A Clinical Trial to Evaluate the Safety and Efficacy of COM701 in Relapsed Platinum Sensitive Ovarian Cancer

The goal of this clinical trial is to learn if the experimental antibody COM701 delays the progression of ovarian cancer in participants with Relapsed Platinum Sensitive Ovarian Cancer. It will also learn about the safety of COM701. The main questions the trial aims to answer are: * Does COM701, when used as a maintenance treatment, stop or slow the progression of ovarian cancer? * Does COM701 delay the time to needing a new anti-cancer treatment? * What side effects do participants have when taking COM701? Participants will: * Visit the clinic once every 3 weeks during which the study treatment will be administered intravenously * Undergo various tests and procedures to monitor general health throughout the trial including physical examinations, vital sign measurements (heart rate, blood pressure, breathing, and body temperature), weight measurements, electrocardiography (ECG), blood and urine tests and pregnancy tests if relevant. * Undergo various tests and procedures to assess disease response throughout the trial including tumor imaging by CT scans or MRI to assess the tumor, its location, and size, and the testing of a sample of tumor tissue (from a prior biopsy or a fresh biopsy if feasible, to evaluate tumor response to treatment and to measure levels of tumor markers,

Trial CPG-01-201 is an adaptive-platform trial comprised of multiple sub-studies. Sub-study 1 will be a parallel group, double-blind, randomized placebo-controlled trial in which participants will be randomized in a 1:2 ratio to either placebo (a look-alike substance that contains no drug) or COM701 treatment arms. This means that there is a 33% chance of being placed in the group getting placebo and a 67% chance of being placed in the group that will get the experimental COM701 antibody. Subsequent sub-studies will evaluate COM701 in combination with other anti-cancer drugs.