Based on the results of two completed Phase III trials, scientists are confident that we could see an effective vaccine against Lyme disease by next year.
The final hurdle will be US Food and Drug Administration (FDA) approval, which the drug-makers will seek despite some study endpoints not being met. It remains to be seen whether this will be enough to derail the vaccine’s progress to market.
Pfizer’s researchers have had their fair share of optimism and letdowns in their quest to develop the first-of-its-kind vaccine. Despite hopes in 2022 that the pharmaceutical company would be the first to deliver a Lyme disease vaccine within a few years, progress stalled during later stages of the high-stakes Vaccine Against Lyme for Outdoor Recreationists (VALOR) trial.
This time the drug-maker is hoping regulatory bodies focus on the vaccine’s efficacy, which was found to be more than 70%.
“Lyme disease can cause potentially serious consequences – where individuals and families face symptoms that can disrupt daily life, work, and long-term health – and there is currently no vaccine available,” says Annaliesa Anderson, Senior Vice President and Chief Vaccines Officer at Pfizer.
“The efficacy shown in the VALOR study of more than 70% is highly encouraging and creates confidence in the vaccine’s potential to protect against this disease that can be debilitating.”
According to the US Centers for Disease Control and Prevention (CDC), 89,000 cases of tick-borne Lyme disease were reported in the US in 2023. Accurate measures are uncertain due to factors, including the treatment of symptoms without a diagnosis. Researchers suggest figures could be closer to nearly 500,000 people being infected annually.
Transmission also makes things more difficult. While it’s primarily contracted following a bite from a certain species of infected ticks (deer ticks, or Ixodes scapularis) that carry the bacteria Borrelia burgdorferi, people often don’t realize they’ve come in contact with the parasites until the appearance of symptoms, which includes fever, fatigue, joint pain and rashes, and, at the more serious end of the spectrum, chronic cardiovascular, and nervous-system conditions.
And while the tick’s common name suggests deer are its only host, these efficient vectors live on many animals – rodents, birds, for example.
While seasonal weather changes don’t impact Lyme disease prevalence, warming climates with increased humidity broaden the tick’s range. An effective vaccine for those at risk – hikers, campers, people who work or spend a lot of time where ticks are prevalent – could drastically reduce the health issues associated with the disease.
The vaccine candidate, PF-07307405 (or LB6V), works by homing in on the protein A (OspA), which is found on the outer surface of the B. burgdorferi bacterium. This activates the production of bacteria-fighting antibodies in the human immune system.
PF-07307405 was 73.2% effective 28 days after the fourth dose, compared with a placebo.
While Pfizer and French pharmaceutical company Valneva announced that their Lyme disease vaccine is effective, they also failed to satisfy the Phase III primary endpoint based on statistical outcomes. They attributed this to a surprisingly low incidence of cases in the study, which featured more than 9,000 people aged five years and older from sites in “areas of high incidence of Lyme disease” across the US, Canada and Europe.
However, the devil is in the detail. The data itself was clinically meaningful (side note: the entire research paper is yet to be released), which has Pfizer and Valneva eager to seek FDA approval.
So what at first may seem like convincing spin to keep this drug development moving forward, it’s so far our greatest candidate in fighting Lyme disease. The final research paper, when released, should offer more clarity given that statistical analysis is not a foolproof method in scientific research.
“These results bring us a step closer to our goal of delivering a much-needed vaccine to help protect against Lyme disease,” says Thomas Lingelbach, CEO and a board member of Valneva. “We are grateful to our partner Pfizer for their strong commitment which we both share in developing this vaccine as quickly as possible.”
The candidate has of course passed its safety benchmarks in earlier trials, so even with a skeptical view of Pfizer’s statements on the Phase III results, PF-07307405 remains a strong possibility of becoming the first vaccine in the fight against Lyme disease.
The results from this drug candidate’s Phase II trial has been published in the journal The Lancet. The results of the Phase III study are yet to be peer-reviewed and released in full.
Source: Pfizer
Fact-checked by Mike McRae.
