Vaxcyte has concluded subject enrolment in the Phase II clinical trial of investigational vaccine, VAX-24, in healthy adults aged 65 years and above for the prevention of invasive pneumococcal disease (IPD).

Nearly 200 subjects were enrolled at 19 US sites in the trial.

The observer-blind, controlled, randomised, dose-finding trial will assess the safety, tolerability, and immunogenicity of VAX-24 in adults aged 65 years and older.

In the trial, a single injectable dose of VAX-24 will be administered at three dose levels and analysed against Prevnar 20.

Evaluating antibody response induction using OPA and IgG, at three dose levels of VAX-24, as well as against Prevnar 20, will be included as the trial’s prespecified immunogenicity endpoints.

The antibody response for the extra four serotypes in VAX-24 and Pneumovax 23, but not present in Prevnar 20, and the percentage of participants with a four-fold increase in antibody titers will also be analysed.

Following dosing, the trial subjects will also be assessed for six months for safety.

A 24-valent pneumococcal conjugate vaccine (PCV) candidate of the company, VAX-24 can potentially offer broad-spectrum protection for IPD prevention.

In August this year, the vaccine received Fast Track Designation from the US Food and Drug Administration (FDA) for use in adults.

Vaxcyte CEO and co-founder Grant Pickering said: “Completing the enrolment of the VAX-24 study in adults 65 years and older is a significant step toward understanding the full clinical potential of our lead vaccine candidate in adults.

“We are very pleased with the progress made to advance the VAX-24 clinical programme and we remain on track to announce the topline data from the VAX-24 Phase I/II study in adults 18-64 years of age in October or November of this year, as well as the topline data from the study in adults 65 and older in the first half of 2023.”