Review our novel molecules

Learn how Nektar is enhancing the science of immuno-oncology. We are developing molecules designed to activate the immunity cycle and generate antitumor immune responses.

Image of BEMPEG molecule

Bempegaldesleukin (BEMPEG)—NKTR-214

Nektar’s late-stage immuno-oncology candidate

BEMPEG is a first-in-class CD122-preferential IL-2 pathway agonist designed to stimulate the patient's own immune system to fight cancer. BEMPEG is designed to grow specific cancer-killing T cells and natural killer (NK) cell populations in the body which fight cancer, which are known as endogenous tumor-infiltrating lymphocytes (TILs). BEMPEG stimulates these 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.1

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Image of NKTR-255 molecule


NKTR-255 is an IL-15 receptor agonist designed to engage the IL-15 pathway to stimulate the proliferation and cytotoxic functions of NK cells and promote the proliferation and survival of memory CD8+ T cells, without inducing suppressive regulatory T cells.

Through optimal engagement of the IL-15Rα/IL-2Rβγ receptor complex, NKTR-255 enhances functional NK cell repopulation and formation of long-term immunological memory, which may lead to sustained antitumor immune response. NKTR-255 is uniquely designed to overcome the challenges of recombinant IL-15, which is rapidly cleared from the body and in high doses, limiting its utility due to toxicity and convenience of use.2

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Image of NKTR-262 molecule


NKTR-262 is a novel small molecule agonist designed to activate toll-like receptors (TLR) 7/8. Intratumoral delivery of NKTR-262 promotes TLR 7/8 activation to induce the development of antigen-specific immunity by initiating the process by which the immune system generates antigen-specific cytotoxic T cells to the patient’s specific tumor.3

BEMPEG targets CD122 specific receptors found on the surface of these cancer-killing immune cells, known as CD8+ effector T cells. By first generating antigen-specific cytotoxic T cells with NKTR-262 and then growing these CD8+ effector T cells with BEMPEG, the patient’s entire immunity cycle can potentially be engaged to fight cancer.1

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References: 1. Diab A, Marcondes M, Kotzin B, et al. REVEAL: A phase 1/2, open-label, multicenter, dose escalation and dose expansion study of NKTR-262 [TLR 7/8 agonist] plus NKTR-214 [CD122-biased agonist] with or without nivolumab (nivo) in patients (pts) with locally advanced or metastatic solid tumor malignancies. Presented at: European Society for Medical Oncology annual meeting. October 19-23, 2018; Munich, Germany. 2. Robinson TO, Schluns KS. The potential and promise of IL-15 in immuno-oncogenic therapies. Immunol Lett. 2017;190:159-168. 3. Adams S. Toll-like receptor agonists in cancer therapy. Immunotherapy. 2009;1(6):949-964. doi:10.2217/imt.09.70.