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A Study of Linvoseltamab in Adult Patients with High-Risk Monoclonal Gammopathy of Undetermined Significance or Non-High-Risk Smoldering Multiple Myeloma

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 study involves people with two conditions that may lead to a type of blood cancer called multiple myeloma. The first condition is High-Risk Monoclonal Gammopathy of Undetermined Significance, which means the body is producing abnormal proteins that could develop into cancer. The second condition is Non-High-Risk Smoldering Multiple Myeloma, where abnormal plasma cells are present in the bone marrow but have not yet caused symptoms or damage. The study will use a medication called Linvoseltamab, also known by its code name REGN5458, which is given through an infusion into a vein. Additional medications may be used to manage side effects, including diphenhydramine hydrochloride (an antihistamine taken by mouth), tocilizumab (given through an infusion), dexamethasone (a corticosteroid that can be taken by mouth or given through an infusion), and paracetamol (a pain and fever reliever taken by mouth).

The purpose of this study is to find out if Linvoseltamab can eliminate the abnormal plasma cells that might turn into multiple myeloma and to determine the safest and most effective dose to use. The study will also look at how well people tolerate the medication and whether it causes any unwanted effects. In the first part of the study, different dose levels of Linvoseltamab will be tested in small groups to identify the highest dose that can be given safely. In the second part, a larger group of people will receive the selected dose to see how well it works at causing a complete response, which means the abnormal cells can no longer be detected.

During the study, participants will receive Linvoseltamab through infusions over a period of up to 27 months. Doctors will monitor participants closely for any side effects and will check blood samples to see if the treatment is working. The study will measure whether participants achieve a complete response, meaning all signs of the abnormal cells have disappeared, and whether this response lasts over time. Other measurements will include checking for minimal residual disease, which looks for very small amounts of abnormal cells that may still be present, and tracking how long people remain free from the disease getting worse. Blood tests will also be done to measure the amount of Linvoseltamab in the body and to check if the body develops antibodies against the medication.

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 treatment preparation

    Before receiving the study medication, premedication will be administered to help reduce potential side effects.

    The premedication includes diphenhydramine hydrochloride 25 mg tablets taken by mouth, dexamethasone 4 mg tablets taken by mouth or dexamethasone sodium phosphate 4 mg per ml given through a vein, and paracetamol 500 mg tablets taken by mouth.

    In some cases, tocilizumab 20 mg per ml may be given through a vein as an infusion. This medication helps to prevent certain reactions to the treatment.

  2. Step 2

    Study medication administration

    The main study medication is linvoseltamab, which will be given through a vein as an infusion.

    The dose of linvoseltamab will depend on which part of the study is being conducted and the specific treatment group assigned.

    During Part 1 of the study, different dose levels will be tested to determine safety and tolerability. The highest safe dose will be selected for further investigation.

    During Part 2 of the study, the selected dose will be used to evaluate how well the medication works in eliminating abnormal plasma cells.

  3. Step 3

    Safety observation period

    After receiving the study medication, a safety observation period will take place.

    During this time, any side effects or adverse reactions will be closely monitored and recorded.

    Blood tests and other laboratory examinations will be performed to check for any abnormalities in blood counts, liver function, and kidney function.

    The kidney function will be assessed using a measurement called estimated glomerular filtration rate, which shows how well the kidneys are filtering waste from the blood.

  4. Step 4

    Regular monitoring and assessments

    Throughout the study, regular visits will be scheduled to monitor health status and treatment response.

    Blood samples will be collected to measure the concentration of linvoseltamab in the bloodstream over time.

    Tests will be performed to check if the body has developed any antibodies against the study medication, which is called anti-drug antibodies.

    Response to treatment will be assessed by the treating physician to determine if a complete response has been achieved, meaning that abnormal plasma cells are no longer detectable, or a partial response, meaning that there has been a significant reduction in abnormal cells.

  5. Step 5

    Minimal residual disease testing

    Minimal residual disease testing will be performed for those who achieve a complete response. This is a highly sensitive test that looks for very small amounts of abnormal cells that may still remain in the body.

