- Pfizer and partner Valneva announced Monday that they have finished enrolling participants in a Phase 3 trial evaluating their experimental vaccine for Lyme disease.
- The announcement ends a lengthy delay that began in February, when the two companies said they were removing half of trial participants due to concerns of study misconduct by an outside trial operator. In October, an inspection by the Food and Drug Administration found no signs of wrongdoing.
- Still, the study is now expected to wrap up later than the companies had originally anticipated. Pfizer and Valneva now expect to obtain study data in 2025 and, assuming positive results, submit regulatory filings in the U.S. and Europe the following year.
Pfizer and Valneva’s vaccine has the chance to become the first marketed, preventive shot for the disease in more than 20 years. The shot, known as VLA15, is the only one currently in clinical development and designed to provide protection against six strains of Lyme disease.
Yet the path to approval has been difficult. The companies first began their Phase 3 trial, dubbed Valor, in August 2022, aiming to build upon promising findings observed in earlier testing in adults and children. Then, in a surprise announcement in February, they disclosed that they were removing half of the study’s participants because of concerns about possible study violations by a key trial site operator.
That contract research company, Care Access, disagreed with the decision and shared information with the Food and Drug Administration as well as an independent review board. Though the FDA eventually cleared Care Access of wrongdoing in October, the company still had to cut about half of its staff during the review. The development of Pfizer and Valneva’s shot was delayed as well, even as the study continued at other trial sites.
On Monday, that delay came to an end, as the partners revealed that they’ve enrolled 9,437 study volunteers at sites in the U.S., Europe and Canada. A second study in children, designed to provide more details on the shot’s safety, has also been fully recruited, the companies said.
There are currently no vaccines for Lyme disease. A GSK vaccine called Lymerix was once available, but withdrawn in 2002 amid low demand. Yet the need for a shot is higher now, as prevalence has been increasing in recent years, according to the Centers for Disease Control and Prevention.