Targeting Medullary Thyroid Carcinomas with Bispecific Antibodies and Bivalent Haptens

Abstract

The present article reviews the clinical trials that have been performed in recurrent medullary thyroid carcinoma patients with the Affinity Enhancement System. This technique uses bispecific antibodies to target radiolabelled bivalent haptens to tumour cells. Its sensitivity in the detection of known tumour sites is high (90%) and this technique also achieves good sensitivity (61 %) in the detection of occult disease as revealed by abnormal thyrocalciton in blood levels. Due to its high targeting capacity, this technique is now considered for use as a therapeutic agent in medullary thyroid carcinoma patients.

Molecular tools for targeted imaging and therapy of cancer

“…Antibodies with dual binding specificity have been prepared which can, for example, cross-link tumor cells to cytokines such as tumor necrosis factor (Robert et al, 1996). Likewise, bispecific antibodies that can bind to tumors and to metal chelates have been developed (Stickney et al, 1991;Rouvier et al, 1997). When pretargeted to tumors, these bispecific antibodies bind to antigens and remain on the target, providing receptors for metal chelates.…”

“…The multivalent binding of antibody IgG molecules to cell surfaces can lead to bound lifetimes of several days (Goodwin and Meares, 1997), and modern bifunctional chelating agents hold their metals for even longer periods (Li and Meares, 1993), so the most important challenge is to increase the antibody-hapten bound lifetime. Bivalent haptens provide some improvement (Rouvier et al, 1997;Goodwin et al, 1992;Sharkey et al, 2003).…”