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

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

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).

Study Overview

• Status: Completed
• Conditions: RSV Infection
• Intervention / Treatment: Biological: Clesrovimab; Biological: Placebo; Biological: Palivizumab

• Study Type: Interventional
• Enrollment (Actual): 1003
• Phase: Phase 3

Contacts and Locations

Study Locations

• Australia
  • Queensland
    • Brisbane, Queensland, Australia, 4101
      • Mater Misericordiae Limited-Neonatalogy ( Site 0102)
  • Western Australia
    • Nedlands, Western Australia, Australia, 6009
      • Telethon Kids Institute-Vaccine Trials Group ( Site 0101)
• Canada
  • Alberta
    • Calgary, Alberta, Canada, T3B 6A8
      • Alberta Children's Hospital-Department of Pediatrics ( Site 0180)
  • Nova Scotia
    • Halifax, Nova Scotia, Canada, B3K 6R8
      • Canadian Center for Vaccinology ( Site 0179)
  • Quebec
    • Montreal, Quebec, Canada, H3T 1C5
      • CHU Sainte-Justine ( Site 0178)
• Chile
  • Region M. de Santiago
    • Santiago, Region M. de Santiago, Chile, 8320325
      • Clínica Alemana de Santiago-Neonatology department ( Site 0207)
    • Santiago, Region M. de Santiago, Chile, 8380418
      • Hospital Roberto del Río-Infectología Pediátrica ( Site 0205)
    • Santiago, Region M. de Santiago, Chile, 8880465
      • Hospital Padre Hurtado-NEONATOLOGY/PEDIATRICS ( Site 0201)
• Colombia
  • Antioquia
    • Medellín, Antioquia, Colombia, 050010
      • Fundación Hospitalaria San Vicente de Paúl ( Site 0233)
    • Medellín, Antioquia, Colombia, 50036
      • Clínica Universitaria Bolivariana ( Site 0227)
  • Atlántico
    • Barranquilla, Atlántico, Colombia, 08001
      • Ciensalud Ips S A S ( Site 0235)
  • Bogota D.C.
    • Bogotá, Bogota D.C., Colombia, 111411
      • Sociedad de Cirugía de Bogotá - Hospital de San Jose ( Site 0230)
  • Valle del Cauca Department
    • Cali, Valle del Cauca Department, Colombia, 760042
      • Clínica Imbanaco S.A.S ( Site 0229)
• Czechia
  • Moravian-Silesian Region
    • Ostrava, Moravian-Silesian Region, Czechia, 708 52
      • Fakultni nemocnice Ostrava-Oddeleni neonatologie ( Site 0252)
  • Praha 4
    • Prague, Praha 4, Czechia, 14700
      • Institute for the Care of Mother and Child ( Site 0251)
• Finland
  • Keski-Pohjanmaa
    • Kokkola, Keski-Pohjanmaa, Finland, 67100
      • FVR, Kokkolan rokotetutkimusklinikka ( Site 0304)
  • North Ostrobothnia
    • Oulu, North Ostrobothnia, Finland, 90220
      • FVR, Oulun rokotetutkimusklinikka ( Site 0303)
  • Pirkanmaa
    • Tampere, Pirkanmaa, Finland, 33100
      • FVR, Tampereen rokotetutkimusklinikka ( Site 0301)
  • South Ostrobothnia
    • Seinäjoki, South Ostrobothnia, Finland, 60100
      • FVR, Seinäjoen rokotetutkimusklinikka ( Site 0305)
  • Southwest Finland
    • Turku, Southwest Finland, Finland, 20520
      • FVR, Turun rokotetutkimusklinikka ( Site 0302)
  • Uusimaa
    • Helsinki, Uusimaa, Finland, 00290
      • MeVac - Meilahti Vaccine Research Center ( Site 0306)
• France
  • Aquitaine
    • Bordeaux, Aquitaine, France, 33076
      • Bordeaux University Hospital - Pellegrin-Pediatrics ( Site 0332)
  • Calvados
    • Caen, Calvados, France, 14033
      • Centre Hospitalier Universitaire de Caen - Hôpital Côte de N-Centre de Recherche Clinique Pédiatriq ( Site 0330)
  • Yvelines
    • Le Chesnay, Yvelines, France, 78157
      • Centre Hospitalier de Versailles André Mignot-NEONATOLOGY ( Site 0331)
• Germany
  • Baden-Wurttemberg
