Clinical testing of the radiosensitiser Ro-07-0582 III. Response of tumours

The nitro-imidazole Ro-07-0582, a known radiosensitiser of hypoxic cells in animals, was administered orally to seven patients with metastatic tumour, before irradiation. The delay imposed on the growth of tumour treated in this way was compared to that of tumour in the same patient treated with radiation alone. Two patients died before any assessment of response could be made. Qualitative evidence from a further three patients suggested some enhancement of radiation effect in two patients but not in the third. Quantitative evidence was obtained from the remaining two patients. In one, a patient with multiple pulmonary metastases from a carcinoma of the breast, no enhancement was shown. In the other, a patient in whom 21 subcutaneous metastases from a carcinoma of the cervix of the uterus were measured, an enhancement ratio of 1·2 was found. This agrees with the value from the same patient's skin when rendered artificially hypoxic, as reported previously. The conditions under which quantitative information may best be obtained in this type of trial are described and various factors affecting the interpretation of results are discussed. Ro-07-0582 has thus been shown to have a radiosensitising effect in man and may therefore prove of value in radiotherapy.