Pfizer has announced plans to seek regulatory approval for a Lyme disease vaccine candidate, despite the shot’s failure in a late-stage clinical trial. The determination to proceed comes after the vaccine did not meet its statistical goals due to an insufficient number of participants contracting Lyme disease during the study. However, Pfizer reported that the vaccine demonstrated over 70% efficacy in reducing infection rates among vaccinated individuals compared to those who received a placebo.
Annaliesa Anderson, Pfizer’s Chief Vaccines Officer, expressed optimism about the results, stating that the efficacy observed in the VALOR study is “highly encouraging.” She emphasized the potential of the vaccine to protect against Lyme disease, which can lead to severe health issues.
Although the Lyme disease vaccine is not expected to become a blockbuster product for Pfizer—whose partner, Valneva, estimates annual sales could peak at around $1 billion—the company had previously highlighted its importance as a significant milestone in its portfolio this year. Pfizer is projecting overall revenue of approximately $60 billion for the year, with its Covid-19 vaccine contributing more than $5 billion to that figure.
Following the announcement, the path forward may be fraught with challenges. Moving ahead with a vaccine that failed to meet clinical trial standards under a regulatory environment prioritizing rigorous scrutiny could present risks for the company. It has the potential to act as a barometer for broader vaccine policies in the United States.
Lyme disease is caused by the Borrelia bacteria, commonly transmitted to humans through tick bites. This illness can result in symptoms such as arthritis and muscle pain. Current estimates from the Centers for Disease Control and Prevention indicate that roughly half a million Americans are either diagnosed or treated for Lyme disease annually, particularly in regions like the Northeast.
Historically, there has been a lack of available vaccines for humans, following the withdrawal of LYMErix by GSK in the early 2000s. This was prompted by public concern over safety, which hindered further development of such vaccines, although canine vaccines are already on the market. In the current study, Pfizer and Valneva encountered setbacks, including the elimination of about half of the initial 18,000 trial participants due to quality concerns associated with a third-party clinical trial operator, reducing the final participant count to approximately 9,400.
The vaccine developed by Pfizer and Valneva targets the outer surface protein A of the Lyme disease-causing bacteria. Upon vaccination, individuals produce antibodies that can be transferred to ticks, effectively blocking the bacteria’s transmission to humans. The vaccination schedule consists of three shots in the first year, followed by a booster dose in the subsequent year. Throughout the trial, the companies reported no safety concerns arising from the vaccine.
