[Immunotherapy and cancer: the role of monoclonal antibodies]

Monoclonal antibodies, produced in vitro from hybridoma supernatants, may be administered to cancer patients either directly or after coupling to an anticancer agent (immunoconjugates). Monoclonal antibodies concentrate in tumor site, where they initiate an anti-tumor effect, either by activation of the patient's immune system or by the cytotoxic agent which is present at high concentration within the tumor, while systemic concentrations of this agent remain low. Monoclonal antibodies which are radiolabelled also allow the immunoscintigraphic study of the immunoconjugates' diffusion within the body. Given certain precautions of administration, the clinical and biological tolerance of this type of treatment is satisfactory, most of the side effects correspond to an allergic response to the murine antibodies used. Clinical studies performed in patients with leukemias have demonstrated a significant antitumor effect although this effect is transitory. Studies performed on small series of patients with solid tumors (gastrointestinal neoplasms, melanoma, leptomeningeal localizations, ovarian peritoneal carcinosis) have shown a few cases of major responses and/or complete remissions having lasted up to periods of many months. These studies as well as the perspectives for the development of this type of therapy are presented and discussed.