Chikungunya vaccine: Valneva reports excellent final Phase 1 results

Valneva SE, a biotech company developing and commercializing vaccines for infectious diseases with major unmet medical needs, today announced excellent final Phase 1 results for its single-shot chikungunya vaccine candidate, VLA1553.

The objectives of the Phase 1 study (VLA1553-101) were to assess the safety and immunogenicity profile of VLA1553 after a single vaccination across three dose levels. Today’s final analysis of the study includes the safety and immunogenicity results up to Month 13 and full results from the “intrinsic human viral challenge.”

The safety profile observed in the prior analysis, announced in May 2019, was confirmed. VLA1553 was generally safe in all dose groups. The low and medium dose groups were well tolerated and showed a superior safety profile, including viremia, compared to the high dose group. No adverse events of special interest (e.g. chikungunya infection related) and no vaccine related Serious Adverse Events (SAEs) were reported up to Month 13. The product candidate’s local tolerability profile was excellent.

The final results showed an excellent immunogenicity profile in all vaccinated dose groups after a single vaccination, with a 100% seroconversion achieved at Day 14 after a single vaccination in all dose groups and titers were sustained at 100% at Month 12.

The study was designed so that all study participants would be re-vaccinated either after 6 months (n=26) or after 12 months (n=68). There was no anamnestic response observed after re-vaccination (either after 6 or 12 months) demonstrating that a single vaccination of VLA1553 is sufficient to induce a sustained high titer of neutralizing antibodies. All subjects receiving a second shot (at Month 6 or Month 12) of the vaccine were protected from vaccine-induced viremia and associated clinical symptoms, serving as “intrinsic human viral challenge” providing first indications of efficacy.

While the study finalization was ongoing, Valneva successfully progressed a number of supportive studies including mosquito transmission, biodistribution and persistence in non-human primates (NHPs) as well as a passive transfer study in NHPs to develop a Correlate Of Protection (COP) using human sera from VLA1553-101. Valneva expects that the data provided from these studies will support the Company’s submission for an end-of-Phase 2 meeting.

Wolfgang Bender, M.D., Ph.D., Chief Medical Officer of Valneva commented, “These fantastic results confirm that VLA1553 is a highly differentiated and promising vaccine candidate that has the potential to address a serious threat to public health. On the basis of all our data, we aim to work with the regulators towards an accelerated approval pathway potentially allowing us to enter directly into pivotal Phase 3 next year.”