Vaxcyte's 31-Valent Vaccine Hits Every Primary Goal, But Two Serotypes Miss Stricter Bar Against Capvaxive
VAX-31 cleared 17 of 19 shared serotypes against Capvaxive at the tougher threshold; a biologics license filing is planned for the first half of 2028.
Vaxcyte said Monday that its 31-valent pneumococcal vaccine candidate, VAX-31, met all prespecified primary endpoints in OPUS-1, its first pivotal adult trial, according to an 8-K and press release. The catch: against Merck's Capvaxive, two of 19 shared serotypes missed the stricter noninferiority bar.
What the trial showed
In adults 50 and older, all 28 VAX-31 serotypes shared with Prevnar 20 and/or Capvaxive met noninferiority at a lower confidence bound above 0.667. The three serotypes unique to VAX-31, plus cross-reactive serotype 20B, met the superiority criterion of above 2.0.
In adults 18-49, VAX-31 met the 0.667 noninferiority criterion on all 32 serotype comparisons against adults 50-64. The company called the safety profile similar to both comparators.
The trial dosed 4,047 participants at about 30 U.S. sites. No serious adverse events were judged related to study vaccines, and no one dropped out over adverse events.
The two serotypes that missed
Compared individually, VAX-31 met the 0.667 threshold for 20 of 20 serotypes shared with Prevnar 20 and 17 of 19 shared with Capvaxive. Serotypes 3 and 12F missed it against Capvaxive but cleared the historical 0.5 threshold, so 19 of 19 passed at that looser level.
Chief Scientific Officer James Wassil said serotypes unique to Capvaxive account for a larger share of adult disease in the U.S. today. "We expect the comparison of VAX-31 to PCV21 to be a particular focus of FDA review," he said.
CEO Grant Pickering described the trial as "inaugurating a more stringent noninferiority standard," which the company argues sets a new benchmark.
What comes next
Vaxcyte expects results from the OPUS-2 and OPUS-3 adult trials in the first half of 2027, with a biologics license application planned for the first half of 2028. A manufacturing consistency study follows the readouts. Infant Phase 2 data are also due by the end of the first half of 2027.
Chief Medical Officer Luis Jodar said VAX-31 could add incremental coverage of 13-36% of invasive pneumococcal disease and 19-31% of pneumococcal pneumonia over current adult vaccines. Management hosts its results call at 8:00 a.m. ET Monday. Market data showed the shares at $56.48, up 0.77%, as of 8:16 a.m. ET Monday.
The next hard data points are OPUS-2 and OPUS-3 in the first half of 2027, ahead of the planned 2028 filing.
Sources
- 8-K Filing — Vaxcyte, Inc. (PCVX) — SEC EDGAR
- Exhibit d21202dex991.htm — Vaxcyte, Inc. 8-K exhibit — SEC EDGAR
- Exhibit d21202dex992.htm — Vaxcyte, Inc. 8-K exhibit — SEC EDGAR
- Vaxcyte Reports Bacterial-Infection Vaccine Met Primary Endpoints in Phase 3 Trial — MarketWatch
- Vaxcyte to Host Webcast and Conference Call to Present — globenewswire.com
