A synthetic derivative of inosinic acid with antiretroviral and immunomodulatory activities. Rintatolimod acts through a number of pathways to stimulate the antiviral activity of the immune system. This agent stimulates interferon production; activates the oligoadenylate synthase-RNase L pathway; stimulates natural killer cell activity; and acts as a non-mitogenic stimulator of the immune system. Rintatolimod also inhibits replication of the human immunodeficiency virus (HIV) in vitro.