Pfizer and Valneva have hit a bump in the road for their Lyme disease vaccine candidate, VLA15. The study, called Vaccine Against Lyme for Outdoor Recreationists (VALOR), is in Phase 3 clinical trials and investigates the vaccine's efficacy, safety, and immunogenicity. However, due to violations of Good Clinical Practice (GCP) at certain clinical trial sites run by a third-party clinical trial site operator, Pfizer has decided to discontinue a significant percentage of participants in the U.S., representing around half of the total recruited participants in the trial. This discontinuation was not due to any safety concerns with the vaccine, and it was not prompted by any participant-reported adverse events.
Following the potential GCP violations, Pfizer conducted a thorough review of the operations and data collection at the clinical trial sites run by the third party and took action to ensure the highest scientific integrity and participants' best interests. The clinical trial remains ongoing with other sites not operated by the third party, and Pfizer continues to enroll new participants at those sites. Pfizer plans to work with regulatory authorities and aims to submit a Biologics License Application (BLA) to the FDA and a Marketing Authorisation Application (MAA) to the European Medicines Agency (EMA) in 2025, subject to the successful completion of the Phase 3 studies and the agreement of these regulatory agencies to proposed modifications of the clinical trial plan. Participants have been notified, and Pfizer has notified the FDA, other regulatory agencies, and the independent Institutional Review Board for this study.
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