Objective: V710, a vaccine containing a SA-surface protein (IsdB), has demonstrated protection in preclinical models. An initial Phase I study (V710-P001) showed that a liquid, aluminum-adjuvanted V710 formulation was immunogenic in healthy subjects. Yet, the adjuvant effect was mixed in preclinical monkey studies, and analytical experiments suggested that lyophilization would improve V710 stability. Two further studies were conducted to evaluate other V710 formulations (without adjuvant [V710-P002] and as lyophilized product [V710-P004]).
Methods: V710-P002 randomized 64 adults (18-70 years) to receive V710 (30 µg) either as liquid, aluminum-adjuvanted formulation or liquid, non-adjuvanted formulation (in 1:1 ratio); V710-P004 randomized 51 adults (18-80 years) to receive a lyophilized formulation of V710 (60 µg) or saline placebo (in 4:1 ratio). In both studies, blood was collected at screening and Day 10 (D10), D14, D28, and D84 postvaccination. Sera were analyzed for IsdB-specific antibodies using a total IgG assay. The primary immunogenicity time-point was D14. Safety was assessed for 14 days postvaccination.
Results: Similar proportions of subjects manifested positive immune responses (defined as >2-fold increase in antibody levels) in the liquid, aluminum-adjuvanted [84% (95% CI 67%, 95%)], liquid, non-adjuvanted [72% (53%, 86%)], and lyophilized [81% (65% ,91%)] formulations. In all V710 groups, antibody responses were noted by D10 and persisted through D84. No SAE or fever was reported. The most common vaccine-related AEs were injection-site pain and headache.
Conclusions: Multiple formulations of V710 (with or without adjuvant; liquid or lyophilized product) showed relatively similar immunogenicity and AE profiles.