Nektar Therapeutics announced that positive phase 1 clinical data for Nektar's lead immuno-oncology agent, NKTR-214, in patients with renal cell carcinoma (RCC) were presented at ASCO GU 2017.  

NKTR-214 is an investigational immuno-stimulatory therapy designed to expand specific cancer-fighting T cells and Natural Killer (NK) cell abundance directly in the tumor micro-environment and increase expression of PD-1 on these immune cells.  The results were presented by Michael Hurwitz, MD, PhD, Assistant Professor of Medicine, Department of Medical Oncology at Yale Cancer Center and were entitled "A Novel Immune Agonist, NKTR-214, Increases the Number and Activity of CD8+ Tumor Infiltrating Lymphocytes in Patients with Advanced Renal Cell Carcinoma."

"NKTR-214 resulted in dramatic increases in tumor-infiltrating lymphocytes (TILs) and also demonstrated encouraging anti-tumor activity, with 40% of RCC patients experiencing tumor reductions, including one patient with a partial response," said Dr. Mary Tagliaferri, vice president, clinical development at Nektar.  "We know that high TIL levels are correlated with clinical response and longer survival in patients treated with checkpoint inhibitor therapies and can be the best predictor of response.  NKTR-214's unique mechanism, favorable safety profile and clinical activity support our combination trials of NKTR-214 with existing checkpoint inhibitors, such as nivolumab and atezolizumab, but also with other I-O mechanisms in development."

Clinical benefit and safety data were presented on 15 patients from the trial with renal cell carcinoma who were treated with single-agent NKTR-214: 6/15 (40%) patients with RCC had radiographic reductions in tumor size per RECIST 1.1 on NKTR-214, including; 3 patients who had progressed on 1 prior tyrosine kinase inhibitor (TKI) and had also progressed on 1 prior checkpoint therapy; 3 patients who had progressed on 1 prior tyrosine kinase inhibitor (TKI) and were checkpoint therapy naïve, including 1 patient who experienced an unconfirmed partial response (uPR); NKTR-214 continues to demonstrate a favorable safety and tolerability profile with convenient, outpatient q3w or q2w administration in all patients evaluable for safety to-date.

Immune pheno-typing was conducted and biomarkers of immune activation were measured in patients with evaluable tumor biopsies and blood samples.  Treatment with NKTR-214 produced a robust elevation in immune cell frequency and activation, including: Increase in total lymphocytes and newly proliferating (Ki67+) CD4+ T cells, CD8+ T cells, and NK cells, with increases greater than 50-fold observed; Increase in CD8+ T cells of up to 10-fold in the tumor micro-environment in patients with evaluable tumor biopsies (pre-dose and post-dose at week 3); Increase in expression of cell-surface PD-1 on T cell subsets of up to 2-fold in the tumor micro-environment; Nektar and Bristol-Myers Squibb are collaborating to develop NKTR-214 as a potential combination treatment regimen with Bristol-Myers Squibb's Opdivo (nivolumab) in five tumor types and eight potential indications. The phase 1/2 clinical program will enroll up to 260 patients and will evaluate the potential for the combination of Opdivo (nivolumab) and NKTR-214 to show improved and sustained efficacy and tolerability above the current standard of care in melanoma, kidney, triple-negative breast cancer, bladder and non-small cell lung cancer patients.  The initial dose-escalation trial is underway with Opdivo (nivolumab) and NKTR-214 in the indications of first-line melanoma, second-line RCC checkpoint therapy-naïve, and second-line non-small cell lung cancer (NSCLC) checkpoint therapy-naïve.

NKTR-214 is an experimental therapy designed to stimulate cancer-killing immune cells in the body by targeting CD122 specific receptors found on the surface of these immune cells, known as CD8+ effector T cells and NK cells. In preclinical studies, treatment with NKTR-214 resulted in a rapid expansion of these cells and mobilization into the tumor micro-environment.1 NKTR-214 has an antibody-like dosing regimen similar to the existing checkpoint inhibitor class of approved medicines. A Phase 1/2 clinical study is ongoing to evaluate single-agent NKTR-214 in cancer patients.

Nektar Therapeutics has a robust R&D pipeline and portfolio of approved partnered medicines in oncology, pain, immunology and other therapeutic areas. Nektar is headquartered in San Francisco, California, with additional operations in Huntsville, Alabama and Hyderabad, India.