In 1976, Russian investigators reported findings from 95 patients with advanced cancer who had been treated with hydrazine sulfate after all previous therapy (surgery, chemotherapy, and/or radiation therapy) had failed. Three partial responses (i.e., reductions in tumor size of greater than 50% observed for a period of 4 weeks or more) and no complete responses were noted after 1 to 5 months of treatment. Tumor regressions of 50% or less and stable disease (i.e., cessation of tumor growth for a period of 1.5 to 2.0 months or more) were reported for 16 and 20 patients, respectively.
In 1981, the same investigators published findings from 225 patients with advanced disease who had been treated with hydrazine sulfate after all previous therapy had failed. It appears that the 225 patients described in this second report  included the 95 patients described in the first report. Partial responses and stable disease were reported for 4 and 95 patients, respectively, after 1 to 6 months of treatment. No patient experienced a complete response. Subjective improvements in appetite, weight stabilization or gain, pain, fever, breathing, and/or mental outlook were reported by 147 patients.
In 1995, the same Russian investigators published findings from 740 patients with advanced cancer. Once again, it appears that 225 of these 740 patients were described in the earlier reports.[9,10] Partial responses and stable disease were reported for 25 and 263 patients, respectively. Complete responses were noted for six patients. Subjective improvements in cancer-related symptoms were reported by 344 patients.
In 1994, the same investigators reported findings from a clinical series involving 46 patients with malignant brain tumors (38 with glioblastomas, four with astrocytomas, and four with meningiomas) and six patients with benign brain tumors. These patients were not described in the other reports.[7,9,10] All patients in this series appear to have been treated with surgery in addition to hydrazine sulfate therapy, and at least some of the patients were also treated with radiation therapy. Complete or partial regression of neurologic symptoms (e.g., seizures, headaches, sensory and motor disorders, and hallucinations) was reported for 73% of the patients. In addition, longer-than-average survival was reported for most patients. Among the patients with glioblastomas, the increase in average survival time was from 6 months to more than 13 months.