[Complete response provided by new antitumor agent, MST-16 (sobuzoxane), in a breast cancer with multiple cutaneous...

A case of recurrent breast carcinoma was successfully treated with MST-16 in an early phase II study. A 60-year-old woman developed skin metastases on the forehead, neck, abdomen and back 8 months after receiving standard radical mastectomy for right breast carcinoma. MST-16 was given p.o. at the dose of 1,200 mg/body/day initially, and the dosage was modified thereafter depending on the grade of leukopenia. All metastatic lesions disappeared completely 38 weeks after the initiation of the treatment. The CR thus obtained has continued for 8 months up to the present. Although leukopenia was observed during the administration of MST-16, it could be well managed by dose modification. Further trials with this drug for breast carcinoma should be conducted, since complete responses are expected with few adverse effects as in the case under study.