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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

Status
Completed
Phases
Phase 3
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT06593587
Enrollment
378
Registered
2024-09-19
Start date
2024-10-07
Completion date
2025-02-03
Last updated
2026-02-09

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Respiratory Syncytial Virus

Keywords

Respiratory tract infection, RSV, Respiratory Syncytial Virus, Vaccine, Older adults

Brief summary

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.

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.

Interventions

BIOLOGICALRSVpreF Vaccine

RSV Vaccine 120 mcg

OTHERPlacebo

Placebo

Sponsors

Pfizer
Lead SponsorINDUSTRY

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Masking description

This study is double-blinded. The participant, study coordinator, and all site staff will be blinded. The majority of sponsor staff will be blinded to study intervention allocation. All laboratory testing personnel performing serological assays or diagnostic assays will remain blinded to the study intervention assigned/received throughout the study

Intervention model description

Parallel

Eligibility

Sex/Gender
ALL
Age
60 Years to No maximum
Healthy volunteers
Yes

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. \-

Design outcomes

Primary

MeasureTime frameDescription
Percentage of Participants With Local Reactions Within 7 Days After VaccinationFrom Day 1 to Day 7 after vaccinationLocal 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.
Percentage of Participants With Systemic Events Within 7 Days After VaccinationFrom Day 1 to Day 7 after vaccinationSystemic 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.
Percentage of Participants With Adverse Events (AEs) From Vaccination Through 1 Month After VaccinationFrom vaccination on Day 1 up to 1 month after vaccinationAn 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.
Percentage of Participants With Serious Adverse Events (SAEs) From Vaccination Throughout the StudyFrom vaccination on Day 1 up to 2 months after vaccinationAn 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.
Percentage of Participants With Newly Diagnosed Chronic Medical Conditions (NDCMCs) From Vaccination Throughout the StudyFrom vaccination on Day 1 up to 2 months after vaccinationA 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.
Geometric Mean Titer (GMT) of Neutralizing Titers (NTs) for RSV A and RSV B Before VaccinationBefore VaccinationGMTs 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.
Geometric Mean Titer (GMT) of Neutralizing Titers (NTs) for RSV A and RSV B at 1 Month After Vaccination1 month after vaccinationGMTs 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.
Geometric Mean Fold Rise (GMFR) of Neutralizing Titers (NTs) for RSV A and RSV B From Before Vaccination to 1 Month After VaccinationFrom before vaccination to 1 month after vaccinationFold 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).

Secondary

MeasureTime frameDescription
Seroresponse Rates of Neutralizing Titers (NTs) for RSV A and RSV B at 1 Month After Vaccination1 month after vaccinationSeroresponse 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.

Countries

South Korea

Contacts

STUDY_DIRECTORPfizer CT.gov Call Center

Pfizer

Participant flow

Recruitment details

This study was conducted at 16 sites in the Republic of Korea.

Pre-assignment details

A total of 384 participants were screened, out of which 6 were screen failures and 378 participants were randomized 2:1 to receive respiratory syncytial virus stabilized prefusion F subunit vaccine (RSVpreF) or placebo.

Baseline characteristics

Characteristic
Age, Continuous67.3 Years
STANDARD_DEVIATION 5.17
Race/Ethnicity, Customized
Ethnicity
Non-Hispanic/non-Latino
126 Participants
Race/Ethnicity, Customized
Race
Asian
126 Participants
Sex: Female, Male
Female
76 Participants
Sex: Female, Male
Male
50 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
deaths
Total, all-cause mortality
0 / 2510 / 126
other
Total, other adverse events
100 / 25143 / 126
serious
Total, serious adverse events
2 / 2511 / 126

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Sep 5, 2026