Safety and Immunogenicity of the Recombinant Respiratory Syncytial Virus (RSV) Vaccine in Adults Aged 18 Years and Older

A Phase I, Randomized, Observer-blinded, Placebo-Controlled, Dose Escalation Clinical Trial to Assess the Safety and Immunogenicity of the Respiratory Syncytial Virus (RSV) Vaccine, LYB005 in Adults Aged 18 Years and Older

This phase 1 study in China will evaluate the safety and immunogenicity of the the Respiratory Syncytial Virus (RSV) Vaccine, LYB005 in adults aged 18 years and older.

Study Overview

• Status: Active, not recruiting
• Conditions: Respiratory Syncytial Virus Infection
• Intervention / Treatment: Biological: Low dose antigen of LYB005 without A01B adjuvant; Biological: Low dose antigen of LYB005 with A01B adjuvant; Biological: Middle dose antigen of LYB005 without A01B adjuvant; Biological: Middle dose antigen of LYB005 with A01B adjuvant; Biological: High dose antigen of LYB005 without A01B adjuvant; Biological: High dose antigen of LYB005 with A01B adjuvant; Biological: Placebo

Detailed Description

A randomized, observer-blinded, placebo-controlled, dose escalation trial will be conducted to observe the safety and immunogenicity of LYB005 in adults aged 18 years and older. A total of 90 healthy subjects will be enrolled and stratified by age (18-59 years and ≥60 years in a 1:1 ratio). Six formulations of LYB005 will be provided, three dose levels of antigen with or without A01B adjuvant.

A sentinel and escalating dosing approach will be used for close monitoring of safety to minimize risk to participants. Participants will be enrolled in one of six cohorts, including Cohort 1 (18-59 years, low dose, n=15), Cohort 2 (18-59 years, middle dose, n=15), Cohort 3 (≥60 years, low dose, n=15), Cohort 4 (18-59 years, high dose, n=15), Cohort 5 (≥60 years, middle dose, n=15), and Cohort 6 (≥60 years, high dose, n=15). In each cohort, five sentinels were set up, and they were randomly vaccinated with the investigational vaccine without A01B adjuvant, the investigational vaccine with A01B adjuvant, or placebo in a 2:2:1 ratio. The remaining participants were randomly vaccinated in a 2:2:1 ratio with the investigational vaccine without A01B adjuvant, the investigational vaccine with A01B adjuvant, or placebo. A single-dose immunization schedule will be adopted.

• Study Type: Interventional
• Enrollment (Estimated): 90
• Phase: Phase 1

Contacts and Locations

Study Locations

• China
  • Dangyang, China
    • Dangyang City Center for Disease Control and Prevention

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

1. Residents aged 18 years and older (at the time of screening), regardless of gender;
2. Participants can provide valid identification, voluntarily agree to participate in the study, and sign the Informed Consent Form, and are able to attend all planned follow-up visits and comply with the protocol requirements;
3. Axillary temperature < 37.3°C on the day of enrollment;
4. Females of childbearing potential should use effective contraceptive measures one month before enrollment; females of childbearing potential (excluding those who have undergone tubal ligation, bilateral oophorectomy, or hysterectomy) and male participants should practice effective contraception and avoid pregnancy plans, as well as sperm or egg donation plans from the time of enrollment until 6 months after the full course of vaccination. Effective contraceptive methods include oral contraceptives (excluding emergency contraceptives), injectable or implantable contraceptives, sustained-release local contraceptives, contraceptive patches, intrauterine devices, sterilization, abstinence, condoms, diaphragms, cervical caps, etc.

