A substance that is used to treat rheumatoid arthritis, and is being studied in the treatment of cancer. Anakinra blocks the action of interleukin 1 (IL-1). It is a type of interleukin receptor antagonist. Also called Kinaret. OR A recombinant human nonglycosylated interleukin-1 (IL-1) receptor antagonist with potential antineoplastic activity. Anakinra binds to the IL-1 receptor, thereby blocking the binding of the IL-1 to and activation of its receptor. Blockade of IL-1 activity may inhibit the cascade of downstream pro-angiogenic factors such as vascular endothelial cell growth factor, tumor necrosis factor-alpha, and IL-6, resulting in inhibition of tumor angiogenesis.