[Phase I-II study of 7-N-(P-hydroxyphenyl)-mitomycin C (KW2083, M83)]

A phase I-II study of KW2083, an analog of mitomycin C (MMC) was performed in a total of 22 patients. KW2083 was escalated by single intravenous administration of 40, 50, 60, 70, and 80 mg/m2 doses. Treatments were repeated every 4-6 weeks unless unacceptable toxicities occurred. The median times taken to reach nadir for each dose level were 9-12 days for leukocytes and 7-13 days for platelets respectively. The median times taken for recovery were 8-22 days for leukopenia and 10-37 days for thrombocytopenia. Variable and non-predictable hematological toxicity was observed in some cases. Biphasic hematological toxicity was observed in 4 courses. Acute toxicity occurred in 17 courses for 11 patients and consisted of nausea (44%), vomiting (13%), diarrhea (2.7%) and stomatitis (2.7%). Nephrotoxicity (elevation of BUN, 8.1% and proteinuria, 5.4%) occurred in 3 patients who had no previous impairment of renal function. Alopecia (8.1%) was also observed. Marked elevations of hepatic enzymes were noted in one patient who developed acute fulminant hepatitis with the second dose of KW2083. Objective response was observed in one of 20 evaluable patients. From this preliminary study, the maximum tolerable dose is 70 mg/m2 and the optimal dose of KW2083 was determined to be 50 mg/m2 at 6-week intervals. KW2083 has been introduced as an MMC analog of potential interest. However, hematological and non of hematological toxicities are very similar to those of MMC and does not appear that KW2083 will supersede MMC.