A phase III double-blind randomized trial is planned to compare a new drug versus placebo as adjuvant therapy for the treatment of women with metastatic ovarian cancer who have had complete clinical response to their primary treatment protocol, consisting of surgical debulking and platium-based chemotherapy. Find the total sample size needed using a two-sided test at the 0.05 level of significance and a statistical power of 80% to detect the alternative hypothesis that the two-year relapse rates in the placebo and the new drug arms are 60% and 40%, respectively.