In this double-blind, randomised study with placebo and active controls, 120 participants received either two doses of 50, 250 or 1000 micrograms of Gamma-PN (n=30 per group); a single dose of licensed pneumococcal vaccine (Pneumovax-23® or Prevenar 13®, n=9 per group); or placebo.

The study met its primary safety objective, demonstrating a safety profile suitable for further development. There were no serious adverse events following administration of Gamma-PN and systemic tolerability was considered excellent. Injection site reactions were largely confined to mild to moderate erythema and swelling, typically of short (1-2 day) duration, with the frequency and extent being dose-related. Local and systemic tolerability after the second injection of Gamma-PN was similar to that after the first.

An immunological assessment of serum IgG responses to vaccination with Gamma-PN was performed using an ELISA developed and run by a GLP-accredited third-party laboratory. This demonstrated that Gamma-PN induced dose-dependent rises in serum IgG levels to Gamma-PN after both the first and second vaccine dose. Neutrophil activation in participants administered Gamma-PN was consistent with vaccine stimulation of innate immune responses.

GPN Vaccines is also conducting additional immunological tests on serum and peripheral blood mononuclear cells (PBMCs), including an assessment of opsonophagocytic antibodies against Streptococcus pneumoniae serotypes covered by current licensed pneumococcal vaccines as well as serotypes not covered by such vaccines. These results will be reported once complete.

Professor Paul Rolan, GPN Vaccines' Chief Medical Officer commented "I would like to extend my appreciation to all of the participants who volunteered to be in this clinical trial. The study demonstrated that Gamma-PN is safe, well tolerated and encompassed the doses to be selected for further clinical development. "

Dr Tim Hirst, Chief Executive Officer and co-founder said "I am delighted we can announce positive clinical trial results on our broad-spectrum pneumococcal vaccine designed to offer protection against all serotypes of Streptococcus pneumoniae. These results provide important insights that will support dose selection for future Phase 2 clinical trials".

This trial was generously supported by a $1 million grant from the South Australian Government's Research and Innovation Fund (RIF).