A Study to Learn About the Safety and Immune Activity of RSVpreF in Children 2 to <18 Years of Age

A PHASE 1, OPEN-LABEL, AGE-DESCENDING, DOSE-FINDING STUDY TO EVALUATE THE SAFETY, TOLERABILITY, AND IMMUNOGENICITY OF RESPIRATORY SYNCYTIAL VIRUS PREFUSION F SUBUNIT VACCINE (RSVpreF) IN CHILDREN 2 TO <18 YEARS OF AGE

Status

Completed

Phases

Phase 1

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT05900154

Acronym

PICASSO

Enrollment

128

Registered

2023-06-12

Start date

2023-06-22

Completion date

2024-02-29

Last updated

2025-03-06

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

Conditions

RESPIRATORY SYNCYTIAL VIRUS (RSV)

Keywords

RESPIRATORY SYNCYTIAL VIRUS, RSV, RSV vaccine, Respiratory illness, Respiratory infection, Pediatric

Brief summary

The purpose of this study is to learn about the safety and immune activity of the vaccine (called RSVpreF) in children 2 to \<18 years of age. This study will identify the dose level to be used in Phase 2/3 trials in this age cohort. All participants will receive one injection of RSVpreF. This study has four study visits, two in-clinic and two telehealth visits. Blood samples will be collected for testing. This study is about 6 months long for each participant and will be conducted in the United States.

Interventions

BIOLOGICALRSVpreF 120 µg

RSVpreF standard dose level

BIOLOGICALRSVpreF 60 µg

RSVpreF low dose level

Study design

Allocation

RANDOMIZED

Intervention model

SEQUENTIAL

Primary purpose

PREVENTION

Masking

NONE

Masking description

This study is open-label therefore no blinding requirements are in place since all participants will receive RSVPreF.

Intervention model description

This is an open-label dose-finding study. A single dose of RSVpreF 120 µg will be given to 40 participants in the 5 to \<18 age group first. Upon safety review and approval, a dose of 60 µg will be given to 20 participants in the 2 to \<5 age group. If, 60 µg is safe, another 20 participants in the 2 to \<5- age group will receive the 120-µg dose. Approximately 60 to 120 participants are expected to be enrolled.

Eligibility

Sex/Gender

ALL

Age

2 Years to 17 Years

Healthy volunteers

Yes

Inclusion criteria

1. Participants 2 to \<18 years of age at enrollment 2. Participants 2 to \<18 years of age should either be healthy or be considered by the investigator to be at high risk of RSV disease based on the presence of 1 of the following chronic medical conditions: * Cystic fibrosis * Medically treated asthma * Other chronic respiratory diseases and malformations of the lung * Down syndrome * Neuromuscular disease * Cerebral palsy * Hemodynamically significant or symptomatic congenital heart disease 3. All participants 2 to \<5 years of age must be seropositive for RSV as confirmed by serology. 4. Participants' parent(s)/legal guardian(s) and participants, as age appropriate, who are willing and able to comply with all scheduled visits, investigational plan, laboratory tests, and other study procedures, including collection of nasal swabs by participants' parent(s)/legal guardian(s) and by study staff when indicated. 5. The participant's parent(s)/legal guardian is capable of giving signed informed consent as described in the protocol. Depending on the age of the participant and according to local requirements, participants will also be asked to provide assent as appropriate (verbal or written).

Exclusion criteria

1. Immunocompromised individuals associated with known or suspected immunodeficiency, as determined by history and/or laboratory/physical examination. 2. Individuals with a history of autoimmune disease or an active autoimmune disease requiring therapeutic intervention, including but not limited to systemic lupus erythematosus. Note: Stable type 1 diabetes and hypothyroidism are permitted. 3. Other 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. 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). 5. Bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection. 6. Individuals with a history of epilepsy or other seizure disorders, or a history of seizures and/or other neurological complications following vaccination. 7. Previous vaccination with any licensed or investigational RSV vaccine or planned receipt during study participation. Children who may have been exposed to investigational RSV vaccines through maternal immunization will be permitted. 8. Receipt of investigational or approved monoclonal antibodies against RSV within 6 months before study intervention administration, or planned receipt throughout the study. 9. Receipt of blood/plasma products or immunoglobulins within 28 days before study intervention administration, or planned receipt throughout the study. 10. Receipt of chronic systemic treatment with known immunosuppressant medications (including cytotoxic agents or systemic corticosteroids), or radiotherapy, within 60 days before study intervention administration, or planned receipt throughout the study. Note: Systemic corticosteroids are defined as those administered for ≥14 days at a dose of ≥20 mg/day of prednisone or equivalent (eg, for cancer or an autoimmune disease). Inhaled/nebulized, intra-articular, intrabursal, or topical (skin, eyes, or ears) corticosteroids are permitted. 11. Participation in other studies involving study intervention within 28 days prior to study entry and/or for the duration of study participation. 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

