Pfizer and Valneva discontinue large part of Lyme disease trial

Shares of French specialty vaccines maker Valneva (Nasdaq: VALN) closed down 8% at 5.86 euros on Friday following the announcement that US giant Pfizer (NYSE: PFE), as the study sponsor, has decided to discontinue a significant percentage of participants in the USA who had been enrolled in the Vaccine Against Lyme for Outdoor Recreationists (VALOR) (NCT05477524) Phase III clinical trial of VLA15.

The decision was not linked to any safety issues, but rather “discontinued following violations of good practice at certain clinical trial sites run by a third party,” said Pfizer.

The clinical trial remains ongoing with other sites not operated by the third party, and Pfizer continues to enroll new participants at those sites.