Pfizer’s Lyme Vaccine Misses Endpoint Despite 73.2% Efficacy
Pfizer and Valneva’s Phase III VALOR study of PF-07307405 enrolled 9,400 individuals but failed to meet its primary endpoint due to low case accrual despite showing 73.2% efficacy 28 days after the fourth dose. Pfizer will proceed with regulatory submissions, its shares remained stable while Valneva stock plunged 37.1%.
1. VALOR Study Results
The VALOR trial enrolled about 9,400 participants aged five and older to assess PF-07307405’s efficacy in preventing Lyme disease. The six-valent OspA-based vaccine achieved 73.2% efficacy 28 days post-fourth dose but failed to reach statistical significance due to fewer Lyme cases than anticipated.
2. Next Steps and Collaboration
Pfizer and Valneva will proceed with regulatory submissions based on the clinically meaningful data, including a lower 95% confidence interval bound above 20 in a pre-specified analysis. The vaccine is developed under a 2020 collaboration granting Pfizer exclusive manufacturing and commercialization rights upon approval.
3. Market Reaction
Pfizer’s stock remained largely stable following the trial miss, reflecting investor confidence in its broader pipeline. Valneva shares plunged 37.1%, from $4.56 to $2.54, highlighting market concern over the delayed vaccine availability given no authorized Lyme vaccines since 2002.