Study of Vintafolide (MK-8109, EC145) in Participants With Advanced Ovarian and Endometrial Cancers (MK-8109-007, EC-FV-02)

Part A: Induction Phase: vintafolide 1.0 mg intravenous injection, Monday through Friday, for the first 3 weeks of each 4 week cycle. Maintenance Phase: vintafolide 2.5 mg intravenous injection, Monday, Wednesday and Friday, weeks 1 and 3 of each 4 week cycle. At the investigator's discretion, participants may receive vintafolide via an ambulatory pump after the first week of therapy has been administered in the clinic setting. Part B: vintafolide 2.5 mg intravenous injection, Monday, Wednesday and Friday, weeks 1 and 3 of each 4 week cycle. At the investigator's discretion, participants may receive vintafolide via an ambulatory pump after the first week of therapy has been administered in the clinic setting.