Clinical study of radioprotective effects of YM-08310 in patients with carcinoma of the cervix uteri

To assess the radioprotective effect of YM-08310 (S-2-[3-aminopropylamino] ethylphosphorothioic acid, WR-2721) on improvement of subjective and objective symptoms, a controlled trial has been performed on 60 patients with carcinoma of the cervix uteri initially undergoing radical and postoperative pelvic radiotherapy. Patients were divided by turns into two groups with and without the radioprotective drug, i.e. the YM-group and the control. Doses of 2 mg/kg of the drug and 0.2 ml/kg of the saline solution were injected intravenously with patients in the YM-group and the control respectively 30 minutes before radiotherapy. There was no improvement in anorexia and/or nausea. The incidence of diarrhea was, however, about 10% lower in the YM-group than in the control. Counts of erythrocytes and amounts of hemoglobin were essentially unchanged in both groups during radiotherapy. The counts of thrombocytes, leukocytes, lymphocytes and their subpopulations (T cells and B cells) fell after treatment and remained depressed 2 to 3 months and 10 to 14 months following treatment. However, all of them but B cells kept the mean values of cell counts consistently higher in the YM-group than in the control. Especially for those of thrombocytes at 30 Gy and 50 Gy and T cells at 30 Gy there were statistically significant differences between these two groups. On the other hand the mean of B cell counts in both groups varied with a decrease and an increase of the same degrees during the course of radiotherapy and at follow-up. Radioprotective effect of YM-08310 on the tumor tissue was also studied by cytological and histological examinations at 40 Gy. There was no evidence of radioprotective effects on carcinoma of the cervix uteri. (J.P.N.)