This clinical trial is focused on studying a rare type of cancer called small cell ovarian carcinoma of hypercalcemic type. The study will explore the effects of a treatment combination that includes the medication pembrolizumab, known by its brand name Keytruda, along with a chemotherapy regimen based on etoposide and cisplatin. These medications are administered as solutions for infusion, which means they are given directly into the bloodstream through a vein.

The purpose of the study is to estimate how well this combination treatment works in achieving a complete response, which means the disappearance of all signs of cancer in response to treatment. Participants will receive the treatment over several cycles, with each cycle involving the administration of the medications. The study is designed to observe the effects of the treatment over time, without using a placebo group. The trial will also monitor the safety of the treatment and document its effectiveness using a standard method called RECIST 1.1, which is a set of rules used to measure how well a cancer treatment works.

This study is non-randomized, meaning all participants will receive the same treatment without being randomly assigned to different groups. It is a phase II trial, which means it is focused on assessing the effectiveness of the treatment and gathering more information about its safety. The trial is multicentric, indicating that it will be conducted at multiple centers or locations. The study aims to provide valuable insights into the potential benefits of combining pembrolizumab with etoposide and cisplatin for treating this specific type of ovarian cancer.