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CLESROVIMAB

Clesrovimab (also known as MK-1654) is an investigational drug being studied for its potential to prevent respiratory syncytial virus (RSV) infections in infants. A clinical trial has been conducted to evaluate the safety, tolerability, and how the drug moves through the body (pharmacokinetics) in both pre-term and full-term infants. The study used different dosing levels to determine the optimal amount of medication while monitoring safety carefully. This article provides information about this clinical trial and what we know so far about clesrovimab’s potential role in protecting vulnerable infants from RSV infections.

Table of Contents

What is Clesrovimab?

Clesrovimab, also known as MK-1654, is an investigational medication that is being studied for its potential to prevent respiratory infections, particularly those caused by Respiratory Syncytial Virus (RSV)[1]. It belongs to a class of medications known as monoclonal antibodies, which are laboratory-made proteins that mimic the immune system’s ability to fight off harmful pathogens like viruses.

Medical Conditions Treated

Clesrovimab is being developed to help prevent and treat respiratory tract infections, with a specific focus on those caused by Respiratory Syncytial Virus (RSV)[1]. RSV is a common respiratory virus that usually causes mild, cold-like symptoms. However, it can be serious, especially for infants and older adults. RSV is the most common cause of bronchiolitis (inflammation of the small airways in the lung) and pneumonia (infection of the lungs) in children younger than 1 year of age in the United States.

How Clesrovimab is Administered

According to the clinical trial information, clesrovimab is administered as a single dose via intramuscular (IM) injection[1]. This means the medication is injected directly into a muscle, which allows for slow absorption into the bloodstream. This administration method is commonly used for medications that need to remain in the body for an extended period.

Clinical Trial Information

Clesrovimab is currently being studied in clinical trials to evaluate its safety, tolerability, and effectiveness. One specific study (identified as MK-1654-002) is a double-blind, randomized, placebo-controlled, single ascending dose study involving pre-term and full-term infants[1].

The study includes several different groups:

  • Pre-term infants (born at 29 to 35 weeks gestational age) receiving different doses of clesrovimab
  • Full-term infants (born at more than 35 weeks gestational age) receiving clesrovimab
  • A control group receiving a placebo (a solution of 0.9% sodium chloride, which has no medicinal effect)

The trial is designed with multiple panels (labeled A through E) to test different doses of the medication, with safety reviews conducted after each panel before proceeding to the next higher dose[1]. This approach, known as a dose escalation design, helps researchers determine the optimal dose that provides the desired effect with minimal side effects.

Participants in the study are monitored for up to 365 days (1 year) or 545 days (approximately 1.5 years) depending on when they enrolled in the study[1].

Safety Monitoring

The clinical trial for clesrovimab carefully monitors participants for safety concerns. This includes tracking:

  • Injection site adverse events – reactions that occur at the location where the medication was injected, such as pain, redness, or swelling[1]
  • Systemic adverse events – reactions that affect the whole body, such as fever or allergic reactions[1]
  • Serious adverse events (SAEs) – significant medical events that may require hospitalization or medical intervention[1]

In the study, these adverse events are monitored closely, particularly during the first 5 days after receiving the injection[1].

How Clesrovimab Works in the Body

The clinical trial is collecting detailed information about how clesrovimab behaves in the body, known as pharmacokinetics. This includes measuring:

  • Maximum serum concentration (Cmax) – the highest level of medication in the bloodstream[1]
  • Time to maximum serum concentration (Tmax) – how long it takes to reach the highest level[1]
  • Half-life (t1/2) – the time it takes for half of the medication to be cleared from the body[1]
  • Area under the curve (AUC) – a measure of the total exposure to the medication over time[1]

The researchers are checking the levels of clesrovimab in participants’ blood at specific time points: 7 days, 14 days, 90 days, 150 days, and 365 days after injection[1]. This helps them understand how long the medication remains in the body and at what levels, which is important for determining how often it would need to be administered to provide protection against RSV.

The study is also monitoring for the development of anti-drug antibodies (ADAs)[1]. These are antibodies produced by the body against the medication itself, which could potentially reduce its effectiveness. Understanding whether patients develop these antibodies is important for evaluating the long-term usefulness of clesrovimab.

Potential Side Effects

As clesrovimab is still in clinical trials, the complete profile of potential side effects is not yet fully established. The current trial is specifically designed to gather information about possible adverse reactions, both at the injection site and throughout the body[1].

Common side effects with monoclonal antibody medications similar to clesrovimab may include:

  • Injection site reactions (pain, redness, swelling)
  • Fever
  • Headache
  • Muscle pain
  • Fatigue

The clinical trial is carefully monitoring participants for any unexpected or serious side effects to ensure the safety of this investigational medication[1].

Study Aspect Details
Drug Name Clesrovimab (MK-1654)
Clinical Trial ID NCT03524118
Study Design Double-blind, randomized, placebo-controlled, single ascending dose study
Target Conditions Respiratory Syncytial Virus (RSV), Respiratory Tract Infection
Study Population Pre-term infants (born at 29 to 35 weeks) and full-term infants (born after 35 weeks)
Administration Method Intramuscular (IM) injection
Study Groups 7 active treatment panels (A, B, C, D1, D2, E1, E2) with ascending doses and 1 placebo group
Follow-up Duration Up to 365 days for Panels A, B, C, D1, and E1; up to 545 days for Panels D2 and E2
Primary Outcomes Safety measures: injection site reactions, systemic side effects, serious adverse events
Secondary Outcomes Pharmacokinetic parameters (how the drug moves through the body) and development of anti-drug antibodies

