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Study of fianlimab plus cemiplimab with chemotherapy or cemiplimab with chemotherapy for patients with pleural mesothelioma who have not received prior treatment

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What is this trial about?

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

This study is looking at a type of cancer called pleural mesothelioma, which affects the lining of the lungs. The study will test two different treatment combinations. One combination includes fianlimab (also known as REGN3767), cemiplimab (also known as LIBTAYO), and chemotherapy with pemetrexed and platinum. The other combination includes cemiplimab and chemotherapy with pemetrexed and platinum. Both fianlimab and cemiplimab are medicines that work with the immune system to help fight cancer. The chemotherapy medicines are drugs that work to kill or slow the growth of cancer cells.

The purpose of this study is to see how well the combination of double immunotherapy with anti-LAG3 and anti-PD-1 medicines along with chemotherapy works in treating this disease. The study will look at how many patients have their disease controlled after six months of treatment. Patients in this study will not have received any previous chemotherapy or immunotherapy for their pleural mesothelioma. The study will also look at how safe these treatment combinations are and what side effects patients may experience. The treatments will be given through an intravenous infusion, which means the medicine is delivered directly into a vein.

During the study, doctors will check how well the treatments are working by using scans and measurements to see if the tumors are getting smaller, staying the same, or growing. The study will also look at how the treatments affect patients' quality of life and symptoms. Patients will be followed to see how long they live and how long they go without their disease getting worse. The study will compare results between patients who have different types of pleural mesothelioma, specifically the epithelioid type versus the non-epithelioid type. Treatment in this study can last up to 24 months.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment and confirmation

    Your diagnosis of pleural mesothelioma (a cancer affecting the lining of the lungs) will be confirmed through tissue samples obtained during a thoracoscopy biopsy (a procedure where samples are taken from the chest). At least 10 slides from your biopsy sample must be available for analysis.

    Your disease will be evaluated to confirm it cannot be removed by surgery. This evaluation will be performed by a specialized team including a thoracic surgeon.

    Imaging tests, specifically a CT scan with contrast (a detailed x-ray using a special dye), will be performed to measure your disease according to specific criteria. The disease must be measurable, either as thickening of the pleural lining of at least 7 millimeters in multiple locations, or as enlarged lymph nodes or other affected areas.

    Your overall health status will be assessed using the ECOG performance status scale, which measures your ability to perform daily activities. You must have a score of 0 or 1, meaning you are fully active or have some restrictions but can perform light work.

    Blood tests will be performed to check your organ function, including kidney function (creatinine clearance must be at least 45 milliliters per minute), blood cell counts (white blood cells, platelets, and hemoglobin levels), and liver function tests.

    If you are a woman of childbearing potential, a pregnancy test will be performed and must be negative.

    If you had a procedure to drain fluid from your chest (thoracocentesis) or a thoracoscopy within 2 months before joining the trial, you should receive radiation therapy to the procedure sites. This involves 3 sessions of 7 Gray each. There should be no more than 42 days between the removal of any drains and the start of radiation. A 7-day waiting period is required between the end of radiation therapy and the start of trial treatment.

  2. Step 2

    Treatment assignment

    You will be assigned to one of two treatment groups. This is a non-comparative trial, meaning the groups are not being directly compared against each other but are being evaluated separately.

    One group receives fianlimab plus cemiplimab plus chemotherapy (pemetrexed and platinum-based drug).

    The other group receives cemiplimab plus chemotherapy (pemetrexed and platinum-based drug).

  3. Step 3

    Treatment administration

    All medications in this trial are given through intravenous infusion, meaning they are administered directly into a vein.

    Fianlimab is provided as a solution for injection and will be given intravenously if you are assigned to the group receiving this medication.

    Cemiplimab (also known as LIBTAYO) is provided as a 350 milligram concentrate that is prepared as a solution for infusion and will be given intravenously.

    The chemotherapy consists of pemetrexed and a platinum-based drug, both given intravenously.

    The specific dosage amounts, frequency of administration, and total duration of treatment are determined by the trial protocol and will be explained to you by your medical team.

