Nektar Announces Preliminary Topline Results from Phase 2 Efficacy Study for NKTR-181 in Chronic Pain Patients with

 Nektar Announces Preliminary Topline Results from Phase 2 Efficacy Study for
      NKTR-181 in Chronic Pain Patients with Osteoarthritis of the Knee

Company to Host Conference Call on Thursday, September 26th at 1:30 PM Pacific
Time/4:30 PM Eastern Time to Discuss Results

PR Newswire

SAN FRANCISCO, Sept. 26, 2013

SAN FRANCISCO, Sept. 26, 2013 /PRNewswire/ -- Nektar Therapeutics (Nasdaq:
NKTR) announced the preliminary topline results from a Phase 2 study of
NKTR-181 for the treatment of moderate-to-severe chronic pain in patients with
osteoarthritis of the knee. The Phase 2 study utilized a double-blind,
placebo-controlled, randomized withdrawal study design to assess the efficacy,
safety and tolerability of NKTR-181.Of the 295 patients that entered the
study, only 9 (3%) patients were unable to achieve meaningful pain relief with
NKTR-181. 53 (18%) patients discontinued treatment during the titration
period because of adverse events, most of which are those commonly associated
with opioids. A total of 213 patients achieved an average 40% reduction in
pain and entered the randomized phase of the study.

Following the titration period, patients were randomized 1:1 to either
continue to receive their analgesic dose of NKTR-181 or to receive placebo for
21 days. NKTR-181 performed as expected as an opioid analgesic throughout the
study with patients continuing to show a reduction in pain scores throughout
the randomized phase of the study as well. However, patients who were
randomized to placebo did not show the expected increase in pain scores
observed in similar enriched enrollment, randomized withdrawal studies. This
unusual lack of a placebo rebound caused the Phase 2 study to miss the primary
endpoint in the study, which was based upon the average change in a patient's
pain score from pre-randomization baseline to the end of the double-blind,
randomized treatment period of the study.

"We are experiencing a major public health problem with prescription opioids
in this country, and need to find new ways to address this problem," said Dr.
Lynn Webster,Chief Medical Officer of CRI Lifetree. "I haveworked with
NKTR-181 since this new molecule entered the clinic, and I believe that
NKTR-181couldbe an important advance in analgesia,maybeeven a
breakthrough. Although this Phase 2 study did not achieve its primary
endpoint, this is not uncommon in opioid development. What is important is
that the large majority of patients in this trial wereable to achieve
meaningful and long-lasting pain relief from NKTR-181. Providing analgesia
without the pronounced CNS effects and euphoria of standard opioids is the
future of analgesic development."

NKTR-181 was also well-tolerated over the entire treatment period. The most
common adverse events observed for patients taking NKTR-181 were constipation
(22.4%) and nausea (10.3%). Discontinuation for adverse events was 18% during
the titration period with the most common adverse events cited for
discontinuation of constipation (8.8%), nausea (4%) and somnolence (3%).

"The results from this Phase 2 trial provide a great deal of additional
insight into the analgesic profile of NKTR-181 and will be invaluable as we
continue the development of this molecule," said Howard W. Robin, President
and Chief Executive Officer of Nektar Therapeutics. "We were very pleased
that this drug clearly performs as an effective analgesic with only 3% of the
patients who received NKTR-181 unable to titrate to meaningful pain relief.
We are carefully evaluating the lack of post-randomization rebound in the
placebo arm in order to design the optimal pivotal trials for this drug.
Based upon the data from this trial, it is clear that NKTR-181 provides pain
relief on par with existing opioids while achieving a very favorable safety
profile that differentiates it from standard opioids. We are committed to
bringing NKTR-181 to patients suffering from chronic pain."

NKTR-181 is a novel mu-opioid agonist molecule designed to have a slow rate of
entry into the brain to reduce the attractiveness of the molecule as a target
of abuse and to reduce other CNS-mediated side effects, such as sedation and
respiratory depression.

