Phase II evaluation of pyrazofurin in patients with metastatic sarcoma

Twenty-seven patients with metastatic sarcoma were treated with weekly doses of iv pyrazofurin. No patient experienced a major therapeutic response; dose-limiting toxic effects included mucositis and anemia not associated with hemorrhage. Although routine studies (haptoglobin, reticulocyte counts, lactic dehydrogenase, bilirubin, and Coombs' tests) did not reveal evidence of hemolysis, this possibility cannot be ruled out at this time. Preliminary studies by Dyke et al have indicated a decrease in survival of ⁵¹Cr-labeled rbcs in a pyrazofurin-treated patient when compared with a pretreatment study. Although all patients treated in the present trial had received prior chemotherapy, their general physical condition was good enough to allow outpatient management. With failure to achieve a partial remission in this number of patients, it can be concluded that pyrozofurin is likely to have a true major response rate of <15% (P=0.05)(9) and it would appear to have little therapeutic value in this schedule as a single agent in previously treated patients with advanced metastatic sarcoma.