Teicoplanin usage in adult patients with haematological malignancy in the UK and Ireland: Is there scope for improvement?

Evaluating the optimal dose of teicoplanin with therapeutic drug monitoring: not too high for adverse event, not too low for treatment efficacy

Therapeutic drug monitoring (TDM) of teicoplanin is aimed at minimizing the clinical impact of pharmacokinetic variability; however, its benefits are still being defined. We performed a retrospective study of teicoplanin TDM focusing on the dose-serum concentration relationship and clinical outcomes in a clinical setting. From January 2017 to December 2018, patients receiving teicoplanin ≥ 72 h with TDM were enrolled. Patients were divided into three groups: non-loading (NL) group, low-dose loading (LD) group (loading dose < 9 mg/kg), and high-dose loading (HD) group (≥ 9 mg/kg). Serum teicoplanin trough concentration (C_min) and adverse events (AEs) were evaluated in each regimen. A subgroup of patients with bacteremia was analyzed to evaluate clinical efficacy. Among 65 patients, 12, 18, and 35 were grouped in NL, LD, and HD, respectively. Achievement rates of C_min > 20 mg/L within 10 days were significantly different among the groups (25.0%, 38.9%, and 68.6% in the NL, LD, and HD groups, respectively; P = 0.014). Fourteen patients (21.5%) had AEs, and higher C_min over 10 days (adjusted odds ratio 2.08 per every 20 mg/L increases, 95% CI 1.13-3.84, P = 0.019) and age ≥ 65 years (P = 0.009) were identified as independent risk factors. In the subgroup analysis, HD regimen (P = 0.050) and high mean C_min over 10 days (P = 0.025) were significantly associated with treatment success. Although HL regimen could achieve C_min targets and improve clinical outcome during teicoplanin treatment, high C_min was associated with AEs during treatment. Routine TDM can be helpful to optimize teicoplanin administration.

Population pharmacokinetics of total and unbound teicoplanin concentrations and dosing simulations in patients with haematological malignancy

Objectives

To develop a pharmacokinetic model describing total and unbound teicoplanin concentrations in patients with haematological malignancy and to perform Monte Carlo simulations to evaluate target attainment of unbound trough concentrations with various dose regimens.

Methods

This was a hospital-based clinical trial (EudraCT 2013-004535-72). The dosing regimen was 600/800 mg q12h for three doses then 600/800 mg daily. Serial total and unbound teicoplanin concentrations were collected. Maximum protein binding was estimated from serum albumin concentration. Population pharmacokinetic analyses and Monte Carlo simulations were conducted using Pmetrics®. Target total and unbound trough concentrations were ≥20 and ≥1.5 mg/L, respectively.

Results

Thirty adult patients were recruited with a mean (SD) bodyweight of 69.1 (15.8) kg, a mean (SD) CLCR of 72 (41) mL/min and a median (IQR) serum albumin concentration of 29 (4) g/L. A three-compartment complex binding pharmacokinetic model best described the concentration-time data. Total and unbound teicoplanin concentrations were related by serum albumin concentration and a dissociation constant. CLCR and bodyweight were supported as covariates for CL and volume of the central compartment, respectively. Dosing simulations showed that high CLCR was associated with reduced probability of achieving target total and unbound trough concentrations. Low serum albumin concentration was associated with a reduced probability of attaining target total but not unbound trough concentrations. A method to estimate the unbound teicoplanin concentration from the measured total concentration at different serum albumin concentration was demonstrated.

Conclusions

Standard teicoplanin dosing regimens should be used with caution in patients with haematological malignancy. Bodyweight, CLCR and serum albumin concentration are important considerations for appropriate dosing.

Variability in Trough Total and Unbound Teicoplanin Concentrations and Achievement of Therapeutic Drug Monitoring Targets in Adult Patients with Hematological Malignancy

The objective of this study was to explore the following aspects of teicoplanin use in patients with hematological malignancy: early attainment of target trough concentrations with current high-dose teicoplanin regimens, variability in unbound teicoplanin fractions, factors associated with observed total and unbound trough concentrations, efficacy and toxicity, and renal function estimation. This was a single-center, prospective study. Samples for determination of trough concentrations were taken on days 3, 4, 7, and 10. Total and unbound teicoplanin concentrations were determined using validated high-performance liquid chromatography methods. Regression analyses were used to identify the factors associated with the trough concentration. Thirty teicoplanin-treated adults with hematological malignancy were recruited. Despite the use of dosages higher than the conventional dosages, the proportions of patients with a trough concentration of ≥20 mg/liter at 48 h and at 72 h were 16.7% and 37.9%, respectively. Renal function was significantly negatively associated with total trough concentrations at 48 h and 72 h (P < 0.05). For an average hematological malignancy patient (creatinine clearance = 70 ml/min), sequential loading doses of at least 12 mg/kg of body weight may be needed to achieve early adequate exposure. In the absence of measured creatinine clearance, estimates obtained using the Cockcroft-Gault (total body weight) equation could prove to be an acceptable surrogate. The unbound fractions of teicoplanin were highly variable (3.4 to 18.8%). Higher unbound fractions were observed in patients with low serum albumin concentrations. Teicoplanin was well tolerated. Teicoplanin loading doses higher than those in current use appear to be necessary. Increased dosing is needed in patients with increased renal function. The high variability in protein binding supports the contention for therapeutic drug monitoring of unbound teicoplanin concentrations. (This study has been registered with EudraCT under registration no. 2013-004535-72.).