The independent DSMB recommended that the study be stopped for futility following interim efficacy analysis.

The purpose of this superiority study is to evaluate the efficacy and safety of exebacase in addition to standard of care antibiotics (SoCA) compared with SoCA alone for the treatment of patients with Staphylococcus aureus (S. aureus) bloodstream infections (BSI), including right-sided infective endocarditis (IE). Patients will be randomized to receive a single intravenous dose of exebacase or placebo. Patients will receive SoCA selected by the investigators based on the protocol.

Exebacase, a direct lytic agent, is an entirely new treatment modality against S. aureus. Exebacase is a recombinantly-produced, purified cell wall hydrolase enzyme that results in rapid bacteriolysis, potent biofilm eradication, synergy with antibiotics, low propensity for resistance, and the potential to suppress antibiotic resistance when used together with antibiotics. Exebacase represents a first-in-field, first-in-class treatment with the potential to improve clinical outcome when used in addition to SoCA to treat S. aureus BSI including IE.

Inclusion Criteria:

• Male or female, 12 years or older
• Blood culture positive for S. aureus
• At least two signs or symptoms attributable to S. aureus BSI/IE
• Known or suspected complicated S. aureus BSI and/or right-sided IE based on Modified Duke Criteria
• Not pregnant or breastfeeding and not of reproductive potential or agrees to remain abstinent or use contraception if of reproductive potential

Exclusion Criteria:

• Previously received exebacase
• Known or suspected left-sided IE
• Treatment with effective systemic anti-staphylococcal antibiotic for more than 72 hours within 7 days before randomization
• Presence of prosthetic valve or cardiac valve support ring, or presence of known or suspected infected hardware (orthopedic), prosthetic joint, or cardiac device
• Known polymicrobial BSI, or known ongoing systemic infection caused by other bacterial and/or fungal pathogen(s), and/or known to have coronavirus disease 2019 (COVID-19)