    • Freiburg im Breisgau, Baden-Wurttemberg, Germany, 79106
      • Universitaetsklinikum Freiburg ( Site 0365)
    • Heidelberg, Baden-Wurttemberg, Germany, 69120
      • Universitaetsklinikum Heidelberg-Zentrum für Kinder-und Jugendmedizin ( Site 0366)
  • Bavaria
    • Munich, Bavaria, Germany, 80337
      • Dr. von Haunersches Kinderspital ( Site 0358)
    • Munich, Bavaria, Germany, 81545
      • München Klinik Harlaching ( Site 0351)
  • Lower Saxony
    • Hanover, Lower Saxony, Germany, 30625
      • Medizinische Hochschule Hannover ( Site 0364)
  • North Rhine-Westphalia
    • Oberhausen, North Rhine-Westphalia, Germany, 46145
      • Kinder und Jugendaerztliche Gemeinschaftspraxis Bedikian & Bouikidis ( Site 0359)
  • Saxony
    • Dresden, Saxony, Germany, 01307
      • Universitaetsklinikum Carl Gustav Carus Dresden-Klinik und Poliklinik für Kinder- und Jugendmedizin ( Site 0363)
    • Leipzig, Saxony, Germany, 04103
      • Universitätsklinikum Leipzig-Neonatology ( Site 0354)
  • Schleswig-Holstein
    • Lübeck, Schleswig-Holstein, Germany, 23538
      • Universitätsklinikum Schleswig-Holstein-Pediatrics ( Site 0361)
• Greece
  • Attica
    • Athens, Attica, Greece, 115 27
      • Aghia Sophia Children's Hospital-First Department of Pediatrics, National and Kapodistrian Universi ( Site 0852)
    • Athens, Attica, Greece, 115 27
      • Children's Hospital Aglaia Kyriakou-2nd Department of Pediatrics NKUA ( Site 0854)
    • Chaïdári, Attica, Greece, 124 62
      • ATTIKON GENERAL UNIVERSITY HOSPITAL-3rd Department of Pediatrics ( Site 0855)
  • Central Macedonia
    • Thessaloniki, Central Macedonia, Greece, 54642
      • Hippokration University Hopsital-3rd Pediatric Department ( Site 0851)
• Hong Kong
  • Shatin, Hong Kong
    • Prince of Wales Hospital ( Site 0926)
  • Tuenmen, Hong Kong, 999077
    • Tuen Mun Hospital ( Site 0927)
• Hungary
  • Budapest, Hungary, 1076
    • Péterfy Kórház-Rendelőintézet és Manninger Jenő Országos Traumatológiai Intézet-PIC ( Site 0384)
  • Budapest, Hungary, 1082
    • Semmelweis University-Szülészeti és Nőgyógyászati Klinika PIC ( Site 0381)
  • Budapest, Hungary, 1096
    • Gottsegen György Országos Kardiovaszkuláris Intézet ( Site 0383)
  • Debrecen, Hungary, 4032
    • Debreceni Egyetem Klinikai Kozpont ( Site 0378)
  • Borsod-Abauj Zemplen county
    • Miskolc, Borsod-Abauj Zemplen county, Hungary, 3526
      • Borsod-Abaúj-Zemplén Megyei Központi Kórház és Egyetemi Oktatókórház-Újszülött Intenzív Osztály ( Site 0388)
  • Bács-Kiskun county
    • Baja, Bács-Kiskun county, Hungary
      • Bajai Szent Rókus Kórház ( Site 0386)
    • Kecskemét, Bács-Kiskun county, Hungary, 6000
      • Bacs-Kiskun Megyei Korhaz-Pediatrics ( Site 0380)
  • Szabolcs-Szatmár-Bereg
    • Nyíregyháza, Szabolcs-Szatmár-Bereg, Hungary, 4400
      • Szabolcs-Szatmar-Bereg Varmegyei Korhazak es Egyetemi Oktatokorhaz - Gyermekosztaly ( Site 0376)
• Italy
  • Parma, Italy, 43126
    • Azienda Ospedaliero Universitaria di Parma-UO Clinica Pediatrica ( Site 0433)
  • Lazio
    • Rome, Lazio, Italy, 00165
      • Ospedale Pediatrico Bambino Gesù IRCCS-UOC Broncopneumologia ( Site 0427)
    • Rome, Lazio, Italy, 00168
      • Fondazione Policlinico Universitario Agostino Gemelli ( Site 0426)
  • Lombardy
    • Milan, Lombardy, Italy, 20122
      • Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico ( Site 0432)
    • Milan, Lombardy, Italy, 20154
      • ASST Fatebenefratelli Sacco ( Site 0434)
  • Veneto
    • Padova, Veneto, Italy, 35128
      • Azienda Ospedaliera di Padova-Department of Women and Child Health ( Site 0428)
