Dose, Safety, Tolerability and Immunogenicity of a Stabilized Prefusion RSV F Subunit Protein Vaccine, VRC-RSVRGP084-00-VP (DS-Cav1), Alone or With Alum Adjuvant, in Healthy Adults

Study Design: This is a Phase I, open-label, dose escalation study to evaluate the dose, safety, tolerability, and immunogenicity of VRC-RSVRGP084-00-VP vaccine alone or with alum adjuvant in a 2-injection regimen. The hypotheses are that the vaccine will be safe and tolerable for human administration, and will induce detectable immune response. The primary objective is to evaluate the safety and tolerability of the investigational vaccine at 3 dose levels administered alone or with alum adjuvant in healthy adults. Secondary objectives relate to humoral and cellular immunogenicity of the investigational vaccine regimen. Product Description: VRC-RSVRGP084-00-VP (DS-Cav1) was developed by VRC, NIAID and is composed of the respiratory syncytial virus (RSV) fusion (F) glycoprotein ectodomain assembled as a trimer stabilized in its prefusion native conformation with a foldon trimerization domain at the C-terminus and 4 internal mutations designated DS-Cav1 (4.1DHFR\_RSVAF). The sequence is based on the RSV A2 strain from subtype A. The product was provided at a concentration of 0.5 mg/mL in 3 mL glass vials filled to 1.2 mL. Adjuvant was an aluminum hydroxide suspension (alum) provided in a sterile, pyrogen-free suspension at a concentration of 5 mg/mL in 3 mL glass vials filled to 0.7 mL. The alum dose was 500 mcg and was field mixed. Subjects: Healthy adult subjects ages 18-50 years Study Plan: Subjects were randomized into DS-Cav1 or DS-Cav1 plus alum in each dose during the study. Dose continuation and dose escalation evaluations occurred to ensure the safety data support proceeding to the higher doses. Subjects were evaluated for safety and immune responses through blood and mucosal sample collection at specified timepoints throughout the study. VRC 317 Study Schema: * Group: 1; Subjects: 15; Dose: 50mcg; Day 0: DS-Cav1; Week 12 \[1\]: DS-Cav1 * Group: 2; Subjects: 15; Dose: 50mcg; Day 0: DS-Cav1 + alum; Week 12 \[1\]: DS-Cav1 + alum * Group: 3; Subjects: 15; Dose: 150mcg; Day 0: DS-Cav1; Week 12 \[1\]: DS-Cav1 * Group: 4; Subjects: 15; Dose: 150mcg; Day 0: DS-Cav1 + alum; Week 12 \[1\]: DS-Cav1 + alum * Group: 5; Subjects: 15; Dose: 500mcg; Day 0: DS-Cav;1 Week 12 \[1\]: DS-Cav1 * Group: 6; Subjects: 15; Dose: 500mcg; Day 0: DS-Cav1 + alum; Week 12 \[1\]: DS-Cav1 + alum All DS-Cav1 vaccinations were administered with needle and syringe into the deltoid muscle. Total Planned Subjects: 90 (Up to 100 subjects could have been enrolled if needed to evaluate safety or immunogenicity.) • \[1\] Week 12 dose: Optional for the last 5 subjects enrolled in each group who received the Day 0 injection and any additional subjects needed to evaluate safety or immunogenicity of a single injection. Duration: The study schedule required 13 clinic visits and a telephone contact after each injection.