Monoclonal antibodies and their fragments in cancer treatment

During the last 15 years, various antibodies specific for antigens associat ed with determined types of cancer have been used therapeutically, includin g some in unlabeled forms as immune effectors. The results of clinical stud ies have been unpromising for patients with colorectal cancer at the advanc ed metastatic stage but much more favorable in terms of increased survival for the adjuvant situations of residual microscopic disease. Antibodies hav e also been used as carriers for cytotoxic substances, but with rather disa ppointing clinical results when they were labeled with toxins or antimitoti c agents. The results have been variable for labeling with radionuclides (m ainly iodine-131), sometimes proving quite favorable for refractory forms o f non-hodgkin's lymphomas or acute leukemias. In this last indication, radi oimmunotherapy has been associated with chemotherapy to enhance action befo re a bone-marrow graft. However, the clinical results have been disappointi ng in the treatment of solid tumors, showing responses only in the case of small targets. In the future, treatment with antibodies will focus on micro scopic tumors, in association with other therapeutic modalities especially, chemotherapy and biotherapy.