Pfizer, Valneva to stop testing Lyme disease vaccine

New York, The Gulf Observer: Drugmaker Pfizer Inc and France’s Valneva will stop testing a Lyme disease vaccine in roughly half of U.S. patients in a late-stage study, the companies said, citing a breach of clinical trial guidelines by a third-party contractor.

The joint statement on Friday did not disclose the number of patients affected but analysts at brokerage Rx Securities estimated it could impact about 2,000 participants.

The decision could delay the time to approval of a vaccine that Valneva expects could become a blockbuster shot as infections rise globally due to a burgeoning population of ticks, which usually cause Lyme disease.

The financial impact is currently difficult to predict, analysts at brokerage Portzamparc said, as it is unclear whether regulatory authorities will accept data from half of the participants.

Pfizer still expects to submit marketing applications for the experimental vaccine in the United States and Europe in 2025.

“However, there is a clear risk to these timelines now, with, we believe, a worst-case scenario of a year’s delay,” said RxSecurities analyst Samir Devani.

The trial was expected to include around 6,000 participants aged 5 and older across Europe and United States, where Lyme disease is highly endemic.

Recruitment will continue at sites not operated by the third-party organization which was not named, and Pfizer said it would work with health regulators on any potential changes to the trial.

Valneva has been pinning its hopes on the vaccine candidate, known as VLA15, to counter the impact of disappointing sales for its COVID shot.

Paris-listed shares of Valneva fell nearly 10% to 5.72 euros following the news and U.S.-listed shares of Pfizer were down marginally in premarket trading.