SAN FRANCISCO, CA, USA I November 4, 2020 I Nektar Therapeutics (NASDAQ:NKTR) announced the presentation of additional clinical data from the Phase 1b study evaluating multiple ascending doses of NKTR-358, a first-in-class T regulatory cell stimulator, currently in development for the treatment of a range of autoimmune disorders, including systemic lupus erythematosus (SLE).

Initial data presented earlier this year at the European Congress of Rheumatology (EULAR) 2020 showed that NKTR-358 was safe and well tolerated in patients with mild-to-moderate SLE and led to a marked and selective, dose-dependent expansion of regulatory T cells (Tregs) that was maintained over multiple administrations. The ACR 2020 presentation includes additional clinical and pharmacodynamic data from this Phase 1b study including key biomarkers of Treg function and assessment of disease characteristics in mild to moderate SLE patients.

“In our data presented at ACR 2020, we were excited to see that NKTR-358 demonstrated a dose-dependent reduction in CLASI-A composite clinical scores in patients with mild-to-moderate SLE after only 3 treatment cycles. Complementing these clinical results, we also observed dose-dependent biomarker changes associated with Treg activation including increases in Treg functional markers, changes in DNA methylation of the FoxP3 locus, and increased expression of Treg functional genes,” said Jonathan Zalevsky, Ph.D., Chief Research & Development Officer at Nektar. “These results support further investigation of NKTR-358 in patients with auto-immune disorders and inflammatory diseases, including the Phase 2 study underway in lupus patients being conducted by our partner Eli Lilly & Co.”

The randomized, double-blind, multiple-ascending dose Phase 1b data from the study being presented at 2020 ACR evaluated safety, pharmacokinetics (PK) and pharmacodynamics (PD) in a total of 48 SLE patients across 4 separate ascending dose cohorts who received subcutaneous Q2W doses of NKTR-358 (n=9 per cohort) or placebo (n=3 per cohort). Subjects were treated for a total of six weeks.

Key conclusions from today’s data presentation at ACR 2020 include:

  • NKTR-358 was safe and well tolerated with a similar safety profile for single and repeat doses in patients with mild-to-moderate SLE as was observed in healthy volunteers from a prior Phase 1 study
  • A selective, dose-dependent expansion of CD25bright Tregs was observed, which was maintained through multiple NKTR-358 administrations
  • Treg induction was further supported by a correlation between the number of Tregs and the extent of demethylated FoxP3
  • Increases in Treg activation markers (CD25, Helios, and CTLA-4) and genes associated with Treg regulation were observed with NKTR-358
  • Low-level increases in NK cell numbers occurred in most patients at the highest NKTR-358 dose; the CD56bright NK cell population was more sensitive than the CD56dim
  • A dose-dependent reduction in CLASI-A1 score was seen with NKTR-358 treatment, which supports further exploration in patients with moderate-to-severe SLE
  • No observed changes in SLEDAI or joint scores were noted due to the short treatment duration in this study

A Phase 2 trial of NKTR-358 in patients with SLE (NCT04433585) as well as two separate Phase 1b studies in patients with atopic dermatitis (NCT04081350) and psoriasis (NCT04119557) are currently recruiting.

Nektar will host a call today for analysts and investors to review the data presented at ACR 2020. Details of the call are as follows:

Date and Time: Wednesday, November 4, 2020 at 4:15 p.m. Eastern Standard Time

Dial- in: (877) 881-2183 (toll-free) or (970) 315-0453 (access code 7083115)

Investors and analysts can view slides and listen to the live audio webcast of the presentation at The event will also be available for replay for two weeks on the company’s website,

About NKTR-358 (LY3471851)

Autoimmune and inflammatory diseases cause the immune system to mistakenly attack and damage healthy cells in a person’s body. A failure of the body’s self-tolerance mechanisms enables the formation of the pathogenic T lymphocytes that conduct this attack. NKTR-358 is a potential first-in-class therapeutic that may address an underlying immune system imbalance in people with many autoimmune conditions. It targets the interleukin (IL-2) receptor complex in the body in order to stimulate proliferation of inhibitory immune cells known as regulatory T cells. By activating these cells, NKTR-358 may act to bring the immune system back into balance. Nektar entered into a strategic collaboration with Lilly in 2017 to develop and commercialize NKTR-358.

NKTR-358 is being developed by Lilly as a self-administered injection for a number of autoimmune and inflammatory diseases. A Phase 2 study of NKTR-358 is underway in adults with systemic lupus erythematosus (ISLAND-SLE) (NCT04433585). The investigational therapy is also currently being evaluated in two separate Phase 1b studies in patients with atopic dermatitis (NCT04081350) and psoriasis (NCT04119557).

About Nektar

Nektar Therapeutics is a biopharmaceutical company with a robust, wholly owned R&D pipeline of investigational medicines in oncology and immunology as well as a portfolio of approved partnered medicines. 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

1.    CLASI-A: cutaneous lupus erythematosus disease area and severity index – activity

SOURCE: Nektar Therapeutics