Inactivated, Adjuvanted COVID-19 Vaccine Candidate Heads to Phase 3

France-based Valneva SE announced positive data for Part A of the Phase 1/2 clinical trial of its inactivated, adjuvanted COVID-19 vaccine candidate, VLA2001. Based on this new data, the Company plans to commence a Phase 3 clinical trial by the end of April 2021, subject to regulatory approval.

In the VLA2001-201 study, three dose levels of VLA2001 (low, medium, high), based on a schedule of two doses with vaccinations three weeks apart, were evaluated in 153 healthy adults aged 18 to 55 years.

VLA2001 was generally safe, and well-tolerated across all dose groups tested, with no safety concerns identified by an independent Data Safety Monitoring Board. There were no statistically significant differences between dose groups and no differences between first and second vaccinations in terms of reactogenicity.

The majority of Adverse Events (AEs) were mild or moderate, and only two subjects reported severe solicited AEs (headache and fatigue). All solicited AEs were transient. Only 17.6% of unsolicited AEs up to day 36 were considered related to the vaccine, and no severe unsolicited AEs were reported. No serious related AEs were reported.

VLA2001 was highly immunogenic, with more than 90% of all study participants developing significant levels of antibodies to the SARS-CoV-2 virus spike protein across all dose groups tested. Seroconversion Rates (SCR) for S-protein binding IgG antibodies were 89.8% in the medium-dose and 100% in the high-dose group.

Two weeks after completing the two-dose schedule, the Geometric Mean Fold Rise (GMFR) from baseline was 26 in the medium-dose and 86 in the high dose group.

Of note, the IgG antibody response was highly correlated with neutralization titers in a micro-neutralization assay (MNA50) (r=0.79, p<0.001).

VLA2001 induced a dose-dependent response with statistically significant higher Geometric Mean Titres (GMTs) for both IgG and neutralizing antibodies in the high dose group compared to the low and medium dose groups. In the high dose group, the GMT of neutralizing antibody titers measured two weeks after completion of the two-dose schedule was at or above levels for a panel of convalescent sera (GMT 530.4 (95% CI: 421.49, 667.52)).

With a GMT ratio of vaccine vs. convalescent sera ≥ 1, vaccine efficacy has been reported above 80% for other vaccines.

VLA2001 induced broad T-cell responses across participants with antigen-specific IFN-gamma producing T-cells against the S-protein, M, and N protein detected in 75.6 %, 35.6%, and 48.9% of study participants, respectively.

Thomas Lingelbach, CEO of Valneva, commented in a press release, “We are extremely pleased with these results, which take us a step closer to providing an inactivated vaccine to help the global fight against COVID-19. The world needs multiple vaccines as well as booster options."

"Given the potential advantages often associated with inactivated whole virus vaccines, we believe that VLA2001 has an important role to play. This includes potential modifications to the vaccine to address variants, using our existing manufacturing process."

Saint-Herblain-based Valneva is a specialty vaccine company focused on developing and commercializing prophylactic vaccines for infectious diseases with significant unmet medical needs. The Company has several vaccines in development, including unique vaccines against Lyme disease, COVID-19, and chikungunya. Valneva’s portfolio also includes two commercial vaccines for travelers.