OSCAR: Oritavancin for Treatment of Serious Cardiac Infections
Serious infections of the heart valves and implanted cardiac devices are difficult to treat and can be life-threatening. Standard care often requires 4–6 weeks of daily intravenous antibiotics, usually in hospital or through hospital-in-the-home services. This can be disruptive, costly and exposes people to risks from long-term IV lines, including clots and line infections. People who inject drugs are disproportionately affected and often face additional barriers to care. New approaches are needed to deliver effective treatment while reducing hospital time, treatment burden and complications.
OSCAR is a multicentre phase II pilot study testing whether the long-acting antibiotic oritavancin can help complete treatment for serious gram-positive cardiac infections. Oritavancin stays in the body for an extended period, meaning it may be given weekly or less often rather than daily. The study compares fixed weekly dosing with dosing guided by therapeutic drug monitoring (TDM), where blood levels help determine when another infusion is needed. OSCAR will assess whether this approach is feasible, acceptable and safe, and whether it supports infection cure while reducing treatment burden.
Adults hospitalised with infective endocarditis or cardiac device infection caused by gram-positive bacteria may be enrolled once they are clinically stable and blood cultures have cleared. Participants receive IV oritavancin in one of two sequential groups: fixed weekly dosing, or TDM-guided dosing informed by blood drug levels and pharmacokinetic modelling. Study visits include safety checks, blood tests, TDM sampling, quality-of-life and acceptability questionnaires, and clinical follow-up to Day 70 and Day 180. The study will recruit up to 40 participants across participating Australian hospital sites.
As a pilot study, OSCAR is designed to generate feasibility and safety data rather than definitive efficacy results. The study is expected to describe oritavancin pharmacokinetics in people with serious cardiac infections, test whether real-time TDM-guided dosing can be implemented, and estimate recruitment, retention, treatment completion, clinical outcomes, adverse events, hospital readmissions and mortality at Day 70 and Day 180. Participant-reported quality of life and treatment acceptability data, including an optional qualitative sub-study, will help identify barriers and enablers for future implementation.
If successful, OSCAR could support a new model of care for selected patients with serious gram-positive cardiac infections, replacing some daily IV antibiotic treatment with fewer supervised infusions. This may reduce time in hospital, limit the need for long-term IV lines, improve patient experience, and make treatment more practical for people who face barriers to prolonged inpatient or outpatient IV therapy. Results will inform dosing models, TDM implementation, future larger trials and potential guideline development for long-acting antibiotics in complex infections.
- St Vincent’s Hospital Sydney
- Prince of Wales Hospital
The OSCAR study is sponsored by UNSW Sydney and coordinated through the Kirby Institute. Oritavancin for the study will be provided as an in-kind drug donation by Menarini.
