OUTLINE: This is a randomized, double-blind, placebo-controlled study. Patients are stratified according to disease status (newly diagnosed vs recurrent) and ECOG status (0 vs 1). Patients are randomized to 1 of 2 treatment arms. Arm I: Patients receive monoclonal antibody C225 IV over 2 hours followed 1 hour later by cisplatin IV over 2 hours on day 1 of course 1. Monoclonal antibody C225 is administered over 1 hour on subsequent courses. Arm II: Patients receive placebo IV over 2 hours followed 1 hour later by cisplatin as in arm I on day 1 of course 1. Placebo is administered over 1 hour on subsequent courses. Treatment continues every 4 weeks for at least 6 courses in the absence of disease progression or unacceptable toxicity. Arm II patients who develop disease progression may then crossover to arm I treatment. Patients are followed at 1 and 3 months and then every 3 months until disease progression.