• Japan
  • Shizuoka, Japan, 422-8527
    • Shizuoka Saiseikai General Hospital ( Site 0456)
  • Tokyo, Japan, 157-8535
    • National Center for Child Health and Development ( Site 0455)
  • Fukuoka
    • Fukuoka, Fukuoka, Japan, 813-0017
      • Fukuoka Children's Hospital ( Site 0452)
    • Iizuka, Fukuoka, Japan, 820-8505
      • Iizuka Hospital ( Site 0457)
    • Kitakyushu-shi, Fukuoka, Japan, 806-8501
      • Japan Community Healthcare Organization Kyushu Hospital ( Site 0454)
  • Gunma
    • Maebashi, Gunma, Japan, 371-0811
      • Maebashi Red Cross Hospital ( Site 0451)
  • Ibaraki
    • Mito, Ibaraki, Japan, 311-4145
      • Ibaraki Children's Hospital ( Site 0458)
  • Tokyo
    • Itabashiku, Tokyo, Japan, 173-8610
      • Nihon University Itabashi Hospital ( Site 0453)
• Malaysia
  • Kuala Lumpur, Malaysia, 50300
    • Hospital Tunku Azizah-Paediatric ( Site 0481)
  • Kelantan
    • Kota Bharu, Kelantan, Malaysia, 15586
      • Hospital Raja Perempuan Zainab II-Department of Pediatric ( Site 0477)
  • Kuala Lumpur
    • Lembah Pantai, Kuala Lumpur, Malaysia, 59100
      • University Malaya Medical Centre-Department of Paediatrics ( Site 0480)
  • Pulau Pinang
    • George Town, Pulau Pinang, Malaysia, 10450
      • Hospital Pulau Pinang ( Site 0482)
  • Sabah
    • Kota Kinabalu, Sabah, Malaysia, 88996
      • Sabah Women and Children Hospital ( Site 0478)
  • Sarawak
    • Sibu, Sarawak, Malaysia, 96000
      • Hospital Sibu ( Site 0476)
• Mexico
  • Durango, Mexico, 34000
    • Instituto de Investigaciones Aplicadas a la Neurociencia A.C. ( Site 0508)
  • Oaxaca City, Mexico, 68000
    • Oaxaca Site Management Organization ( Site 0504)
  • San Luis Potosí City, Mexico, 78209
    • ONCOLOGICO POTOSINO, S.C. ( Site 0505)
  • Guanajuato
    • León, Guanajuato, Mexico, 37000
      • Morales Vargas Centro de Investigacion ( Site 0509)
  • Jalisco
    • Guadalajara, Jalisco, Mexico, 44650
      • Centro de Investigación Médico Biológica y Terapia Avanzada ( Site 0502)
  • Mexico City
    • Mexico City, Mexico City, Mexico, 04530
      • Instituto Nacional de Pediatria ( Site 0506)
• New Zealand
  • Auckland, New Zealand, 2025
    • Middlemore Clinical Trials ( Site 0526)
  • Wellington Region
    • Newtown, Wellington Region, New Zealand, 6021
      • Capital and Coast District Health Board-Clinical Trials Unit ( Site 0527)
• Norway
  • Oslo, Norway, 0450
    • Oslo Universitetssykehus Ullevål ( Site 0551)
• Peru
  • Lima, Peru, 15001
    • HOSPITAL DOCENTE MADRE-NIÑO SAN BARTOLOME-NEUMOLOGIA PEDIATRICA ( Site 0576)
  • Lima
    • Jesús María, Lima, Peru, 15072
      • Instituto Nacional Cardiovascular INCOR Carlos Peschiera Carrillo - EsSalud ( Site 0577)
• Puerto Rico
  • San Juan, Puerto Rico, 00935
    • UPR Medical Sciences Campus-Pediatrics ( Site 0626)
• Singapore
  • South West
    • Singapore, South West, Singapore, 229899
      • KK Women's and Children's Hospital-Department of Neonatology ( Site 0877)
• South Africa
  • Gauteng
    • Boksburg, Gauteng, South Africa, 1459
      • Reimed ( Site 0706)
    • Soweto, Gauteng, South Africa, 2013
      • Chris Hani Baragwanath Academic Hospital ( Site 0701)
  • KwaZulu-Natal
    • Durban, KwaZulu-Natal, South Africa, 4001
      • King Edward VIII Hospital ( Site 0704)
  • Western Cape
    • Cape Town, Western Cape, South Africa, 7500
      • Family Clinical Research Unit (Fam-Cru)-Pediatric ( Site 0703)
    • Cape Town, Western Cape, South Africa, 7500
      • Panorama Medical Centre ( Site 0702)
    • Cape Town, Western Cape, South Africa, 7700