Measure	Time frame	Description
Percentage of Participants Reporting Newly Diagnosed Chronic Medical Condition (NDCMCs) Throughout the Study	Within 6 months post Vaccination	An NDCMC was defined as a disease or medical condition, which was not previously identified, that was expected to be persistent or otherwise long-lasting in its effects.
Percentage of Participants With Systemic Events Within 7 Days After Vaccination	Day 1 through Day 7 after Vaccination	Systemic events included fever, fatigue, headache, vomiting, diarrhea, muscle pain and joint pain and were recorded by participants using e-diary. Fever: oral temperature \>= 38.0 degree Celsius (deg C) and categorized as \>=38.0 to 38.4 deg C (mild), \>38.4 to 38.9 deg C (moderate), and \>38.9 to 40.0 deg C (severe). Fatigue, headache, muscle pain and joint pain were graded as mild (did not interfere with activity), moderate (some interference with activity), and severe (prevented daily routine activity). Vomiting was graded mild: 1-2 times in 24 hours (h), moderate: \>2 times in 24h, and severe: required intravenous hydration. Diarrhea was graded mild: 2-3 loose stools in 24h, moderate: 4-5 loose stools in 24h and severe: 6 or more loose stools in 24h.
Percentage of Participants With Adverse Events (AEs) Within 1 Month After Vaccination	Within 1 month post Vaccination	AE was defined as any untoward medical occurrence in clinical study participant, temporally associated with use of study intervention, whether or not considered related to study intervention. AEs included serious and all non-serious AE. SAEs were defined as AE that, at any dose: resulted in death; was life-threatening; required inpatient hospitalization or prolongation of existing hospitalization; resulted in persistent disability/incapacity; was congenital anomaly or birth defect; was suspected transmission via Pfizer product of infectious agent, pathogenic or nonpathogenic or was considered to be an important medical event. Only AEs collected by non-systematic assessment (i.e., excluding local reactions and systemic events) were included.
Percentage of Participants With Serious Adverse Events (SAEs) Throughout the Study	Within 6 months post Vaccination	An AE was defined as 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. SAEs were defined as an AE that, at any dose: resulted in death; was life-threatening; required inpatient hospitalization or prolongation of existing hospitalization; resulted in persistent disability or incapacity; was a congenital anomaly or birth defect; was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or nonpathogenic or that was considered to be an important medical event.
Percentage of Participants With Local Reactions Within 7 Days After Vaccination	Day 1 through Day 7 after Vaccination	Local reactions were collected in the electronic diary (e-diary) from Day 1 through Day 7 after vaccination. Local reactions included pain at injection site, redness, and swelling. For participants greater than or equal to (\>=) 2 years to \<12 years of age, redness and swelling were graded as mild: 0.5 to 2.0 centimeter (cm), moderate: \>2.0 to 7.0 cm, and severe: \> 7 cm; for participants \>=12 years of age, mild: \> 2.0 to 5.0 cm, moderate: \>5.0 to 10.0 cm, and severe: \>10 cm. Pain at injection site was graded as mild (did not interfere with activity), moderate (interfered with activity), and severe (prevented daily activity).

Secondary

Measure	Time frame	Description
Geometric Mean Fold Rise (GMFR) of the NTs for RSV A and RSV B From Before Vaccination to 1 Month After Vaccination	From before vaccination to 1 month after vaccination	GMFR of neutralizing titers of RSV A and RSV B from before vaccination to 1 month after vaccination were reported in this outcome measure. GMFR and the corresponding 2-sided CIs were calculated by exponentiating the mean logarithm of the fold rises and the corresponding CIs (based on the Student's t distribution).
Median Frequencies of RSV F Antigen-Specific Cluster of Differentiation 4 (CD4+) Thymus-Derived Lymphocytes (T) Cells Expressing Interferon (IFN) Gamma and Interleukin-4 (IL-4) Before Vaccination and 1 Month After Vaccination	Before vaccination and 1 Month after vaccination	Median frequencies of RSV F antigen-specific CD4+ T cells expressing IFN gamma and IL-4 before vaccination and 1 month after vaccination were reported in this outcome measure. RSV F enzyme-linked immune absorbent spot assay (ELISpot) limit of detection (LOD) values were IFN gamma = 20 spot forming cell (SFC) per million peripheral blood mononuclear cell (PBMCs) and IL-4 = 4 SFC/million PBMCs. Assay results below LOD=0.5\*LOD for analysis. Frequencies were defined as the count of the RSV F antigen-specific CD4+ T cells and median frequencies were defined as the median of the counts.
Geometric Mean Titer of the Neutralizing Titers for RSV A and RSV B Before Vaccination and 1 Month After Vaccination	Before vaccination and 1 month after vaccination	Geometric mean titer (GMT) of neutralizing titers (NTs) of respiratory syncytial virus subgroup A and respiratory syncytial virus subgroup B (RSV A and RSV B) before vaccination and 1 month after vaccination were reported in this outcome measure. Assay results below the lower limit of quantification (LLOQ) were set to 0.5\*LLOQ. GMTs and corresponding 2-sided CIs were calculated by exponentiating mean logarithm of titers and corresponding CIs (based on Student's t distribution).

