials, and other future events and operations. These forward-looking statements involve uncertainties and other risks that are detailed in Nektar's reports and other filings with the SEC, including its Annual Report on Form 10-K, as amended, for the year ended December 2004 and its Quarterly Report on 10-Q for the quarter ended June 30, 2005. Actual results could differ materially from these forward-looking statements.