211At-81C6-mAb (anti tenascin, human/mouse chimeric antibody) is a radiotherapeutic based on 81C6, a chimeric monoclonal antibody, known to seek out and bind specifically to brain cancer cells. This antibody labeled with 211At was tested in the intra-cavitary treatment of brain tumors. More than 100 brain tumor patients have already been treated with 131I-labeled murine 81C6 mAb, with results demonstrating excellent retention of radionuclide within the surgically created (tumor) resection cavities (SCRC).

As this compound was the first 211At-labeled compound injected in human, extensive studies were made prior to application to confirm the limit of dose for astatine (Duke University). This set of toxicology data is now used as the basis for any other 211At-labeled compound.

In 2005-2007, 18 patients with recurrent malignant brain tumors were treated with 211At-81C6 mAb (escalating dose, 2 to 10 mCi, intra-lesional application). In this Phase I study, besides the confirmation of the safety of the therapeutic, clinicians observed an extended survival rate, ranging from an average of 52 weeks to 3 years, compared to 26 weeks for most recurrent brain tumor patients.

The study described above was the only one performed with this compound and the recruitment was completed in 2005. Since then no other study has been performed as a consequence of lack of funds.