Thymosin Apha 1–A Peptide Immune Modulator with a Broad Range of Clinical Applications

Abstract

Thymosin alpha 1 (thymalfasin, Ta1), the active ingredient in ZADAXIN ® , is a peptidic biological response modifier which activates various cells of the immune system. Ta1 is therefore expected to have clinical benefits in disorders where immune responses are impaired or ineffective, such as acute and chronic infections, cancers, and vaccine non-responsiveness, all of which are hallmarks of an impaired or inadequate immune response. Importantly, Ta1 acts without overstimulation of cytokine production and is generally well tolerated; it has an excellent safety profile and does not appear to induce the side effects and toxicities commonly associated with agents in this class such as interferon-alpha and interleukin-2. Ta1 has been shown to act through Toll-like receptors, linking to intracellular cell-signaling pathways and leading to stimulation of the immune system, including T helper cells, cytotoxic T cells, and natural killer cells. Clinical studies with Ta1 have been conducted and shown evidence of benefit in subjects with acute or chronic viral or bacterial infections, including subjects with severe sepsis, infections after bone marrow transplant, chronic hepatitis B or C, or acquired immune deficiency syndrome. Ta1 has also shown promise in clinical evaluation as an adjunctive treatment in subjects suffering from various types of cancer, including hepatocellular carcinoma, non-small-cell lung cancer, melanoma, renal, breast and gastric cancers; and in subjects receiving vaccines (geriatric subjects receiving influenza vaccine and subjects with renal failure receiving influenza or hepatitis vaccine).