Pfizer and Valneva have announced their intention to proceed with regulatory filings for their Lyme disease vaccine candidate (PF-07307405/VLA15), even after its Phase 3 trial failed to meet the pre-specified primary efficacy target.
Key takeaways from the clinical findings:
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Real-world Efficacy: In the VALOR trial involving 9,500 participants, the vaccine demonstrated 73.5% efficacy in preventing Lyme disease in individuals aged five and older. While clinically significant, the study missed its statistical goal because there were fewer infection cases than anticipated during the two-season observation period.
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Mechanism of Action: The three-dose regimen targets the outer surface protein A (OspA) of the Borrelia burgdorferi bacteria. It aims to become the first available human vaccine for the most common vector-borne illness in the Northern Hemisphere.
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Overcoming Setbacks: The program faced a major hurdle in 2023 when approximately 50% of U.S. participants were discontinued due to breaches of Good Clinical Practice (GCP) standards at certain sites, delaying the timeline by about a year.
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Market Landscape: No human Lyme vaccine has been available since GSK’s Lymerix was withdrawn in 2002. Pfizer’s leadership expressed confidence that an efficacy rate exceeding 70% provides a strong foundation for protecting patients from the debilitating long-term effects of the disease.
Having invested hundreds of millions of dollars in the alliance since 2020, including taking an 8% stake in Valneva, Pfizer is signaling its readiness to enter the market ahead of competitors like Moderna, whose candidates are still in mid-stage testing.
Source: https://pharmaphorum.com/news/pfizer-valneva-shrug-phase-3-lyme-disease-vaccine-miss