Editor's Bio Products Circle 

Vaxcyte has released Phase 1/2 data for its 31 valent pneumococcal vaccine candidate, which analysts have described as "astonishing". If these data can be replicated in large-scale critical studies, it could pose a serious threat to Pfizer's Prevnar 20.
Vaxcyte's half period data for VAX-31 in adults aged 50 and above against Prevnar 20 is "extraordinary" and suggests a "killer product in the pneumococcal conjugate vaccine category," said analysts at Leerink Partners in a report on Tuesday.
Leerink analyst said, "We believe that these data support VAX-31's potential to gain a significant market share in the pneumococcal conjugate vaccine market expected to exceed $10 billion by 2030+
Due to this positive reading, Mizuho analysts referred to it as the "best case scenario," and Vaxcyte's stock price jumped about 44% at the release time on Tuesday morning.Today, we are opening a new chapter for Vaxcyte as we transition from an emerging company to a potential powerhouse, "Grant Pickering, co-founder and CEO of Vaxcyte, said during an investor conference call on Tuesday
One key point that excites analysts is that the antibody immune response (measured by phagocytic activity assay) displayed by VAX-31 at medium and high doses either matches or exceeds the immune response of Prevnar 20 on the 20 serotypes shared by the two vaccines.
For medium doses, VAX-31 has a geometric mean ratio (GMR) greater than 1 compared to Prevnar 20 in 13 out of 20 serotypes, and achieved statistically higher immune responses in five serotypes. For high doses, 18 serotypes have a GMR higher than 1, and 7 serotypes are considered statistically higher than Prevnar 20.
Leerink analysts concluded that for common serotypes, the immune response of VAX-31 is on average 25% higher than high doses and 10% higher than medium doses.
VAX-31 demonstrated non inferiority across all 20 serotypes, surprising analysts as the additional carrier protein required to handle the vaccine's extra immunogens is expected to reduce antibody responses in certain serotypes. This is a trade-off made to achieve broader serotype coverage. As pointed out by the Leerink analyst, many analysts previously believed that high doses of VAX-31 would not meet non inferiority requirements on approximately three out of 20 shared serotypes.
Vaxcyte's ability to contain 31 serotypes is attributed to its proprietary carrier saving technology. This platform allows for more precise binding of polysaccharides to carrier proteins while preserving exposure to key T cell epitopes, according to the company.
In addition to all serotypes covered by Pfizer vaccines, VAX-31 also includes 11 additional serotypes. For the unique serotype of VAX-31, the Vaxcyte vaccine outperformed Pfizer's choice in all three test doses.
By covering 31 serotypes, VAX-31 aims to prevent over 95% of invasive pneumococcal disease in adults aged 50 and older in the United States. In contrast, Prevnar 20 can cover 52% of the disease burden in this age group, while Merck's newly approved Capvaxive target is 84%.
Given these positive data, Mizuho analysts suggest that VAX-31 has the potential to replace Prevnar 20 or even Capvaxive, although the team warns that authorities may preserve some redundancy in the system by allowing multiple participants. VAX-31 also has advantages over Capvaxive because it contains serotype 4, which was particularly of concern to the Center for Disease Control and Prevention's Advisory Committee on Immunization Practices during its June meeting, as noted by Leerink analysts in an earlier report.
The Merck vaccine does not include serotype 4, which is considered important for health equity as it most commonly affects certain underrepresented populations.
Vaxcyte also faces the pleasant issue of selecting the correct Phase 3 dose for VAX-31. As biotech companies weigh their options, Vaxcyte is still analyzing more data, including pre specified age cohort analysis, "CEO Pickering said in a conference call on Tuesday.
Pickering said, "As we move towards decision-making, we will examine the overall situation of the data. Obviously, using fewer materials to drive immune responses can create efficiency. But as long as we don't see any safety differences, creating higher immune responses is also attractive
After meeting with the FDA, the company plans to begin critical Phase 3 trials in mid-2025, with top line results expected in 2026.
In addition to VAX-31, Vaxcyte is also developing the 24 valent candidate VAX-24, and the company expects to report top line safety and immunogenicity data from the Phase 2 infant study in the first quarter of 2025. Another phase 2 infant trial of VAX-31 is scheduled to begin early next year.