      • MRC Unit on Child And Adolescent Health-Department of Paediatrics and child Health ( Site 0710)
    • Cape Town, Western Cape, South Africa, 7824
      • 2 Military Hospital ( Site 0708)
• Spain
  • Madrid, Spain, 28046
    • Hospital Universitario La Paz ( Site 0726)
  • Málaga, Spain, 29015
    • Grupo Pediatrico Uncibay ( Site 0734)
  • Barcelona
    • Badalona, Barcelona, Spain, 08916
      • Hospital Germans Trias i Pujol ( Site 0738)
    • Esplugues de Llobregat, Barcelona, Spain, 08950
      • Hospital Sant Joan de Déu ( Site 0730)
    • Sant Cugat del Vallès, Barcelona, Spain, 08195
      • Hospital Universitary General de Catalunya-Pediatrics ( Site 0737)
  • La Coruna
    • Santiago de Compostela, La Coruna, Spain, 15706
      • CHUS - Hospital Clinico Universitario-Servicio de Pediatría ( Site 0731)
  • Madrid
    • Boadilla del Monte, Madrid, Spain, 28660
      • Hospital Universitario HM Monteprincipe-pediatric ( Site 0743)
    • Pozuelo de Alarcón, Madrid, Spain, 28223
      • HOSPITAL UNIVERSITARIO QUIRONSALUD MADRID ( Site 0739)
  • Madrid, Comunidad de
    • Madrid, Madrid, Comunidad de, Spain, 28041
      • Hospital Universitario 12 de Octubre-Unidad Pediátrica de Investigación y Ensayos Clínicos ( Site 0728)
  • Principality of Asturias
    • Oviedo, Principality of Asturias, Spain, 33011
      • Hospital Universitario Central de Asturias ( Site 0740)
• Taiwan
  • Taichung, Taiwan, 407
    • Taichung Veterans General Hospital ( Site 0754)
  • Taipei, Taiwan, 10449
    • Mackay Memorial Hospital-Pediatrics ( Site 0753)
  • Taipei, Taiwan, 10002
    • National Taiwan University Hospital ( Site 0751)
  • Taoyuan, Taiwan, 33305
    • Chang Gung Medical Foundation-Linkou Branch ( Site 0752)
• Thailand
  • Bangkok
    • Bangkok, Bangkok, Thailand, 10330
      • Chulalongkorn University-Pediatrics ( Site 0777)
    • Bangkok, Bangkok, Thailand, 10700
      • Faculty of Medicine Siriraj Hospital-Pediatric Infectious Diseases ( Site 0778)
  • Changwat Songkhla
    • Hat Yai, Changwat Songkhla, Thailand, 90110
      • Songklanagarind hospital-Department of Pediatrics ( Site 0776)
• Turkey (Türkiye)
  • Ankara, Turkey (Türkiye), 06100
    • Ankara University Hospital Cebeci ( Site 0801)
  • Ankara, Turkey (Türkiye), 06560
    • Gazi Universitesi ( Site 0806)
  • Ankara, Turkey (Türkiye), 06800
    • Ankara Bilkent Şehir Hastanesi. ( Site 0807)
  • Kayseri, Turkey (Türkiye), 38039
    • Erciyes University Medical Faculty-pediatric infection ( Site 0804)
  • Adana
    • Sarçam, Adana, Turkey (Türkiye), 01030
      • cukurova universty ( Site 0805)
• United Kingdom
  • Liverpool, United Kingdom, L12 2AP
    • Alder Hey Children's Hospital-Paediatric Respiratory Medicine ( Site 0843)
  • England
    • London, England, United Kingdom, E11 1NR
      • Whipps Cross University Hospital ( Site 0846)
    • London, England, United Kingdom, SW17 0RE
      • St. George's Hospital ( Site 0845)
  • Glasgow City
    • Glasgow, Glasgow City, United Kingdom, G51 4TF
      • Queen Elizabeth University Hospital ( Site 0842)
  • Great Britain
    • London, Great Britain, United Kingdom, SE1 7EH
      • Evelina London Children's Hospital ( Site 0829)
  • Hampshire
    • Southampton, Hampshire, United Kingdom, SO16 0YD
      • Southampton General Hospital ( Site 0826)
  • London, City of
    • London, London, City of, United Kingdom, E1 1BB
      • Barts Health NHS Trust-Children's Clinical Research Facility ( Site 0844)
  • Oxfordshire
    • Oxford, Oxfordshire, United Kingdom, OX3 9DU
