Treatment of metastatic colorectal cancer by means of specific monoclonal antibodies conjugated with iodine-131: a phase II study.

Eighteen consecutive patients with advanced and/or metastatic colorectal carcinoma have been treated with intraperitoneal administration of radiolabelled (iodine-131) monoclonal antibodies raised against different antigens associated to these kinds of tumours: anti-CEA FO23C5, anti-CEA BW494/32, anti-TAG B72.3, AUA1. The doses of isotope ranged between 21 and 150 mCi (777-5550 MBq) which delivered a radiation dose to the target tumour from 768 to 4628 cGy. Thirteen patients were previously treated with conventional regimens which consisted of chemotherapy (5-fluoracil with or without other anti-neoplastic drugs) both in adjuvant or palliative setting. Three patients are considered non-evaluable owing to concomitant chemotherapy in 2 and lack of objective parameters in 1. Out of 15 evaluable patients 2 achieved complete remission and 2 partial remission with a response rate of 26.6%. Three stable and 8 with progressive disease have also been registered. The toxicity was negligible consisting of hematologic WHO grade 1 in 7 patients, grade 2 in 1 patient and grade 3 in 1 patient, as well as hepatic WHO grade 1 in 8 and grade 2 in 2 patients. The authors conclude that this innovative way of treatment for advanced colorectal carcinoma seems to offer promising therapy; from these data, therefore, a new trial is justified employing radiolabelled MoAbs in well selected patients with metastatic or locally advanced colorectal carcinoma.

Radioimmunotherapy trials in germ testicular carcinoma: a phase I study.

Two patients with germ cell testicular cancer were submitted to radioimmunotherapy (RIT) by using the monoclonal antibody 131I-radiolabelled (MoAb) H17E2, raised against placental alkaline phosphatase (PLAP). Both patients had been previously treated with repeated chemotherapy regimens assisted by autologous bone marrow transplant (ABMT), that, in the end were unsuccessful, thus necessitating further experimental treatment. RIT was well tolerated and the targeting of multiple neoplastic lesions was satisfactory. Nevertheless, the clinical results of treatment were minimal owing to the extension of the tumour. The data obtained suggest the possibility of applying this form of treatment in patients with minimal residual disease after previous traditional chemotherapy regimens.