Phase 1 Study to Evaluate the Safety and Immunogenicity of a Candidate Vaccine Against Respiratory Syncytial Virus

Overview

The primary and secondary objectives of this Phase 1 study are respectively to assess the safety and the immunogenicity of two administrations of the RSV vaccine candidate at three different doses. The study has a randomized, placebo-controlled, double-blind, sequential, parallel cohorts, dose-escalation (three dosages) design. Each of the three cohorts (N=20 subjects per cohort, total of 60 subjects) will receive placebo (n=5), or a low (15 µg, n=15), intermediate (50 µg, n=15) or high dosage (150 µg, n=15) of candidate vaccine, on two occasions (Day 0 and Day 56). Subjects will be healthy adult women aged between 18 and 45 years. There will be two phases: an active treatment phase from Day 0 to Month 3, and a follow-up phase from Month 3 + 1 day to Month 12. During the active phase, subjects will complete diary cards to record oral temperature (daily), solicited local and general adverse events (AEs) and unsolicited AEs for 7 days after each administration. Unsolicited AEs will be recorded up to Day 28 post-each administration. Serious adverse events (SAEs) and adverse events of specific interest (AESI) will be recorded throughout the duration of the active phase. Subjects will visit the clinical site for safety monitoring on Days 1, 7 and 28 following each administration. Blood will be drawn at a screening visit and the safety test data will be available just before 1st administration. The screening set includes markers of infection with hepatitis B virus, hepatitis C virus and human immunodeficiency virus. A serum sample will be taken for detection of pregnancy. At the next scheduled time points, pregnancy will be screened in a urine sample. Laboratory safety parameters will be examined further at Days 0, 1, 7, 28, 56, 57, 63 and 84. During the follow-up phase, visits for safety monitoring are scheduled at Months 6, 9 and 12 post-1st administration. SAEs and AESI will be recorded at each visit. Humoral immunity will be measured on Days 0, 28, 56, Month 3, Month 6, Month 9 and Month 12. Cellular immunity will be measured on Days 0, 7, 28, 56, 63 and 84. The duration of the study for each subject will be approximately 13 months. The total duration of the study will be approximately 18 months.

Virometix designed and developed a candidate vaccine coded V-306 based on synthetic virus like particles (SVLP) that present the neutralizing Palivizumab epitope of the antigenic site II region of the F-protein (FsII). V-306 has been evaluated in cotton rats, mice and rabbits for safety and immunogenicity. Strong immunogenicity was demonstrated in mice and rabbits by ELISA and RSV A and B neutralization. Full protection with no vaccine-associated enhanced respiratory disease (VAERD) was demonstrated in a validated mouse challenge model. Reduction of the viral load with no VAERD was also shown in the cotton rat challenge model. The primary objective of the first-in-human Phase 1 study is to assess the safety of two administrations of the RSV vaccine candidate at three different dosages of V-306. The secondary objective is to assess the immunogenicity of two administrations of the RSV vaccine candidate at three different dosages of V-306. The study has a randomized, placebo-controlled, double-blind, sequential, parallel cohorts, dose-escalation (three dosages) design. It will be conducted in one centre. Each of the three cohorts (N=20 subjects per cohort, total of 60 subjects) will receive placebo (n=5), or a low (15 µg/administration, n=15), intermediate (50 µg/administration, n=15) or high dosage (150 µg/administration, n=15) of candidate vaccine, on two occasions (Day 0 and Day 56). Subjects will be healthy adult women aged between 18 and 45 years. The enrolment schedule with sentinel dosing will be the same in each cohort. After each administration, the subject will be observed in the clinical trial centre for 120 minutes, before being discharged. The study will be in two phases: (1) an active treatment phase from Day 0 to Month 3, i.e. one month post 2nd administration, with unblinding and primary analysis of data collected up to Month 3, and (2) a follow-up phase from Month 3 + 1 day to Month 12 post-1st administration for safety and immunogenicity. The sponsor will be unblinded at Month 3, while the clinical site and laboratory will remain blinded during the whole study. During the active phase, subjects will complete diary cards to record oral temperature (daily), solicited local and general adverse events (AEs) and unsolicited AEs for 7 days after each administration. Unsolicited AEs will be recorded up to Day 28 post-each administration. Serious adverse events (SAEs) and adverse events of specific interest (AESI) will be recorded throughout the duration of the active phase. Subjects will visit the clinical site for safety monitoring on Days 1, 7 and 28 following each administration. A time window will be defined for each visit. Blood will be drawn at a screening visit (up to 14 days before Day 0 for lab safety analyses and up to 2 months before Day 0 for serology analyses) and the safety test data will be available just before 1st administration. The screening set includes markers of infection with hepatitis B virus, hepatitis C virus and human immunodeficiency virus. These data will be part of the baseline health status of each subject. A serum sample will be taken for detection of pregnancy. At the next scheduled time points, pregnancy will be screened in a urine sample and if positive will be confirmed by blood analysis. Laboratory safety parameters will be examined further at Days 0, 1, 7, 28, 56, 57, 63 and 84. During the follow-up phase, visits for safety monitoring are scheduled at Months 6, 9 and 12 post-1st administration. SAEs and AESI will be recorded at each visit. Humoral immunity will be measured on Days 0, 28, 56, Month 3, Month 6, Month 9 and Month 12. Months 6, 9 and 12 aim to evaluate the persistence of the humoral response. Cellular immunity will be measured on Days 0, 7, 28, 56, 63 and 84. Data collection will use an electronic Case Report Form (eCRF). The duration of the study for each subject will be approximately 13 months. The total duration of the study will be approximately 18 months.