      • The John Radcliffe Hospital-Paediatrics Infectious Diseases ( Site 0827)
• United States
  • California
    • Long Beach, California, United States, 90806
      • Miller Children's & Women's Hospital Long Beach ( Site 0001)
    • Orange, California, United States, 92868
      • Children's Hospital of Orange County ( Site 0047)
  • Colorado
    • Aurora, Colorado, United States, 80045
      • Children's Hospital Colorado ( Site 0011)
  • District of Columbia
    • Washington D.C., District of Columbia, United States, 20010
      • Children's National Medical Center ( Site 0020)
  • Florida
    • Orlando, Florida, United States, 32827
      • Nemours Children's Health, Lake Nona Medical City ( Site 0032)
    • Orlando, Florida, United States, 32806
      • Orlando Health - Arnold Palmer Hospital-Orlando Health-Arnold Palmer Hospital Pulmonary and Sleep M ( Site 0022)
    • Tampa, Florida, United States, 33606
      • University of South Florida-Department of Pediatrics ( Site 0045)
  • Georgia
    • Atlanta, Georgia, United States, 30310
      • Morehouse School Of Medicine ( Site 0049)
  • Idaho
    • Idaho Falls, Idaho, United States, 83404
      • Clinical Research Prime ( Site 0046)
  • Kentucky
    • Lexington, Kentucky, United States, 40536
      • University of Kentucky HealthCare - Turfland ( Site 0044)
  • Louisiana
    • Baton Rouge, Louisiana, United States, 70809
      • Our Lady of the Lake Children's Hospital ( Site 0031)
    • New Orleans, Louisiana, United States, 70112
      • Tulane University School of Medicine ( Site 0010)
  • Minnesota
    • Minneapolis, Minnesota, United States, 55454
      • M Health Fairview University of Minnesota Masonic Children's Hospital, West Bank-Peds Research ( Site 0037)
  • New Jersey
    • New Brunswick, New Jersey, United States, 08901
      • Rutgers University-Pediatric Clinical Research Center ( Site 0007)
  • New York
    • Mineola, New York, United States, 11501
      • NYU Langone Hospital - Long Island-Pediatrics ( Site 0028)
    • Rochester, New York, United States, 14642
      • University of Rochester Medical Center ( Site 0017)
  • North Carolina
    • Chapel Hill, North Carolina, United States, 27514
      • The University of North Carolina at Chapel Hill ( Site 0035)
    • Durham, North Carolina, United States, 27710
      • Duke University ( Site 0021)
  • Ohio
    • Dayton, Ohio, United States, 45449
      • Dayton Children's Hospital ( Site 0053)
  • South Carolina
    • Greenville, South Carolina, United States, 29607
      • Tribe Clinical Research, LLC ( Site 0002)
  • Texas
    • Corpus Christi, Texas, United States, 78411
      • Driscoll Children's Hospital ( Site 0025)
    • Edinburg, Texas, United States, 78539
      • DHR Health Institute for Research and Development ( Site 0029)
    • San Antonio, Texas, United States, 78207
      • Christus Children's-Clinical Research Center ( Site 0038)
    • San Antonio, Texas, United States, 78229
      • University Hospital-Pediatrics ( Site 0019)
    • San Antonio, Texas, United States, 78249
      • Road Runner Research, Ltd ( Site 0052)
  • Utah
    • Salt Lake City, Utah, United States, 84113
      • Intermountain - Primary Children's Hospital ( Site 0026)
  • Washington
    • Spokane, Washington, United States, 99202
      • Multicare Rockwood Main Clinic-Rockwood Pediatrics ( Site 0004)
    • Spokane, Washington, United States, 99204
      • Providence Sacred Heart Medical Center & Children's Hospital ( Site 0030)
    • Tacoma, Washington, United States, 98405
      • MultiCare Health System-Baker Center ( Site 0036)

