There are no preventive vaccines or effective treatments available for chikungunya.
Valneva's vaccine, which was recently awarded Breakthrough Designation status by the US Food and Drug Administration (FDA), expects final trial results in the next six months once the trial has completed a final analysis including 6 months of safety data.
The candidate has also received FDA Fast Track designation (December 2018) and the European Medicines Agency’s PRIME designation (October 2020). The sponsor of the first chikungunya vaccine approved in the US will be eligible to receive a Priority Review Voucher (granting priority review for a subsequent application that does not already qualify for priority review).
Chikungunya impact expected to grow
Chikungunya is a mosquito-borne viral disease caused by the chikungunya virus (CHIKV), a Togaviridaevirus, transmitted by Aedes mosquitoes.
Infection leads to symptomatic disease in 72-92% of humans after four to seven days following the mosquito bite. While mortality with CHIKV is low, morbidity is high.
The high risk areas of infection for travelers are places where chikungunya virus-carrying mosquitos are endemic, including the Americas, parts of Africa, and Southeast Asia. As of September 2020, there were more than 3 million reported cases in the Americas: with the impact expected to grow as mosquitos carrying the virus continue to spread geographically.
Valneva's vaccine is a live-attenuated, single-dose vaccine candidate: which has been designed by deleting a part of the chikungunya virus genome.
In the Phase 3 trial, the candidate VLA1553 met its primary endpoint, inducing protective CHIKV neutralizing antibody titers in 98.5% of participants 28 days after vaccination.
The seroprotection rate result of 98.5% exceeded the 70% threshold (for non-acceptance) agreed with the FDA (The seroprotective titer was agreed with the FDA to serve as a surrogate of protection that can be utilized in a potential FDA submission of VLA1553 under the accelerated approval pathway.)
The vaccine candidate was highly immunogenic with a GMT of approximately 3,270, confirming the immunogenicity profile seen in the Phase 1 trial.
Additionally, VLA1553 was also highly immunogenic in elderly study participants, who achieved equally high seroprotection rates and neutralizing antibody titers as younger adults, as well as an equally good safety profile, says Valneva.
The trial involved 4,115 adults, aged 18 years and above, across 44 sites in the US.
Other chikungunya vaccine candidates include:
- The University of Oxford published Phase 1 data for ChAdOx1 Chik last month, showing a single-dose induced neutralising antibodies against 4 chikungunya virus lineages (the vaccine uses the ChAdOx1-vectored vaccine platform also used for the COVID-19 vaccine)
- MV-CHIK is a vaccine candidate using Themis’ measles vector platform, consisting of recombinant live Schwarz-strain measles-vectored vaccine expressing chikungunya virus structural proteins. The vaccine is in a Phase 2 study.
Juan Carlos Jaramillo, M.D, Chief Medical Officer of Valneva said: “We are delighted with these Phase 3 results confirming the compelling profile of our vaccine candidate across all age groups.
“These first-ever Phase 3 trial results for a chikungunya vaccine mean that we are a step closer to addressing this major, growing and unmet public health threat.
"I would like to thank everyone who participated in the trial and who continued to advance the trial during the pandemic.
"We will continue to work with regulators to bring VLA1553 to market as soon as possible.”
VLA1553 would expand Valneva’s existing travel vaccine portfolio, with the company estimating the global market for vaccines against chikungunya being worth more than $500m annually by 2032.
Valneva currently has two travel vaccines on the market: Ixiaro (Japanese Encephalitis) and Dukoral (cholera). Other vaccines in the pipeline include a COVID-19 vaccine (Phase 3); and its Lyme’s Disease candidate in partnership with Pfizer.