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Home » Pfizer-Valneva Lyme disease vaccine — phase 2 pediatric trials results

Pfizer-Valneva Lyme disease vaccine — phase 2 pediatric trials results

Last updated on August 28th, 2023 at 01:24 pm

I have previously discussed a Lyme disease vaccine candidate from Pfizer and Valneva that is starting a phase 3 clinical trial. However, the companies are keeping us updated with their phase 2 results, and there has been exciting news — the pediatric trial (in 5-17-year-olds) showed strong immunogenicity for the new Pfizer-Valneva vaccine.

Of course, dogs have had access to a Lyme disease vaccine, but there has not been a vaccine available for humans for over 20 years. It’s not that dogs are more important than humans (though many of us might argue that point), but about 20 years ago, the anti-vaxxers got the vaccine pulled from the market, one of their few “successes” in getting rid of useful vaccines.

But a small company, Valneva, in partnership with Pfizer, has developed a new vaccine that will be entering Phase 3 clinical trials real soon. Hopefully, we’ll have it in just a few more years.

Let’s first take a look at this disease, and then we will review the vaccine itself along with new results.

Lyme disease vaccine
This cute dog can get a Lyme disease vaccine. We can’t, for now. Photo by Richard Brutyo on Unsplash

What is Lyme disease?

Lyme disease is an infectious disease caused by at least three species of bacteria belonging to the genus Borrelia. Of the three species, Borrelia burgdorferi is the main cause of Lyme disease in North America, whereas Borrelia afzelii and Borrelia garinii are more prevalent in Europe. The disease was named after the towns of Lyme and Old Lyme, Connecticut, where several cases were initially identified in 1975.

Borrelia is transmitted to humans when bitten by infected ticks which belong to a few species of the genus Ixodes, called “hard-bodied” ticks. Although deer ticks, Ixodes scapularis, Ixodes pacificus, or Ixodes ricinus, are commonly considered to be vectors for Borrelia infection, some of the other species in the Ixodes genus can transmit the disease. Lyme disease is the most common tick-borne disease in the United States.

There are several initial symptoms of Lyme disease – fever, headache, fatigue, depression, and a circular skin rash called erythema migrans (EM). If the Borrelia infection is not treated quickly, further symptoms may appear that can involve the joints, heart, and central nervous system.

There is generally only one known treatment for a Borrelia infection – antibiotics, which may include doxycycline, amoxicillin, and cefuroxime. Generally, the symptoms of the infection resolve after antibiotic treatment.

As I’ve written previously, the existence of “chronic Lyme disease,” a condition that some claim is a set of vague symptoms that are claimed to be a consequence of a permanent B. burgdorferi infection and somehow persists after antibiotic therapy. The existence of chronic Lyme disease is not supported by robust scientific evidence published in peer-reviewed, high-impact-factor biomedical journals.

Not real scientists not working on the Lyme disease vaccine.

The Valneva-Pfizer Lyme disease vaccine

Without a doubt, we need a Lyme disease vaccine, because the infection is debilitating and takes some significant effort by medicine to diagnose and treat the disease. According to a Nature editorial,

It may go against the scientific grain for marketing considerations to play such a part in steering vaccine development. But in the real world, this may be unavoidable. Lyme disease is a serious illness and those who live in areas where it is spreading deserve a vaccine.

Luckily for those in areas with endemic Lyme disease, a small French vaccine company, Valneva, has been developing a new Lyme disease vaccine, code-named VLA15. According to Valneva’s website, VLA 15 is a multivalent vaccine that targets one of the most dominant outer surface proteins of Borrelia. Valneva has partnered with Pfizer to complete clinical trials and to bring the vaccine to the market in North America and Europe.

This investigational multivalent protein subunit vaccine uses an established mechanism of action for a Lyme disease vaccine that targets the outer surface protein A (OspA) of Borrelia burgdorferi. OspA is one of the most dominant surface proteins expressed by the bacteria when present in a tick.

Blocking OspA inhibits the bacterium’s ability to leave the tick and infect humans. Importantly, VLA15 covers the six most common OspA serotypes expressed by B. burgdorferi species prevalent in North America and Europe.

Preclinical studies showed that the vaccine was broadly effective against Borrelia. These types of studies are how most vaccines are developed, by trying them in animal models.

Soon thereafter, Phase 1 clinical trials, in which the vaccine is tested on healthy volunteers, were successful.  Valneva proceeded with two Phase 2 clinical trials.  

In pediatric participants who received VLA15 in either the two-dose schedule (N=93) or three-dose schedule (N=97), Valneva reported that VLA15 was more immunogenic than in adults with both vaccination schedules tested. These new data build on the strong immunogenicity profile reported for adults in February 2022.

Based on these new results, Valneva and Pfizer plan to proceed with the inclusion of pediatric participants in their planned Phase 3 trial, which is expected to be initiated in the third quarter of 2022, subject to regulatory approval.

As far as I can tell, VLA15 is the only Lyme disease vaccine candidate currently in clinical development. There may be others in various pipelines but they haven’t started clinical trials yet.

Now, as I’ve written extensively regarding the rush for a coronavirus vaccine, we should reserve any optimism until the results are published in a peer-reviewed journal. And seroconversion does not necessarily mean immunity, although it would strongly indicate that.

VLA15 was granted a Fast Track designation by the FDA in July 2017. Because this designation is often misunderstood, I’ll try to explain it. Fast Track is granted by the FDA to investigational products that are under development for serious conditions and have the potential to fulfill an unmet medical need (in other words, the Lyme disease vaccine is a perfect example).

The process facilitates clinical development and expedites the review of new drugs and vaccines. It accelerates the availability of promising products on the market.

This does not mean that the vaccine gets less than a thorough review. It does not mean that Valneva and Pfizer can skip any of the phases of human clinical trials. Fast Track speeds up the review process. The process does not become easier.

At this time, Valneva and Pfizer have not posted any information about a phase 3 clinical trial on the clinical trials database for the vaccine. In the non-COVID-19 world of vaccine development, usually, the FDA reviews phase 2 data before a company proceeds with phase 3. This allows for both the agency and the sponsoring company to thoroughly vet the data to make sure there are no anomalies that may cause either to tap the brakes on phase 3.

Apparently, Valneva and Pfizer have submitted phase 2 clinical trial results to the FDA and are awaiting the go-ahead for phase 3. At that time, the clinical trial will be posted on the website. You may be able to contact one of the investigators to be included in the phase 3 trials, although you may end up in a placebo group. However, if you are, and if the vaccine shows strong safety and effectiveness in the phase 3 trials, the placebo group will be unblinded and will have an opportunity to get the vaccine.

At this time, Lyme disease is most prevalent in the Northeast along with the mid-Atlantic and upper Midwest with many areas in Northern Europe. However, there have been reports of Lyme disease outside of these, since the Ioxedes tick has been found outside of the traditional Lyme disease areas, putting these areas at risk of outbreaks of the disease. The clinical trials will probably focus on those areas of Europe, the USA, and Canada.

Phase 3 trials usually take two or three years, though if data is strongly positive in phase 3 studies, it could be speeded up. I know we are all spoiled with the speed of the COVID-19 vaccines, but that’s not normal, unfortunately.

As soon as I have information about a phase 3 clinical trial, I promise to post information in an article here, because I know many of you would volunteer themselves and their children for it. Lyme disease is an entirely preventable disease, and if we can have a vaccine, I know most of us will jump on it. I’d even bet that a few anti-vaxxers will sneak into their physician’s office and beg to get this vaccine. But I’m just speculating.


Michael Simpson

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