Valneva Successfully Completes Chikungunya Vaccine Phase 3 Trial

There is no vaccine to prevent or treat chikungunya virus. Valneva announced 98.9% of phase 3 trial participants achieved CHIKV neutralizing antibodies after a signle dose of their vaccine candidate, VLA1553.

Today, the specialty vaccine company Valneva announced the successful completion of the phase 3 trial for their single-dose chikungunya vaccine, VLA1553.

VLA1553 met its preliminary endpoint, with 98.9% of participants reaching protective levels of chikungunya virus (CHIKV) neutralizing antibodies 1 months after vaccination. The positive results included a 6-month follow-up period, after which 96.3% of participants maintained CHIKV neutralizing antibodies.

Valneva chief medical officer, Juan Carlos Jamamillo, MD, said, “Delivering these first-ever final Phase 3 results for a chikungunya vaccine candidate means that we are a step closer to addressing a major, growing and unmet public health threat. We would like to thank everyone who participated in the trial and who continued to advance the trial during the pandemic.” Valneva anticipates completing the US Food and Drug Administration’s (FDA) pre-submission process in the second quarter of 2022.

The phase 3 clinical trial, VLA1553-301, included 4115 adults 18 years and older. The prospective, double-blind, multicenter, randomized trial commenced in September 2020. Participants received a single dose of lyophilized VLA1553 or placebo, administered as an intramuscular injection.

VLA1553 was also found to be highly immunogenic in study participants 65 years and older, who demonstrated high seroprotection and neutralizing antibody titers comparable to younger participants. Valneva confirmed they will continue monitoring a subset of participants for at least 5 years after VLA1553 vaccination to verify the expected long-term protection of a single injection.

VLA1553 was generally well-tolerated among the 3082 participants evaluated for safety across all age groups. The trial was moderated by an independent data safety monitoring board, which neglected to find any safety concerns. Most reported adverse events following VLA1553 injection were mild-to-moderate and resolved within 3 days. 2.0% of participants reported severe adverse events, most commonly fever, while 50% of participants reported “solicited systemic adverse events,” including headache, myalgia, and fatigue.

Chikungunya virus is a vector-borne disease transmitted via the bite of an infected mosquito. The US Centers for Disease Control and Prevention (CDC) reports the most common symptoms are fever and joint pain; other common symptoms may include headache, rash, joint swelling, or muscle pain. Chikungunya outbreaks have occurred around the world, though infections are most common in Africa, Asia, and the Indian subcontinent. The virus may be spread by infected travelers, and there is currently no vaccine to prevent or treat infection with the chikungunya virus.

Valneva focuses on developing and commercializing prophylactic vaccines for infectious diseases with a significant unmet need. In addition to chikungunya, Valneva is currently also developing Lyme disease and COVID-19 vaccine candidates.