A phase II study of KW2083 [7-N-(p-Hydroxyphenyl)-Mitomycin C], a derivative of Mitomycin C, was carried out in 20 patients with carcinoma of the lung and in 19 patients with metastatic pulmonary tumor. KW2083 was administered by single intravenous injection at a dose of 20-30 mg/m2 weekly or a single 70 mg/m2 dose. Patients treated with a dose of 20-30 mg/m2 should be given at least 3 doses for eligibility. Of 17 evaluable patients with carcinoma of the lung (11 adenocarcinomas, 3 squamous cell carcinomas, 2 small cell carcinomas and 1 large cell carcinoma), two patients with adenocarcinoma showed a partial response (11.8%). Two patients who achieved PR had adenocarcinoma without prior therapy received KW2083 at a single dose of 70 mg/m2 Objective response rates were 18.2% for 11 patients with adenocarcinoma and 25% for 8 patients with adenocarcinoma treated with a single dose of 70 mg/m2 of 15 evaluable patients with metastatic pulmonary tumor, no patients showed any objective responses. The hematologic toxicities were thrombocytopenia (less than 5 X 10(4)/mm3, 41.6%) and leukocytopenia (less than 2000/mm3, 28.1%); it was observed in 19% of the patients, that thrombocytopenia continued for more than 6 weeks after stopping therapy. Gastrointestinal symptoms such as anorexia (81%), nausea (66%) and vomiting (16%) were severe in patients treated with a single dose of 70 mg/m2. Fever in 19%, alopecia in 13%, phlebitis in 9%, eruption in 6%, stomatitis in 6% and liver insufficiency in 13% were also observed.