Testing the Addition of Herceptin Hylecta or Phesgo to the Usual Chemotherapy for HER2 Positive Endometrial Serous Carcinoma or Carcinosarcoma

This phase III trial tests whether adding trastuzumab and hyaluronidase-oysk (Herceptin Hylecta \[TM\]) or pertuzumab, trastuzumab and hyaluronidase-zzxf (Phesgo \[TM\]) to the usual chemotherapy (paclitaxel and carboplatin) works to shrink tumors in patients with HER2 positive endometrial cancer. Trastuzumab and pertuzumab are monoclonal antibodies and forms of targeted therapy that attach to specific molecules (receptors) on the surface of tumor cells, known as HER2 receptors. When trastuzumab or pertuzumab attach to HER2 receptors, the signals that tell the cells to grow are blocked and the tumor cell may be marked for destruction by the body's immune system. Hyaluronidase is an endoglycosidase. It helps to keep pertuzumab and trastuzumab in the body longer, so that these medications will have a greater effect. Hyaluronidase also allows trastuzumab and trastuzumab/pertuzumab to be given by injection under the skin and shortens their administration time compared to trastuzumab or pertuzumab alone. Paclitaxel is a taxane and in a class of medications called antimicrotubule agents. It stops tumor cells from growing and dividing and may kill them. Carboplatin is in a class of medications known as platinum-containing compounds. It works in a way similar to the anticancer drug cisplatin, but may be better tolerated than cisplatin. Carboplatin works by killing, stopping or slowing the growth of tumor cells. Giving Herceptin Hylecta or Phesgo in combination with paclitaxel and carboplatin may shrink the tumor and prevent the cancer from coming back in patients with HER2 positive endometrial cancer.