Lyme vaccine test completion is pushed back by a year as Pfizer, Valneva say they’ll adjust trial

Valneva and Pfizer have adjusted the end date for the Phase III study of their investigational Lyme disease vaccine, pushing it back by a year after issues at a contract researcher led to thousands of US patients being dropped from the test.

In a March 20 update to clinicaltrials.gov, Valneva and Pfizer moved the primary completion date on the trial, called VALOR, from the end of 2024 to the end of 2025.

The companies have previously said that they planned to take the drug to US and European regulators in 2025. Valneva and Pfizer both say they hope to keep that goal, and are working with regulators to modify the trial to stick to it.

Valneva, in a March 23 update, said that Pfizer aims to “potentially maintain the original submission timelines, pending successful completion of the Phase 3 studies and subject to the agreement of these regulatory agencies to proposed modifications of the clinical trial plan.” In an emailed statement, a Pfizer spokesperson reiterated the “potentially submit” language, noting the trial continues to enroll new participants.

In mid-February, Pfizer made the surprise announcement that it was dropping about half of the 7,000 enrolled participants from the Lyme disease trial. At the time of the announcement, it said that there had been violations of quality standards known as “good clinical practice” by a contractor. Endpoints News reported that the contractor was a company called Care Access, whose parent Reify Health has raised close to half a billion in venture funds to try and disrupt the clinical trials industry.

Enrollment challenges

Dropping those patients means that the French biotech and Pfizer would have to enroll more than 14,000 additional people to meet their original 18,000-person target. The seasonality of Lyme disease, though, makes the situation challenging, Valneva CEO and president Thomas Lingelbach said on an analyst call on Thursday.

“One scenario is just to add another season. This is the obvious one,” Lingelbach said. “Restarting again this summer for the next tick season 2024. There are other, what I would call more creative scenarios, that may potentially allow still a filing but those are in the make right now, or in the discussions, and we can’t comment on those.”

Thomas Lingelbach

Jefferies analyst Maury Raycroft wrote in a Friday morning note that Valneva “reiterated there would be no need for new trials, and that worst-case scenario would be a 1-yr delay, given trial relies on subjects receiving 3 doses prior to end of tick season (roughly Spring to Fall).” Jefferies analysts think a rehashed trial plan could be “contingent on fluid enrollment status at landmarks, which would likely impact endpt powering assumptions.”

Valneva and Pfizer declined to disclose the proposed modifications. Valneva did not respond to inquiries from Endpoints.

“But by the end of the day, it is always a matter of risk-benefit and judgment, and that’s all I can say at this point in time,” Lingelbach said on the call.

The FDA fast track-designated vaccine would be the first for Lyme disease in about two decades. The regulator greenlit a vaccine in 1998 after a trial showed it was effective, but reports of side effects and lawsuits derailed the shot, produced by what is now GSK. No association was founded between vaccination and longer-term side effects, but a commercial flop doomed it, and the company removed it from the market in the early 2000s.

Lyme disease impacts nearly half a million people per year, the Centers for Disease Control and Prevention has said.

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