This booster extension is intended to provide both homologous and first heterologous booster data to complement previous positive Phase 1/2 booster results. The data are not intended for the initial regulatory approval process which the Company expects to finalize in the coming weeks.
The trial extension will evaluate a booster dose of VLA2001 in adults, aged 18 and above, who received primary vaccination with two doses of VLA2001, as well as participants, aged 30 and above, who received two doses of AstraZeneca’s (AZD1222).
The VLA2001 booster vaccination will be given at least seven months after completion of the primary vaccination series. The trial is currently ongoing in the UK and is supported by the National Institute for Health Research (NIHR). It is expected to provide topline data during the second quarter of 2022.
Valneva announced first positive homologous booster results at the end of December 2021. The data showed an excellent immune response after a booster dose of VLA2001 administered seven to eight months after the second dose of primary vaccination.
In addition, Valneva plans to initiate a further dedicated heterologous booster only trial of VLA2001 in the coming weeks. Valneva also recently reported laboratory results demonstrating that serum antibodies induced by three doses of VLA2001 neutralize the initial SARS-CoV-2 virus as well as the Omicron and Delta variants.
Cov-Compare is a randomized, observer-blind, controlled, comparative immunogenicity study for which Valneva reported positive topline data in October 2021. As part of the study’s booster extension, all participants are offered a third vaccination, except those who already received a licensed COVID-19 vaccine outside of the study.
Participants will receive a VLA2001 shot at least seven months after completion of the primary vaccination series with VLA2001 or AZD1222; follow-up visits will be performed 14 days and six months after the booster vaccination. Participants who will not receive a VLA2001 booster vaccination will continue with their scheduled Month 12 follow up visit.
In addition to evaluating tolerability of a VLA2001 booster dose, blood samples will be taken for immunogenicity analysis from a subset of adults who received primary vaccination with two doses of VLA2001, as well as from a subset of participants who received two doses of AZD1222 for primary immunization.
VLA2001 is currently the only whole virus, inactivated, adjuvanted vaccine candidate in clinical trials against COVID-19 in Europe. It is intended for active immunization of at-risk populations to prevent carriage and symptomatic infection with COVID-19 during the ongoing pandemic and potentially later for routine vaccination including addressing new variants.
VLA2001 may also be suited for boosting, as repeat booster vaccinations have been shown to work well with whole virus inactivated vaccines. VLA2001 is produced on Valneva’s established Vero-cell platform, leveraging the manufacturing technology for Valneva’s licensed Japanese encephalitis vaccine, IXIARO.
VLA2001 consists of inactivated whole virus particles of SARS-CoV-2 with high S-protein density, in combination with two adjuvants, alum and CpG 1018. This adjuvant combination has consistently induced higher antibody levels in preclinical experiments than alum-only formulations and shown a shift of the immune response towards Th1.
CpG 1018 adjuvant, supplied by Dynavax Technologies Corporation is a component of the US FDA- and EMA-approved HEPLISAV-B vaccine. VLA2001’s manufacturing process, which has already been upscaled to final industrial scale, includes chemical inactivation to preserve the native structure of the S-protein. VLA2001 is expected to conform with standard cold chain requirements (2 to 8 degrees Celsius). ■