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Completed

NCT Number: NCT04938830

Clesrovimab (MK-1654) in Infants and Children at Increased Risk for Severe Respiratory Syncytial Virus (RSV) Disease (MK-1654-007)

This study aims to evaluate the safety and tolerability of clesrovimab compared to palivizumab as assessed by the proportion of participants experiencing adverse events (AEs).

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Key information

Conditions

RSV Infection Infections Mononegavirales Infections Paramyxoviridae Infections Pneumovirus Infections RNA Virus Infections Respiratory Syncytial Virus Infections Virus Diseases

Age range

Up to 1 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

Mater Misericordiae Limited-Neonatalogy ( Site 0102), Brisbane, Queensland, Australia

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Participants at increased risk for severe RSV infection recommended to receive palivizumab in accordance with national or local guidelines or professional society recommendations and meet defined criteria for the Early or Moderate Pre-term Group or the chronic lung disease (CLD)/congenital heart disease (CHD) Group.
  • Is available to complete the follow-up period.

Additional inclusion criteria for participation in RSV Season 2:

  • RSV Season 2 participants enrolled in the CLD/CHD Group in RSV Season 1. Participants with CHD must also have the following:
  • Hemodynamically significant CHD at the beginning of RSV Season 2, or
  • If the participant has had surgically repaired hemodynamically significant CHD that did not include extracorporeal membrane oxygenation (ECMO) or cardiopulmonary bypass: 1) continues to require medications to manage CHD, or 2) any additional medical intervention related to their CHD.
  • RSV Season 2 participants enrolled in the Early or Moderate Pre-term Group in RSV Season 1, with the following:
  • Neuromuscular disease or congenital pulmonary anomaly that impairs the ability to clear secretions from the upper airway because of ineffective cough
  • Down Syndrome (trisomy of chromosome 21)
  • Cystic fibrosis with nutritional compromise
  • Native Americans and Alaskan Indians or other indigenous populations at high risk for severe RSV disease

Exclusion criteria

  • Requires mechanical ventilation at time of enrollment.
  • Has a life expectancy <6 months.
  • Has known hepatic or renal dysfunction, or chronic seizure disorder.
  • Is hospitalized at the time of randomization unless discharge is expected within 7 days after randomization.
  • Has severe immunodeficiency or is severely immunocompromised.
  • Has known hypersensitivity to any component of clesrovimab or palivizumab.

Additional exclusion criteria for participation in RSV Season 2:

  • Had 1) ECMO or 2) surgical intervention during the RSV season for CHD and required cardiopulmonary bypass during the procedure in RSV Season 1.

Treatment and study plan

Clesrovimab

Biological

IM injection

Other names: MK-1654

Palivizumab

Biological

IM injection

Other names: Synagis™

Placebo

Biological

IM injection

Primary outcomes

  1. Number of Participants With Solicited Injection-site Adverse Events (AEs) in RSV Season 1

    Time frame: Up to 5 days after each dose in RSV Season 1 (Up to ~33 days)

    An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Solicited injection-site AEs included erythema, pain, and swelling. The number of participants with solicited injection-site AEs in RSV Season 1 is reported.

  2. Number of Participants With Solicited Daily Body Temperatures With Fever in RSV Season 1

    Time frame: Up to 5 days after each dose in RSV Season 1 (Up to ~33 days)

    Fever was defined as maximum rectal temperature ≥102.2 °F (39.0 °C) or maximum axillary temperature ≥101.7 °F. The number of participants with solicited daily body temperature of fever in RSV Season 1 is reported.

  3. Number of Participants With Solicited Systemic AEs in RSV Season 1

    Time frame: Up to 5 days after each dose in RSV Season 1 (Up to ~33 days)

    An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Solicited systemic AEs included decreased appetite, irritability, and somnolence. The number of participants with solicited systemic AEs in RSV Season 1 is reported.

  4. Number of Participants With Anaphylaxis/Hypersensitivity AEs of Special Interest (AESI) in RSV Season 1

    Time frame: Up to 42 days in RSV Season 1

    An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. The number of participants with anaphylaxis/hypersensitivity AESI in RSV Season 1 is reported.

  5. Number of Participants With Rash AESI in RSV Season 1

    Time frame: Up to 42 days in RSV Season 1

    An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Rash AESI included urticaria and drug eruption. The number of participants with rash AESI in RSV Season 1 is reported.

  6. Number of Participants With Nonserious AEs in RSV Season 1

    Time frame: Up to 42 days in RSV Season 1

    An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. The number of participants with nonserious AEs in RSV Season 1 is reported.

