Staphylococcal osteoarticular infections (OAIs), including prosthetic joint infections and chronic osteomyelitis, represent a major cause of morbidity. Rifampicin is a key bactericidal antibiotic effective against staphylococcal biofilm. However, its pharmacokinetics exhibit substantial inter-individual variability due to complex hepatic metabolism and drug interactions. Currently, no prospective population pharmacokinetic (PopPK) model of rifampicin combined with levofloxacin or ciprofloxacin exists in patients with OAIs. Objectives: The primary objective of this study is to develop a population pharmacokinetic model of oral rifampicin in patients undergoing medico-surgical treatment for staphylococcal osteoarticular infections. Secondary objectives include evaluating the pharmacokinetics of the partner antibiotic (levofloxacin or ciprofloxacin), investigating the correlation between antibiotic exposure metrics (AUC, Cmax, AUC/MIC) and clinical/biological tolerance, and assessing 1-year infection relapse-free survival and resistance emergence. Study Design: Prospective, single-center, interventional study with minimal risks and constraints (RIPH 2) involving 40 participants recruited at the Reference Center for Complex Osteoarticular Infections (CRIOAC).
Study Workflow and Pharmacokinetic Sampling Protocol: Screening and Baseline: Adult patients hospitalized for staphylococcal prosthetic joint infection, chronic osteomyelitis, or native joint infection sensitive to rifampicin and levofloxacin/ciprofloxacin are screened. Clinical, demographic (age, sex, actual and ideal body weight), and biological data (renal function, liver function, serum albumin) are collected. Pharmacokinetic Blood Sampling (12 samples total, 60 mL total volume): Day 2 / Day 3: 5 blood samples (5 mL each) collected pre-dose (t0, fasting) and at 1h, 2h, 4h, and 8h post-dose of rifampicin. Day 8 / Day 10: 5 blood samples (5 mL each) collected pre-dose (t0, fasting) and at 1h, 2h, 4h, and 8h post-dose of rifampicin and partner antibiotic (levofloxacin or ciprofloxacin). Day 28 / Day 32 (1-month follow-up visit): 2 blood samples (5 mL each) collected pre-dose and 2 hours post-dose during outpatient consultation. Pharmacokinetic and Statistical Modeling: Population PK parameters (CL/F, V/F, ka) and inter-individual variability will be estimated using non-linear mixed-effects modeling (NONMEM v7.5). Influence of covariates (age, sex, weight, renal function, serum albumin) will be evaluated. One-Year Follow-up: Clinical follow-up at 12 months post-treatment initiation to evaluate infection relapse, tolerance, and microbiological
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
40
This study primarily aims to evaluate the pharmacokinetics of rifampicin, but also of one of the two partner antibiotics, levofloxacin or ciprofloxacin, used in the treatment of staphylococcal osteoarticular infections, whether or not they are present in the body. To this end, 12 blood samples, totaling 60 ml per patient, will be required. These samples will be collected specifically for this clinical research. The remainder of the study will be conducted as part of standard patient care.
Groupe hospitalier Diaconesses Croix Saint Simon
Paris, Paris, France
RECRUITINGArea Under the Plasma Concentration-Time Curve (AUC) of Rifampicin
Area under the plasma concentration-time curve of oral rifampicin, estimated using a population pharmacokinetic non-linear mixed-effects model (NONMEM).
Time frame: Day 2/3, Day 8/10, and Day 28/32 post-initiation of antibiotic therapy
Peak Plasma Concentration (Cmax) of Rifampicin
Maximum observed plasma concentration (Cmax) of oral rifampicin, measured following administration.
Time frame: Day 2/3, Day 8/10, and Day 28/32 post-initiation of antibiotic therapy
Apparent Oral Clearance (CL/F) of Rifampicin
Apparent oral clearance (CL/F) of rifampicin estimated using a population pharmacokinetic model (NONMEM), including evaluation of inter-individual variability and covariate effects.
Time frame: Through 4 weeks post-initiation of antibiotic therapy
Apparent Volume of Distribution (V/F) of Rifampicin
Apparent volume of distribution (V/F) of rifampicin estimated using a population pharmacokinetic model (NONMEM), including evaluation of inter-individual variability and covariate effects.
Time frame: Through 4 weeks post-initiation of antibiotic therapy
Incidence of Clinical and Biological Adverse Events Related to Rifampicin Exposure
Proportion of patients experiencing clinical or biological adverse events (recorded in CRF) evaluated in relation to rifampicin Cmax and AUC.
Time frame: Through 4 weeks post-initiation of antibiotic therapy
Infection Relapse-Free Survival at 1 Year Relative to Rifampicin AUC/MIC Ratio
Time to staphylococcal infection relapse over a 1-year follow-up period, analyzed in relation to the rifampicin AUC/MIC (Minimum Inhibitory Concentration) ratio.
Time frame: 12 months post-initiation of antibiotic therapy
Emergence of Rifampicin Resistance at Relapse
Assessment of rifampicin MIC (determined by E-test) at the time of infection relapse compared to baseline, evaluated according to Cmax/MIC and AUC/MIC ratios.
Time frame: 12 months post-initiation of antibiotic therapy
Peak Plasma Concentration (Cmax) of Partner Antibiotic
Maximum observed plasma concentration (Cmax) of the partner antibiotic (levofloxacin or ciprofloxacin) administered in combination with rifampicin.
Time frame: Day 8/10 and Day 28/32 post-initiation of antibiotic therapy
Trough Plasma Concentration (Cmin) of Partner Antibiotic
Trough plasma concentration (Cmin) of the partner antibiotic (levofloxacin or ciprofloxacin) measured prior to the next scheduled dose.
Time frame: Day 8/10 and Day 28/32 post-initiation of antibiotic therapy
Apparent Clearance (CL/F) of Partner Antibiotic
Apparent clearance (CL/F) of the partner antibiotic (levofloxacin or ciprofloxacin) administered in combination with rifampicin.
Time frame: Day 8/10 and Day 28/32 post-initiation of antibiotic therapy
Area Under the Plasma Concentration-Time Curve (AUC) of Partner Antibiotic
Area under the plasma concentration-time curve (AUC) of the partner antibiotic (levofloxacin or ciprofloxacin) administered in combination with rifampicin.
Time frame: Day 8/10 and Day 28/32 post-initiation of antibiotic therapy
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