  4. Step 4

    Monitoring and assessments during treatment

    Throughout the trial, you will have regular visits for monitoring and assessments.

    Imaging scans will be performed at scheduled intervals to evaluate how your disease is responding to treatment. These assessments will use RECIST 1.1 criteria modified for mesothelioma, which is a standardized method for measuring tumor response.

    Your scans will be reviewed by both your treating physician and an Independent Review Committee, which is a separate group of specialists who evaluate the images independently.

    At 6 months, your disease status will be assessed to determine the Disease Control Rate, which measures whether your disease has responded to treatment, remained stable, or progressed.

    Blood tests and physical examinations will be conducted regularly to monitor your health and check for any side effects.

    Any side effects or adverse events you experience will be recorded and graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events, Version 5.0, which is a standard system for classifying the severity of side effects.

    Quality of life questionnaires will be completed at various time points to assess changes in your symptoms and daily functioning. These include the EQ-5D-5L and LCSS-meso questionnaires.

  5. Step 5

    Contraception requirements during treatment

    If you are a woman of childbearing potential, you must use effective contraception during the entire trial and for 6 months after receiving the last dose of treatment.

    If you are a male participant with a female partner of childbearing potential, you must use condoms during the trial and for 6 months after the last dose of treatment, unless you have had a vasectomy.

    Women must agree not to donate eggs during the trial and for 6 months after the last treatment.

    Men must agree not to donate sperm during the trial and for 6 months after receiving the last dose.

  6. Step 6

    Long-term follow-up

    After completing treatment, you will continue to be followed to assess long-term outcomes.

    Progression-Free Survival will be measured, which is the length of time you live without your disease getting worse.

    Overall Survival will be tracked, which is the length of time you live from the start of treatment.

    The response of your disease will be categorized according to your specific histological subtype (epithelioid or non-epithelioid), which refers to the type of cells in your mesothelioma.

    Any instances of Hyper-Progressive Disease (unusually rapid disease progression) will be documented.

Who can join the trial?

17 criteria

  • You must sign a written consent form before any study procedures begin, and you must be willing to follow the study schedule and testing requirements.
  • You must have a confirmed diagnosis through a biopsy, which means a tissue sample was taken and examined under a microscope. A diagnosis based only on fluid samples is not allowed, and a thoracoscopy biopsy is recommended, which is a procedure where a small camera is used to look inside your chest and take tissue samples.
  • Your disease must be non-removable by surgery, as determined by a specialized team of doctors including a chest surgeon.
  • Your disease must be able to be measured on a CT scan, which is a special type of X-ray that creates detailed pictures of the inside of your body. The measurements must meet specific size requirements for the thickening of the pleura, which is the lining around your lungs, or for lymph nodes or areas where the disease has spread.
  • Your general health and ability to perform daily activities must be good to very good, rated as 0 or 1 on the ECOG scale, which is a scoring system doctors use to measure how a disease affects your daily living abilities.
  • You must not have lost more than 10% of your body weight in the 3 months before joining the study.
  • You must not have received chemotherapy, which is cancer treatment using drugs, or immunotherapy, which is treatment that helps your immune system fight cancer, before this study.
  • You must be at least 18 years old and younger than 76 years old.
  • Your expected survival time must be more than 3 months.
  • Tissue samples from your biopsy must be available for testing, with at least 10 slides from the biopsy sample.
  • Your body functions must meet certain standards: your kidneys must work well enough with a creatinine clearance of at least 45, which measures how well your kidneys filter waste; your blood must have enough white blood cells called neutrophils, enough platelets which help blood clot, and enough hemoglobin which carries oxygen; your liver function tests including AST and ALT must be within acceptable ranges, and your bilirubin, a substance produced by the liver, must also be within limits.
  • If you are a woman who can become pregnant, you must have a negative pregnancy test at the start of the study.
  • If you are a man with a female partner who can become pregnant, you must use condoms during the study and for 6 months after the last treatment, unless you have had a vasectomy, which is a surgical procedure to prevent pregnancy.
  • If you have had a vasectomy or your partner has had a vasectomy, the success of the surgery must have been confirmed by a doctor.
  • If you are a woman who can become pregnant, you must agree not to donate eggs during the study and for 6 months after the last treatment.
  • If you are a man, you must agree not to donate sperm during the study and for 6 months after the last treatment.
  • If you had a procedure to drain fluid from your chest or a thoracoscopy within 2 months before joining the study, you should receive radiation therapy, which uses high-energy rays to treat cancer, to the sites where tubes were inserted. This radiation should be given no more than 42 days after the procedure, and you must wait 7 days after radiation ends before starting the study treatment.

