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yesterday

Pfizer, Valneva Lyme Vaccine Shows Over 70% Protection but Misses Primary Goal

Regulators now weigh strong protection against a missed primary benchmark.

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Nantucket, MA -- 06/07/16 -- Hikers walk past a warning sign about ticks and Lyme Disease as they enter the "Sanford Farm, Ram Pasture, The Woods, Barn and Back Trail" hiking area on June 7, 2016, in Nantucket, Massachusetts. A view grassy rolling sand dunes, and marshy area is seen along the soft sand road leading to Eel point on June 6, 2016, in Nantucket, Massachusetts. This area consists of rolling grassy sand dunes, as well as several shallow saltwater lagoons. Ticks that carry Lyme Disease are present island-wide, and are commonly found in sites where the moisture is high, including woods, marshy areas, high grass and along the brushy edges of fields. The area traverses a former farm and grazing area, and includes grassland, shrubland, a pine grove, and a glacially formed freshwater pond. (Kayana Szymczak for STAT)
A Pfizer logo is shown at a research facility in the La Jolla neighborhood of San Diego, California, U.S., September 30, 2025. REUTERS/Mike Blake
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Overview

  • Pfizer and Valneva said Monday their phase 3 trial cut confirmed Lyme cases by 73.2% from 28 days after a fourth dose, yet the primary endpoint failed because the lower confidence bound was 15.8% instead of the required 20%.
  • A pre-specified analysis that started one day after the fourth dose found 74.8% efficacy and met the statistical bar, and the companies plan regulatory submissions in the United States and Europe.
  • The VALOR study ultimately included about 9,400 participants ages 5 and up in the U.S., Canada, and Europe after the sponsors removed roughly half of the original ~18,000 enrollees in 2023 over quality problems at a third‑party site operator called Care Access.
  • The companies reported no safety concerns at the time of analysis, and Valneva’s shares fell more than a third after the mixed results while Pfizer’s stock was little changed.
  • The candidate targets the OspA protein to raise antibodies that pass into the tick during a bite and block Borrelia transmission, and if cleared it would be the first human Lyme vaccine since GSK withdrew LYMErix in 2002 with a potential launch projected for late 2027.