Nektar Announces UCB's Cimzia(R) Approved by U.S. FDA for Adult Patients Suffering From Moderate to Severe Rheumatoid Arthritis

Nektar Advanced Polymer Conjugate Technology Used in Cimzia(R) Through Exclusive Nektar-UCB Collaboration

Nektar Therapeutics (Nasdaq: NKTR) confirmed today UCB's announcement that the US Food and Drug Administration (FDA) has approved Cimzia(R) (certolizumab pegol), the only PEGylated anti-TNFa (Tumor Necrosis Factor alpha), for the treatment of adult patients with moderately to severely active rheumatoid arthritis. Cimzia(R) utilizes Nektar's polymer conjugate technology through an exclusive Nektar-UCB collaboration.

It is estimated that 5 million people suffer from RA globally. In the United States alone, an estimated 1.3 million people have the disease. Prevalence is not split evenly between genders, since women are three times more likely to be affected than men. Although RA can affect people of all ages, the onset of the disease usually occurs between 35-55 years of age.

Under the terms of the agreement between Nektar and UCB, Nektar receives manufacturing revenues during research, clinical development, and commercialization of Cimzia(R). Nektar also receives royalties on end product sales.

About Cimzia(R)

Cimzia(R) is the only PEGylated anti-TNF (Tumor Necrosis Factor). Cimzia(R) has a high affinity for human TNF-alpha, selectively neutralizing the pathophysiological effects of TNF-alpha. Over the past decade, TNF-alpha has emerged as a major target of basic research and clinical investigation. This cytokine plays a key role in mediating pathological inflammation, and excess TNF-alpha production has been directly implicated in a wide variety of diseases. The U.S. Food and Drug Administration (FDA) has approved Cimzia(R) for reducing signs and symptoms of Crohn's disease and maintaining clinical response in adult patients with moderate to severe active disease who have had an inadequate response to conventional therapy and for the treatment of adults with moderate to severely active rheumatoid arthritis. Cimzia(R) was approved in Switzerland for induction of a clinical response and for the maintenance of a clinical response and remission in patients with active Crohn's disease who have not responded adequately to conventional treatment in September 2007. UCB is also developing Cimzia(R) in other autoimmune disease indications. Cimzia(R) is a registered trademark of UCB PHARMA S.A.

About Nektar

Nektar Therapeutics is a biopharmaceutical company developing novel therapeutics based on its PEGylation and advanced polymer conjugation technology platforms. Nektar's technology and drug development expertise have enabled nine approved products for partners, which include leading biopharmaceutical companies. Nektar is also developing a robust pipeline of its own potentially high-value therapeutics that address unmet medical needs by leveraging and expanding its technology platforms to improve and enable molecules.

The company recently announced positive Phase 2 results for Oral NKTR-118, its proprietary novel peripheral opioid antagonist that combines Nektar's advanced small molecule polymer conjugate technology platform with naloxol, a derivative of the opioid-antagonist drug, naloxone. Nektar's technology has been shown to increase oral bioavailability and inhibit penetration across the blood-brain barrier, an important potential advance for small molecule therapies. The product is being developed to treat opioid-induced constipation (OIC).

NKTR-102, PEGylated irinotecan, is currently in Phase 2 clinical studies in ovarian, breast and colorectal cancer. NKTR-105, PEGylated docetaxel, is currently in a Phase 1 study in patients with refractory solid tumors.

Nektar technology is used in nine approved partnered products in the U.S. or Europe today, including Roche's PEGASYS(R) for hepatitis C and Amgen's Neulasta(R) for neutropenia.

Nektar is headquartered in San Carlos, California, with additional R&D operations in Huntsville, Alabama and Hyderabad, India.

This press release contains forward-looking statements that reflect management's current views regarding the value and potential of the company's technology platform, and the company's collaborations with third parties. These forward-looking statements involve numerous risks and uncertainties, including (1) the commercial success of Cimzia(R) cannot be assured and the amount of our future manufacturing revenue from Cimzia(R) is uncertain, (2) any success with Cimzia(R) is not necessarily predictive of clinical or commercial success with any other PEGylated or advanced polymer conjugation products, and (3) other important risks and uncertainties set forth in the company's most recent Quarterly Report on Form 10-Q filed on May 8, 2009 and its Annual Report on Form 10-K filed with the Securities and Exchange Commission on March 6, 2009. Actual results could differ materially from the forward-looking statements contained in this press release. The company undertakes no obligation to update forward-looking statements, whether as a result of new information, future events or otherwise.

For more information on Nektar Therapeutics, please visit www.nektar.com.

    Contact:
    Jennifer Ruddock, 650-631-4954
    Nektar Therapeutics