Vaxcyte Doses First Participant in Phase 1 Group A Strep Vaccine Trial
PCVX•Vaxcyte has dosed the first participant in its Phase 1, two-stage, dose-escalation trial of VAX-A1 in 18- to 40-year-old healthy adults. The randomized, double-blind study will assess safety, tolerability and immunogenicity across three dose levels and expects topline data in the second half of 2027.
1. Trial Design and Enrollment
Vaxcyte has initiated a randomized, double-blind, placebo-controlled Phase 1 study of VAX-A1 in approximately 80 healthy adults aged 18 to 40 years. Stage 1 will enroll 12 participants randomized 3:1 across low, mid and high dose levels, with an independent Data Safety Monitoring Board review of unblinded safety data before Stage 2.
2. Study Objectives and Timeline
The two-stage, dose-escalation trial has primary objectives of evaluating safety and tolerability and secondary objectives of measuring antigen-specific immune responses to Group A Strep antigens. Enrollment across both stages is underway, with topline safety and immunogenicity data expected in H2 2027.
3. Public Health Significance
Group A Streptococcus causes an estimated 800 million new cases and over 600,000 deaths globally each year, with no approved vaccine and rising antibiotic resistance. VAX-A1 targets conserved pathogen elements to elicit broad protective responses, aiming to address a significant clinical burden and reduce healthcare costs.
