Guadecitabine and Pembrolizumab in Treating Patients With Recurrent Ovarian, Primary Peritoneal, or Fallopian Tube Cancer

The purpose of this study is to look at how patients respond to treatment with guadecitabine and pembrolizumab. The researchers will also be looking at the amount of time it takes for cancer to get worse when participants take the study drugs. All participants will be treated with guadecitabine and pembrolizumab. Guadecitabine interferes with the cancer cells' DNA and can increase the production of certain proteins, making cancer cells more recognizable by the immune system. Pembrolizumab helps your immune system to kill cancer cells. Thus the combination of guadecitabine and pembrolizumab may increase the ability of the immune system to eliminate cancer cells. Researchers want to find out whether the combination of guadecitabine and pembrolizumab is effective in treating ovarian cancer that has not responded to traditional chemotherapy. Participants will keep receiving treatment until their cancer gets worse, they have side effects, or they decide they don't want to receive the treatment anymore. After stopping treatment, the study doctor will watch participants for side effects and follow their condition every 6-12 weeks. The study aims to keep track of participants' medical conditions for the rest of their lives. This helps us look at the long-term effects of the study drugs.