FAQ

  • What is clesrovimab and what is it being studied for? Clesrovimab (also known as MK-1654) is an investigational drug being studied for its potential to prevent respiratory syncytial virus (RSV) infections. RSV is a common respiratory virus that can cause serious infections in infants, especially those born prematurely. In the clinical trial, researchers administered single doses of clesrovimab via intramuscular injection to both pre-term and full-term infants to evaluate its safety and how it works in the body.
  • How was the clinical trial for clesrovimab structured? The clinical trial (NCT03524118) was designed as a double-blind, randomized, placebo-controlled, single ascending dose study. This means neither the participants nor the researchers knew who received the actual drug versus placebo (randomized and double-blind), and the doses were gradually increased after safety was confirmed at each level. The study included multiple panels (A through E) with different doses. Pre-term infants (born at 29 to 35 weeks) were placed in Panels A, B, C, and D, while full-term infants (born after 35 weeks) were in Panel E. After a protocol amendment, some participants were followed for up to 545 days instead of the original 365 days.
  • What safety measures were monitored during the clesrovimab trial? The trial closely monitored several safety aspects, including injection site reactions (like pain, redness, or swelling at the injection site) from Day 1 to Day 5, systemic side effects (effects throughout the body) also from Day 1 to Day 5, and any serious adverse events throughout the study period. Researchers reviewed the safety data after each dose panel before proceeding to the next higher dose, ensuring that safety was maintained as doses increased. The study also monitored for anti-drug antibodies (ADAs), which are antibodies the body might produce against the drug itself.
  • How long does clesrovimab stay in an infant's body? The clinical trial measured how long clesrovimab remains in an infant's body through several measurements. Researchers took blood samples at specific times (Days 7, 14, 90, 150, and 365) to measure the concentration of the drug in the blood. They also calculated the drug's half-life, which is the time it takes for half of the drug to be cleared from the body. This information helps determine how long a single dose might provide protection and how the drug is processed differently in pre-term versus full-term infants.
  • What is the difference between the various panels in the clesrovimab study? The study organized participants into different panels based on their gestational age at birth and the dose they received. Panels A, B, and C involved pre-term infants receiving progressively higher doses (Dose 1, 2, and 3). Panel D included pre-term infants receiving the highest dose (Dose 4), while Panel E included full-term infants also receiving Dose 4. After a protocol amendment, Panels D and E were further subdivided into D1/D2 and E1/E2, with the D2 and E2 groups being followed for a longer period (545 days instead of 365 days). This design allowed researchers to compare how different doses worked in pre-term infants and how the same dose worked in pre-term versus full-term infants.

Ongoing Clinical Trials on CLESROVIMAB

  • Study on the Safety and Effectiveness of Clesrovimab and Palivizumab for Preventing Severe RSV in Infants and Children at High Risk

    Not recruiting

    1 1 1
    Investigated drugs:
    Czechia Finland France Germany Greece Hungary +3

Glossary

  • Clesrovimab: An investigational drug (also known as MK-1654) being studied for the prevention of respiratory syncytial virus (RSV) infections in infants.
  • Respiratory Syncytial Virus (RSV): A common respiratory virus that can cause infections in the lungs and breathing passages. RSV can be particularly serious in infants, especially those born prematurely.
  • Pharmacokinetics: The study of how a drug moves through the body, including how it's absorbed, distributed, metabolized, and eliminated. This helps determine appropriate dosing.
  • Anti-Drug Antibodies (ADAs): Antibodies that the body may produce against a therapeutic drug. These can potentially reduce the effectiveness of the drug or cause immune reactions.
  • Pre-term infant: A baby born before 37 weeks of pregnancy. In this study, pre-term specifically referred to infants born between 29 and 35 weeks gestational age.
  • Full-term infant: A baby born at or after 37 weeks of pregnancy. In this study, full-term specifically referred to infants born after 35 weeks gestational age.
  • Intramuscular (IM) injection: A method of administering medication by injecting it directly into a muscle. In this study, clesrovimab was given as an IM injection.
  • Double-blind study: A research design where neither the participants nor the researchers know who is receiving the experimental drug versus placebo, which helps prevent bias in assessing outcomes.
  • Randomized controlled trial: A study design where participants are randomly assigned to either receive the experimental treatment or a control (such as placebo), allowing for more reliable comparison of effects.
  • Placebo: An inactive substance (in this case, 0.9% sodium chloride solution) given to some study participants to compare its effects with the active drug.
  • Single ascending dose: A study design where participants receive a single dose of medication, with different groups receiving progressively higher doses after safety is confirmed at lower doses.
  • Adverse Event (AE): Any undesirable experience associated with the use of a medical product. These may or may not be related to the medication being studied.
  • Serious Adverse Event (SAE): A serious health event that may or may not be related to the study drug, resulting in death, hospitalization, disability, or other medically significant outcomes.
  • Maximum Serum Concentration (Cmax): The highest concentration of a drug in the blood after administration, which helps determine how much of the drug reaches the bloodstream.
  • Half-life (t1/2): The time required for the concentration of a drug in the body to decrease by half, which helps determine how long the drug remains active in the body.
  • Area Under the Curve (AUC): A measurement of the total exposure to a drug over time, calculated from the concentration-time curve of the drug in the blood.
  • Solicited Injection Site Adverse Event: Specific, predefined reactions at the site where a drug is injected (such as pain, redness, or swelling) that are actively monitored during a clinical trial.
  • Solicited Systemic Adverse Event: Specific, predefined reactions that affect the whole body (such as fever or fatigue) that are actively monitored during a clinical trial.

References

  1. https://clinicaltrials.gov/study/NCT03524118