It has been shown in phase II studies that 254-S, a new anticancer platinum complex, is effective in the treatment of various cancers. In order to more objectively evaluate the clinical usefulness of this compound, a randomized comparative study of 254-S plus VDS vs. CDDP plus VDS was conducted in patients with advanced NSCLC. 254-S or CDDP was intravenously administered at 90 mg/m2, at least 2 times at 4-week intervals. VDS was intravenously administered at 3 mg/m2 on Days 1 and 8 of each treatment of 254-S or CDDP. Of 136 patients registered, 121 (64 of the 254-S/VDS group and 57 of the CDDP/VDS group) were evaluable for tumor response (complete cases). There was no significant intergroup difference in the tumor response rate (254-S/VDS group: 12.5% [8/64], CDDP/VDS group: 15.8% [9/57]), nor by cancer staging, histological type or survival. As for toxic effects, leukopenia was significantly less frequent in the 254-S/VDS group while thrombocytopenia was significantly less frequent in the CDDP/VDS group. Nephrotoxicity such as an elevation of BUN and a decrease in serum creatinine was significantly less frequent in the 254-S/VDS group in spite of the lower volume hydration performed. In addition, nausea and vomiting as well as anorexia were observed with significantly lower incidences in the 254-S/VDS group despite the less frequent anti-emetic treatment. Based on these results, it was concluded that combination treatment with 254-S and VDS is a safe and useful regimen for treatment of NSCLC, generating antitumor effects equivalent to the CDDP/VDS regimen.