The primary objective of this study is to assess the safety and tolerability and to determine the recommended Phase 2 dose (RP2D) of E7386 in combination with other anticancer drug(s), and to determine the optimal dose of E7386 in combination with lenvatinib in endometrial carcinoma (EC) (for EC Dose Optimization Part only).

This phase III trial studies how well active surveillance help doctors to monitor subjects with low risk germ cell tumors for recurrence after their tumor is removed. When the germ cell tumor has spread outside of the organ in which it developed, it is considered metastatic. Chemotherapy drugs, such as bleomycin, carboplatin, etoposide, and cisplatin, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. The trial studies whether carboplatin or cisplatin is the preferred chemotherapy to use in treating metastatic standard risk germ cell tumors.