This study is looking at how well a new drug called **Rina-S** works for people with a type of cancer called **endometrial cancer (EC)**, which affects the lining of the uterus. Participants will either get Rina-S or a standard treatment chosen by their doctor, like **paclitaxel** or **doxorubicin**. These are types of chemotherapy, which use strong drugs to kill cancer cells. The study will last for about 3 years, but most people will get treatment for 4 to 6 months. Everyone in the study will receive real medicine, not a placebo (a fake treatment). The study requires visits to a medical site.

• The study lasts approximately 3 years with treatment lasting 4 to 6 months.
• Participants will either receive the new drug Rina-S or a standard treatment.
• Participation involves visits to the study site.