    The goal is to determine if the treatment has eliminated all detectable abnormal cells.

    This testing will be repeated on an annual basis to check if the response is sustained over time.

  6. Step 6

    Long-term follow-up

    The study includes long-term follow-up to monitor for any progression of the condition.

    Biochemical progression-free survival will be tracked, which measures the time from the start of treatment until there are signs that the condition is getting worse based on laboratory test results.

    Duration of response will also be measured, which is the length of time that the treatment continues to work effectively.

    The study is expected to continue until May 2032, with regular assessments throughout this period.

Who can join the trial?

5 criteria

  • You must have a diagnosis of High-Risk Monoclonal Gammopathy of Undetermined Significance (a condition where abnormal proteins are found in the blood but have not yet caused symptoms, with higher risk of progression) or Non-High-Risk Smoldering Multiple Myeloma (an early stage of a blood disorder where abnormal plasma cells are present in the bone marrow but cause few or no symptoms), as defined by the study requirements
  • Your ECOG performance status must be 1 or lower. This is a scale that measures how well you can perform daily activities, where 0 means you are fully active and 1 means you have some restrictions but can still do light work
  • Your blood tests must show that your blood cells and liver are working well enough, according to specific levels set by the study
  • Your estimated glomerular filtration rate (a measure of how well your kidneys filter waste from your blood) must be at least 30 milliliters per minute per 1.73 square meters of body surface area, calculated using a specific formula
  • You must meet other requirements as described in the full study plan

Who cannot join the trial?

3 criteria

  • The source data does not provide specific exclusion criteria for this clinical trial
  • Exclusion criteria are reasons why a person cannot join a study, such as having certain other medical conditions, taking specific medications, or having certain test results that would make participation unsafe or affect the study results
  • If you are interested in this trial, the research team would need to review your complete medical history to determine if you meet all requirements for participation
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Investigated drugs

Linvoseltamab is an investigational medication being studied in this clinical trial. It is given to patients to help treat conditions related to abnormal proteins in the blood and bone marrow. The study is testing different amounts of this medication to find out which dose works best and is safest for patients. The medication aims to help eliminate abnormal cells and achieve a complete response, meaning the signs of disease are no longer detectable.

What is already known about the treatment

Linvoseltamab – Linvoseltamab is an investigational medication currently being studied in clinical trials for the treatment of early stages of blood disorders that may progress to multiple myeloma, a type of blood cancer. The drug is administered through injection or infusion into the bloodstream, and researchers are testing different doses to find the safest and most effective amount. It works by helping the body's immune system recognize and attack abnormal plasma cells (a type of white blood cell) by binding to specific proteins on their surface, bringing immune cells close to the cancer cells to destroy them. Linvoseltamab belongs to a class of drugs called bispecific antibodies, which are designed to connect two different targets simultaneously to enhance the immune response against disease.

Investigated diseases

  • Monoclonal Gammopathy of Undetermined Significance

    This is a condition where the body produces an abnormal protein called monoclonal protein or M protein in the blood. The condition occurs when plasma cells in the bone marrow make too much of a single type of protein. Most people with this condition do not experience any symptoms and may not know they have it. In some cases, the condition remains stable for many years without causing health problems. However, in certain individuals classified as high-risk, the abnormal protein production may increase over time. The condition requires monitoring because it can sometimes progress to more serious blood disorders.

  • Smoldering Multiple Myeloma

    This is an early stage condition where abnormal plasma cells accumulate in the bone marrow and produce abnormal proteins. The condition is characterized by higher levels of abnormal plasma cells or M protein compared to monoclonal gammopathy, but without causing symptoms or organ damage. People with this condition typically do not experience bone pain, anemia, kidney problems, or other symptoms associated with active disease. The condition progresses slowly and can remain stable for months or years. Non-high-risk smoldering multiple myeloma refers to cases where the likelihood of progression to active disease is lower based on certain laboratory and clinical features. Regular monitoring is important as the condition may eventually progress in some individuals.

Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2023-505242-25-00Protocol codeR5458-ONC-2257Estimated enrolment116 patientsSponsorRegeneron Pharmaceuticals Inc.

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