Therapeutic Drug Monitoring of Antibiotic Drugs: The Role of the Clinical Laboratory

Role of therapeutic drug monitoring in the treatment of multi-drug resistant tuberculosis

Tuberculosis (TB) is a leading cause of mortality worldwide, and resistance to anti-tuberculosis drugs is a challenge to effective treatment. Multi-drug resistant TB (MDR-TB) can be difficult to treat, requiring long durations of therapy and the use of second line drugs, increasing a patient's risk for toxicities and treatment failure. Given the challenges treating MDR-TB, clinicians can improve the likelihood of successful outcomes by utilizing therapeutic drug monitoring (TDM). TDM is a clinical technique that utilizes measured drug concentrations from the patient to adjust therapy, increasing likelihood of therapeutic drug concentrations while minimizing the risk of toxic drug concentrations. This review paper provides an overview of the TDM process, pharmacokinetic parameters for MDR-TB drugs, and recommendations for dose adjustments following TDM.

A three-level model for therapeutic drug monitoring of antimicrobials at the site of infection

The silent pandemic of bacterial antimicrobial resistance is a leading cause of death worldwide, prolonging hospital stays and raising health-care costs. Poor incentives to develop novel pharmacological compounds and the misuse of antibiotics contribute to the bacterial antimicrobial resistance crisis. Therapeutic drug monitoring (TDM) based on blood analysis can help alleviate the emergence of bacterial antimicrobial resistance and effectively decreases the risk of toxic drug concentrations in patients' blood. Antibiotic tissue penetration can vary in patients who are critically or chronically ill and can potentially lead to treatment failure. Antibiotics such as β-lactams and glycopeptides are detectable in non-invasively collectable biofluids, such as sweat and exhaled breath. The emergence of wearable sensors enables easy access to these non-invasive biofluids, and thus a laboratory-independent analysis of various disease-associated biomarkers and drugs. In this Personal View, we introduce a three-level model for TDM of antibiotics to describe concentrations at the site of infection (SOI) by use of wearable sensors. Our model links blood-based drug measurement with the analysis of drug concentrations in non-invasively collectable biofluids stemming from the SOI to characterise drug concentrations at the SOI. Finally, we outline the necessary clinical and technical steps for the development of wearable sensing platforms for SOI applications.

Therapeutic drug monitoring (TDM) as intervention: A cross-sectional analysis of characteristics of 173 registered clinical trials

Background

To examine fundamental characteristics of clinical trials with therapeutic drug monitoring (TDM) as intervention on world major clinical trials registry platform.

Methods

Cross-sectional analysis of clinical trials with TDM as intervention that were registered on WHO International Clinical Trials Registry Platform (ICTRP) or ClinicalTrials.gov. Relevant trial entries registered before and on March 2nd, 2022 were downloaded, deduplicated, and reviewed. Recruit country, monetary source, start years, study design, medical conditions, involved drugs, outcome measure, and subject information were extracted and analyzed.

Results

Overall, 173 clinical trials were included in this study. Majority of the trials were conducted in several economically prosperous countries. The earliest initiated trials dates back to 2002. Most of the trials were funded by hospitals (36.4%). A higher proportion of trials were conducted within one country (86.1%), as phase Ⅳ (34.1%) interventional study (82.7%), randomized (52.6%), parallel assignment (53.8%) and open label (67.0%). The most concerned medical condition were infectious or parasitic disease and neoplasms, with the most monitored drugs were immunosuppressants and β-lactam antibacterials. Most of the trials enroll no more than 50 subjects (30.6%), with both gender (95.4%), and adults (67.0%).

Conclusion

The trials were mainly conducted in several economically prosperous countries. The number of registered trials had gradually increased during the past years. Novel biological drugs have increasingly become the research hotspot. We expect that with abundant financial support, more high-quality large-scale, multicenter randomized clinical trials (RCTs) are designed and implemented to promote the development of TDM in the future.

Assessment of current practice for β-lactam therapeutic drug monitoring in French ICUs in 2021: a nationwide cross-sectional survey

BACKGROUND

Current guidelines and literature support the use of therapeutic drug monitoring (TDM) to optimize β-lactam treatment in adult ICU patients.

OBJECTIVES

To describe the current practice of β-lactam monitoring in French ICUs.

METHODS

A nationwide cross-sectional survey was conducted from February 2021 to July 2021 utilizing an online questionnaire that was sent as an email link to ICU specialists (one questionnaire per ICU).

RESULTS

Overall, 119 of 221 (53.8%) French ICUs participated. Eighty-seven (75%) respondents reported having access to β-lactam TDM, including 52 (59.8%) with on-site access. β-Lactam concentrations were available in 24-48 h and after 48 h for 36 (41.4%) and 26 (29.9%) respondents, respectively. Most respondents (n = 61; 70.1%) reported not knowing whether the β-lactam concentrations in the TDM results were expressed as unbound fractions or total concentrations. The 100% unbound fraction of the β-lactam above the MIC was the most frequent pharmacokinetic and pharmacodynamic target used (n = 62; 73.0%).

CONCLUSIONS

Despite the publication of international guidelines, β-lactam TDM is not optimally used in French ICUs. The two major barriers are β-lactam TDM interpretation and the required time for results.