Vaxcyte (PCVX) TD Cowen 45th Annual Healthcare Conference summary

Company overview and technology

• Focuses on bacterial vaccines using a proprietary cell-free protein synthesis platform enabling site-specific conjugation and production of complex antigens.

• Lead programs are 24-valent and 31-valent pneumococcal conjugate vaccines, both showing positive phase II data in adults with broader protection and improved immune responses over current standards.

• Upcoming milestone is the initial phase II readout in infants for the 24-valent vaccine, expected later this quarter.

Clinical development and expectations

• Infant phase II study uses a seroconversion endpoint, measuring the percentage of subjects achieving protective antibody thresholds compared to Prevnar 20.

• Current infant vaccines (15-valent and 20-valent) have shown lower antibody responses and seroconversion rates than previous standards, with Prevnar 20 missing non-inferiority on six serotypes but still gaining approval.

• The 24-valent vaccine aims to improve both breadth of coverage and seroconversion rates, with potential for superior immune responses on certain serotypes.

• Phase II studies are smaller, so wider confidence intervals are expected; success is defined as being within 15 points of comparator rates, aligning with industry precedent.

Dose strategy and pipeline decisions

• Three dosing arms are tested: two uniform doses and a mixed dose arm with higher antigen levels for seven serotypes, informed by adult data.

• Dose adjustments are possible between phase II and phase III based on observed immunogenicity, as demonstrated in adult studies.

• Both 24-valent and 31-valent vaccines are advancing through phase II in infants; a decision on which to prioritize for phase III will be made after reviewing all data and considering operational, financial, and competitive factors.