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: No older than 1 year (Child)
• Accepts Healthy Volunteers: No

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Clesrovimab; Participants will receive intramuscular (IM) injections of clesrovimab and placebo	Biological: Clesrovimab; IM injection; Other Names: MK-1654; Biological: Placebo; IM injection
Active Comparator: Palivizumab; Participants will receive IM injections.	Biological: Palivizumab; IM injection; Other Names: Synagis™

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants With Solicited Injection-site Adverse Events (AEs) in RSV Season 1	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.	Up to 5 days after each dose in RSV Season 1 (Up to ~33 days)
Number of Participants With Solicited Daily Body Temperatures With Fever in RSV Season 1	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.	Up to 5 days after each dose in RSV Season 1 (Up to ~33 days)
Number of Participants With Solicited Systemic AEs in RSV Season 1	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.	Up to 5 days after each dose in RSV Season 1 (Up to ~33 days)
Number of Participants With Anaphylaxis/Hypersensitivity AEs of Special Interest (AESI) 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.	Up to 42 days in RSV Season 1
Number of Participants With Rash AESI 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.	Up to 42 days in RSV Season 1
Number of Participants With Nonserious AEs 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.	Up to 42 days in RSV Season 1
Number of Participants With Serious AEs (SAEs) Through the Duration of Participation 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.	Up to 365 days in RSV Season 1

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Cases of RSV-associated Medically Attended Lower Respiratory Infection (MALRI) 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.	Up to 150 days in RSV Season 1
Number of Cases of RSV-associated Hospitalization 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.	Up to 150 days in RSV Season 1
Number of Participants With Solicited Injection-site AEs in RSV Season 2	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.	Up to 5 days postdose in RSV Season 2 (Up to ~400 days)
Number of Participants With Solicited Daily Body Temperature With Fever in RSV Season 2	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.	Up to 5 days postdose in RSV Season 2 (Up to ~400 days)
Number of Participants With Solicited Systemic AEs in RSV Season 2	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.	Up to 5 days postdose in RSV Season 2 (Up to ~400 days)
Number of Participants With Anaphylaxis/Hypersensitivity AESI in RSV Season 2	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.	Up to 42 days postdose in RSV Season 2 (Up to ~440 days)
Number of Participants With Rash AESI in RSV Season 2	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.	Up to 42 days postdose in RSV Season 2 (Up to ~440 days)
Number of Participants With Nonserious AEs in RSV Season 2	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.	Up to 42 days postdose in RSV Season 2 (Up to ~440 days)
Number of Participants With SAEs in RSV Season 2	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.	Up 180 days postdose in RSV Season 2 (Up to ~575 days)
Concentration of Clesrovimab 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.	At Day 7, Day 150, and Day 240 in RSV Season 1
Concentration of Clesrovimab 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.	At Day 7 and Day 150 postdose in RSV Season 2

Collaborators and Investigators

• Sponsor: Merck Sharp & Dohme LLC
• Investigators: Study Director: Medical Director, Merck Sharp & Dohme LLC

Publications and helpful links

General Publications

• Zar HJ, Bont LJ, Manzoni P, Munoz FM, Ramilo O, Chen PY, Novoa JM, Ordonez GA, Tsolia M, Tapiero B, Acuna-Avila MI, Castellanos JM, Meyer M, Morioka I, Chen Z, Railkar RA, Zang X, Maas BM, Likos A, Lee AW, Castagnini LA, Sinha A; SMART (MK-1654-007) Study Group. Clesrovimab in Infants and Children at Increased Risk for Severe RSV Disease. N Engl J Med. 2025 Oct 2;393(13):1343-1345. doi: 10.1056/NEJMc2506107. Epub 2025 Sep 17. No abstract available.
• Sinha A, Railkar RA, Castagnini L, Guerra A, Likos A, Lutkiewicz J, Maas BM, Zang X, Roadcap BA, Choi Y, Nahhas GJ, Arriola CS, Bont L, Manzoni P, Ramilo O, Munoz FM, Finelli L, Lee AW. Evaluation of a monoclonal antibody against respiratory syncytial virus, clesrovimab, in infants and children: Comprehensive rationale and study design for the late-stage clinical trials. Contemp Clin Trials. 2025 Oct;157:107995. doi: 10.1016/j.cct.2025.107995. Epub 2025 Jun 30.

Helpful Links

• Merck Clinical Trials Information
• Plain Language Summary

Study record dates

Study Major Dates

• Study Start (Actual): November 30, 2021
• Primary Completion (Actual): April 28, 2025
• Study Completion (Actual): August 1, 2025

Study Registration Dates

• First Submitted: June 22, 2021
• First Submitted That Met QC Criteria: June 22, 2021
• First Posted (Actual): June 24, 2021

Study Record Updates

• Last Update Posted (Actual): May 8, 2026
• Last Update Submitted That Met QC Criteria: April 17, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Infections; RNA Virus Infections; Virus Diseases; Pneumovirus Infections; Paramyxoviridae Infections; Mononegavirales Infections; Respiratory Syncytial Virus Infections; Amino Acids, Peptides, and Proteins; Proteins; Antibodies, Monoclonal, Humanized; Antibodies, Monoclonal; Antibodies; Immunoglobulins; Immunoproteins; Blood Proteins; Serum Globulins; Globulins; Palivizumab; MK-1654
• Other Study ID Numbers: 1654-007; MK-1654-007 (Other Identifier: MSD); jRCT2031210664 (Registry Identifier: jRCT); 2020-005996-11 (EudraCT Number); U1111-1278-0093 (Registry Identifier: UTN); 2022-500752-39-00 (Registry Identifier: EU CT)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No