Pfizer/Valneva Trial at Risk After Possible GCP Violations

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Pfizer and Valneva are dropping approximately half of enrolled participants in the Phase III VALOR study for their Lyme disease vaccine candidate, VLA15, after they found potential violations in good clinical practice (GCP) standards, the partners announced Friday.

“The violations were related to study conduct,” Kit Longley, spokesperson, Pfizer, told BioSpace in an email. The discontinuation of these participants “was not due to any safety concerns” with the vaccine candidate, nor was it triggered by any adverse event, Longley said.

GCP refers to the international ethical and scientific standards that clinical researchers must follow to ensure that their trials meet a certain bar of quality and integrity.

The potential breaches in GCP occurred at clinical sites in the U.S. being run by a third-party clinical trial site operator. Pfizer launched a thorough review of these sites after it had learned of potential violations. The company has also already notified affected participants, the FDA and other regulatory bodies and VALOR’s independent Institutional Review Board regarding the incident.

“The trial, in its current form, continues to enroll,” Longley said, and the study will remain ongoing at other clinical sites where no potential GCP violations have been found. Around 7,000 patients have already been enrolled into VALOR.

Pfizer and Valneva are working with the FDA, as well as other regulatory agencies such as the European Medicines Agency, regarding the proposed adjustments to VLA15’s clinical trial plan. The pharma partners expect to complete Phase III studies and submit a Biologics License Application for the candidate by 2025.

One of a Kind

As the only Lyme disease vaccine currently in clinical development, VLA15 is a multivalent shot that targets six of the most common serotypes of the OspA protein found on Borrelia burgdorferi, the bacteria that causes Lyme disease. By blocking OspA, VLA15 prevents the bacterium from moving from its tick vector to humans.

VLA15 was originally discovered by Valneva, which demonstrated the candidate’s potential to provide immune protection against most Borrelia species known to be pathogenic to humans. The FDA granted VLA15 its Fast Track designation in 2017.

In April 2020, Pfizer bought into VLA15, signing a potential $308 million pact with Valneva to co-develop and commercialize the Lyme shot. The deal involved a $130 million upfront payment, with $35 million and $143 million in development and early commercialization milestones, respectively.

As per the agreement, Pfizer will take the lead in late-stage development, which includes VALOR. The randomized and placebo-controlled trial launched in August 2022 and was originally set to have up to 50 sites in areas where Lyme disease is highly endemic, such as the U.S., Sweden and Germany.