Isoprinosine (Inosiplex): Immunological and Clinical Effects

Summary

Immunological and clincial properties of isoprinosine are reviewed. Isoprinosine increases in vitro T cell function macrophage activity. It induces the appearance of T cell markers and enhances the lymphocyte response to mitogens. This property appears to be due to the synthesis of a mitogenic helper factor by isoprinosine-treated lymphocytes probably interleukin 2. In vivo, it also increases antibody formation, T cell functions and macrophage activity. It restores T cell immunosuppression in post-radiotherapy cancer patients and the lymphocyte response to mitogens in cancer. It potentiates the antiviral and antitumor activity of interferon. It delays the early appearance of autoimmunity and the early tumor development of interferon treated NZB-NZW mice suggesting a potential benefit in autoimmune syndromes.

Clinically, isoprinosine, in open studies, has been shown to be beneficial in various viral diseases like subacute sclerosing panencephalitis, cutaneous herpes and aphthous stomatitis, influenza challenge, cytomegalovirus hepatitis, Reiter Syndrome and possibly warts. Isoprinosine also shows promising results in rheumatoid arthritis where clinical improvement has been observed two to six weeks after the onset of treatment. Immune monitoring performed in patients receiving isoprinosine suggests a modification of the inducer-suppressor/cytotoxic phenotypes of blood lymphocytes.

In summary, isoprinosine is a synthetic immunomodulatory agent with activities responding to the criteria of a biological response modifier. It is likely that its immunological properties explain partially or totally its clinical beneficial effects.