Valneva Vaccine Achieves 73.2% Efficacy but Fails Endpoint, Shares Plunge 37.1%
Valneva’s Lyme disease vaccine candidate PF-07307405 achieved 73.2% efficacy in its 9,400-patient VALOR Phase III study but failed to meet the primary endpoint due to low case accrual. Valneva shares plunged 37.1% as the company confirmed it will proceed with regulatory submissions.
1. Phase III VALOR Trial Results
The VALOR study enrolled approximately 9,400 participants aged five and above to evaluate PF-07307405, a six-valent OspA-based Lyme disease vaccine candidate. The vaccine demonstrated 73.2% efficacy 28 days after the fourth dose, but low Lyme case accrual meant the primary endpoint was not met despite a second analysis showing the confidence interval lower bound above 20.
2. Market Reaction and Share Impact
Following the announcement, Valneva shares fell sharply by 37.1%, reflecting investor disappointment over the trial’s statistical shortfall. Pfizer’s stock remained largely unchanged, underscoring market focus on Valneva’s clinical and commercial risk profile.
3. Regulatory Path and Collaboration
Despite the endpoint miss, Valneva and Pfizer plan to advance submissions to U.S. and EU regulatory authorities based on the clinically meaningful efficacy data. The vaccine program operates under an April 2020 license deal granting Pfizer exclusivity to manufacture and commercialize PF-07307405 upon approval.