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Study on the Safety and Effectiveness of REGN5668 with Cemiplimab or Ubamatamab for Patients with Ovarian, Fallopian Tube, or Primary Peritoneal Cancer

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying the safety and effectiveness of a new treatment for certain types of cancer, specifically Ovarian Cancer, Primary Peritoneal Cancer, and Fallopian Tube Cancer. The study involves a combination of medications, including REGN5668, Cemiplimab, and REGN4018. These medications are designed to work together to help the body's immune system fight cancer cells more effectively. REGN5668 is a bispecific antibody, which means it can bind to two different targets, potentially enhancing the immune response against cancer. Cemiplimab and REGN4018 are also antibodies that help the immune system recognize and attack cancer cells.

The purpose of this study is to determine the best dose of these medications when used together and to evaluate how well they work in treating the cancers mentioned. The study is divided into two phases: the Dose Escalation Phase and the Dose Expansion Phase. In the Dose Escalation Phase, researchers will focus on finding the safest and most effective dose of the medications. In the Dose Expansion Phase, they will look at how well the treatment works in a larger group of patients. Participants in the study may receive either the combination of REGN5668 with Cemiplimab or REGN5668 with REGN4018.

Throughout the study, participants will receive the medications through an intravenous infusion, which means the drugs are given directly into a vein. The study will monitor the participants for any side effects and measure how the cancer responds to the treatment. The trial aims to provide valuable information on the potential benefits of these new treatment combinations for patients with these specific types of cancer.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment

    Upon joining the study, an initial assessment will be conducted to confirm eligibility. This includes verifying a diagnosis of advanced epithelial ovarian cancer, primary peritoneal, or fallopian tube cancer, and ensuring previous treatment with at least one line of platinum-based therapy.

    Blood tests will be performed to check the serum CA-125 level and assess organ and bone marrow function. A performance status evaluation will also be conducted to ensure it is 0 or 1, indicating the ability to carry out daily activities.

  2. Step 2

    Dose escalation phase

    In this phase, the safety and tolerability of the medication REGN5668 will be assessed, both alone and in combination with cemiplimab or REGN4018. The goal is to determine the most appropriate dose for further study.

    You will receive the medication through an intravenous infusion, which means it will be administered directly into your vein. The frequency and duration of administration will be determined by the study team based on your response and any side effects experienced.

  3. Step 3

    Dose expansion phase

    Once the appropriate dose is identified, the study will move to the dose expansion phase. This phase aims to evaluate how well the medication works in treating the cancer.

    You will continue to receive the medication as determined in the previous phase. Regular assessments will be conducted to monitor the effectiveness of the treatment and any side effects.

  4. Step 4

    Regular monitoring

    Throughout the trial, regular monitoring will be conducted to assess your health and the effects of the treatment. This includes blood tests, imaging studies, and other evaluations as needed.

    The study team will closely observe for any adverse events or side effects, adjusting the treatment plan as necessary to ensure safety and effectiveness.

  5. Step 5

    End of trial

    At the end of the trial, a final assessment will be conducted to evaluate the overall response to the treatment. This will include a review of all collected data and any changes in your condition.

    You will be informed of the results and any potential next steps or follow-up care required.

Who can join the trial?

7 criteria

  • Has a confirmed diagnosis of advanced epithelial ovarian cancer, primary peritoneal cancer, or fallopian tube cancer. This means the cancer has been identified through specific medical tests.
  • Has received at least one treatment with a platinum-based therapy. This is a type of chemotherapy used to treat cancer.
  • Has a blood test showing a serum CA-125 level that is at least twice the normal limit. CA-125 is a protein that can be a marker for ovarian cancer.
  • Has adequate organ and bone marrow function. This means the organs and bone marrow are working well enough, as determined by medical tests.
  • Has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. This is a scale used to assess how well a person can perform daily activities, with 0 being fully active and 1 being restricted in physically strenuous activity but able to carry out light work.
  • Has a life expectancy of at least 3 months.
  • For certain groups in the study: Has at least one tumor that can be measured by specific medical criteria called RECIST 1.1.

Who cannot join the trial?

