A Study to Assess the Safety, Tolerability, and Immunogenicity of RSVpreF in Older Adults in Korea

A PHASE 3 STUDY TO EVALUATE THE SAFETY, TOLERABILITY, AND IMMUNOGENICITY OF RESPIRATORY SYNCYTIAL VIRUS (RSV) PREFUSION F SUBUNIT VACCINE IN OLDER ADULTS IN KOREA

The goal of this clinical trial is to quantify the immune response in older Korean adults after a RSVpreF vaccination. It will also learn about the safety and tolerability of RSVpreF vaccination. The main questions it aims to answer are:

What local reactions and systemic events do participants have after a RSVpreF vaccination? What medical problems do participants have after a RSVpreF vaccination? Researchers will compare RSVpreF to a placebo (a look-alike substance that contains no RSVpreF) to see if RSVpreF is safe and well tolerated. It will also examine the change in antibody levels (immune responses) before and after vaccination.

Participants will:

Receive the RSVpreF vaccination or a placebo injection once at Visit 1. Visit the clinic a month later for a checkup and tests. Receive a phone call 1 week after vaccination, and 2 months after vaccination, for health checks.

Keep a diary of their symptoms for 7 days after vaccination.

Study Overview

• Status: Completed
• Conditions: Respiratory Syncytial Virus
• Intervention / Treatment: Other: Placebo; Biological: RSVpreF Vaccine

Detailed Description

This is a Phase 3, randomized, double-blinded, placebo-controlled, multicenter trial to describe the safety, tolerability, and immunogenicity of bivalent RSVpreF in adults 60 years of age and older in Korea.

The study duration is approximately 2 months. 4 study visits are required and are comprised of 2 scheduled clinic visits and 2 scheduled telephone calls.

Approximately 360 study-eligible participants will be randomized to receive either the 120-µg dose of RSVpreF or placebo in a 2:1 ratio.

After screening and confirmation of eligibility, a prevaccination blood sample will be collected for immunogenicity assessments and a single dose of study intervention (RSVpreF or placebo) will be administered.

Participants will report daily reactogenicity data using an electronic device for 7-days or until resolution.

Participants will return approximately 1 month later for a follow-up blood draw for immunogenicity assessments and collection of safety information.

A telephone follow-up visit will be conducted approximately 1 week after vaccination to review reactogenicity and approximately 2 months after vaccination to collect safety information.

For all participants, adverse events (AEs) will be collected from informed consent through 1 month following study intervention administration. Serious adverse events (SAEs) newly diagnosed chronic medical conditions (NDCMCs), and adverse events of special interest (AESIs) will be collected from informed consent throughout study participation.

• Study Type: Interventional
• Enrollment (Actual): 378
• Phase: Phase 3

Contacts and Locations

Study Locations

• South Korea
  • Incheon-gwangyeoksi [incheon]
    • Incheon, Incheon-gwangyeoksi [incheon], South Korea, 22332
      • Inha University Hospital
  • Jeonrabugdo
    • Jeonju, Jeonrabugdo, South Korea, 54907
      • Jeonbuk National University Hospital
  • Kwangju-kwangyǒkshi
    • Gwangju, Kwangju-kwangyǒkshi, South Korea, 61469
      • Chonnam National University Hospital
  • Kyǒnggi-do
    • Ansan-si, Kyǒnggi-do, South Korea, 15355
      • Korea University Ansan Hospital
    • Bucheon-si, Kyǒnggi-do, South Korea, 14584
      • Soon Chun Hyang University Bucheon Hospital
    • Suwon, Kyǒnggi-do, South Korea, 16499
      • Ajou University Hospital
    • Suwon, Kyǒnggi-do, South Korea, 16247
      • The Catholic University Of Korea St. Vincent's Hospital
  • Pusan-kwangyǒkshi
    • Busan, Pusan-kwangyǒkshi, South Korea, 49201
      • Dong-A University Hospital
  • Seoul-teukbyeolsi [seoul]
    • Seoul, Seoul-teukbyeolsi [seoul], South Korea, 06351
      • Samsung Medical Center
    • Seoul, Seoul-teukbyeolsi [seoul], South Korea, 08308
      • Korea University Guro Hospital
    • Seoul, Seoul-teukbyeolsi [seoul], South Korea, 06591
      • The Catholic Univ. of Korea Seoul St. Mary's Hospital
    • Seoul, Seoul-teukbyeolsi [seoul], South Korea, 03722
      • Severance Hospital, Yonsei University Health System
    • Seoul, Seoul-teukbyeolsi [seoul], South Korea, 05355
      • Hallym University Kangdong Sacred Heart Hospital
    • Seoul, Seoul-teukbyeolsi [seoul], South Korea, 07441
      • Hallym University Kangnam Sacred Heart Hospital
    • Seoul, Seoul-teukbyeolsi [seoul], South Korea, 07985
      • Ewha Womans University Mokdong Hospital
  • Taegu-kwangyǒkshi
    • Daegu, Taegu-kwangyǒkshi, South Korea, 41944
      • Kyungpook National University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. Participants 60 years of age or older at Visit 1

