Monoclonal antibodies to two epitopes of beta-human chorionic gonadotropin for the treatment of cancer.

Human chorionic gonadotropin (hCG) is expressed by many histological types of cancer and may play an important role in tumor maintenance and progression. Vaccination of patients with the therapeutic peptide Avicine (CTP37; AVI BioPharma Inc/SuperGen Inc), that contains 37 amino acids from the carboxyl terminus (CTP37; AVI BioPharma Inc/SuperGen Inc) of hCG, can result in two distinct antibody responses to separate epitopes within the peptide. Colorectal cancer patients who develop both anti-hCG responses show a significant improvement in median survival time. These observations provide a compelling rationale for the development of two human monoclonal antibodies (mAbs), one for each of the epitopes within the 37 amino acid peptide region of hCG. Two such human mAbs, both exhibiting a high degree of specificity and affinity have been prepared using XenoMouse technology. These mAbs may prove useful in multiple clinical settings for the treatment of various cancers. Treatment options may include passive immunotherapy with both mAbs, mixed passive supplement to active specific immunotherapy with Avicine and conjugation of the mAbs with radioisotopes or cytotoxic drugs. The requirement for dual mAb therapy is consistent with current trends in the development of complex, non-toxic therapies for cancer.