PCMV technology has been successfully applied to anthrax, tularemia, pneumococcal, enteric fever, and meningococcal polysaccharide antigens. These PCMV products were evaluated in murine preclinical studies and demonstrated to elicit high-titer antibody immune responses. Further, the antibody responses were proven functional, elicited immunological ‘memory’, and in the case of a pneumococcal PCMV conferred protection against pneumococcal challenge. Matrivax has demonstrated that a PCMV containing <2 % the amount of a pneumococcal capsular antigen as that contained in Prevnar 7® elicited an antibody response comparable to that induced by Prevnar 7®. Recently, Matrivax demonstrated that a 13-valent pneumococcal PCMV synthesized in one reaction is highly immunogenic in preclinical studies.
Vi antigen, the capsular polysaccharide of Salmonella Typhi was used to make Vi PCMV particles which elicited antibody titers in mice that were vastly superior to TyphimVi®, the current commercialized polysaccharide vaccine. Matrivax is progressing towards a Phase 1 clinical trial with our proof-of-concept vaccine candidate, a Vi PCMV.
Murine immunogenicity studies are underway with PCMVs synthesized with meningococcal and C. difficile polysaccharides.