Exclusion Criteria:

1. Allergy to the investigational vaccine or its excipients, or a history of anaphylactic shock or other serious adverse reactions to other vaccines;
2. Previous vaccination against Respiratory Syncytial Virus;
3. A confirmed diagnosis or etiological evidence of respiratory syncytial virus infection and related diseases caused by the infection within 12 months before enrollment;
4. Has taken antipyretics, analgesics or anti-allergy drugs within 24 hours before enrollment;
5. Has received any vaccine within 14 days before vaccination, or have received a live vaccine within 28 days;
6. Has received blood or blood-related products, including immunoglobulin, within 3 months prior to enrollment; or plan to use them during the study period;

7. Individual with the following diseases:

   • Has acute diseases or are in the acute exacerbation period of chronic diseases within 3 days before vaccination;
   • Diagnosed with congenital malformations or developmental disorders, genetic defects, severe malnutrition, etc.;
   • History of congenital or acquired immunodeficiency or autoimmune diseases;
   • Chronic administration (≥14 consecutive days) of corticosteroids (dose ≥ 20 mg/day prednisone or equivalent dose) or other immunosuppressants within the past 3 months, with the exception of inhaled or topical steroids, or short-term use (<14 consecutive days) of oral corticosteroids;
   • Neurological diseases or family history (seizures, epilepsy, encephalopathy, etc.); history of psychiatric disorders or family history;
   • Asplenia or functional asplenia;
   • Severe or uncontrolled or hospitalization-required cardiovascular diseases, diabetes, blood and lymphatic system diseases, immune system diseases, liver and kidney diseases, respiratory system diseases, metabolic and skeletal system diseases, or malignant tumors;
   • Contraindications for intramuscular injection and blood drawing, such as coagulation disorders, thrombosis or hemorrhagic diseases, or situations requiring continuous use of anticoagulants;
   • Severe hypertension that cannot be controlled by medication (measured on-site: systolic blood pressure ≥ 160 mmHg and/or diastolic blood pressure ≥ 100 mmHg);
8. History of major surgery within 12 weeks prior to enrollment (as determined by the investigator), or not fully recovered from the surgery, or having plans for major surgery during the anticipated period of the subject's participation in the study;
9. History of long-term alcohol abuse and/or drug abuse;
10. Individual who is currently participating in other research or unregistered product (drugs, vaccines, or devices, etc.) clinical studies, or plan to participate in other clinical studies before the end of this clinical study;
11. Other conditions that may impact the subject's safety or influence the assessment of vaccine response, as determined by the investigator;
12. Exclusion criteria for specific populations: lactating or pregnant women during the clinical research period, or women of childbearing age with a positive pregnancy test before vaccination.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

7

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Low dose antigen of LYB005 without A01B adjuvant; Subjects aged 18 years and older will be vaccinated with 1 dose of LYB005 (low dose antigen without A01B adjuvant) at Day 0.	Biological: Low dose antigen of LYB005 without A01B adjuvant; 0.5 mL per dose, containing a total of 30 μg antigen without A01B adjuvant.
Experimental: Low dose antigen of LYB005 with A01B adjuvant; Subjects aged 18 years and older will be vaccinated with 1 dose of LYB005 (low dose antigen with A01B adjuvant) at Day 0.	Biological: Low dose antigen of LYB005 with A01B adjuvant; 0.5 mL per dose, containing a total of 30 μg antigen adjuvanted with A01B.
Experimental: Middle dose antigen of LYB005 without A01B adjuvant; Subjects aged 18 years and older will be vaccinated with 1 dose of LYB005 (middle dose antigen without A01B adjuvant) at Day 0.	Biological: Middle dose antigen of LYB005 without A01B adjuvant; 0.5 mL per dose, containing a total of 60 μg antigen without A01B adjuvant.
Experimental: Middle dose antigen of LYB005 with A01B adjuvant; Subjects aged 18 years and older will be vaccinated with 1 dose of LYB005 (middle dose antigen with A01B adjuvant) at Day 0.	Biological: Middle dose antigen of LYB005 with A01B adjuvant; 0.5 mL per dose, containing a total of 60 μg antigen adjuvanted with A01B.
Experimental: High dose antigen of LYB005 without A01B adjuvant; Subjects aged 18 years and older will be vaccinated with 1 dose of LYB005 (high dose antigen without A01B adjuvant) at Day 0.	Biological: High dose antigen of LYB005 without A01B adjuvant; 0.5 mL per dose, containing a total of 120 μg antigen without A01B adjuvant.
Experimental: High dose antigen of LYB005 with A01B adjuvant; Subjects aged 18 years and older will be vaccinated with 1 dose of LYB005 (high dose antigen with A01B adjuvant) at Day 0.	Biological: High dose antigen of LYB005 with A01B adjuvant; 0.5 mL per dose, containing a total of 120 μg antigen adjuvanted with A01B.
Placebo Comparator: Placebo; Subjects aged 18 years and older will be vaccinated with 1 dose of placebo at Day 0.	Biological: Placebo; 0.5 mL 0.9% sodium chloride (normal saline) injection per dose

