The multivalent candidate, being developed by Pfizer and French partner Valneva under a 2020 pact, generated higher than 73% efficacy against the tick-borne disease in a Phase 3 trial—but failed to hit a predetermined confidence interval.
Pfizer and Valneva touted a late-stage win in Lyme disease Monday, reporting “strong efficacy” in the Phase 3 VALOR trial—but to analysts at RBC Capital Markets, the results were less than “Sub-Lyme.”
PF-07307405 (LB6V), an investigational multivalent protein subunit vaccine, delivered mixed results in VALOR, which enrolled 9,437 individuals aged 5 years and older in regions of the U.S., Canada and Europe with high incidence of Lyme, a tick-borne bacterial infection. LB6V elicited efficacy of 74.8% from one day after the fourth and final dose in reducing the rate of confirmed Lyme disease cases vs. placebo. Efficacy dropped slightly to 73.2% at that timepoint. However, the trial’s primary endpoint, a predetermined 95% confidence interval, was not met, the partners reported in a Monday press release.
Pfizer, however, did not appear to be concerned about the endpoint miss, attributing it to fewer than anticipated Lyme disease cases having accrued during the study period. “Given the clinically meaningful efficacy and the fact that the 95% confidence interval lower bound was above 20 in the second pre-specified analysis, Pfizer is confident in the vaccine’s potential and is planning submissions to regulatory authorities,” the New York pharma said Monday.
In a Monday note to investors, RBC said that once LB6V’s application arrives at the FDA, “it could be met with a sympathetic ear,” as Health and Human Services Secretary Robert F. Kennedy Jr. has emphasized the need to address Lyme disease. The health secretary in December 2025 convened a panel of patients with Lyme disease and providers in the space to strengthen prevention, diagnosis and long-term care for people with the condition. There is currently no vaccine available for Lyme disease.
Successfully marketing an approved Lyme vaccine could prove to be a challenge for Pfizer and Valneva, however. GSK’s vaccine for the disease, called LYMERix, had similar efficacy to LB6V—76% in the year following vaccination—and stayed on the market for a few years following its December 1998 approval, but GSK pulled the product “due to weak demand and public concerns about adverse events,” according to RBC.
Nevertheless, RBC continues to model peak, unadjusted sales of $525 million for LB6V, given Monday’s mixed results, historical approval precedence, the current unmet need and the renewed regulatory focus on Lyme.
The vaccine is being developed as part of a partnership struck between Pfizer and Valneva in April 2020. Under the terms of the deal, Valneva was eligible to receive a total of $308 million cash payments, including $130 million upfront.
