Affinivax’s lead vaccine candidate, ASP3772, is a Streptococcus pneumoniae vaccine that is being co-developed in collaboration with Japanese drugmaker Astellas.

ASP3772 includes 24 pneumococcal polysaccharides, more than any other vaccine on the market or in clinical trials today, as well as two conserved pneumococcal proteins.  This candidate was observed to be safe and highly immunogenic in a Phase I study in adults aged 18 to 64.

In January 2021, Affinivax announced that it had closed a $226 million Series C financing to raise funds for advancing its pipeline of vaccines.