Cardiac infections, including infective endocarditis and cardiovascular implantable electronic device infections, are associated with substantial morbidity and mortality and are commonly caused by gram-positive bacteria. Standard management typically requires prolonged courses of intravenous antibiotics and extended hospitalisation, which are costly, burdensome, and associated with complications related to long-term vascular access. People who inject drugs are disproportionately affected and often experience stigma, barriers to care, and poorer outcomes. Long-acting lipoglycopeptides such as oritavancin maintain therapeutic serum concentrations for prolonged periods and may offer an alternative to conventional intravenous antibiotic regimens. Oritavancin is not TGA-registered in Australia and is accessed as an unregistered medicine (for example, via SAS or clinical trials). It is approved in other jurisdictions, including the United States and European Union, for acute bacterial skin and skin structure infections. Prospective data in cardiac infections remain limited, and optimal dosing strategies, including the role of therapeutic drug monitoring, are uncertain. This multicentre, open-label pilot study will assess the feasibility, pharmacokinetics, safety, acceptability, and preliminary efficacy of oritavancin for gram-positive cardiac infections using both standard fixed dosing and TDM-guided dosing strategies. Findings will inform PK/PD modelling, the potential role of TDM, and the design of future larger-scale trials and models of care, including alternatives to prolonged inpatient intravenous therapy.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
20
Oritavancin administered by intravenous infusion using a fixed weekly dosing schedule consistent with the protocol-defined guideline-based regimen (1.2 g IV once weekly)
Participants will receive an initial oritavancin dose (e.g. 1.2 g IV), with subsequent dosing intervals and/or additional doses informed by pre-specified TDM algorithms and individual PK estimates derived from the population model developed in Group B1.
St Vincent's Hospital
Sydney, New South Wales, Australia
Prince of Wales Hospital
Sydney, New South Wales, Australia
Royal Prince Alfred Hospital
Sydney, New South Wales, Australia
Desirability of Outcome Ranking (DOOR) at Day 70
Composite ordinal outcome adapted for Gram-positive cardiac infections. Participants will be ranked from most to least desirable outcome as follows: 1. = alive with no clinical failure, infectious complication, or serious adverse event/adverse event leading to study drug discontinuation; 2. = alive with 1 of these events; 3. = alive with 2 of these events; 4. = alive with all 3 of these events; 5. = death. Within each rank, ties will be resolved using net change in EQ-5D score from baseline to Day 70, with greater improvement indicating a more desirable outcome.
Time frame: Day 70 post-enrolment
Total oritavancin plasma concentration at scheduled sampling time points
Observed total oritavancin plasma concentrations measured at protocol-specified sampling time points to support development of the population pharmacokinetic model.
Time frame: From post-dose Day 1 through Day 70 post-enrolment
Oritavancin dosing interval achieved in the therapeutic drug monitoring-guided cohort
Time interval in days between consecutive oritavancin doses in participants managed using therapeutic drug monitoring-guided dosing.
Time frame: From Day 1 to Day 70 post-enrolment
Number of participants with treatment-emergent adverse events in the oritavancin cohorts
Number of participants receiving oritavancin with at least 1 treatment-emergent adverse event.
Time frame: From enrolment to Day 180 post-enrolment
Number of participants with serious adverse events in the oritavancin cohorts
Number of participants receiving oritavancin with at least 1 serious adverse event.
Time frame: From enrolment to Day 180 post-enrolment
Number of participants with infusion-related reactions in the oritavancin cohorts
Number of participants receiving oritavancin with at least 1 infusion-related reaction.
Time frame: From enrolment to Day 180 post-enrolment
Change from Baseline to Day 70 in EuroQol 5-Dimension 5-Level Index Score
Health-related quality of life will be assessed using the EuroQol 5-Dimension 5-Level questionnaire (EQ-5D-5L). The EQ-5D-5L index score is derived from participant responses across five domains: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Using the Australian EQ-5D-5L value set, possible index scores range from -0.30 to 1.00, where 1.00 represents full health, 0 represents a health state equivalent to death, and scores below 0 represent health states valued worse than death. Higher scores indicate better health-related quality of life. Change will be calculated as the Day 70 score minus the baseline score; a positive change indicates improvement.
Time frame: Baseline to Day 70 post-enrolment
Proportion of participants completing protocol-specified dosing and monitoring through Day 70
Proportion of participants who complete the protocol-specified dosing schedule and planned therapeutic drug monitoring/sample collection through Day 70.
Time frame: From enrolment to Day 70 post-enrolment
Recruitment rate
Proportion of eligible participants who are enrolled into the study.
Time frame: From study opening to completion of enrolment
Retention rate at Day 70
Proportion of enrolled participants who complete Day 70 follow-up.
Time frame: From enrolment to Day 70 post-enrolment
Number of participants who complete planned study treatment
Number of participants who complete their planned study treatment course as determined by the treating clinician and protocol-defined study treatment period.
Time frame: By Day 70 post-enrolment
Number of participants with clinical or microbiological failure
Number of participants with clinical or microbiological failure, including worsening or recurrent signs of cardiac infection, need for change/addition of antibiotic therapy due to inadequate response, or relapse with the same organism following study treatment.
Time frame: By Day 70 post-enrolment
Number of participants with hospital readmission by Day 70
Number of participants with at least 1 hospital readmission.
Time frame: By Day 70 post-enrolment
Number of participants who die by Day 70
All-cause mortality.
Time frame: By Day 70 post-enrolment
Number of participants with hospital readmission by Day 180
Number of participants with at least 1 hospital readmission.
Time frame: By Day 180 post-enrolment
Number of participants who die by Day 180
All-cause mortality.
Time frame: By Day 180 post-enrolment
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