Who cannot join the trial?

3 criteria

  • The source data does not provide specific exclusion criteria (reasons why you cannot participate) for this clinical trial
  • You should ask the study team directly about which conditions or situations would prevent you from joining this study
  • Common reasons that often prevent participation in cancer treatment studies may include having other serious medical conditions, being pregnant or breastfeeding, taking certain medications, or having had recent treatments, but these specific restrictions are not listed in the available information
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Investigated drugs

  • Fianlimab

    is a medicine that helps your immune system fight cancer by blocking a protein called LAG-3. By blocking this protein, it helps your body's natural defenses recognize and attack cancer cells more effectively.

  • Cemiplimab

    is a medicine that helps your immune system fight cancer by blocking a protein called PD-1. This allows your immune system to better identify and destroy cancer cells that might otherwise hide from your body's defenses.

  • Pemetrexed

    is a chemotherapy medicine that works by stopping cancer cells from growing and multiplying. It interferes with the substances cancer cells need to make new cells, which helps slow down or stop the spread of cancer.

  • Platinum chemotherapy

    refers to a group of chemotherapy medicines that contain platinum. These medicines damage the DNA inside cancer cells, which prevents them from dividing and growing. This helps kill cancer cells or stop them from spreading.

What is already known about the treatment

  • Fianlimab

    Fianlimab is an investigational medication given by injection into a vein that is currently being studied in clinical trials and is not yet approved for general medical use. It is being tested in combination with other treatments for pleural mesothelioma, a type of cancer affecting the lining of the lungs. Fianlimab works by blocking a protein called LAG-3 on immune cells, which helps the body's immune system recognize and attack cancer cells more effectively.

  • Cemiplimab

    Cemiplimab is an immunotherapy medication administered through an intravenous infusion that is approved for certain types of cancer and is being studied for pleural mesothelioma in this trial. It belongs to a class of drugs called PD-1 inhibitors that help the immune system fight cancer. Cemiplimab works by blocking the PD-1 protein on immune cells, preventing cancer cells from hiding from the immune system and allowing the body to better recognize and destroy tumors.

  • Pemetrexed

    Pemetrexed is a chemotherapy medication given through a vein that is already approved and widely used for treating pleural mesothelioma and certain types of lung cancer. It belongs to a group of drugs called antifolate agents that interfere with cancer cell growth. Pemetrexed works by blocking specific enzymes that cancer cells need to make DNA and RNA, which stops the cancer cells from dividing and growing.

Investigated diseases

Pleural mesothelioma – Pleural mesothelioma is a type of cancer that develops in the pleura, which is the thin layer of tissue covering the lungs and lining the chest cavity. This disease typically begins when cells in the pleura start to grow abnormally and uncontrollably. The cancer usually spreads along the surfaces of the pleura and can eventually affect nearby tissues and organs in the chest. As the disease progresses, fluid may accumulate between the layers of the pleura, causing breathing difficulties and chest pain. The tumor can grow and thicken the pleural lining, restricting lung expansion and making it harder to breathe. Symptoms often develop gradually and may include persistent cough, shortness of breath, chest discomfort, and unexplained weight loss.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-519208-29-00Estimated enrolment126 patientsSponsorIntergroupe Francophone De Cancerologie Thoracique

sourced from the EU Clinical Trials Register and site verification

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On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

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