PCVX: PFE’s Headline Ph 2 Peds Data on Serotype 3 Raises the Bar; VAX-31 Peds a Well-Known Must Have, VAX-31 Adult Still Next and Potentially BIC

Research evidence excerpt

PCVX: PFE’s Headline Ph 2 Peds Data on Serotype 3 Raises the Bar; VAX-31 Peds a Well-Known Must Have, VAX-31 Adult Still Next and Potentially BIC

FLASH NOTE

May 20, 2026

Seamus Fernandez seamus.fernandez@guggenheimpartners.com PCVX: PFE’s Headline Ph 2 Peds Data on Serotype

617 859 4637 3 Raises the Bar; VAX-31 Peds a Well-Known Must

Evan Wang

evan.wang@guggenheimpartners.com Have, VAX-31 Adult Still Next and Potentially BIC

212 651 9756

Colleen Garvey, Ph.D. Key Message: This morning’s news on PFE’s Ph 2 pediatric data for its 25v PCV

colleen.garvey@guggenheimpartners.com (presented today at ISPPD) suggests an impressive immunogenicity response to 617 859 4664

serotype 3, delivering 8.8- to 15-fold higher geometric mean titers (at dose 3 and dose 4,

Alana Lelo, Ph.D. respectively) as compared to Prevnar 20. To our understanding, this is an unprecedented

alana.lelo@guggenheimpartners.com magnitude of response against serotype 3, where the disease burden continues to be

212 518 9955 among the highest circulating serotypes in children and adults and an elusive target of

Zach Dunn, Ph.D. PCV development. According to experts, targeting serotype 3 successfully likely would

zach.dunn@guggenheimpartners.com require a response as much as 10-fold greater than baseline, a bar that PFE's novel

617 859 4603 25v PCV appears to meet. We have reached out to PFE for the presentation to evaluate

the overall results, including responses to the other 24 serotypes and to understand if

there are any tolerability or safety risks associated with this novel vaccine. However,

PCVX assumingwith no losstheseof protectionresults areagainstrobust otherand genuinelykey circulatingresult serotypes,in protectiononlyagainstPCVX'sserotypeVAX-313

Vaxcyte, Inc.