Nektar Therapeutics: Topline Results from Phase 2 Clinical Trial of Oral NKTR-118 Presented at 20th American Academy of Pain Management Annual Clinical Meeting (AAPM) in Phoenix

PHOENIX and SAN CARLOS, Calif., Oct. 10 /PRNewswire-FirstCall/ -- Nektar Therapeutics presented topline data today from its Phase 2 clinical trial of oral NKTR-118 at the American Academy of Pain Management's (AAPM) 20th Annual Clinical Meeting in Phoenix, Arizona. NKTR-118, an oral peripherally-acting opioid antagonist, is a late stage investigational product candidate in clinical development for the treatment of opioid-induced constipation. NKTR-118 was developed by Nektar, utilizing its proprietary small molecule advanced polymer conjugate technology platform.

Today's presentation at AAPM includes topline data previously announced by the company in March 2009. In a Phase 2 double-blind, randomized, placebo-controlled study of 208 patients with opioid-induced constipation, NKTR-118 met the primary endpoint of increase in spontaneous bowel movements over the baseline period. There was no reversal or reduction of opioid-mediated analgesia in any dose groups. NKTR-118 was also well tolerated with the most commonly reported side effects being dose-dependent gastrointestinal-related effects.

Download Today's Poster Presentation for NKTR-118

The poster presentation from today's AAPM 20th Annual Clinical Meeting can be found on Nektar's website at http://www.nektar.com/product_pipeline/cns_pain_oral_nktr-118and119.html

AAPM Poster #39: "NKTR-118 Significantly Reverses Opioid-Induced Constipation"

Complete Data from NKTR-118 Phase 2 Clinical Trial to be presented in Oral Plenary Session at ACG 2009

Data from the Phase 2 clinical trial of NKTR-118 have been accepted for presentation in an oral plenary session of the American College of Gastroenterology (ACG) 2009 Annual Scientific Meeting to be held in San Diego, California on October 27, 2009. The data will be presented by Dr. Lynn Webster, medical director of Lifetree Clinical Research and lead clinical investigator of the Phase 2 trial.

On September 21, 2009, Nektar Therapeutics announced it had entered into an exclusive worldwide license agreement with AstraZeneca for its NKTR-118 and NKTR-119 programs.

About Opioid-Induced Constipation

The oral peripheral antagonist NKTR-118 targets mu-opioid receptors within the enteric nervous system, which mediate opioid-induced bowel dysfunction, a symptom complex resulting from opioid use that encompasses symptoms such as constipation, bloating, abdominal cramping, and gastroesophageal reflux. Constipation is the hallmark of this syndrome and is generally its most prominent component. In patients who take opiates chronically for pain management, anywhere from 45-90% of patients will develop debilitating constipation associated with other symptoms of opioid-induced bowel dysfunction as a result of the drug binding to the mu-opioid receptor in the gut(1).

According to IMS Health, about 230 million prescriptions were written for opioids in 2007 in the United States alone. Currently, there are no oral drugs approved that are indicated to treat opioid-induced constipation (OIC). Opioid bowel dysfunction and OIC can significantly impact quality of life and increase healthcare utilization.

NKTR-119 is an investigational drug candidate that is a co-formulation of oral NKTR-118 and an opioid analgesic. The product is designed to provide good analgesic properties in the chronic treatment of moderate to severe pain patients while avoiding the debilitating side effects that are common with opioid use, such as constipation and other symptoms of bowel dysfunction.

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 in the U.S. or Europe for partners, which include leading biopharmaceutical companies, including UCB's Cimzia(R) for rheumatoid arthritis and Crohn's Disease, Roche's PEGASYS(R) for hepatitis C and Amgen's Neulasta(R) for neutropenia. Nektar has created a robust pipeline of potentially high-value therapeutics to address unmet medical needs by leveraging and expanding its technology platforms to improve and enable molecules. Nektar is currently conducting clinical and preclinical programs in oncology, pain and other therapeutic areas. 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 clinical study in patients with refractory solid tumors.

Nektar is headquartered in San Carlos, California, with additional R&D operations in Huntsville, Alabama and Hyderabad, India. Further information about the company and its drug development programs and capabilities may be found online at http://www.nektar.com.

This press release contains forward-looking statements that reflect the company's current views regarding the scientific and commercial potential of NKTR-118, the results of the Phase 2 study for that drug candidate and the potential of the company's product development pipeline and technology platform. These forward-looking statements involve risks and uncertainties, including but not limited to: (i) NKTR-118 is in mid-stage clinical development and the risk of failure remains high and failure can unexpectedly occur at any stage prior to regulatory approval due to efficacy, safety or other factors; (ii) the timing or success of the commencement or end of clinical trials and commercial launch of new drugs may be delayed or unsuccessful due to regulatory delays, clinical trial design, slower than anticipated patient enrollment, drug manufacturing challenges, changing standards of care, clinical outcomes, or delay or failure in obtaining regulatory approval in one or more important markets; (iii) the company's patent applications for its proprietary or partner product candidates may not issue, patents that have issued may not be enforceable, or intellectual property licenses from third parties may be required in the future; (iv) the outcome of any existing or future intellectual property or other litigation related to the company's proprietary product candidates; and (v) those risks and uncertainties regarding the company's agreement with AstraZeneca for the development and commercialization of NKTR-118 and NKTR-119 that are set forth in the company's Current Report on Form 8-K filed with the Securities and Exchange Commission on September 21, 2009. Other important risks and uncertainties are detailed in the company's reports and other filings with the Securities and Exchange Commission, including its most recent Quarterly Report on Form 10-Q and Annual Report on Form 10-K.

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 http://www.nektar.com.

1. Panchal SJ, Muller-Schwefe P, Wurzelmann JI. Opioid-induced bowel dysfunction: prevalence, pathophysiology and burden. Int J Clin Pract. 2007;61(7):1181-1187.

SOURCE Nektar Therapeutics

CONTACT: Jennifer Ruddock for Nektar Therapeutics, +1-650-631-4954

Web site: http://www.nektar.com/