The challenges of developing an effective vaccine against S. aureus due to the different strains and evasion mechanisms have been well documented. Clinical results with vaccines and therapeutic IgG antibodies suggest failure is a result of S. aureus’ evasion of humoral immunity.
XBiotech has completed enrollment in a Phase I/II randomized, placebo-controlled, dose escalation study for the treatment of serious infections due to S. aureus. Patients with these types of infections typically have severe complications, extended hospital stays, and a 30-day mortality of approximately 20 percent. The 514G3 monoclonal targets all forms of S. aureus, mediates phagocytosis, and neutralizes the immune evasion mechanism. The Company recently announced top-line results from the study, which reported a reduction in adverse events and shorter hospitalization associated with the 514G3 therapy, even with 514G3-treated subjects tending to be sicker than those receiving placebo.
The U.S. FDA, recognizing the potential of this treatment, has designated this as a Fast Track development program.