Analyst Call to be Held 1:30 PM Pacific Time/4:30 PM Eastern Time on Thursday,
September 26, 2013

The company will be hosting a call to discuss these data with analysts and
investors at 1:30 PM Pacific time/4:30 PM Eastern time today. Hosting the
call will be Howard Robin, President and CEO of Nektar, and Robert Medve, MD,
Chief Medical Officer. Joining company management will be Jeffrey Gudin, MD,
Director of Pain Management and Palliative Care, Englewood Hospital & Medical
Center and Clinical Instructor of Anesthesiology at Mt. Sinai School of

A live audio-only Webcast of the conference call can be accessed through a
link that is posted on the home page and Investor Relations section of the
Nektar website: To access the conference call live,
follow these instructions:

Dial: (877) 881-2183 (U.S.); (970) 315-0453 (international)
Passcode: 71977583 (Nektar Therapeutics is the host)

The webcast replay of the conference call will be available through October 7,
2013, 2013.

About Opioids and Pain Management

Pain is one of the most common reasons people seek medical treatment.^1 The
American Pain Society estimates that 36 percent of the U.S. population, or 105
million people, suffer from chronic pain in the United States. Chronic pain
conditions, such as osteoarthritis, back pain and cancer pain, affect at least
126 million adults in the U.S. annually and contribute to over $100 billion a
year in direct healthcare expenditures and lost work time.^2 Opioids are
considered the most effective therapeutic option for pain, with sales
exceeding over $10 billion a year in the U.S. alone.^3,4 However, opioids can
cause serious side effects such as respiratory depression and sedation and
have the potential for addiction, abuse and misuse. In 2010, the Centers for
Disease Control and Prevention (CDC) reported that emergency room visits for
non-medical use of opioid analgesics increased 111 percent over a five-year

About Nektar

Nektar Therapeutics is a biopharmaceutical company developing novel
therapeutics based on its PEGylation and advanced polymer conjugation
technology platforms. Nektar has a robust R&D pipeline of potentially
high-value therapeutics in oncology, pain and other therapeutic areas. In the
area of pain, Nektar has an exclusive worldwide license agreement with
AstraZeneca for naloxegol (NKTR-118), an investigational drug candidate, which
has completed Phase 3 development as a once- daily, oral tablet for the
treatment of opioid-induced constipation. For naloxegol, a Marketing
Authorisation Application (MAA) in the EU and a New Drug Application (NDA) in
the US have been submitted for filing. The agreement with AstraZeneca also
includes NKTR-119, an earlier stage development program that is a
co-formulation of naloxegol and an opioid. NKTR-181, a novel mu-opioid
analgesic candidate for chronic pain conditions, is in Phase 2 development in
osteoarthritis patients with chronic knee pain. NKTR-192, a novel mu-opioid
analgesic in development to treat acute pain is in Phase 1 clinical
development. In oncology, etirinotecan pegol (NKTR-102) is being evaluated in
a Phase 3 clinical study (the BEACON study) for the treatment of metastatic
breast cancer and is also in Phase 2 studies for the treatment of ovarian and
colorectal cancers. In anti-infectives, Amikacin Inhale is in Phase 3 studies
conducted by Bayer Healthcare as an adjunctive treatment for intubated and
mechanically ventilated patients with Gram-negative pneumonia.

Nektar's technology has enabled eight approved products in the U.S. or Europe
through partnerships with leading biopharmaceutical companies, including UCB's
Cimzia® for Crohn's disease and rheumatoid arthritis, Roche's PEGASYS® for
hepatitis C and Amgen's Neulasta® for neutropenia. Additional
development-stage products that leverage Nektar's proprietary technology
platform include Baxter's BAX 855, a long-acting PEGylated rFVIII program,
which is in Phase 3 clinical development.

