This study involves patients with certain types of cancer, specifically ovarian cancer, fallopian tube cancer, cancer of the lining of the abdomen called primary peritoneal cancer, and endometrial cancer. These cancers have returned or grown after previous treatment. The study uses several medications. The main treatment being tested is ubamatamab, also known by its code name REGN4018, which is a type of medicine designed to help the immune system attack cancer cells. This medication may be given alone or together with another medication called cemiplimab, which also works with the immune system to fight cancer. Some patients may receive sarilumab, marketed as Kevzara, or tocilizumab to help manage side effects. These medications are given either through injection under the skin or through a vein.
The study has two main parts. The first part aims to find the right dose of ubamatamab when given alone or with cemiplimab by checking how safe it is and how the body processes the medication. The second part looks at how well these treatments work in shrinking or controlling the cancer. For patients with ovarian, fallopian tube, or primary peritoneal cancer, they must have received at least one previous treatment with platinum-based chemotherapy and have cancer that has returned or is no longer responding to treatment. For patients with endometrial cancer, they must have previously received treatment with a type of immune therapy and platinum-based chemotherapy, and their cancer must show a certain protein marker called MUC16 in at least one quarter of the tumor cells.
During the study, patients will receive their assigned treatment and be monitored regularly for side effects and to see how their cancer responds. Doctors will use scans and blood tests to check if the cancer is shrinking, staying the same, or growing. The study will also measure how the treatment affects quality of life and daily functioning through questionnaires. Blood samples will be taken to measure the amount of medication in the body and to check if the body develops any reaction to the medications. The study will continue until enough information is gathered about the safety and effectiveness of these treatments.



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