Vaxcyte, Inc. (NASDAQ:PCVX) shares rose 50% on Monday after the company reported topline results from its pivotal OPUS-1 Phase 3 trial evaluating VAX-31, its 31-valent pneumococcal conjugate vaccine candidate.
VAX-31 met all prespecified primary endpoints across the age groups studied in comparisons with Prevnar 20 and Capvaxive.
In adults aged 50 and older, the vaccine met the prespecified noninferiority threshold of greater than 0.667 for all 28 VAX-31 serotypes shared with the comparator vaccines. Three serotypes unique to VAX-31 and cross-reactive serotype 20B met the trial’s superiority criteria.
OPUS-1 Enrolled More Than 4,000 Participants
The OPUS-1 trial enrolled 4,047 participants across approximately 30 sites in the United States.
Participants aged 50 and older were randomised to receive a single dose of VAX-31, PCV20 or PCV21, while those aged 18 to 49 received either VAX-31 or PCV20.
In separate comparator analyses, VAX-31 met the noninferiority criterion for all 20 serotypes shared with PCV20 and 17 of the 19 serotypes shared with PCV21.
Serotypes 3 and 12F did not meet the greater than 0.667 noninferiority threshold against PCV21, although both met the historical threshold of greater than 0.5.
Vaxcyte said VAX-31 was well tolerated, with a safety profile similar to PCV20 and PCV21 across the age groups studied. No serious adverse events were considered related to the study vaccines, and no participants discontinued the study because of adverse events.
Additional Phase 3 Results Expected in 2027
Vaxcyte expects to report results from its OPUS-2 and OPUS-3 adult Phase 3 trials during the first half of 2027.
The company plans to use results from its Phase 3 programme to support a Biologics License Application submission for VAX-31 in the first half of 2028.
Following the OPUS-1 results, Guggenheim analyst Seamus Fernandez raised his price target for Vaxcyte to $125 from $116 while maintaining a Buy rating.
“The adult VAX-31 OPUS-1 Phase 3 was a major win not only vs. investor expectations and delivering our Best Case scenario, but also setting up VAX-31 for clear commercial leadership,” Fernandez said.