SAN FRANCISCO, CA, USA I September 21, 2015 I 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

SOURCE: Nektar Therapeutics