Bavarian Nordic’s phase 3 chikungunya virus vaccine clinical trial has hit its primary endpoint, keeping the Danish drugmaker in the slipstream of Valneva’s near-approval candidate in the race to market.
Valneva is set to learn whether the FDA will approve its vaccine against the mosquito-borne viral infection in August, but it may only enjoy a brief period without competition. Bavarian Nordic joined the race earlier this year by securing the rights to a chikungunya vaccine candidate from Emergent BioSolutions as part of a deal worth $270 million upfront.
The first of two phase 3 data drops suggests Bavarian Nordic can challenge Valneva for the market, while leaving scope to question whether it can match the high bar set by its rival. The results come from a trial that randomized 413 people aged 65 years and older to receive the vaccine candidate or placebo.
In the 22 days after receiving a single intramuscular injection of the viruslike particle vaccine, 87% of the participants had neutralizing antibodies above the threshold for seroprotection agreed with authorities. Most, 82%, of the participants passed the threshold by Day 15, validating Bavarian Nordic’s belief that a single dose provides fast protection.
Potential differences between the Bavarian Nordic and Valneva trials and how they measured antibody levels mean comparing data between the two studies could give a misleading impression of how the two vaccines match up. With those caveats, all 59 of the people aged 65 years and older who took Valneva’s vaccine in a phase 3 trial had seroprotective levels of neutralizing antibodies on Day 29.
Most of the subjects enrolled in the Valneva trial were aged 18 to 64 years old. Bavarian Nordic is running a second phase 3 trial targeting people aged 12 to 64 years old. Data are due in the third quarter, and, as younger people typically have more robust immune responses to vaccines, the results in seniors suggest Bavarian Nordic’s vaccine will provide high rates of seroprotection in the second study.