Pfizer removes HALF of patients from its Lyme disease vaccine trial

Pfizer is removing half of patients from its Lyme disease vaccine trial after a third-party clinical trial site operator was found to be violating quality standards.

Around 3,500 patients will be pulled from the Phase III study due to violations of Good Clinical Practice (GCP) rules, which refer to ethical and scientific standards for clinical trials.

It is not clear exactly which elements of GCP had been breached, but Pfizer said it was not due to any safety concerns and was not prompted by an adverse event.

The trial was looking to see how effective and safe the Lyme disease vaccine is, as well as how able it is to produce an immune response in humans.

It is not the first time Pfizer clinical trials have come under scrutiny. A BMJ investigation found that just one in 20 trial sites for its widely adopted Covid vaccine had proper FDA oversight. 

 Trial participants were getting either VLA15 or a placebo to determine the ability of the shot to reduce the chances of contracting Lyme disease

The investigational shot, VLA15, is the only Lyme disease vaccine currently in clinical development.

Pfizer spokesman Kit Longley said in an email that the issues were ‘related to study conduct’.

He added: ‘As soon as Pfizer was notified, Pfizer conducted a thorough review of the operations and data collection at all sites.’

Common breaches of GCP include not having participants’ full informed consent, entering ineligible participants and storing drugs incorrectly.

The trial was designed for 18,000 healthy people, and around 7,000 people had been enrolled so far.

It remains ongoing at other sites not operated by the third party and participants are still being enrolled. 

However, pulling thousands of participants could cause delays. 

The study began in August and was due to finish by the end of next year.

Pfizer said it was still aiming to file for FDA and the European Medicine Agency approval in 2025.

It made a $308million deal for the vaccine, created by biotech company Valneva, in 2020.

Trial participants were getting either VLA15 or a placebo to determine the ability of the shot to reduce the chances of contracting Lyme disease.

The VLA15 is a three dose vaccine. The first shot would be given in the first two months, another between five and nine months and a booster shot roughly a year later.

The study involved people in the US, Finland, Sweden, Netherlands, Germany and Poland living in areas with frequent Lyme disease who are at a greater risk because they do activities such as forestry work or hiking.

Lyme disease is a bacterial infection that is spread to humans by infected ticks.

It causes symptoms including a circle or oval-shaped rash around a tick bite, which usually appears within four weeks of being bitten, but may take up to three months to show.

It is the most common disease transmitted by ticks, mosquitoes or fleas in the US, affecting up to 30,000 a year. In the UK, there are around 1,500 cases a year.