Nektar is headquartered in San Francisco, California, with additional
operations in Huntsville, Alabama and Hyderabad, India. Further information
about the company and its drug development programs and capabilities may be
found online at

Cautionary Note Regarding Forward-Looking Statements
This press release contains "forward-looking statements" within the meaning of
the Private Securities Litigation Reform Act of 1995. Forward-looking
statements can be identified by words such as: "anticipate," "intend," "plan,"
"expect," "believe," "should," "may," "will" and similar references to future
periods. Examples of forward-looking statements include, among others,
statements we make regarding the potential for NKTR-181 as a potentially new
analgesic opioid therapy for the treatment of chronic pain based on
observations and findings from Phase 2 clinical data, potential future
clinical develop plans for NKTR-181, and the value and potential of our
technology and other drug candidates in our research and development
pipeline. Forward-looking statements are neither historical facts nor
assurances of future performance. Instead, they are based only on our current
beliefs, expectations and assumptions regarding the future of our business,
future plans and strategies, anticipated events and trends, the economy and
other future conditions. Because forward-looking statements relate to the
future, they are subject to inherent uncertainties, risks and changes in
circumstances that are difficult to predict and many of which are outside of
our control. Our actual results may differ materially from those indicated in
the forward-looking statements. Therefore, you should not rely on any of these
forward-looking statements. Important factors that could cause our actual
results to differ materially from those indicated in the forward-looking
statements include, among others: (i) NKTR-181 is in the clinical development
stage and could fail at any time due to numerous unpredictable and significant
risks related to safety, efficacy and other important findings that can
negatively impact clinical development prior to approval of a drug candidate;
(ii) future develop plans for NKTR-181 are preliminary only and subject to
change based on, among other factors, our continued review of the clinical
study results and interactions with health authorities; (iii) the preliminary
topline results reported in this press release are subject to change based on
final audit and verification procedures; (iv) although we have conducted
various experiments using laboratory and home-based chemistry techniques that
have so far been unable to convert NKTR-181 into a rapid-acting, more abusable
opioid, it is possible that an alternative chemistry technique or process may
be discovered in the future that would enable the conversion of NKTR-181 into
a more abusable opioid; (v) the statements regarding the therapeutic potential
of NKTR-181 as an opioid analgesic are based on our findings and observations
from preclinical and clinical data and results from future clinical studies
for NKTR-181 may fail to confirm these earlier findings and observations; (vi)
scientific discovery of new medical breakthroughs is an inherently uncertain
process and the future success of the application of Nektar's technology
platform to potential new drug candidates such as NKTR-181 is very uncertain
and unpredictable and these potential new drug candidates could unexpectedly
fail at any time; (vii) patents may not issue from our patent applications for
NKTR-181, patents that have issued may not be enforceable, or additional
intellectual property licenses from third parties may be required; and (viii)
certain other important risks and uncertainties set forth in our Quarterly
Report on Form 10-Q filed with the Securities and Exchange Commission on
August 9, 2013. Any forward-looking statement made by us in this press release
is based only on information currently available to us and speaks only as of
the date on which it is made. We undertake no obligation to update any
forward-looking statement, whether written or oral, that may be made from time
to time, whether as a result of new information, future developments or

Nektar Investor and Media Inquiries:
Jennifer Ruddock/Nektar Therapeutics (415) 482-5585
Susan Noonan/SA Noonan Communications, LLC (212) 966-3650

(1) Hyman, Steven E., Harvard Review of Psychiatry. 2(1):43-46, May/June 1994.

(2) 2011 National Academy of Sciences. Relieving Pain in America: A Blueprint
for Transforming Prevention, Care, Education and Research, 2010 Decision
Resources, and Harstall, C. How prevalent is chronic pain? Pain Clinical
Updates X, 1—4 (2003).

(3) IMS, NSP, NPA and Defined Health 2010 Estimates.

(4)Melnikova, I, Pain Market, Nature Reviews Drug Discovery, Volume 9, 589-90
(August 2010).

(5) Morbidity and Mortality Weekly Report (MMWR), Emergency Department Visits
Involving Nonmedical Use of Selected Prescription Drugs --- United States,
2004—2008, 59(23);705-709 (June 2010).

SOURCE Nektar Therapeutics

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