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Occurrence of immediate adverse events	The incidence and severity of any adverse events (AEs) within 30 minutes after vaccination	Within 30 minutes after vaccination
Incidence of solicited AE	Occurrence and severity of solicited local injection site reactions for 7 days (Day 0-Day 7) following vaccination. (i.e., pain, redness, swelling). Occurrence and severity of solicited systemic reactions for 7 days (Day 0-Day 7) following vaccination. (i.e., myalgia, fatigue, headache, chills, fever).	Within 0-7 days after vaccination
Incidence of unsolicited AEs	The incidence and severity of any unsolicited AEs, including all AEs, except solicited AEs reported Days 0~28 after the vaccination.	Within 28 days after vaccination
Incidence of clinically significant abnormalities in clinical laboratory tests	The incidence of clinically significant abnormalities in clinical laboratory tests (hematology, blood chemistry, coagulation function, and urinalysis) on Day 3 after vaccination.	3 days after vaccination
Occurrence of serious adverse events (SAEs) and adverse events of special interests (AESIs)	The incidence of any SAEs and AESIs from the first vaccination up to 12 months after vaccination.	12 months after vaccination

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The geometric mean titer (GMT) of Neutralizing Antibodies Against RSV A and RSV B	Measured by microneutralization assay.	14 days, 28 days, 3 months, 6 months and 12 months after vaccination
Geometric Mean Fold Rise (GMFR) for Neutralizing Antibodies Against RSV A and RSV B	Change from prevaccination in geometric mean fold rise of Neutralizing antibody titer Against RSV A and RSV B	14 days, 28 days, 3 months, 6 months and 12 months after vaccination
The geometric mean concentration (GMC) for Pre-fusion Protein Specific Binding Antibodies	Measured by Enzyme-Linked Immunosorbent Assay (ELISA).	14 days, 28 days, 3 months, 6 months and 12 months after vaccination
Number of Pre-fusion Protein Specific Interferon-gamma and Interleukin-4 spot-forming cells	T-cell responses to vaccine antigen in peripheral blood mononuclear cells (PBMCs) determined by enzyme-linked immunosorbent spot (ELISpot).	28 days after vaccination

Collaborators and Investigators

• Sponsor: Guangzhou Patronus Biotech Co., Ltd.
• Investigators: Principal Investigator: Beifang Yang, Hubei Provincial Center for Disease Control and Prevention

Study record dates

Study Major Dates

• Study Start (Actual): April 15, 2025
• Primary Completion (Estimated): August 1, 2026
• Study Completion (Estimated): August 1, 2026

Study Registration Dates

• First Submitted: March 24, 2025
• First Submitted That Met QC Criteria: March 31, 2025
• First Posted (Actual): April 1, 2025

Study Record Updates

• Last Update Posted (Actual): August 22, 2025
• Last Update Submitted That Met QC Criteria: August 18, 2025
• Last Verified: August 1, 2025

More Information

Terms related to this study

• Keywords: Respiratory Syncytial Virus; Acute Respiratory Infection; Lower Respiratory Track Disease
• Additional Relevant MeSH Terms: Infections; RNA Virus Infections; Virus Diseases; Pneumovirus Infections; Paramyxoviridae Infections; Mononegavirales Infections; Respiratory Syncytial Virus Infections
• Other Study ID Numbers: LYB005/CT-CHN-101

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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