Valneva announced positive initial booster data and final Phase 1 data for its leading, unique Lyme disease vaccine candidate VLA15. To investigate whether a VLA15 booster will elicit an anamnestic response1, Valneva amended its Phase 1 study protocol during 2018, adding a booster dose in a sub-cohort of the Phase 1 study population. At the same time the full Phase 1 study population has been followed-up across all doses for up to one year, providing the final Phase 1 data.
The final Phase 1 data confirmed the safety and tolerability profile observed at all time-points, as reported in the interim analysis. VLA15 demonstrated a favorable safety profile and had no associated safety concerns. In addition, the final Phase 1 immunogenicity results indicated that the alum-adjuvanted formulations elicit higher immune-responses at all time-points, confirming the interim data findings. As expected, based on the interim Phase 1 data, antibody titres declined post Day 84 across all groups, trending towards baseline at approximately one year post initial vaccination.
To evaluate the benefit of a booster dose, 64 subjects across the two higher dose groups (48µg and 90µg, both with and without alum) from Phase 1 received a booster in the period 12 to 15 months after their initial dose in the primary immunization. These single re-vaccinations resulted in a significant immune-response, yielding OspA antibody titres at levels 2.7-fold (ST32) – 5.8-fold (ST1) over the initial titres observed at Day 84 (geometric mean fold rise (GMFR)). These results are in line with published data from other OspA-based Lyme vaccines that had previously been in development.