Current vaccines and limitations

Streptococcus pneumoniae (Spn) remains a major infectious disease worldwide despite widespread vaccination schedules with pneumococcal conjugate vaccines (PCV). Vaccine effectiveness is contingent upon adequate coverage of prevalent disease-causing serotypes. However, as more bacterial serotypes emerge in the community there is a continuous need to update existing vaccines by inclusion of additional serotype polysaccharide antigens. Technical and cost constraints limit the capacity of the conjugate vaccine technology to maintain adequate protective immune ‘coverage’, therefore, invasive disease coupled with increasing antibiotic resistance results in a global death incidence of approximately 2 million people annually. Historical data, combined with current industry trends, demonstrate that the current PCV-era vaccines are insufficient in fighting against the evolution of S. pneumoniae.

Introducing V-212

V-212 is a peptide-based vaccine candidate based on a small number of well-conserved antigenic epitopes presented on a Synthetic Virus-Like Particle (SVLP). The antigenic epitopes, parts of Spn virulent surface protein domains shared among serotypes, are synthesized using solid-phase peptide synthesis and subsequently conjugated to a lipopeptidic backbone carrying elements to activate innate and adaptive immune responses. The SVLP vaccine delivery platform has previously been proven to be safe and immunogenic in man. ​

V-212 has demonstrated a solid and long-lasting immune response in preclinical models. In a serotype 3 lethal sepsis mouse model, administration of V-212 prevents pneumococcal disease by reducing bacterial presence in the lungs and extends animal survival by blocking bacterial dissemination in blood after intranasal challenge with serotype 3. Moreover, V-212 has demonstrated protection against bacteremia-induced death in a serotype 8 sepsis model. Antibodies triggered upon V-212 immunization recognize and bind several different Spn serotypes – including non-PCV13 vaccine serotypes – in vitro, supporting native epitope recognition on bacterial surfaces and the serotype-independent potential of V-212. ​ V-212 has the potential to overcome limitations that remain persistent in the PCV era. It addresses the unmet need due to new serotype emergence and the poor coverage of existing PCV serotypes. As a result, V-212 has the potential to shift the current paradigm, offering a proactive approach to combating pneumonia or invasive disease, in contrast to the reactionary approach taken by the current PCV-dominant trend. Additional studies are ongoing to elucidate the mechanism of protection conferred by V-212 and to evaluate its potential to be combined with approved pneumococcal conjugate vaccines.