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Study on MaaT033 and Cemiplimab for Patients with Advanced Non-Small Cell Lung Cancer Resistant to PD-1/PD-L1 Blockade Due to Antibiotic Use

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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 a treatment for advanced non-small cell lung cancer (NSCLC), a type of lung cancer that is more challenging to treat when it has spread or cannot be surgically removed. The study is investigating the effects of a new treatment combination involving an oral medication called MaaT033, which is a type of microbiotherapy, and an intravenous medication called Cemiplimab, also known by its code name CB. The purpose of the study is to see if this combination can improve the control of the disease in patients who have developed resistance to certain cancer treatments due to the use of antibiotics.

Participants in the study will be randomly assigned to receive either the combination of MaaT033 and Cemiplimab or the best treatment option chosen by their doctor, which is referred to as the best investigator's choice (BIC). The study will monitor the participants over a period of time to assess how well the treatment works in controlling the cancer. This will include regular assessments to check the response of the cancer to the treatment, as well as monitoring for any side effects or changes in the participants' health.

The study aims to determine if the combination of MaaT033 and Cemiplimab can improve outcomes such as the disease control rate, which measures how well the cancer is being managed, and overall survival, which is the length of time patients live after starting the treatment. The study will also look at how the treatment affects the gut microbiota, which are the microorganisms living in the digestive tract, and other health markers. This research is important for finding new ways to treat advanced NSCLC, especially for patients who have limited options due to resistance to existing treatments.

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

    Upon joining the study, you will undergo an initial assessment to confirm eligibility. This includes a review of your medical history and a physical examination.

    You will also have laboratory tests to check your organ function and overall health status. These tests must be completed within 28 days before starting the study treatment.

  2. Step 2

    Treatment allocation

    You will be randomly assigned to one of two groups: one receiving the combination of MaaT033 and cemiplimab, and the other receiving the best investigator's choice of treatment.

    The allocation will determine the specific treatment regimen you will follow during the study.

  3. Step 3

    Treatment administration

    If you are in the MaaT033 and cemiplimab group, you will take MaaT033 orally. Cemiplimab will be administered through an intravenous infusion.

    The frequency and dosage of the medications will be determined by the study protocol and your healthcare provider.

  4. Step 4

    Regular monitoring

    Throughout the study, you will have regular visits to monitor your health and response to the treatment.

    These visits will include physical examinations, laboratory tests, and imaging studies to assess the status of your cancer.

  5. Step 5

    Response assessment

    Your response to the treatment will be evaluated at 12 weeks using specific criteria to determine if there is a complete response, partial response, or stable disease.

    A follow-up assessment will be conducted 4-8 weeks after the initial response assessment to confirm the results.

  6. Step 6

    Long-term follow-up

    You will continue to be monitored for up to 60 months to evaluate the long-term effects of the treatment.

    This includes assessments at 12, 24, 36, and 60 months to track disease progression, overall survival, and any side effects.

Who can join the trial?

18 criteria

  • Participants must be at least 18 years old.
  • Participants must have advanced non-small cell lung cancer (NSCLC).
  • Participants must have progressed after receiving immunotherapy or immunotherapy combined with platinum-based chemotherapy.
  • Participants must have received antibiotics (ATB) within 60 days before and 42 days after the first immunotherapy and have shown disease progression within 6 months after the first immunotherapy.
  • Male participants must agree to avoid heterosexual activity or use contraception during the treatment and for at least 9 months after the last dose of study medication. They must also refrain from donating sperm during this period.
  • Female participants must not be pregnant or breastfeeding. If they are of childbearing potential, they must have a negative pregnancy test before starting the study medication and agree to use contraception or abstain from heterosexual activity during the treatment and for at least 180 days after the last dose.
  • Participants must understand, sign, and date the informed consent form before any study-specific procedures are performed.
  • Participants must be able and willing to attend study visits and follow study procedures.
  • Participants must understand the spoken and written national language.
  • There are no limits on the number of previous treatments participants have received.
  • Participants must be part of a social security system or be a beneficiary of one.
  • Participants must have an estimated life expectancy of more than 3 months.
  • If participants are taking steroids, they must not exceed a daily dose equivalent to 10 mg of prednisone.
  • Participants must have measurable disease based on specific medical criteria (RECIST 1.1).
  • Participants must have adequate organ function as defined in the study protocol.
  • Participants must have a confirmed diagnosis of NSCLC through a tissue sample.
  • Participants must have metastatic or unresectable NSCLC and be considered suitable for a new line of immunotherapy by their doctor.
  • Participants must have an Eastern Cooperative Oncology Group performance status (ECOG-PS) of 0 to 2, which is a scale used to assess how a patient's disease is progressing and how the disease affects their daily living abilities.

Who cannot join the trial?

6 criteria

  • Patients with any other type of cancer besides advanced non-small cell lung cancer.
  • Patients who have not shown a response to immune-checkpoint inhibitors (ICI) treatment. These are medicines that help the immune system fight cancer.
  • Patients who are not able to have a follow-up assessment 4-8 weeks after the initial response assessment.
  • Patients who are not within the specified age range for the study.
  • Patients who are not willing or able to follow the study procedures.
  • Patients who are part of a vulnerable population that requires special protection.
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Investigated drugs

  • MaaT033

    is an oral treatment that involves using a mixture of healthy bacteria from the gut, known as fecal microbiotherapy. This therapy aims to restore the balance of good bacteria in the intestines, which can be disrupted by antibiotics. In this trial, MaaT033 is being tested to see if it can help improve the effectiveness of cancer treatment in patients with advanced non-small cell lung cancer who have not responded well to certain immune therapies due to previous antibiotic use.

  • Cemiplimab

    is a type of cancer treatment known as an immune checkpoint inhibitor. It works by helping the body's immune system recognize and attack cancer cells more effectively. In this trial, Cemiplimab is being used in combination with MaaT033 to see if this combination can better control the disease in patients with advanced non-small cell lung cancer who have become resistant to similar treatments after taking antibiotics.

What is already known about the treatment

  • MaaT033

    MaaT033 is administered orally and is a form of pooled fecal microbiotherapy. It is currently being studied in clinical trials for its potential to improve treatment outcomes in patients with advanced non-small cell lung cancer who have developed resistance to certain cancer therapies due to antibiotic use. The main therapeutic indication is to enhance the disease control rate in these patients. At the molecular level, it works by restoring the balance of gut bacteria, which may help the immune system respond better to cancer treatments. MaaT033 is classified as a microbiome therapeutic.

  • Cemiplimab

    Cemiplimab is administered through an intravenous infusion. It is an approved medication used in the treatment of certain types of cancer, including advanced non-small cell lung cancer. The main therapeutic indication is to help the immune system attack cancer cells. Its mechanism of action involves blocking a protein called PD-1 on immune cells, which can enhance the body's immune response against cancer. Cemiplimab is classified as an immune checkpoint inhibitor.

Investigated diseases

Advanced Non-Small Cell Lung Cancer – This is a type of lung cancer that begins in the cells lining the lungs and is characterized by larger cell size compared to small cell lung cancer. It progresses by spreading to nearby tissues and organs, often through the lymphatic system or bloodstream. As the disease advances, it can cause symptoms such as persistent cough, chest pain, and difficulty breathing. The cancer may metastasize to other parts of the body, including the brain, bones, and liver. The progression of the disease can lead to increased severity of symptoms and impact on lung function. Advanced stages indicate that the cancer has spread beyond the lungs to other areas of the body.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-517018-14-00Protocol code2024/3967Estimated enrolment162 patientsSponsorInstitut Gustave Roussy

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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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