NCT05639894

Study of a Respiratory Syncytial Virus Candidate Encapsulated in a Lipid Nanoparticle Based Formulation in Adults Aged 18 to 50 Years and 60 Years and Older

Completed Phase 1, PHASE2 Last updated 31 May 2025

What this trial tests

Phase 1, PHASE2 trial testing RSV vaccine candiate formulation 1 in Respiratory Syncytial Virus Immunization in 865 participants. Completed in 2 May 2025.

Timeline

17 November 2022

Primary endpoint
2 May 2025

2 May 2025

Quick facts

Lead sponsor	Sanofi Pasteur, a Sanofi Company
Phase	Phase 1, PHASE2
Status	Completed
Study type	INTERVENTIONAL
Allocation	randomized
Design	parallel
Masking	quadruple
Primary purpose	prevention
Enrollment	865
Start date	17 November 2022
Primary completion	2 May 2025
Estimated completion	2 May 2025
Sites	33 locations across Puerto Rico, United States, Australia

Drugs / interventions tested

• RSV vaccine candiate formulation 1 — full drug profile →
• RSV vaccine candidate formulation 2 — full drug profile →
• Placebo

Conditions studied

• Respiratory Syncytial Virus Immunization — all drugs for Respiratory Syncytial Virus Immunization →

Sponsor

Sanofi Pasteur, a Sanofi Company — full company profile →

Who can join

18 and older, any sex, with Respiratory Syncytial Virus Immunization. Patients with the condition only — healthy volunteers not accepted.

Sponsor's own description

Brief Summary of Stage 1:

The purpose Stage 1 (Phase I/IIa) is to assess the safety and immunogenicity of a single intramuscular (IM) injection of 3 dose-levels of an Respiratory Syncytial Virus (RSV) vaccine candidate formulated with 2 different lipid nanoparticles (LNPs) in healthy adult participants aged between 18 to 50 years, and 60 years and older. The primary objectives of this stage are to assess the safety and immunogenicity profiles across the dose-level groups (low, medium, and high doses) with 2 LNPs. This stage will evaluate the safety and immunogenicity of a booster vaccination administered 12 months after the primary vaccination in a subset of the study population.

Brief Summary of Stage 2:

The study also also incorporates a Stage 2 (Phase IIa, dose-ranging design) that includes adults aged 60 years and older to assess the safety and immunogenicity of different doses of RSV vaccine encapsulated in one of the LNPs. In the Phase IIa dose-ranging stage, eligible participants will be randomly assigned in a 1:1:1 ratio to receive a single IM administration of RSV vaccine candidate doses, or placebo. Multiple safety analyses will be performed, minimally at D07 and D28. Additional analyses may be performed as data are available.

Publications & conference data

8 peer-reviewed publications reference this trial (live from Europe PMC):

1. Nanotechnology's frontier in combatting infectious and inflammatory diseases: prevention and treatment.
   Huang Y, Guo X, Wu Y, Chen X, et al · · 2024 · cited 188× · PMID 38378653 · DOI 10.1038/s41392-024-01745-z
2. mRNA vaccines in disease prevention and treatment.
   Zhang G, Tang T, Chen Y, Huang X, et al · · 2023 · cited 148× · PMID 37726283 · DOI 10.1038/s41392-023-01579-1
3. mRNA vaccines for infectious diseases - advances, challenges and opportunities.
   Pardi N, Krammer F. · · 2024 · cited 111× · PMID 39367276 · DOI 10.1038/s41573-024-01042-y
4. Respiratory Syncytial Virus Vaccines: A Review of the Candidates and the Approved Vaccines.
   Topalidou X, Kalergis AM, Papazisis G. · · 2023 · cited 84× · PMID 37887775 · DOI 10.3390/pathogens12101259
5. Optimized lipid nanoparticles (LNPs) for organ-selective nucleic acids delivery <i>in vivo</i>.
   Zhang T, Yin H, Li Y, Yang H, et al · · 2024 · cited 42× · PMID 38770138 · DOI 10.1016/j.isci.2024.109804
6. The recent landscape of RSV vaccine research.
   Kelleher K, Subramaniam N, Drysdale SB. · · 2025 · cited 25× · PMID 39802673 · DOI 10.1177/25151355241310601
7. Key Design Features of Lipid Nanoparticles and Electrostatic Charge-Based Lipid Nanoparticle Targeting.
   Gyanani V, Goswami R. · · 2023 · cited 20× · PMID 37111668 · DOI 10.3390/pharmaceutics15041184
8. Landscape of respiratory syncytial virus.
   Duan Y, Liu Z, Zang N, Cong B, et al · · 2024 · cited 17× · PMID 39501814 · DOI 10.1097/cm9.0000000000003354