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Antibody-based radiopharmaceuticals are of increasing interest today in cancer imaging and radiotherapy. The cetuximab monoclonal antibody binds to the epidermal growth factor receptor (EGFR) and thus provides therapeutic and diagnostic protocols against this receptor. Following purification and conjugation with freshly prepared DOTA-NHS, the cetuximab antibody was labeled with lutetium 177 and samarium chloride-153. Labeling efficiency and in vitro stability were measured using thin-layer chromatography. Cellular tests were performed to determine radioimmunoactivity in cancer cells. The results showed that the labeling efficiencies of 177Lu-DOTA-cetuximab and 153Sm-DOTA-cetuximab were more than 97±1% and 96±2%, respectively. Also, the in vitro stability of the labeled products in fresh human serum after 96 hours was 83± 22% and 78%, respectively. Immunoreactivity was 91% for 177Lu-DOTA-cetuximab and 66±1% for 153Sm-DOTA-cetuximab. With different intensities based on time and beta energy, both products inhibited the growth of HT29 colon cancer cells. The results showed that the immunoconjugate complexes of 177Lu-DOTA-cetuximab and 153Sm-DOTA-cetuximab can be considered a novel radiopharmaceutical for cancer radioimmunotherapy.

Purpose: The purpose of this study is to assess the efficacy of 153Sm-EDTMP (Quadramet®) in a clinical setting.Methods: We have conducted a retrospective study of all consecutive patients (pts) treated with 153Sm-EDTMP for painful bone metastases. At each visit (before and after treatment), four parameters were collected: (i) pain assessment according to the 10-step visual analogue scale (VAS), (ii) sleep disturbance related to pain, (iii) dose of analgesic medication, and (iv) answer to the following closed question "Do you think you obtained a benefit from treatment?" Success of treatment was defined by the combination of these four parameters.Results: Three hundred seventy consecutive 153Sm-EDTMP treatments for painful bone metastases were given. Patients had the following primary tumors: breast carcinoma (153), prostate carcinoma (155), lung carcinoma (27), or other cancers (35). Fifty-eight percent of the patients had received previous external osseous radiotherapy. Ninety-seven percent of the patients were treated with concomitant analgesics and 61% were treated with diphosphonates. A clinical benefit was described in 55.0% of cases at D30. Treatment was more effective in cases of breast and prostate cancers compared with other types of primary cancers. Patients described a benefit at D30 in 62, 58, 6, and 38% of cases of breast, prostate, lung, and other cancers. The subjective efficacy was accompanied by a decrease in analgesic intake in 35.0% of cases.Conclusion: 153Sm-EDTMP therapy is an effective supportive treatment in patients who suffer from bone metastases, especially in patients with breast or prostate cancer. [ABSTRACT FROM AUTHOR]