13 September 2017 - - San Francisco, California-based research-based development stage biopharmaceutical company Nektar Therapeutics (NASDAQ: NKTR) has begun dosing in the PROPEL clinical study which will evaluate the efficacy and safety of NKTR-214, the company's lead immuno-oncology candidate, in combination with approved checkpoint inhibitors, Tecentriq (atezolizumab) and Keytruda (pembrolizumab), the company said.
NKTR-214 is an investigational immuno-stimulatory therapy designed to expand specific cancer-fighting T cells and natural killer cells directly in the tumor microenvironment and increase expression of PD-1 on these immune cells.
Atezolizumab is a monoclonal antibody designed to bind with programmed death-ligand 1 (PD-L1). Pembrolizumab is an anti-PD-1 therapy that works by increasing the ability of the body's immune system to help detect and fight tumor cells.
NKTR-214 targets CD122 specific receptors found on the surface of cancer-fighting immune cells in order to stimulate their proliferation and activation. In clinical and preclinical studies, treatment with NKTR-214 resulted in expansion of these cells and mobilization into the tumor micro-environment.1,2 NKTR-214 has an antibody-like dosing regimen similar to the existing checkpoint inhibitor class of approved medicines.
The Phase 1/2 PROPEL study is a Nektar-sponsored trial that will enroll patients into two separate arms concurrently. 
The first arm will evaluate an every three-week dose regimen of NKTR-214 in combination with atezolizumab in up to 30 patients in approved treatment settings of atezolizumab, including patients with non-small cell lung cancer or bladder cancer.
The second arm will evaluate an every three-week dose regimen of NKTR-214 in combination with pembrolizumab in up to 30 patients in approved treatment settings of pembrolizumab, including patients with melanoma, non-small cell lung cancer or bladder cancer.
Nektar Therapeutics is a research-based development stage biopharmaceutical company whose mission is to discover and develop innovative medicines to address the unmet medical needs of patients. Its R and D pipeline of new investigational medicines includes treatments for cancer, auto-immune disease and chronic pain. Nektar is headquartered in San Francisco, California, with additional operations in Huntsville, Alabama and Hyderabad, India.