Countries

United States

Participant flow

Recruitment details

A total of 128 participants were enrolled, however 1 participant was assigned to a vaccine group but did not receive vaccination. Consequently, a total of 127 participants were vaccinated.

Pre-assignment details

Participants were divided into 2 age groups: 5 to less than (\<) 18 years and 2 to \< 5 years. Participants in 5 to \<18 years age group were further stratified as healthy and with high-risk chronic medical conditions.

Participants by arm

Arm	Count
RSVpreF 120 mcg: 5 to <18 Years [Healthy Participants] Healthy participants of age 5 to \<18 years received a single dose of RSVpreF 120 mcg intramuscularly on Day 1.	25
RSVpreF 120 mcg: 5 to <18 Years [High Risk Participants] Participants who had high risk chronic medical conditions of age 5 to \<18 years received a single dose of RSVpreF 120 mcg intramuscularly on Day 1.	23
RSVpreF 120 mcg: 2 to < 5 Years Participants of age 2 to \<5 years received a single dose of RSVpreF 120 mcg intramuscularly on Day 1.	24
RSVpreF 60 mcg: 5 to <18 Years [Healthy Participants] Healthy participants of age 5 to \<18 years received a single dose of RSVpreF 60 mcg intramuscularly on Day 1.	17
RSVpreF 60 mcg: 5 to <18 Years [High Risk Participants] Participants who had high risk chronic medical conditions of age 5 to \<18 years received a single dose of RSVpreF 60 mcg intramuscularly on Day 1.	18
RSVpreF 60 mcg: 2 to < 5 Years Participants of age 2 to \<5 years received a single dose of RSVpreF 60 mcg intramuscularly on Day 1.	20
Total	127

Withdrawals & dropouts

Period	Reason	FG000	FG001	FG002	FG003	FG004	FG005
Follow-Up Period	Lost to Follow-up	1	2	1	0	1	1

Baseline characteristics

Characteristic	Total	RSVpreF 120 mcg: 5 to <18 Years [Healthy Participants]	RSVpreF 120 mcg: 5 to <18 Years [High Risk Participants]	RSVpreF 120 mcg: 2 to < 5 Years	RSVpreF 60 mcg: 5 to <18 Years [Healthy Participants]	RSVpreF 60 mcg: 5 to <18 Years [High Risk Participants]	RSVpreF 60 mcg: 2 to < 5 Years
Age, Customized Adolescents (12-17 years)	39 Participants	16 Participants	12 Participants	0 Participants	5 Participants	6 Participants	0 Participants
Age, Customized Children (2-11 years)	88 Participants	9 Participants	11 Participants	24 Participants	12 Participants	12 Participants	20 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	18 Participants	5 Participants	0 Participants	1 Participants	3 Participants	4 Participants	5 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	107 Participants	20 Participants	23 Participants	22 Participants	14 Participants	13 Participants	15 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	2 Participants	0 Participants	0 Participants	1 Participants	0 Participants	1 Participants	0 Participants
Race (NIH/OMB) American Indian or Alaska Native	1 Participants	0 Participants	0 Participants	1 Participants	0 Participants	0 Participants	0 Participants
Race (NIH/OMB) Asian	2 Participants	2 Participants	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants
Race (NIH/OMB) Black or African American	28 Participants	7 Participants	6 Participants	3 Participants	2 Participants	6 Participants	4 Participants
Race (NIH/OMB) More than one race	9 Participants	0 Participants	0 Participants	3 Participants	2 Participants	3 Participants	1 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants
Race (NIH/OMB) White	87 Participants	16 Participants	17 Participants	17 Participants	13 Participants	9 Participants	15 Participants
Sex: Female, Male Female	58 Participants	15 Participants	11 Participants	13 Participants	5 Participants	7 Participants	7 Participants
Sex: Female, Male Male	69 Participants	10 Participants	12 Participants	11 Participants	12 Participants	11 Participants	13 Participants

Adverse events

Event type	EG000 affected / at risk	EG001 affected / at risk	EG002 affected / at risk	EG003 affected / at risk	EG004 affected / at risk	EG005 affected / at risk
deaths Total, all-cause mortality	0 / 25	0 / 23	0 / 24	0 / 17	0 / 18	0 / 20
other Total, other adverse events	17 / 25	15 / 23	9 / 24	12 / 17	14 / 18	13 / 20
serious Total, serious adverse events	0 / 25	1 / 23	0 / 24	0 / 17	1 / 18	0 / 20

Outcome results

Primary

Percentage of Participants Reporting Newly Diagnosed Chronic Medical Condition (NDCMCs) Throughout the Study

An NDCMC was defined as a disease or medical condition, which was not previously identified, that was expected to be persistent or otherwise long-lasting in its effects.

Time frame: Within 6 months post Vaccination