Vaxcyte shares surge as VAX-31 pneumococcal vaccine meets main Phase 3 goals
Vaxcyte said its experimental 31-valent pneumococcal vaccine met its main goals in the pivotal OPUS-1 adult trial, sending its shares up 91% before the bell — with an FDA filing planned for the first half of 2028.
Vaxcyte said on Monday its experimental pneumococcal vaccine met its main goals in a late-stage study in adults aged 50 and older, sending its shares up 91% before the bell, Reuters reported.
The vaccine, VAX-31, is a 31-valent pneumococcal conjugate vaccine candidate for the prevention of invasive pneumococcal disease and pneumococcal pneumonia. In the pivotal OPUS-1 adult Phase 3 trial, it met all prespecified co-primary immunogenicity endpoints: all 28 VAX-31 serotypes shared with Pfizer’s Prevnar 20 and/or Merck’s Capvaxive met the prespecified noninferiority criterion, the company said.
VAX-31 also produced stronger immune responses against three strains unique to it and against strain 20B, and showed a consistent safety profile across the age groups studied, with no serious adverse events considered related to the vaccines. In separate comparisons it met the study’s efficacy benchmark for all 20 strains it shares with Prevnar 20 and for 17 of 19 shared with Capvaxive; for the other two it met a less stringent threshold historically used in vaccine studies.
Vaxcyte expects results from two other late-stage trials in the first half of 2027 and plans to submit a US marketing application for VAX-31 in the first half of 2028. The Dow Jones Newswires put the premarket gain at about 64% to $92.67.
Pneumococcal disease is caused by bacteria that can lead to pneumonia, meningitis and bloodstream infections, with older adults particularly at risk.
Sources: Reuters (5 Oct 2026) — https://www.reuters.com/business/healthcare-pharmaceuticals/vaxcyte-shares-surge-pneumococcal-vaccine-meets-main-trial-goals-2026-10-05/ ; Dow Jones Newswires via Morningstar (5 Oct 2026) — https://www.morningstar.com/news/dow-jones/202610052034/vaxcyte-reports-bacterial-infection-vaccine-met-primary-endpoints-in-phase-3-trial ; Vaxcyte press release via Globe Newswire (5 Oct 2026) — https://marketwirenews.com/stock/pcvx/news/vaxcyte-reports-positive-topline-data-from-opus-1-th-6175442942892630.html ; Wall Street Journal (5 Oct 2026) — https://www.wsj.com/livecoverage/stock-market-today-dow-sp-500-nasdaq-10-05-2026/card/-under-the-radar-vaxcyte-stock-jumps-after-pneumonia-vaccine-holds-up-in-study-IT6RW8wPF4Ckc6CNDOgj
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