Vaxcyte's experimental pneumococcal vaccine, VAX-31, met all primary efficacy goals in a Phase 3 trial, according to results reported Monday. The shot is designed to cover 31 bacterial serotypes, more than Pfizer's Prevnar 20 and Merck's Capvaxive, which cover 20 and 21 respectively. All three sources agree on the headline result, and STAT adds that the trial randomized just over 3,500 adults age 50 and older, measuring antibody responses against the different strains.
BioPharma Dive reports that VAX-31 matched the effectiveness of both comparators on 28 strains and was superior against three unique strains. It was inferior to Capvaxive on two strains only when using a stricter statistical threshold, a finding analysts described as a "near best-case scenario." The sources agree the vaccine was well tolerated, with a safety profile similar to the existing shots and most adverse events mild-to-moderate and resolving within two days.
Vaxcyte still needs results from two additional late-stage studies before it can file for approval: one testing VAX-31 alongside an influenza vaccine and another in adults who previously received a different pneumococcal shot. The sources agree on this next step. BioPharma Dive notes that Vaxcyte's shares jumped about 50% in early trading, pushing its market value above $12 billion, and that analysts see the shot as a potential challenger in a vaccine market worth $8 billion annually.