3 criteria

  • Patients with medical conditions other than Primary Peritoneal Cancer, Ovarian Cancer, or Fallopian Tube Cancer cannot participate.
  • Only female patients are eligible; male patients cannot participate.
  • Patients who are considered part of a vulnerable population, such as those who may not be able to give informed consent, are not eligible.
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Investigated drugs

  • REGN5668

    is a special type of medication designed to help the body's immune system fight cancer. It works by connecting two different proteins, MUC16 and CD28, which are found on the surface of certain cancer cells and immune cells. By linking these proteins, REGN5668 helps activate the immune cells to attack the cancer cells more effectively. This medication is being tested to see how safe it is and how well it works when used alone or with other treatments.

  • Cemiplimab

    is a medication that helps the immune system fight cancer by blocking a protein called PD-1. This protein can stop immune cells from attacking cancer cells. By blocking PD-1, cemiplimab allows the immune cells to better recognize and destroy cancer cells. It is being tested in combination with other treatments to see if it can improve the body's ability to fight cancer.

  • REGN4018

    is another medication that helps the immune system target cancer cells. It works by connecting two proteins, MUC16 and CD3, which are found on cancer cells and immune cells, respectively. This connection helps direct the immune cells to attack the cancer cells. REGN4018 is being studied to determine its safety and effectiveness when used with other treatments.

What is already known about the treatment

  • REGN5668

    REGN5668 is administered as an injection and is currently being studied in clinical trials for its potential use in treating certain types of cancer, including primary peritoneal cancer, ovarian cancer, and fallopian tube cancer. It is a bispecific antibody designed to enhance the immune system's ability to fight cancer by targeting specific proteins on cancer cells. This medication works by binding to MUC16 and CD28, which helps activate immune cells to attack the cancer. REGN5668 is classified as an immunotherapy agent, specifically a costimulatory bispecific antibody.

  • Cemiplimab

    Cemiplimab is given as an injection and is an approved medication used in the treatment of certain cancers, with ongoing research exploring its effectiveness in combination with other drugs. It is primarily used to treat skin cancer but is being studied for other cancers like ovarian cancer. Cemiplimab works by blocking a protein called PD-1 on immune cells, which helps the immune system recognize and attack cancer cells. It is classified as a checkpoint inhibitor, a type of immunotherapy.

  • REGN4018

    REGN4018 is administered via injection and is currently under investigation in clinical trials for its potential to treat cancers such as ovarian cancer. It is a bispecific antibody that targets MUC16 and CD3, aiming to recruit and activate T-cells to attack cancer cells. This medication is part of a class of drugs known as bispecific T-cell engagers, which are designed to enhance the body's immune response against cancer.

Investigated diseases

  • Primary Peritoneal Cancer

    Primary Peritoneal Cancer is a rare cancer that originates in the peritoneum, a thin layer of tissue lining the abdomen. It shares similarities with epithelial ovarian cancer in terms of symptoms and progression. The disease often begins with the abnormal growth of cells in the peritoneum, which can spread to other abdominal organs. As it progresses, it may cause abdominal swelling, pain, and digestive issues. The cancer cells can also produce fluid, leading to ascites, which is an accumulation of fluid in the abdominal cavity. Over time, the disease can affect the function of nearby organs.

  • Ovarian Cancer

    Ovarian Cancer is a type of cancer that begins in the ovaries, which are the reproductive glands found in women. It typically starts when cells in the ovaries grow uncontrollably and form a tumor. The disease can progress by spreading to the pelvis and abdomen, and in advanced stages, it may affect other parts of the body. Symptoms often include bloating, pelvic pain, and changes in bowel habits. As the cancer advances, it can lead to fluid accumulation in the abdomen and weight loss. The progression of the disease can impact the function of the reproductive and surrounding organs.

  • Fallopian Tube Cancer

    Fallopian Tube Cancer is a rare type of cancer that originates in the fallopian tubes, which connect the ovaries to the uterus. It usually begins with the abnormal growth of cells in the lining of the fallopian tubes. The disease can progress by spreading to nearby organs and tissues, including the ovaries and uterus. Symptoms may include pelvic pain, abnormal vaginal discharge, and a palpable mass in the pelvic area. As the cancer advances, it can lead to more widespread abdominal symptoms and affect the function of reproductive organs. The progression of the disease can also result in the spread of cancer cells to distant parts of the body.

Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase I/IITrial ID2022-501904-83-00Protocol codeR5668-ONC-1938Estimated enrolment504 patientsSponsorRegeneron Pharmaceuticals Inc.

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