  7. Number of Participants With Serious AEs (SAEs) Through the Duration of Participation in RSV Season 1

    Time frame: Up to 365 days in RSV Season 1

    An SAE is any untoward medical occurrence in a clinical study participant that results in death, is life-threatening, requires hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, or is another important medical event. The number of participants with SAEs in RSV Season 1 is reported.

Secondary outcomes

  1. Number of Cases of RSV-associated Medically Attended Lower Respiratory Infection (MALRI) in RSV Season 1

    Time frame: Up to 150 days in RSV Season 1

    Outpatient and inpatient MALRI was defined as the presence of the following in a clinical setting: 1) cough or difficulty breathing; AND 2) 1 or more of wheezing, chest wall in-drawing/retraction, rales/crackles, hypoxemia, tachypnea, or dehydration due to respiratory symptoms; AND 3) RSV-positive reverse transcriptase polymerase chain reaction (RT-PCR) nasopharyngeal (NP) sample. The number of cases of outpatient and inpatient RSV-associated MALRI were reported together for RSV season 1. For each participant, only the first occurrence of the case is counted for the analysis.

  2. Number of Cases of RSV-associated Hospitalization in RSV Season 1

    Time frame: Up to 150 days in RSV Season 1

    RSV-associated hospitalization is defined as a hospital admission for respiratory illness and RSV-positive RT-PCR NP sample. The number of cases of RSV-associated hospitalization in RSV Season 1 is reported. For each participant, only the first occurrence of the case is counted for the analysis.

  3. Number of Participants With Solicited Injection-site AEs in RSV Season 2

    Time frame: Up to 5 days postdose in RSV Season 2 (Up to ~400 days)

    An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Solicited injection-site AEs included erythema, pain, and swelling. The number of participants with solicited injection-site AEs in RSV Season 2 is reported.

  4. Number of Participants With Solicited Daily Body Temperature With Fever in RSV Season 2

    Time frame: Up to 5 days postdose in RSV Season 2 (Up to ~400 days)

    Fever was defined as maximum rectal temperature ≥102.2 °F (39.0 °C) or maximum axillary temperature ≥101.7 °F. The number of participants with solicited daily body temperature of fever in RSV Season 2 is reported.

  5. Number of Participants With Solicited Systemic AEs in RSV Season 2

    Time frame: Up to 5 days postdose in RSV Season 2 (Up to ~400 days)

    An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Solicited systemic AEs included decreased appetite, irritability, and somnolence. The number of participants with solicited systemic AEs in RSV Season 2 is reported.

  6. Number of Participants With Anaphylaxis/Hypersensitivity AESI in RSV Season 2

    Time frame: Up to 42 days postdose in RSV Season 2 (Up to ~440 days)

    An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. The number of participants with anaphylaxis/hypersensitivity AESI in RSV Season 2 is reported.

  7. Number of Participants With Rash AESI in RSV Season 2

    Time frame: Up to 42 days postdose in RSV Season 2 (Up to ~440 days)

    An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Rash AESI included urticaria and drug eruption. The number of participants with rash AESI in RSV Season 2 is reported.

  8. Number of Participants With Nonserious AEs in RSV Season 2

    Time frame: Up to 42 days postdose in RSV Season 2 (Up to ~440 days)

    An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. The number of participants with nonserious AEs in RSV Season 2 is reported.

  9. Number of Participants With SAEs in RSV Season 2

    Time frame: Up 180 days postdose in RSV Season 2 (Up to ~575 days)

    An SAE is any untoward medical occurrence in a clinical study participant that results in death, is life-threatening, requires hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, or is another important medical event. The number of participants with SAEs in RSV Season 2 is reported.

  10. Concentration of Clesrovimab in RSV Season 1

    Time frame: At Day 7, Day 150, and Day 240 in RSV Season 1

    Blood samples were collected to determine the serum concentration of clesrovimab at Days 7, 150, and 240 in RSV Season 1.

  11. Concentration of Clesrovimab in RSV Season 2

    Time frame: At Day 7 and Day 150 postdose in RSV Season 2

    Blood samples were collected to determine the serum concentration of clesrovimab at Days 7 and 150 in RSV Season 2. RSV Season 2 began 246-393 days after RSV Season 1 dose 1.

Sponsors and collaborators

Lead sponsor

Merck Sharp & Dohme LLC

Industry

Registry information

Official study title

A Phase 3, Multicenter, Randomized, Partially Blinded, Palivizumab- Controlled Study to Evaluate the Safety, Efficacy, and Pharmacokinetics of MK-1654 in Infants and Children at Increased Risk for Severe RSV Disease

Acronym: SMART

Important dates

Study start
2021
Primary completion
2025
Study completion
2025
First posted
Jun 24, 2021
Registry last updated
May 8, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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