Nektar Presents Data Demonstrating that NKTR-214, a CD122-Biased Immunostimulatory Cytokine, Induces Durable and Specific Anti-Tumor Immunity As a Single-Agent and When Combined with Checkpoint Inhibitors in Preclinical Models

SAN FRANCISCO, Sept. 21, 2015 /PRNewswire/ -- Nektar Therapeutics (NASDAQ: NKTR) today announced positive preclinical results for NKTR-214, a CD122-biased cytokine designed to preferentially stimulate the production and maintenance of tumor-killing T cells which are found naturally in the body. CD122, which is also known as the Interleukin-2 receptor beta subunit, is a key signaling receptor that is known to increase the proliferation of CD8-positive effector T cells, and these CD8-positive T cells comprise a key component of the tumor infiltrating lymphocytes that provide cell-mediated anti-tumor effects.1

Results were presented this past Friday at the Inaugural CRI-CIMT-EATI-AACR Immunotherapy Conference in New York. NKTR-214 shows efficacy in multiple preclinical models as a single agent. Combination regimens with NKTR-214 and either anti-CTLA4 or anti-PD-1 checkpoint inhibitor therapies resulted in durable anti-tumor immunotherapeutic effects, which persisted long after the termination of dosing.

"We are very encouraged by these remarkable preclinical findings, which show an immune-educating vaccine-like effect with the combination and sequencing of NKTR-214 and checkpoint inhibition," said Stephen Doberstein, Ph.D., Senior Vice President and Chief Scientific Officer of Nektar Therapeutics. "This is the ultimate goal of immune-oncology and we look forward to initiating our planned Phase 1/2 clinical trial of NKTR-214 in the fourth quarter of 2015."

In a preclinical tumor re-challenge study presented, sequential dosing of anti-CTLA-4 followed by NKTR-214 resulted in durable and complete responses.  At 142 days following the final dose, with no additional treatment, the complete responders demonstrated sustained resistance to multiple tumor re-challenges.

In highly-resistant established melanoma tumor models, data presented show that treatment with NKTR-214 resulted in a controlled, sustained and biased T-cell activating signal and a mean ratio of CD8-positive T cells to T-regulatory cells ratio of 450:1 in the tumor infiltrating lymphocytes.

NKTR-214 Preclinical Data Presentation
The presentation entitled, "Antitumor activity of NKTR-214, a CD122-biased immunostimulatory cytokine, combined with immune checkpoint blockade requires innate and adaptive immunity," which was presented at The Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival by CRI-CIMT-EATI-AACR can be accessed at

About NKTR-214

NKTR-214 is a CD122-biased immune-stimulatory cytokine, which is designed to stimulate the patient's own immune system to eliminate cancer cells. By biasing activation to the CD122 receptor, NKTR-214 enhances CD8-positive T cells (tumor-killing cells) in the tumor. In preclinical studies, a single dose of NKTR-214 resulted in an approximate 400-fold AUC exposure within the tumor compared with an equivalent dose of aldesleukin, an existing IL-2 therapy.  This increase potentially enables, for the first time, an antibody-like dosing regimen for a cytokine.2 In dosing studies in non-human primates, there was no evidence of low blood pressure or vascular leak syndrome with NKTR-214 at predicted clinical therapeutic doses.3 

About Nektar

Nektar Therapeutics has a robust R&D pipeline in pain, oncology, hemophilia and other therapeutic areas. In the area of pain, Nektar has an exclusive worldwide license agreement with AstraZeneca for MOVANTIK™ (naloxegol), the first FDA-approved once-daily oral peripherally-acting mu-opioid receptor antagonist (PAMORA) medication for the treatment of opioid-induced constipation (OIC), in adult patients with chronic, non-cancer pain. The product is also approved in the European Union as MOVENTIG® (naloxegol) and is indicated for adult patients with OIC who have had an inadequate response to laxatives. The AstraZeneca agreement also includes NKTR-119, an earlier stage development program that is a co-formulation of MOVANTIK and an opioid. NKTR-181, a wholly-owned mu-opioid analgesic molecule for chronic pain conditions, is in Phase 3 development. NKTR-171, a wholly-owned new sodium channel blocker being developed as an oral therapy for the treatment of peripheral neuropathic pain, is in Phase 1 clinical development. In hemophilia, ADYNOVATE™ [Antihemophilic Factor (Recombinant)], a longer-acting PEGylated Factor VIII therapeutic has been filed for approval in the U.S. by partner Baxalta Inc. 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 nine approved products in the U.S. or Europe through partnerships with leading biopharmaceutical companies, including AstraZeneca's MOVANTIK™, UCB's Cimzia® for Crohn's disease and rheumatoid arthritis, Roche's PEGASYS® for hepatitis C and Amgen's Neulasta® for neutropenia.

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

MOVANTIK™ is a trademark and MOVENTIG® is a registered trademark of the AstraZeneca group of companies.

ADYNOVATE is a trademark of Baxalta Inc.

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 therapeutic potential of NKTR-214 based on preclinical findings and the value and potential of our technology and 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) positive preclinical efficacy findings, such as those for NKTR-214 reported in this press release, are subject to inherent scientific and medical uncertainties typical for this early stage of drug development and may not be confirmed in clinical trials; (ii) our drug candidates and those of our collaboration partners are in various stages of clinical development and the risk of failure is high and can unexpectedly occur at any stage prior to regulatory approval for numerous reasons including safety and efficacy findings even after positive findings in previous preclinical and clinical studies; (iii) the timing of the commencement or end of clinical trials and the commercial launch of drug candidates may be delayed or unsuccessful due to regulatory delays, slower than anticipated patient enrollment, manufacturing challenges, changing standards of care, evolving regulatory requirements, clinical trial design, clinical outcomes, competitive factors, or delay or failure in ultimately obtaining regulatory approval in one or more important markets; (iv) scientific discovery of new medical breakthroughs is an inherently uncertain process and the future success of the application of our technology platform to potential new drug candidates is therefore highly uncertain and unpredictable and one or more research and development programs could fail; (v) patents may not issue from our patent applications for our drug candidates including NKTR-214, patents that have issued may not be enforceable, or additional intellectual property licenses from third parties may be required; and (vii) the outcome of any existing or future intellectual property or other litigation related to our drug candidates and those of our collaboration partners.  Other important risks and uncertainties set forth in our Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on August 6, 2015. 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 otherwise.

Jennifer Ruddock of Nektar Therapeutics

Nadia Hasan of WCG

1. Boyman, J., et al., Nature Reviews Immunology, 2012, 12, 180-190.
2. Hoch U, at al. AACR; Mol Cancer Ther. 2013;12(11 Suppl):Abstract nr B296.
3. Data on file. Nektar Therapeutics


SOURCE Nektar Therapeutics

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