This trial is studying the overall survival of patients taking carboplatin, paclitaxel, and bevacizumab to see how well they work compared to carboplatin, paclitaxel, and placebo in treating patients with stage III or stage IV ovarian epithelial or primary peritoneal cancer.

This study may help determine whether bevacizumab, when given in combination with carboplatin and gemcitabine, is safe, able to delay tumor growth, shrink tumors, or affect how long people with platinum-sensitive ovarian, peritoneal, or fallopian tube cancer live.