   • Male participants able to father children must agree to use a highly effective method of contraception from the time of informed consent through at least 28 days after study intervention administration
   • Female participants must not be of childbearing potential

2. Healthy participants who are determined by medical history, physical examination (if required), and clinical judgment of the investigator to be eligible for inclusion in the study.

   Healthy participants with preexisting stable disease, defined as disease not requiring significant change in therapy or hospitalization for worsening disease during the 6 weeks before enrollment, can be included.

3. Participants who are willing and able to comply with all scheduled visits, investigational plan, laboratory tests, frequent symptom assessment by mobile device application (e-diary), and other study procedures.
4. Participants who are ambulatory and live in the community, or in assisted-living or long-term care residential facilities that provide minimal assistance, such that the participant is primarily responsible for self-care and activities of daily living (ADL).
5. Capable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the informed consent document (ICD) and the protocol.

Exclusion Criteria:

1. A confirmed diagnosis of RSV infection ≤180 days before study intervention administration.
2. Bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular (IM) injection.
3. Prior history of any subtype of Guillain-Barré syndrome (GBS) of any etiology.
4. History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the study intervention(s) or any related vaccine.
5. Serious chronic disorder, including metastatic malignancy, end-stage renal disease with or without dialysis, clinically unstable cardiac disease, or any other disorder that, in the investigator's opinion, excludes the participant from participating in the study.
6. Immunocompromised individuals with known or suspected immunodeficiency, as determined by history and/or laboratory/physical examination.
7. Any medical or psychiatric condition, including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality, that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study.

8. Individuals who receive chronic systemic treatment with immunosuppressive therapy (other than systemic corticosteroids meeting the criteria noted below), including cytotoxic agents, immunosuppressive monoclonal antibodies, or radiotherapy, eg, for cancer or an autoimmune disease, from 60 days before study intervention administration or planned receipt throughout the study.

   • Receipt of systemic corticosteroids (≥20 mg/day of prednisone or equivalent) for

     ≥14 days from 28 days before study intervention.

   • Inhaled/nebulized, intra articular, intrabursal, or topical (skin or eyes) corticosteroids are permitted.
9. Receipt of blood/plasma products or immunoglobulin within 60 days before study intervention administration.
10. Previous vaccination with any licensed or investigational RSV vaccine, or planned receipt throughout the study.
11. Previous administration with an investigational product (drug or vaccine) within 6 months prior to study intervention administration. Participation in other studies involving an investigational product (drug or vaccine) at any time during participation in this study.

12. Investigator site staff directly involved in the conduct of the study and their family members, site staff otherwise supervised by the investigator, and sponsor and sponsor delegate employees directly involved in the conduct of the study and their family members.

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Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo	Other: Placebo; Placebo
Experimental: RSVpreF	Biological: RSVpreF Vaccine; RSV Vaccine 120 mcg

