Definition

A soluble, recombinant human heterodimer composed of the cytokine interleukin (IL)-15 and the IL-15 receptor alpha (IL-15Ra), with potential antineoplastic activity. Upon subcutaneous administration, the IL-15/IL-15Ra heterodimer (hetIL-15) NIZ985 targets and binds to interleukin-2 (IL-2)/IL-15 receptor beta/gamma. This activates and increases the levels of natural killer (NK) cells and memory CD8+ T cells. The memory T cells enhance the secretion of the cytokine interferon-gamma (IFN-g), which further potentiates the immune response against tumor cells. This may increase tumor cell killing and decrease tumor cell proliferation. IL-15 regulates CD8+ T- and NK-cell development, activation and proliferation. NIZ985 does not require endogenous IL-15Ra for its activation.