CEACAM5 and medullary thyroid gland carcinoma: A phase I/II clinical trial was implemented in 1996 to evaluate toxicity, pharmacokinetics, dosimetry, and antitumor activity, using the murine anti-CEA bispecific antibody F6x734 and the bivalent indium-DTPA hapten labeled with iodine-131 in 26 patients with recurrence of MTC (Kraeber-Bodéré et al., 1999b).