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of Participants With Local Reactions Within 7 Days After Vaccination	Local reactions included redness, swelling and pain at injection site. Redness and swelling were measured and recorded in measuring device units. 1 measuring device unit=0.5 centimeter (cm). Redness and swelling were graded as mild: > 2.0 cm to 5.0 cm, moderate: > 5.0 cm to 10.0 cm, severe: >10.0 cm. Pain at injection site was graded as mild: did not interfere with activity, moderate: interfered with activity, severe: prevented daily activity. Any local reaction: any redness, any swelling, or pain at the injection site of at least mild severity. Exact 2-sided 95% confidence interval (CI) was based on the Clopper and Pearson method.	From Day 1 to Day 7 after vaccination
Percentage of Participants With Systemic Events Within 7 Days After Vaccination	Systemic events included fever, fatigue, headache, vomiting, nausea, diarrhea, muscle pain and joint pain. Fever defined as oral temperature >=38.0 degrees Celsius (deg C) and categorized as mild: >=38.0 to 38.4 deg C, moderate: >38.4 to 38.9 deg C, severe: >38.9 to 40.0 deg C, and Grade 4: >40.0 deg C. Vomiting categorized as mild: 1-2 times in 24 hours (h); moderate: >2 times in 24h; severe: required intravenous (IV) hydration. Diarrhea categorized as mild: 2-3 loose stools in 24h; moderate: 4-5 loose stools in 24h; severe: 6 or more loose stools in 24h. Headache, fatigue, nausea, muscle pain and joint pain were categorized as mild: didn't interfere with activity; moderate: some interference with activity; severe: prevented daily routine activity. Exact 2-sided 95% CI was based on the Clopper and Pearson method.	From Day 1 to Day 7 after vaccination
Percentage of Participants With Adverse Events (AEs) From Vaccination Through 1 Month After Vaccination	An AE was any untoward medical occurrence in a participant temporally associated with the use of study intervention, whether or not considered related to the study intervention. Exact 2-sided 95% CI was based on the Clopper and Pearson method. Only AEs collected by non-systematic assessment (i.e. excluding local reactions and systemic events) were reported in this outcome measure.	From vaccination on Day 1 up to 1 month after vaccination
Percentage of Participants With Serious Adverse Events (SAEs) From Vaccination Throughout the Study	An SAE was defined as an AE that, at any dose met one of the following criteria: resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity; was a congenital anomaly/birth defect; was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or nonpathogenic; other significant medical events as judged by investigator. Exact 2-sided 95% CI was based on the Clopper and Pearson method.	From vaccination on Day 1 up to 2 months after vaccination
Percentage of Participants With Newly Diagnosed Chronic Medical Conditions (NDCMCs) From Vaccination Throughout the Study	A NDCMC was defined as a disease or medical condition that was not identified prior to study start and was expected to be persistent or otherwise long-lasting in its effects. Newly diagnosed chronic medical condition did not include illnesses considered to be temporary conditions. Exact 2-sided 95% CI was based on the Clopper and Pearson method.	From vaccination on Day 1 up to 2 months after vaccination
Geometric Mean Titer (GMT) of Neutralizing Titers (NTs) for RSV A and RSV B Before Vaccination	GMTs and the corresponding 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on the Student t distribution). Assay results below the lower limit of quantification (LLOQ) were set to 0.5*LLOQ for analysis.	Before Vaccination
Geometric Mean Titer (GMT) of Neutralizing Titers (NTs) for RSV A and RSV B at 1 Month After Vaccination	GMTs and the corresponding 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on the Student t distribution). Assay results below the LLOQ were set to 0.5*LLOQ for analysis.	1 month after vaccination
Geometric Mean Fold Rise (GMFR) of Neutralizing Titers (NTs) for RSV A and RSV B From Before Vaccination to 1 Month After Vaccination	Fold rises was defined as ratios of the results after vaccination to the results before vaccination. GMFRs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of fold rises and the corresponding CIs (based on the Student t distribution).	From before vaccination to 1 month after vaccination

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Seroresponse Rates of Neutralizing Titers (NTs) for RSV A and RSV B at 1 Month After Vaccination	Seroresponse rate was defined as the percentage of participants with a postvaccination NT >=4 times the LLOQ if the baseline titer (before vaccination) was below the LLOQ; or a >=4-fold rise from baseline if the baseline titer was>=LLOQ. 95% CI was based on Clopper-Pearson method.	1 month after vaccination

Collaborators and Investigators

• Sponsor: Pfizer
• Investigators: Study Director: Pfizer CT.gov Call Center, Pfizer

Publications and helpful links

Helpful Links

• To obtain contact information for a study center near you, click here.

Study record dates

Study Major Dates

• Study Start (Actual): October 7, 2024
• Primary Completion (Actual): February 3, 2025
• Study Completion (Actual): February 3, 2025

Study Registration Dates

• First Submitted: September 9, 2024
• First Submitted That Met QC Criteria: September 9, 2024
• First Posted (Actual): September 19, 2024

Study Record Updates

• Last Update Posted (Actual): February 9, 2026
• Last Update Submitted That Met QC Criteria: January 21, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Vaccine; RSV; Older adults; Respiratory tract infection; Respiratory Syncytial Virus
• Additional Relevant MeSH Terms: Infections; Respiratory Tract Diseases; Respiratory Tract Infections
• Other Study ID Numbers: C3671053; NCT06593587 (Registry Identifier: ClinicalTrials.gov)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes